Python2/PyMuPDF: mupdf-source/source/pdf/pdf-object.c comparison

comparison mupdf-source/source/pdf/pdf-object.c @ 2:b50eed0cc0ef upstream

ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. The directory name has changed: no version number in the expanded directory now.

author	Franz Glasner <fzglas.hg@dom66.de>
date	Mon, 15 Sep 2025 11:43:07 +0200
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-:1d09e1dec1d9
+:b50eed0cc0ef
+// Copyright (C) 2004-2025 Artifex Software, Inc.
+//
+// This file is part of MuPDF.
+//
+// MuPDF is free software: you can redistribute it and/or modify it under the
+// terms of the GNU Affero General Public License as published by the Free
+// Software Foundation, either version 3 of the License, or (at your option)
+// any later version.
+//
+// MuPDF is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+// FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+// details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with MuPDF. If not, see <https://www.gnu.org/licenses/agpl-3.0.en.html>
+//
+// Alternative licensing terms are available from the licensor.
+// For commercial licensing, see <https://www.artifex.com/> or contact
+// Artifex Software, Inc., 39 Mesa Street, Suite 108A, San Francisco,
+// CA 94129, USA, for further information.
+#include "mupdf/fitz.h"
+#include "mupdf/pdf.h"
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#define PDF_MAKE_NAME(STRING,NAME) STRING,
+static const char *PDF_NAME_LIST[] = {
+	"", "", "", /* dummy slots for null, true, and false */
+#include "mupdf/pdf/name-table.h"
+};
+#undef PDF_MAKE_NAME
+typedef enum pdf_objkind_e
+{
+	PDF_INT = 'i',
+	PDF_REAL = 'f',
+	PDF_STRING = 's',
+	PDF_NAME = 'n',
+	PDF_ARRAY = 'a',
+	PDF_DICT = 'd',
+	PDF_INDIRECT = 'r'
+} pdf_objkind;
+struct keyval
+{
+	pdf_obj *k;
+	pdf_obj *v;
+};
+enum
+{
+	PDF_FLAGS_MARKED = 1,
+	PDF_FLAGS_SORTED = 2,
+	PDF_FLAGS_DIRTY = 4,
+	PDF_FLAGS_MEMO_BASE = 8,
+	PDF_FLAGS_MEMO_BASE_BOOL = 16
+};
+struct pdf_obj
+{
+	short refs;
+	unsigned char kind;
+	unsigned char flags;
+};
+typedef struct
+{
+	pdf_obj super;
+	union
+	{
+		int64_t i;
+		float f;
+	} u;
+} pdf_obj_num;
+typedef struct
+{
+	pdf_obj super;
+	char *text; /* utf8 encoded text string */
+	size_t len;
+	char buf[FZ_FLEXIBLE_ARRAY];
+} pdf_obj_string;
+typedef struct
+{
+	pdf_obj super;
+	char n[FZ_FLEXIBLE_ARRAY];
+} pdf_obj_name;
+typedef struct
+{
+	pdf_obj super;
+	pdf_document *doc;
+	int parent_num;
+	int len;
+	int cap;
+	pdf_obj **items;
+} pdf_obj_array;
+typedef struct
+{
+	pdf_obj super;
+	pdf_document *doc;
+	int parent_num;
+	int len;
+	int cap;
+	struct keyval *items;
+} pdf_obj_dict;
+typedef struct
+{
+	pdf_obj super;
+	pdf_document *doc; /* Only needed for arrays, dicts and indirects */
+	int num;
+	int gen;
+} pdf_obj_ref;
+/* Each journal fragment represents a change to a PDF xref object. */
+typedef struct pdf_journal_fragment
+{
+	struct pdf_journal_fragment *next;
+	struct pdf_journal_fragment *prev;
+	int obj_num;
+	int newobj;
+	pdf_obj *inactive;
+	fz_buffer *stream;
+} pdf_journal_fragment;
+/* A journal entry represents a single notional 'change' to the
+* document, such as 'signing it' or 'filling in a field'. Each such
+* change consists of 1 or more 'fragments'. */
+typedef struct pdf_journal_entry
+{
+	struct pdf_journal_entry *prev;
+	struct pdf_journal_entry *next;
+	char *title;
+#ifdef PDF_DEBUG_JOURNAL
+	int changed_since_last_dumped;
+#endif
+	pdf_journal_fragment *head;
+	pdf_journal_fragment *tail;
+} pdf_journal_entry;
+/* A journal consists of a list of journal entries, rooted at head.
+* current is either NULL, or points to somewhere in the list. Anything
+* between head and current inclusive represents a journalled change
+* that is currently in force. Anything after current represents a
+* journalled change that has been 'undone'. If current is NULL, then
+* ALL changes in the list have been undone. */
+struct pdf_journal
+{
+	pdf_journal_entry *head;
+	pdf_journal_entry *current;
+	int nesting;
+	pdf_journal_entry *pending;
+	pdf_journal_entry *pending_tail;
+};
+#define NAME(obj) ((pdf_obj_name *)(obj))
+#define NUM(obj) ((pdf_obj_num *)(obj))
+#define STRING(obj) ((pdf_obj_string *)(obj))
+#define DICT(obj) ((pdf_obj_dict *)(obj))
+#define ARRAY(obj) ((pdf_obj_array *)(obj))
+#define REF(obj) ((pdf_obj_ref *)(obj))
+pdf_obj *
+pdf_new_int(fz_context *ctx, int64_t i)
+{
+	pdf_obj_num *obj;
+	obj = Memento_label(fz_malloc(ctx, sizeof(pdf_obj_num)), "pdf_obj(int)");
+	obj->super.refs = 1;
+	obj->super.kind = PDF_INT;
+	obj->super.flags = 0;
+	obj->u.i = i;
+	return &obj->super;
+}
+pdf_obj *
+pdf_new_real(fz_context *ctx, float f)
+{
+	pdf_obj_num *obj;
+	obj = Memento_label(fz_malloc(ctx, sizeof(pdf_obj_num)), "pdf_obj(real)");
+	obj->super.refs = 1;
+	obj->super.kind = PDF_REAL;
+	obj->super.flags = 0;
+	obj->u.f = f;
+	return &obj->super;
+}
+pdf_obj *
+pdf_new_string(fz_context *ctx, const char *str, size_t len)
+{
+	pdf_obj_string *obj;
+	unsigned int l = (unsigned int)len;
+	if ((size_t)l != len)
+		fz_throw(ctx, FZ_ERROR_LIMIT, "Overflow in pdf string");
+	obj = Memento_label(fz_malloc(ctx, offsetof(pdf_obj_string, buf) + len + 1), "pdf_obj(string)");
+	obj->super.refs = 1;
+	obj->super.kind = PDF_STRING;
+	obj->super.flags = 0;
+	obj->text = NULL;
+	obj->len = l;
+	memcpy(obj->buf, str, len);
+	obj->buf[len] = '\0';
+	return &obj->super;
+}
+pdf_obj *
+pdf_new_name(fz_context *ctx, const char *str)
+{
+	pdf_obj_name *obj;
+	int l = 3; /* skip dummy slots */
+	int r = nelem(PDF_NAME_LIST) - 1;
+	while (l <= r)
+	{
+		int m = (l + r) >> 1;
+		int c = strcmp(str, PDF_NAME_LIST[m]);
+		if (c < 0)
+			r = m - 1;
+		else if (c > 0)
+			l = m + 1;
+		else
+			return (pdf_obj*)(intptr_t)m;
+	}
+	obj = Memento_label(fz_malloc(ctx, offsetof(pdf_obj_name, n) + strlen(str) + 1), "pdf_obj(name)");
+	obj->super.refs = 1;
+	obj->super.kind = PDF_NAME;
+	obj->super.flags = 0;
+	strcpy(obj->n, str);
+	return &obj->super;
+}
+pdf_obj *
+pdf_new_indirect(fz_context *ctx, pdf_document *doc, int num, int gen)
+{
+	pdf_obj_ref *obj;
+	if (num < 0 || num > PDF_MAX_OBJECT_NUMBER)
+	{
+		fz_warn(ctx, "invalid object number (%d)", num);
+		return PDF_NULL;
+	}
+	if (gen < 0 || gen > PDF_MAX_GEN_NUMBER)
+	{
+		fz_warn(ctx, "invalid generation number (%d)", gen);
+		return PDF_NULL;
+	}
+	obj = Memento_label(fz_malloc(ctx, sizeof(pdf_obj_ref)), "pdf_obj(indirect)");
+	obj->super.refs = 1;
+	obj->super.kind = PDF_INDIRECT;
+	obj->super.flags = 0;
+	obj->doc = doc;
+	obj->num = num;
+	obj->gen = gen;
+	return &obj->super;
+}
+#define OBJ_IS_NULL(obj) (obj == PDF_NULL)
+#define OBJ_IS_BOOL(obj) (obj == PDF_TRUE || obj == PDF_FALSE)
+#define OBJ_IS_NAME(obj) ((obj > PDF_FALSE && obj < PDF_LIMIT) || (obj >= PDF_LIMIT && obj->kind == PDF_NAME))
+#define OBJ_IS_INT(obj) \
+	(obj >= PDF_LIMIT && obj->kind == PDF_INT)
+#define OBJ_IS_REAL(obj) \
+	(obj >= PDF_LIMIT && obj->kind == PDF_REAL)
+#define OBJ_IS_NUMBER(obj) \
+	(obj >= PDF_LIMIT && (obj->kind == PDF_REAL || obj->kind == PDF_INT))
+#define OBJ_IS_STRING(obj) \
+	(obj >= PDF_LIMIT && obj->kind == PDF_STRING)
+#define OBJ_IS_ARRAY(obj) \
+	(obj >= PDF_LIMIT && obj->kind == PDF_ARRAY)
+#define OBJ_IS_DICT(obj) \
+	(obj >= PDF_LIMIT && obj->kind == PDF_DICT)
+#define OBJ_IS_INDIRECT(obj) \
+	(obj >= PDF_LIMIT && obj->kind == PDF_INDIRECT)
+#define RESOLVE(obj) \
+	if (OBJ_IS_INDIRECT(obj)) \
+		obj = pdf_resolve_indirect_chain(ctx, obj); \
+int pdf_is_indirect(fz_context *ctx, pdf_obj *obj)
+{
+	return OBJ_IS_INDIRECT(obj);
+}
+int pdf_is_null(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	return OBJ_IS_NULL(obj);
+}
+int pdf_is_bool(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	return OBJ_IS_BOOL(obj);
+}
+int pdf_is_int(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	return OBJ_IS_INT(obj);
+}
+int pdf_is_real(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	return OBJ_IS_REAL(obj);
+}
+int pdf_is_number(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	return OBJ_IS_NUMBER(obj);
+}
+int pdf_is_string(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	return OBJ_IS_STRING(obj);
+}
+int pdf_is_name(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	return OBJ_IS_NAME(obj);
+}
+int pdf_is_array(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	return OBJ_IS_ARRAY(obj);
+}
+int pdf_is_dict(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	return OBJ_IS_DICT(obj);
+}
+/* safe, silent failure, no error reporting on type mismatches */
+int pdf_to_bool(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	return obj == PDF_TRUE;
+}
+int pdf_to_bool_default(fz_context *ctx, pdf_obj *obj, int def)
+{
+	RESOLVE(obj);
+	return obj == PDF_TRUE ? 1 : obj == PDF_FALSE ? 0 : def;
+}
+int pdf_to_int(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	if (obj < PDF_LIMIT)
+		return 0;
+	if (obj->kind == PDF_INT)
+		return (int)NUM(obj)->u.i;
+	if (obj->kind == PDF_REAL)
+		return (int)floorf(NUM(obj)->u.f + 0.5);
+	return 0;
+}
+int pdf_to_int_default(fz_context *ctx, pdf_obj *obj, int def)
+{
+	RESOLVE(obj);
+	if (obj < PDF_LIMIT)
+		return def;
+	if (obj->kind == PDF_INT)
+		return (int)NUM(obj)->u.i;
+	if (obj->kind == PDF_REAL)
+		return (int)floorf(NUM(obj)->u.f + 0.5);
+	return def;
+}
+int64_t pdf_to_int64(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	if (obj < PDF_LIMIT)
+		return 0;
+	if (obj->kind == PDF_INT)
+		return NUM(obj)->u.i;
+	if (obj->kind == PDF_REAL)
+		return (int64_t)floorf(NUM(obj)->u.f + 0.5);
+	return 0;
+}
+float pdf_to_real(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	if (obj < PDF_LIMIT)
+		return 0;
+	if (obj->kind == PDF_REAL)
+		return NUM(obj)->u.f;
+	if (obj->kind == PDF_INT)
+		return NUM(obj)->u.i;
+	return 0;
+}
+float pdf_to_real_default(fz_context *ctx, pdf_obj *obj, float def)
+{
+	RESOLVE(obj);
+	if (obj < PDF_LIMIT)
+		return def;
+	if (obj->kind == PDF_REAL)
+		return NUM(obj)->u.f;
+	if (obj->kind == PDF_INT)
+		return NUM(obj)->u.i;
+	return def;
+}
+const char *pdf_to_name(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	if (obj < PDF_LIMIT)
+		return PDF_NAME_LIST[((intptr_t)obj)];
+	if (obj->kind == PDF_NAME)
+		return NAME(obj)->n;
+	return "";
+}
+char *pdf_to_str_buf(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	if (OBJ_IS_STRING(obj))
+		return STRING(obj)->buf;
+	return "";
+}
+size_t pdf_to_str_len(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	if (OBJ_IS_STRING(obj))
+		return STRING(obj)->len;
+	return 0;
+}
+const char *pdf_to_string(fz_context *ctx, pdf_obj *obj, size_t *sizep)
+{
+	RESOLVE(obj);
+	if (OBJ_IS_STRING(obj))
+	{
+		if (sizep)
+			*sizep = STRING(obj)->len;
+		return STRING(obj)->buf;
+	}
+	if (sizep)
+		*sizep = 0;
+	return "";
+}
+const char *pdf_to_text_string(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	if (OBJ_IS_STRING(obj))
+	{
+		if (!STRING(obj)->text)
+			STRING(obj)->text = pdf_new_utf8_from_pdf_string(ctx, STRING(obj)->buf, STRING(obj)->len);
+		return STRING(obj)->text;
+	}
+	return "";
+}
+void pdf_set_int(fz_context *ctx, pdf_obj *obj, int64_t i)
+{
+	if (OBJ_IS_INT(obj))
+		NUM(obj)->u.i = i;
+}
+void pdf_set_str_len(fz_context *ctx, pdf_obj *obj, size_t newlen)
+{
+	RESOLVE(obj);
+	if (!OBJ_IS_STRING(obj))
+		return; /* This should never happen */
+	if (newlen > STRING(obj)->len)
+		return; /* This should never happen */
+	STRING(obj)->buf[newlen] = 0;
+	STRING(obj)->len = newlen;
+}
+int pdf_to_num(fz_context *ctx, pdf_obj *obj)
+{
+	if (OBJ_IS_INDIRECT(obj))
+		return REF(obj)->num;
+	return 0;
+}
+int pdf_to_gen(fz_context *ctx, pdf_obj *obj)
+{
+	if (OBJ_IS_INDIRECT(obj))
+		return REF(obj)->gen;
+	return 0;
+}
+/*
+	DEPRECATED: Do not use in new code.
+*/
+pdf_document *pdf_get_indirect_document(fz_context *ctx, pdf_obj *obj)
+{
+	if (OBJ_IS_INDIRECT(obj))
+		return REF(obj)->doc;
+	return NULL;
+}
+/*
+	DEPRECATED: Do not use in new code.
+*/
+pdf_document *pdf_get_bound_document(fz_context *ctx, pdf_obj *obj)
+{
+	if (obj < PDF_LIMIT)
+		return NULL;
+	if (obj->kind == PDF_INDIRECT)
+		return REF(obj)->doc;
+	if (obj->kind == PDF_ARRAY)
+		return ARRAY(obj)->doc;
+	if (obj->kind == PDF_DICT)
+		return DICT(obj)->doc;
+	return NULL;
+}
+/*
+	This implementation will do to provide the required
+	API change in advance of the rewrite to use weak references
+	in the next version.
+*/
+pdf_document *pdf_pin_document(fz_context *ctx, pdf_obj *obj)
+{
+	return pdf_keep_document(ctx, pdf_get_bound_document(ctx, obj));
+}
+int pdf_objcmp_resolve(fz_context *ctx, pdf_obj *a, pdf_obj *b)
+{
+	RESOLVE(a);
+	RESOLVE(b);
+	return pdf_objcmp(ctx, a, b);
+}
+static int
+do_objcmp(fz_context *ctx, pdf_obj *a, pdf_obj *b, int check_streams)
+{
+	int i, j;
+	if (a == b)
+		return 0;
+	/* a or b is null, true, or false */
+	if (a <= PDF_FALSE || b <= PDF_FALSE)
+		return 1;
+	/* a is a constant name */
+	if (a < PDF_LIMIT)
+	{
+		if (b < PDF_LIMIT)
+			return a != b;
+		if (b->kind != PDF_NAME)
+			return 1;
+		return strcmp(PDF_NAME_LIST[(intptr_t)a], NAME(b)->n);
+	}
+	/* b is a constant name */
+	if (b < PDF_LIMIT)
+	{
+		if (a->kind != PDF_NAME)
+			return 1;
+		return strcmp(NAME(a)->n, PDF_NAME_LIST[(intptr_t)b]);
+	}
+	/* both a and b are allocated objects */
+	if (a->kind != b->kind)
+		return 1;
+	switch (a->kind)
+	{
+	case PDF_INT:
+		return NUM(a)->u.i - NUM(b)->u.i;
+	case PDF_REAL:
+		if (NUM(a)->u.f < NUM(b)->u.f)
+			return -1;
+		if (NUM(a)->u.f > NUM(b)->u.f)
+			return 1;
+		return 0;
+	case PDF_STRING:
+		if (STRING(a)->len < STRING(b)->len)
+		{
+			if (memcmp(STRING(a)->buf, STRING(b)->buf, STRING(a)->len) <= 0)
+				return -1;
+			return 1;
+		}
+		if (STRING(a)->len > STRING(b)->len)
+		{
+			if (memcmp(STRING(a)->buf, STRING(b)->buf, STRING(b)->len) >= 0)
+				return 1;
+			return -1;
+		}
+		return memcmp(STRING(a)->buf, STRING(b)->buf, STRING(a)->len);
+	case PDF_NAME:
+		return strcmp(NAME(a)->n, NAME(b)->n);
+	case PDF_INDIRECT:
+		if (REF(a)->num == REF(b)->num)
+			return REF(a)->gen - REF(b)->gen;
+		return REF(a)->num - REF(b)->num;
+	case PDF_ARRAY:
+		if (ARRAY(a)->len != ARRAY(b)->len)
+			return ARRAY(a)->len - ARRAY(b)->len;
+		for (i = 0; i < ARRAY(a)->len; i++)
+			if (pdf_objcmp(ctx, ARRAY(a)->items[i], ARRAY(b)->items[i]))
+				return 1;
+		return 0;
+	case PDF_DICT:
+		if (DICT(a)->len != DICT(b)->len)
+			return DICT(a)->len - DICT(b)->len;
+		if ((a->flags & b->flags) & PDF_FLAGS_SORTED)
+		{
+			/* Both a and b are sorted. Easy. */
+			for (i = 0; i < DICT(a)->len; i++)
+			{
+				if (pdf_objcmp(ctx, DICT(a)->items[i].k, DICT(b)->items[i].k))
+					return 1;
+				if (pdf_objcmp(ctx, DICT(a)->items[i].v, DICT(b)->items[i].v))
+					return 1;
+			}
+		}
+		else
+		{
+			/* Either a or b is not sorted. We need to work harder. */
+			int len = DICT(a)->len;
+			for (i = 0; i < len; i++)
+			{
+				pdf_obj *key = DICT(a)->items[i].k;
+				pdf_obj *val = DICT(a)->items[i].v;
+				for (j = 0; j < len; j++)
+				{
+					if (pdf_objcmp(ctx, key, DICT(b)->items[j].k) == 0 &&
+						pdf_objcmp(ctx, val, DICT(b)->items[j].v) == 0)
+						break; /* Match */
+				}
+				if (j == len)
+					return 1;
+			}
+		}
+		/* Dicts are identical, but if they are streams, we can only be sure
+		 * they are identical if the stream contents match. If '!check_streams',
+		 * then don't test for identical stream contents - only match if a == b.
+		 * Otherwise, do the full, painful, comparison. */
+		{
+			/* Slightly convoluted to know if something is a stream. */
+			pdf_document *doc = DICT(a)->doc;
+			int ap = pdf_obj_parent_num(ctx, a);
+			int bp;
+			int a_is_stream = 0;
+			pdf_xref_entry *entrya = pdf_get_xref_entry_no_change(ctx, doc, ap);
+			pdf_xref_entry *entryb;
+			if (entrya != NULL && entrya->obj == a && pdf_obj_num_is_stream(ctx, doc, ap))
+			{
+				/* It's a stream, and we know a != b from above. */
+				if (!check_streams)
+					return 1; /* mismatch */
+				a_is_stream = 1;
+			}
+			bp = pdf_obj_parent_num(ctx, b);
+			entryb = pdf_get_xref_entry_no_change(ctx, doc, bp);
+			if (entryb != NULL && entryb->obj == b && pdf_obj_num_is_stream(ctx, doc, bp))
+			{
+				/* It's a stream, and we know a != b from above. So mismatch. */
+				if (!check_streams || !a_is_stream)
+					return 1; /* mismatch */
+			}
+			else
+			{
+				/* b is not a stream. We match, iff a is not a stream. */
+				return a_is_stream;
+			}
+			/* So, if we get here, we know check_streams is true, and that both
+			 * a and b are streams. */
+			{
+				fz_buffer *sa = NULL;
+				fz_buffer *sb = NULL;
+				int differ = 1;
+				fz_var(sa);
+				fz_var(sb);
+				fz_try(ctx)
+				{
+					unsigned char *dataa, *datab;
+					size_t lena, lenb;
+					sa = pdf_load_raw_stream_number(ctx, doc, ap);
+					sb = pdf_load_raw_stream_number(ctx, doc, bp);
+					lena = fz_buffer_storage(ctx, sa, &dataa);
+					lenb = fz_buffer_storage(ctx, sb, &datab);
+					if (lena == lenb && memcmp(dataa, datab, lena) == 0)
+						differ = 0;
+				}
+				fz_always(ctx)
+				{
+					fz_drop_buffer(ctx, sa);
+					fz_drop_buffer(ctx, sb);
+				}
+				fz_catch(ctx)
+				{
+					fz_rethrow(ctx);
+				}
+				return differ;
+			}
+		}
+	}
+	return 1;
+}
+int
+pdf_objcmp(fz_context *ctx, pdf_obj *a, pdf_obj *b)
+{
+	return do_objcmp(ctx, a, b, 0);
+}
+int
+pdf_objcmp_deep(fz_context *ctx, pdf_obj *a, pdf_obj *b)
+{
+	return do_objcmp(ctx, a, b, 1);
+}
+int pdf_name_eq(fz_context *ctx, pdf_obj *a, pdf_obj *b)
+{
+	RESOLVE(a);
+	RESOLVE(b);
+	if (a <= PDF_FALSE || b <= PDF_FALSE)
+		return 0;
+	if (a < PDF_LIMIT || b < PDF_LIMIT)
+		return (a == b);
+	if (a->kind == PDF_NAME && b->kind == PDF_NAME)
+		return !strcmp(NAME(a)->n, NAME(b)->n);
+	return 0;
+}
+static char *
+pdf_objkindstr(pdf_obj *obj)
+{
+	if (obj == PDF_NULL)
+		return "null";
+	if (obj == PDF_TRUE || obj == PDF_FALSE)
+		return "boolean";
+	if (obj < PDF_LIMIT)
+		return "name";
+	switch (obj->kind)
+	{
+	case PDF_INT: return "integer";
+	case PDF_REAL: return "real";
+	case PDF_STRING: return "string";
+	case PDF_NAME: return "name";
+	case PDF_ARRAY: return "array";
+	case PDF_DICT: return "dictionary";
+	case PDF_INDIRECT: return "reference";
+	}
+	return "<unknown>";
+}
+pdf_obj *
+pdf_new_array(fz_context *ctx, pdf_document *doc, int initialcap)
+{
+	pdf_obj_array *obj;
+	int i;
+	if (doc == NULL)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "cannot create array without a document");
+	obj = Memento_label(fz_malloc(ctx, sizeof(pdf_obj_array)), "pdf_obj(array)");
+	obj->super.refs = 1;
+	obj->super.kind = PDF_ARRAY;
+	obj->super.flags = 0;
+	obj->doc = doc;
+	obj->parent_num = 0;
+	obj->len = 0;
+	obj->cap = initialcap > 1 ? initialcap : 6;
+	fz_try(ctx)
+	{
+		obj->items = Memento_label(fz_malloc_array(ctx, obj->cap, pdf_obj*), "pdf_array_items");
+	}
+	fz_catch(ctx)
+	{
+		fz_free(ctx, obj);
+		fz_rethrow(ctx);
+	}
+	for (i = 0; i < obj->cap; i++)
+		obj->items[i] = NULL;
+	return &obj->super;
+}
+static void
+pdf_array_grow(fz_context *ctx, pdf_obj_array *obj)
+{
+	int i;
+	int new_cap = (obj->cap * 3) / 2;
+	obj->items = fz_realloc_array(ctx, obj->items, new_cap, pdf_obj*);
+	obj->cap = new_cap;
+	for (i = obj->len ; i < obj->cap; i++)
+		obj->items[i] = NULL;
+}
+pdf_obj *
+pdf_copy_array(fz_context *ctx, pdf_obj *obj)
+{
+	pdf_document *doc;
+	pdf_obj *arr;
+	int i;
+	int n;
+	RESOLVE(obj);
+	if (!OBJ_IS_ARRAY(obj))
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "not an array (%s)", pdf_objkindstr(obj));
+	doc = ARRAY(obj)->doc;
+	n = pdf_array_len(ctx, obj);
+	arr = pdf_new_array(ctx, doc, n);
+	fz_try(ctx)
+		for (i = 0; i < n; i++)
+			pdf_array_push(ctx, arr, pdf_array_get(ctx, obj, i));
+	fz_catch(ctx)
+	{
+		pdf_drop_obj(ctx, arr);
+		fz_rethrow(ctx);
+	}
+	return arr;
+}
+int
+pdf_array_len(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	if (!OBJ_IS_ARRAY(obj))
+		return 0;
+	return ARRAY(obj)->len;
+}
+pdf_obj *
+pdf_array_get(fz_context *ctx, pdf_obj *obj, int i)
+{
+	RESOLVE(obj);
+	if (!OBJ_IS_ARRAY(obj))
+		return NULL;
+	if (i < 0 || i >= ARRAY(obj)->len)
+		return NULL;
+	return ARRAY(obj)->items[i];
+}
+/* Call this to enable journalling on a given document. */
+void pdf_enable_journal(fz_context *ctx, pdf_document *doc)
+{
+	if (ctx == NULL || doc == NULL)
+		return;
+	if (doc->journal == NULL)
+		doc->journal = fz_malloc_struct(ctx, pdf_journal);
+}
+static void
+discard_fragments(fz_context *ctx, pdf_journal_fragment *head)
+{
+	while (head)
+	{
+		pdf_journal_fragment *next = head->next;
+		pdf_drop_obj(ctx, head->inactive);
+		fz_drop_buffer(ctx, head->stream);
+		fz_free(ctx, head);
+		head = next;
+	}
+}
+static void
+discard_journal_entries(fz_context *ctx, pdf_journal_entry **journal_entry)
+{
+	pdf_journal_entry *entry = *journal_entry;
+	if (entry == NULL)
+		return;
+	*journal_entry = NULL;
+	while (entry)
+	{
+		pdf_journal_entry *next = entry->next;
+		discard_fragments(ctx, entry->head);
+		fz_free(ctx, entry->title);
+		fz_free(ctx, entry);
+		entry = next;
+	}
+}
+static void
+new_entry(fz_context *ctx, pdf_document *doc, char *operation)
+{
+	fz_try(ctx)
+	{
+		pdf_journal_entry *entry;
+		/* We create a new entry, and link it into the middle of
+		 * the chain. If we actually come to put anything into
+		 * it later, then the call to pdf_add_journal_fragment
+		 * during that addition will discard everything in the
+		 * history that follows it. */
+		entry = fz_malloc_struct(ctx, pdf_journal_entry);
+		if (doc->journal->current == NULL)
+		{
+			entry->prev = NULL;
+			entry->next = doc->journal->head;
+			doc->journal->head = entry;
+		}
+		else
+		{
+			entry->prev = doc->journal->current;
+			entry->next = doc->journal->current->next;
+			if (doc->journal->current->next)
+				doc->journal->current->next->prev = entry;
+			doc->journal->current->next = entry;
+		}
+		doc->journal->current = entry;
+		entry->title = operation;
+	}
+	fz_catch(ctx)
+	{
+		fz_free(ctx, operation);
+		fz_rethrow(ctx);
+	}
+}
+/* Call this to start an operation. Undo/redo works at 'operation'
+* granularity. Nested operations are all counted within the outermost
+* operation. Any modification performed on a journalled PDF without an
+* operation having been started will throw an error. */
+static void
+do_begin_operation(fz_context *ctx, pdf_document *doc, const char *operation_)
+{
+	char *operation;
+	/* If we aren't journalling this doc, just give up now. */
+	if (ctx == NULL || doc == NULL || doc->journal == NULL)
+		return;
+	/* Always increment nesting. */
+	doc->journal->nesting++;
+	operation = operation_ ? fz_strdup(ctx, operation_) : NULL;
+#ifdef PDF_DEBUG_JOURNAL
+	fz_write_printf(ctx, fz_stddbg(ctx), "Beginning: (->%d) %s\n", doc->journal->nesting, operation ? operation : "<implicit>");
+#endif
+	fz_try(ctx)
+	{
+		pdf_journal_entry *entry;
+		/* We create a new entry, and link it into the middle of
+		 * the chain. If we actually come to put anything into
+		 * it later, then the call to pdf_add_journal_fragment
+		 * during that addition will discard everything in the
+		 * history that follows it. */
+		entry = fz_malloc_struct(ctx, pdf_journal_entry);
+		if (doc->journal->pending_tail == NULL)
+		{
+			entry->prev = NULL;
+			entry->next = doc->journal->pending;
+			doc->journal->pending = entry;
+		}
+		else
+		{
+			entry->prev = doc->journal->pending_tail;
+			entry->next = doc->journal->pending_tail->next;
+			if (doc->journal->pending_tail->next)
+				doc->journal->pending_tail->next->prev = entry;
+			doc->journal->pending_tail->next = entry;
+		}
+		doc->journal->pending_tail = entry;
+		entry->title = operation;
+	}
+	fz_catch(ctx)
+	{
+		doc->journal->nesting--;
+		fz_free(ctx, operation);
+		fz_rethrow(ctx);
+	}
+}
+void pdf_begin_operation(fz_context *ctx, pdf_document *doc, const char *operation)
+{
+	if (operation == NULL)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "All operations must be named");
+	do_begin_operation(ctx, doc, operation);
+}
+void pdf_begin_implicit_operation(fz_context *ctx, pdf_document *doc)
+{
+	do_begin_operation(ctx, doc, NULL);
+}
+void pdf_drop_journal(fz_context *ctx, pdf_journal *journal)
+{
+	if (ctx == NULL || journal == NULL)
+		return;
+	discard_journal_entries(ctx, &journal->head);
+	/* Shouldn't be any pending ones, but be safe. */
+	discard_journal_entries(ctx, &journal->pending);
+	fz_free(ctx, journal);
+}
+#ifdef PDF_DEBUG_JOURNAL
+static void
+dump_changes(fz_context *ctx, pdf_document *doc, pdf_journal_entry *entry)
+{
+	pdf_journal_fragment *frag;
+	if (entry == NULL || entry->changed_since_last_dumped == 0)
+		return;
+	for (frag = entry->head; frag; frag = frag->next)
+	{
+		pdf_obj *obj;
+		fz_write_printf(ctx, fz_stddbg(ctx), "Changing obj %d:\n", frag->obj_num);
+		pdf_debug_obj(ctx, frag->inactive);
+		fz_write_printf(ctx, fz_stddbg(ctx), " To:\n");
+		obj = pdf_load_object(ctx, doc, frag->obj_num);
+		pdf_debug_obj(ctx, obj);
+		pdf_drop_obj(ctx, obj);
+	}
+	entry->changed_since_last_dumped = 0;
+}
+#endif
+/* We build up journal entries as being a list of changes (fragments) that
+* happen all together as part of a single step. When we reach pdf_end_operation
+* we have all the changes that have happened during this operation in a list
+* that basically boils down to being:
+*
+*     change object x from being A to the value in the xref.
+*     change object y from being B to the value in the xref.
+*     change object z from being C to the value in the xref.
+*     etc.
+*
+* The idea is that we can undo, or redo by stepping through that list.
+* Every object can only be mentioned once in a fragment (otherwise we
+* get very confused when undoing and redoing).
+*
+* When we come to glue 2 entries together (as happens when we end a
+* nested or implicit operation), we need to be sure that the 2 entries
+* don't both mention the same object.
+*
+* Imagine we've edited a text field from being empty to containing
+* 'he' by typing each char at a time:
+*
+*     Entry 1:
+*        change object x from being ''.
+*     Entry 2 (implicit):
+*        change object x from being 'h'.
+*
+* with current xref entry for x being 'he'.
+*
+* When we come to combine the two, we can't simply go to:
+*
+*     change object x from being ''.
+*     change object x from being 'h'.
+*
+* If we 'undo' that, however, because we run forwards through the list for
+* both undo and redo, we get it wrong.
+*
+* First we replace 'he' by ''.
+* Then we replace '' by 'h'.
+*
+* i.e. leaving us only partly undone.
+*
+* Either we need to run in different directions for undo and redo, or we need to
+* resolve the changes down to a single change for each object. Given that we don't
+* really want more than one change for each object in each changeset (needless memory
+* etc), let's resolve the changesets.
+**/
+static void resolve_undo(fz_context *ctx, pdf_journal_entry *entry)
+{
+	pdf_journal_fragment *start, *current;
+	pdf_journal_fragment *tail = NULL;
+	/* Slightly nasty that this is n^2, but any alternative involves
+	 * sorting. Shouldn't be huge lists anyway. */
+	for (start = entry->head; start; start = start->next)
+	{
+		pdf_journal_fragment *next;
+		tail = start;
+		for (current = start->next; current; current = next)
+		{
+			next = current->next;
+			if (start->obj_num == current->obj_num)
+			{
+				pdf_drop_obj(ctx, current->inactive);
+				fz_drop_buffer(ctx, current->stream);
+				/* start->newobj should not change */
+				/* Now drop current */
+				if (next)
+					next->prev = current->prev;
+				current->prev->next = next;
+				fz_free(ctx, current);
+			}
+		}
+	}
+	entry->tail = tail;
+}
+/* Call this to end an operation. */
+void pdf_end_operation(fz_context *ctx, pdf_document *doc)
+{
+	pdf_journal_entry *entry;
+	if (ctx == NULL || doc == NULL || doc->journal == NULL)
+		return;
+	/* Decrement the operation nesting count. */
+	if (--doc->journal->nesting > 0)
+	{
+		/* We need to move the contents of doc->pending_tail down to
+		 * be on doc->pending_tail->prev. i.e. we combine fragments
+		 * as these operations become one. */
+		entry = doc->journal->pending_tail;
+		/* An implicit operation before we start the file can result in us getting here
+		 * with no entry at all! */
+		if (entry && entry->prev)
+		{
+			if (entry->tail == NULL)
+			{
+				/* Nothing to move. */
+			}
+			else if (entry->prev->tail == NULL)
+			{
+				/* Nothing where we want to move it. */
+				entry->prev->head = entry->head;
+				entry->prev->tail = entry->tail;
+			}
+			else
+			{
+				/* Append one list to the other. */
+				entry->prev->tail->next = entry->head;
+				entry->head->prev = entry->prev->tail;
+				entry->prev->tail = entry->tail;
+				/* And resolve any clashing objects */
+				resolve_undo(ctx, entry->prev);
+			}
+#ifdef PDF_DEBUG_JOURNAL
+			fz_write_printf(ctx, fz_stddbg(ctx), "Ending! (->%d) \"%s\" <= \"%s\"\n", doc->journal->nesting,
+					entry->prev->title ? entry->prev->title : "<implicit>",
+					entry->title ? entry->title : "<implicit>");
+#endif
+			doc->journal->pending_tail = entry->prev;
+			entry->prev->next = NULL;
+			fz_free(ctx, entry->title);
+			fz_free(ctx, entry);
+		}
+		else
+		{
+#ifdef PDF_DEBUG_JOURNAL
+			fz_write_printf(ctx, fz_stddbg(ctx), "Ending! (->%d) no entry\n", doc->journal->nesting);
+#endif
+		}
+		return;
+	}
+	/* Now, check to see whether we have actually stored any changes
+	 * (fragments) into our entry. If we have, we need to move these
+	 * changes from pending onto current. */
+	entry = doc->journal->pending;
+	assert(entry);
+	/* We really ought to have just a single pending entry at this point,
+	 * but implicit operations when we've just loaded a file can mean
+	 * that we don't have an entry at all. */
+	if (entry == NULL)
+	{
+		/* Never happens! */
+	}
+	else if (entry->head == NULL)
+	{
+		/* Didn't actually change anything! Remove the empty entry. */
+#ifdef PDF_DEBUG_JOURNAL
+		fz_write_printf(ctx, fz_stddbg(ctx), "Ending Empty!\n");
+#endif
+		discard_journal_entries(ctx, &doc->journal->pending);
+	}
+	else if (entry->title != NULL)
+	{
+		/* Explicit operation. Move the entry off the pending list. */
+		assert(entry->next == NULL);
+		if (doc->journal->current)
+		{
+			doc->journal->current->next = entry;
+			entry->prev = doc->journal->current;
+			doc->journal->current = entry;
+		}
+		else
+		{
+			doc->journal->head = entry;
+			doc->journal->current = entry;
+		}
+#ifdef PDF_DEBUG_JOURNAL
+		fz_write_printf(ctx, fz_stddbg(ctx), "Ending!\n");
+#endif
+	}
+	else if (doc->journal->current == NULL)
+	{
+		/* Implicit operation, with no previous one. */
+#ifdef PDF_DEBUG_JOURNAL
+		fz_write_printf(ctx, fz_stddbg(ctx), "Ending implicit with no previous!\n");
+#endif
+		/* Just drop the record of the changes. */
+		discard_journal_entries(ctx, &doc->journal->pending);
+	}
+	else
+	{
+		/* Implicit operation. Roll these changes into the previous one.*/
+#ifdef PDF_DEBUG_JOURNAL
+		fz_write_printf(ctx, fz_stddbg(ctx), "Ending implicit!\n");
+#endif
+		doc->journal->current->tail->next = entry->head;
+		entry->head->prev = doc->journal->current->tail;
+		doc->journal->current->tail = entry->tail;
+		entry->head = NULL;
+		entry->tail = NULL;
+		fz_free(ctx, entry->title);
+		fz_free(ctx, entry);
+		/* And resolve any clashing objects */
+		resolve_undo(ctx, doc->journal->current);
+	}
+	doc->journal->pending = NULL;
+	doc->journal->pending_tail = NULL;
+}
+/* Call this to find out how many undo/redo steps there are, and the
+* current position we are within those. 0 = original document,
+* *steps = final edited version. */
+int pdf_undoredo_state(fz_context *ctx, pdf_document *doc, int *steps)
+{
+	int i, c;
+	pdf_journal_entry *entry;
+	if (ctx == NULL || doc == NULL || doc->journal == NULL)
+	{
+		*steps = 0;
+		return 0;
+	}
+	if (doc->journal->pending != NULL || doc->journal->nesting > 0)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "Can't undo/redo during an operation");
+	i = 0;
+	c = 0;
+	for (entry = doc->journal->head; entry != NULL; entry = entry->next)
+	{
+		i++;
+		if (entry == doc->journal->current)
+			c = i;
+	}
+	*steps = i;
+	return c;
+}
+int pdf_can_undo(fz_context *ctx, pdf_document *doc)
+{
+	int steps, step;
+	step = pdf_undoredo_state(ctx, doc, &steps);
+	return step > 0;
+}
+int pdf_can_redo(fz_context *ctx, pdf_document *doc)
+{
+	int steps, step;
+	step = pdf_undoredo_state(ctx, doc, &steps);
+	return step != steps;
+}
+/* Call this to find the title of the operation within the undo state. */
+const char *pdf_undoredo_step(fz_context *ctx, pdf_document *doc, int step)
+{
+	pdf_journal_entry *entry;
+	if (ctx == NULL || doc == NULL || doc->journal == NULL)
+		return NULL;
+	if (doc->journal->pending != NULL || doc->journal->nesting > 0)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "Can't undo/redo during an operation");
+	for (entry = doc->journal->head; step > 0 && entry != NULL; step--, entry = entry->next);
+	if (step != 0 || entry == NULL)
+		return NULL;
+	return entry->title;
+}
+static void
+swap_fragments(fz_context *ctx, pdf_document *doc, pdf_journal_entry *entry)
+{
+	pdf_journal_fragment *frag;
+#ifdef PDF_DEBUG_JOURNAL
+	entry->changed_since_last_dumped = 1;
+#endif
+	if (doc->local_xref_nesting != 0)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "Can't undo/redo within an operation");
+	pdf_drop_local_xref_and_resources(ctx, doc);
+	for (frag = entry->head; frag != NULL; frag = frag->next)
+	{
+		pdf_xref_entry *xre;
+		pdf_obj *old;
+		fz_buffer *obuf;
+		int type;
+		xre = pdf_get_incremental_xref_entry(ctx, doc, frag->obj_num);
+		old = xre->obj;
+		obuf = xre->stm_buf;
+		xre->obj = frag->inactive;
+		type = xre->type;
+		xre->type = frag->newobj ? 0 : 'o';
+		frag->newobj = type == 0;
+		xre->stm_buf = frag->stream;
+		frag->inactive = old;
+		frag->stream = obuf;
+	}
+}
+/* Abandon an operation - unwind back to the previous begin. */
+void pdf_abandon_operation(fz_context *ctx, pdf_document *doc)
+{
+	pdf_journal_entry *entry;
+	if (ctx == NULL || doc == NULL || doc->journal == NULL)
+		return;
+	if (doc->journal->nesting == 0)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "Can't abandon a non-existent operation!");
+	doc->journal->nesting--;
+	entry = doc->journal->pending_tail;
+	assert(entry);
+	/* Undo the changes we are about the discard. */
+	swap_fragments(ctx, doc, entry);
+	/* And discard entry. */
+	if (entry->prev == NULL)
+	{
+		doc->journal->pending = NULL;
+		doc->journal->pending_tail = NULL;
+	}
+	else
+	{
+		doc->journal->pending_tail = entry->prev;
+		entry->prev->next = NULL;
+		entry->prev = NULL;
+	}
+#ifdef PDF_DEBUG_JOURNAL
+	fz_write_printf(ctx, fz_stddbg(ctx), "Abandoning!\n");
+#endif
+	discard_journal_entries(ctx, &entry);
+}
+/* Move backwards in the undo history. Throws an error if we are at the
+* start. Any edits to the document at this point will discard all
+* subsequent history. */
+void pdf_undo(fz_context *ctx, pdf_document *doc)
+{
+	pdf_journal_entry *entry;
+	pdf_journal_fragment *frag;
+	if (ctx == NULL || doc == NULL)
+		return;
+	if (doc->journal == NULL)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "Cannot undo on unjournaled PDF");
+	if (doc->journal->nesting != 0)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "Can't undo during an operation!");
+	entry = doc->journal->current;
+	if (entry == NULL)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "Already at start of history");
+#ifdef PDF_DEBUG_JOURNAL
+	fz_write_printf(ctx, fz_stddbg(ctx), "Undo!\n");
+#endif
+	doc->journal->current = entry->prev;
+	swap_fragments(ctx, doc, entry);
+	// nuke all caches
+	pdf_drop_page_tree_internal(ctx, doc);
+	pdf_sync_open_pages(ctx, doc);
+	for (frag = entry->head; frag; frag = frag->next)
+		pdf_purge_object_from_store(ctx, doc, frag->obj_num);
+}
+/* Move forwards in the undo history. Throws an error if we are at the
+* end. */
+void pdf_redo(fz_context *ctx, pdf_document *doc)
+{
+	pdf_journal_entry *entry;
+	pdf_journal_fragment *frag;
+	if (ctx == NULL || doc == NULL)
+		return;
+	if (doc->journal == NULL)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "Cannot redo on unjournaled PDF");
+	if (doc->journal->nesting != 0)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "Can't redo during an operation!");
+#ifdef PDF_DEBUG_JOURNAL
+	fz_write_printf(ctx, fz_stddbg(ctx), "Redo!\n");
+#endif
+	entry = doc->journal->current;
+	if (entry == NULL)
+	{
+		/* If journal->current is null then everything has been undone. */
+		/* Go to the first change in journal->head if it exists. */
+		entry = doc->journal->head;
+	}
+	else
+	{
+		entry = entry->next;
+	}
+	if (entry == NULL)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "Already at end of history");
+	// nuke all caches
+	pdf_drop_page_tree_internal(ctx, doc);
+	pdf_sync_open_pages(ctx, doc);
+	for (frag = entry->head; frag; frag = frag->next)
+		pdf_purge_object_from_store(ctx, doc, frag->obj_num);
+	doc->journal->current = entry;
+	swap_fragments(ctx, doc, entry);
+}
+void pdf_discard_journal(fz_context *ctx, pdf_journal *journal)
+{
+	if (ctx == NULL || journal == NULL)
+		return;
+	discard_journal_entries(ctx, &journal->head);
+	/* Should be NULL, but belt and braces. */
+	discard_journal_entries(ctx, &journal->pending);
+	journal->head = NULL;
+	journal->current = NULL;
+	journal->pending = NULL;
+	journal->pending_tail = NULL;
+}
+static void
+pdf_fingerprint_file(fz_context *ctx, pdf_document *doc, unsigned char digest[16], int i)
+{
+	fz_md5 state;
+	fz_md5_init(&state);
+	fz_md5_update_int64(&state, doc->num_xref_sections-i);
+	for (; i < doc->num_xref_sections; i++)
+	{
+		pdf_xref_subsec *subsec = doc->xref_sections[i].subsec;
+		fz_md5_update_int64(&state, doc->xref_sections[i].num_objects);
+		while (subsec)
+		{
+			fz_md5_update_int64(&state, subsec->start);
+			fz_md5_update_int64(&state, subsec->len);
+			subsec = subsec->next;
+		}
+	}
+	fz_md5_final(&state, digest);
+}
+void
+pdf_serialise_journal(fz_context *ctx, pdf_document *doc, fz_output *out)
+{
+	pdf_journal_entry *entry;
+	int currentpos = 0;
+	unsigned char digest[16];
+	int i;
+	int nis = doc->num_incremental_sections;
+	pdf_fingerprint_file(ctx, doc, digest, nis);
+	if (!pdf_has_unsaved_changes(ctx, doc))
+		nis = 0;
+	fz_write_printf(ctx, out, "%!MuPDF-Journal-100\n");
+	fz_write_string(ctx, out, "\njournal\n<<\n");
+	fz_write_printf(ctx, out, "/NumSections %d\n", nis);
+	fz_write_printf(ctx, out, "/FileSize %ld\n", doc->file_size);
+	fz_write_printf(ctx, out, "/Fingerprint <");
+	for (i = 0; i < 16; i++)
+		fz_write_printf(ctx, out, "%02x", digest[i]);
+	fz_write_printf(ctx, out, ">\n");
+	if (doc->journal->current != NULL)
+		for (entry = doc->journal->head; entry != NULL; entry = entry->next)
+		{
+			currentpos++;
+			if (entry == doc->journal->current)
+				break;
+		}
+	fz_write_printf(ctx, out, "/HistoryPos %d\n", currentpos);
+	fz_write_string(ctx, out, ">>\n");
+	for (entry = doc->journal->head; entry != NULL; entry = entry->next)
+	{
+		pdf_journal_fragment *frag;
+		fz_write_printf(ctx, out, "entry\n%(\n", entry->title);
+		for (frag = entry->head; frag != NULL; frag = frag->next)
+		{
+			if (frag->newobj)
+			{
+				fz_write_printf(ctx, out, "%d 0 newobj\n", frag->obj_num);
+				continue;
+			}
+			fz_write_printf(ctx, out, "%d 0 obj\n", frag->obj_num);
+			pdf_print_encrypted_obj(ctx, out, frag->inactive, 1, 0, NULL, frag->obj_num, 0, NULL);
+			if (frag->stream)
+			{
+				fz_write_printf(ctx, out, "\nstream\n");
+				fz_write_data(ctx, out, frag->stream->data, frag->stream->len);
+				fz_write_string(ctx, out, "\nendstream");
+			}
+			fz_write_string(ctx, out, "\nendobj\n");
+		}
+	}
+	fz_write_printf(ctx, out, "endjournal\n");
+}
+void
+pdf_add_journal_fragment(fz_context *ctx, pdf_document *doc, int parent, pdf_obj *copy, fz_buffer *copy_stream, int newobj)
+{
+	pdf_journal_entry *entry;
+	pdf_journal_fragment *frag;
+	if (doc->journal == NULL)
+		return;
+	entry = doc->journal->pending_tail;
+	/* We must be in an operation. */
+	assert(entry != NULL);
+	if (entry == NULL)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "Can't add a journal fragment absent an operation");
+	/* This should never happen, as we should always be appending to the end of
+	 * the pending list. */
+	assert(entry->next == NULL);
+	if (entry->next)
+	{
+		discard_journal_entries(ctx, &entry->next);
+		doc->journal->pending_tail = NULL;
+	}
+#ifdef PDF_DEBUG_JOURNAL
+	entry->changed_since_last_dumped = 1;
+#endif
+	fz_try(ctx)
+	{
+		frag = fz_malloc_struct(ctx, pdf_journal_fragment);
+		frag->obj_num = parent;
+		if (entry->tail == NULL)
+		{
+			frag->prev = NULL;
+			entry->head = frag;
+		}
+		else
+		{
+			frag->prev = entry->tail;
+			entry->tail->next = frag;
+		}
+		entry->tail = frag;
+		frag->newobj = newobj;
+		frag->inactive = copy;
+		frag->stream = copy_stream;
+	}
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+}
+void pdf_deserialise_journal(fz_context *ctx, pdf_document *doc, fz_stream *stm)
+{
+	int num, version, c, nis, pos;
+	pdf_obj *obj = NULL, *fingerprint_obj;
+	fz_buffer *buffer;
+	unsigned char digest[16];
+	int64_t file_size;
+	int digests_match = 0;
+	pdf_token tok;
+	if (!doc || !stm)
+		return;
+	if (doc->journal)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "Can't load a journal over another one");
+	if (fz_skip_string(ctx, stm, "%!MuPDF-Journal-"))
+		fz_throw(ctx, FZ_ERROR_FORMAT, "Bad journal format");
+	fz_var(obj);
+	fz_var(digests_match);
+	fz_try(ctx)
+	{
+		version = 0;
+		while (1)
+		{
+			c = fz_peek_byte(ctx, stm);
+			if (c < '0' || c > '9')
+				break;
+			version = (version*10) + c - '0';
+			(void)fz_read_byte(ctx, stm);
+		}
+		if (version != 100)
+			fz_throw(ctx, FZ_ERROR_FORMAT, "Bad journal format");
+		fz_skip_space(ctx, stm);
+		if (fz_skip_string(ctx, stm, "journal\n"))
+			fz_throw(ctx, FZ_ERROR_FORMAT, "Bad journal format");
+		tok = pdf_lex(ctx, stm, &doc->lexbuf.base);
+		if (tok != PDF_TOK_OPEN_DICT)
+			fz_throw(ctx, FZ_ERROR_FORMAT, "Bad journal format");
+		obj = pdf_parse_dict(ctx, doc, stm, &doc->lexbuf.base);
+		nis = pdf_dict_get_int(ctx, obj, PDF_NAME(NumSections));
+		if (nis < 0 || nis > doc->num_xref_sections)
+			fz_throw(ctx, FZ_ERROR_FORMAT, "Bad journal format");
+		pdf_fingerprint_file(ctx, doc, digest, nis);
+		file_size = pdf_dict_get_int(ctx, obj, PDF_NAME(FileSize));
+		fingerprint_obj = pdf_dict_get(ctx, obj, PDF_NAME(Fingerprint));
+		if (pdf_to_str_len(ctx, fingerprint_obj) != 16)
+			fz_throw(ctx, FZ_ERROR_FORMAT, "Bad journal fingerprint");
+		digests_match = (memcmp(pdf_to_str_buf(ctx, fingerprint_obj), digest, 16) == 0);
+		pos = pdf_dict_get_int(ctx, obj, PDF_NAME(HistoryPos));
+	}
+	fz_always(ctx)
+	{
+		pdf_drop_obj(ctx, obj);
+	}
+	fz_catch(ctx)
+	{
+		fz_rethrow(ctx);
+	}
+	if (!digests_match)
+		return;
+	if (doc->file_size < file_size)
+		return;
+	doc->journal = fz_malloc_struct(ctx, pdf_journal);
+	while (1)
+	{
+		int newobj;
+		fz_skip_space(ctx, stm);
+		if (fz_skip_string(ctx, stm, "entry\n") == 0)
+		{
+			/* Read the fragment title. */
+			char *title;
+			tok = pdf_lex(ctx, stm, &doc->lexbuf.base);
+			if (tok != PDF_TOK_STRING)
+				fz_throw(ctx, FZ_ERROR_FORMAT, "Bad string in journal");
+			title = fz_malloc(ctx, doc->lexbuf.base.len+1);
+			memcpy(title, doc->lexbuf.base.buffer, doc->lexbuf.base.len);
+			title[doc->lexbuf.base.len] = 0;
+			new_entry(ctx, doc, title);
+			continue;
+		}
+		if (fz_skip_string(ctx, stm, /*en*/"djournal") == 0)
+			break;
+		if (doc->journal->current == NULL)
+			fz_throw(ctx, FZ_ERROR_FORMAT, "Badly formed journal");
+		/* Read the object/stream for the next fragment. */
+		obj = pdf_parse_journal_obj(ctx, doc, stm, &num, &buffer, &newobj);
+		pdf_add_journal_fragment(ctx, doc, num, obj, buffer, newobj);
+	}
+	fz_skip_space(ctx, stm);
+	doc->journal->current = NULL;
+	if (pos > 0)
+	{
+		if (doc->journal->head == NULL)
+			fz_throw(ctx, FZ_ERROR_FORMAT, "Badly formed journal");
+		doc->journal->current = doc->journal->head;
+		while (--pos)
+		{
+			doc->journal->current = doc->journal->current->next;
+			if (doc->journal->current == NULL)
+				break;
+		}
+	}
+	doc->file_size = file_size;
+	/* We're about to make the last xref an incremental one. All incremental
+	 * ones MUST be solid, but the snapshot might not have saved it as such,
+	 * so solidify it now. */
+	pdf_ensure_solid_xref(ctx, doc, pdf_xref_len(ctx, doc));
+	doc->num_incremental_sections = nis;
+	if (nis > 0)
+	{
+		/* Ditch the trailer object out of the xref. Keep the direct
+		 * trailer reference. */
+		pdf_delete_object(ctx, doc, pdf_obj_parent_num(ctx, doc->xref_sections[0].trailer));
+		pdf_set_obj_parent(ctx, doc->xref_sections[0].trailer, 0);
+	}
+}
+static void prepare_object_for_alteration(fz_context *ctx, pdf_obj *obj, pdf_obj *val)
+{
+	pdf_document *doc, *val_doc;
+	int parent;
+	pdf_journal_fragment *frag;
+	pdf_journal_entry *entry;
+	pdf_obj *copy = NULL;
+	pdf_obj *orig;
+	fz_buffer *copy_stream = NULL;
+	int was_empty;
+	/*
+		obj should be a dict or an array. We don't care about
+		any other types, as they aren't 'containers'.
+	*/
+	if (obj < PDF_LIMIT)
+		return;
+	switch (obj->kind)
+	{
+	case PDF_DICT:
+		doc = DICT(obj)->doc;
+		parent = DICT(obj)->parent_num;
+		break;
+	case PDF_ARRAY:
+		doc = ARRAY(obj)->doc;
+		parent = ARRAY(obj)->parent_num;
+		break;
+	default:
+		return;
+	}
+	assert(doc != NULL);
+	/* Do we need to drop the page maps? */
+	if (doc->rev_page_map || doc->fwd_page_map)
+	{
+		if (doc->non_structural_change)
+		{
+			/* No need to drop the reverse page map on a non-structural change. */
+		}
+		else if (parent == 0)
+		{
+			/* This object isn't linked into the document - can't change the
+			 * pagemap. */
+		}
+		else if (doc->local_xref && doc->local_xref_nesting > 0)
+		{
+			/* We have a local_xref and it's in force. By convention, we
+			 * never do structural changes in local_xrefs. */
+		}
+		else
+			pdf_drop_page_tree_internal(ctx, doc);
+	}
+	if (val)
+	{
+		val_doc = pdf_get_bound_document(ctx, val);
+		if (val_doc && val_doc != doc)
+			fz_throw(ctx, FZ_ERROR_ARGUMENT, "container and item belong to different documents");
+	}
+	/*
+		The newly linked object needs to record the parent_num.
+	*/
+	if (parent != 0)
+		pdf_set_obj_parent(ctx, val, parent);
+	/*
+		parent_num == 0 while an object is being parsed from the file.
+		No further action is necessary.
+	*/
+	if (parent == 0 || doc->save_in_progress || doc->repair_in_progress)
+		return;
+	if (doc->journal && doc->journal->nesting == 0)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "Can't alter an object other than in an operation");
+	if (doc->local_xref)
+	{
+		/* We have a local_xref. If it's in force, then we're
+		 * ready for alteration already. */
+		if (doc->local_xref_nesting > 0)
+		{
+			pdf_xref_ensure_local_object(ctx, doc, parent);
+			return;
+		}
+		else
+		{
+			/* The local xref isn't in force, and we're about
+			 * to edit the document. This invalidates it, so
+			 * throw it away. */
+			pdf_drop_local_xref_and_resources(ctx, doc);
+		}
+	}
+	// Empty store of items keyed on the object being changed.
+	if (parent != 0)
+		pdf_purge_object_from_store(ctx, doc, parent);
+	entry = NULL;
+	if (doc->journal)
+	{
+		/* We are about to add a fragment. Everything after 'current' in the
+		 * history must be thrown away. If current is NULL, then *everything*
+		 * must be thrown away. */
+		discard_journal_entries(ctx, doc->journal->current ? &doc->journal->current->next : &doc->journal->head);
+		/* We should be collating into a pending block. */
+		entry = doc->journal->pending_tail;
+		assert(entry);
+		/* If we've already stashed a value for this object in this fragment,
+		 * we don't need to stash another one. It'll only confuse us later. */
+		for (frag = entry->head; frag != NULL; frag = frag->next)
+			if (frag->obj_num == parent)
+			{
+				entry = NULL;
+				break; /* Already stashed this one! */
+			}
+	}
+	/*
+		We need to ensure that the containing hierarchy of objects
+		has been moved to the incremental xref section.
+	*/
+	was_empty = pdf_xref_ensure_incremental_object(ctx, doc, parent);
+	/* If we're not journalling, or we've already stashed an 'old' value for this
+	 * object, just exit now. */
+	if (entry == NULL)
+		return;
+	/* Load the 'old' value and store it in a fragment. */
+	orig = pdf_load_object(ctx, doc, parent);
+	fz_var(copy);
+	fz_var(copy_stream);
+	fz_try(ctx)
+	{
+		if (was_empty)
+		{
+			/* was_empty = 1 iff, the the entry in the incremental xref was empty,
+			 * and we copied any older value for that object forwards from an old xref.
+			 * When we undo, we just want to blank the one in the incremental section.
+			 * Effectively this is a "new object". */
+			copy = NULL;
+			copy_stream = NULL;
+		}
+		else
+		{
+			copy = pdf_deep_copy_obj(ctx, orig);
+			pdf_set_obj_parent(ctx, copy, parent);
+			if (pdf_obj_num_is_stream(ctx, doc, parent))
+				copy_stream = pdf_load_raw_stream_number(ctx, doc, parent);
+		}
+		pdf_add_journal_fragment(ctx, doc, parent, copy, copy_stream, was_empty);
+	}
+	fz_always(ctx)
+	{
+		pdf_drop_obj(ctx, orig);
+	}
+	fz_catch(ctx)
+	{
+		fz_drop_buffer(ctx, copy_stream);
+		pdf_drop_obj(ctx, copy);
+		fz_rethrow(ctx);
+	}
+}
+void
+pdf_array_put(fz_context *ctx, pdf_obj *obj, int i, pdf_obj *item)
+{
+	RESOLVE(obj);
+	if (!OBJ_IS_ARRAY(obj))
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "not an array (%s)", pdf_objkindstr(obj));
+	if (i == ARRAY(obj)->len)
+	{
+		pdf_array_push(ctx, obj, item);
+		return;
+	}
+	if (i < 0 || i > ARRAY(obj)->len)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "index out of bounds");
+	prepare_object_for_alteration(ctx, obj, item);
+	pdf_drop_obj(ctx, ARRAY(obj)->items[i]);
+	ARRAY(obj)->items[i] = pdf_keep_obj(ctx, item);
+}
+void
+pdf_array_put_drop(fz_context *ctx, pdf_obj *obj, int i, pdf_obj *item)
+{
+	fz_try(ctx)
+		pdf_array_put(ctx, obj, i, item);
+	fz_always(ctx)
+		pdf_drop_obj(ctx, item);
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+}
+void
+pdf_array_push(fz_context *ctx, pdf_obj *obj, pdf_obj *item)
+{
+	RESOLVE(obj);
+	if (!OBJ_IS_ARRAY(obj))
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "not an array (%s)", pdf_objkindstr(obj));
+	prepare_object_for_alteration(ctx, obj, item);
+	if (ARRAY(obj)->len + 1 > ARRAY(obj)->cap)
+		pdf_array_grow(ctx, ARRAY(obj));
+	ARRAY(obj)->items[ARRAY(obj)->len] = pdf_keep_obj(ctx, item);
+	ARRAY(obj)->len++;
+}
+void
+pdf_array_push_drop(fz_context *ctx, pdf_obj *obj, pdf_obj *item)
+{
+	fz_try(ctx)
+		pdf_array_push(ctx, obj, item);
+	fz_always(ctx)
+		pdf_drop_obj(ctx, item);
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+}
+void
+pdf_array_insert(fz_context *ctx, pdf_obj *obj, pdf_obj *item, int i)
+{
+	RESOLVE(obj);
+	if (!OBJ_IS_ARRAY(obj))
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "not an array (%s)", pdf_objkindstr(obj));
+	if (i < 0 || i > ARRAY(obj)->len)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "index out of bounds");
+	prepare_object_for_alteration(ctx, obj, item);
+	if (ARRAY(obj)->len + 1 > ARRAY(obj)->cap)
+		pdf_array_grow(ctx, ARRAY(obj));
+	memmove(ARRAY(obj)->items + i + 1, ARRAY(obj)->items + i, (ARRAY(obj)->len - i) * sizeof(pdf_obj*));
+	ARRAY(obj)->items[i] = pdf_keep_obj(ctx, item);
+	ARRAY(obj)->len++;
+}
+void
+pdf_array_insert_drop(fz_context *ctx, pdf_obj *obj, pdf_obj *item, int i)
+{
+	fz_try(ctx)
+		pdf_array_insert(ctx, obj, item, i);
+	fz_always(ctx)
+		pdf_drop_obj(ctx, item);
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+}
+void
+pdf_array_delete(fz_context *ctx, pdf_obj *obj, int i)
+{
+	RESOLVE(obj);
+	if (!OBJ_IS_ARRAY(obj))
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "not an array (%s)", pdf_objkindstr(obj));
+	if (i < 0 || i >= ARRAY(obj)->len)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "index out of bounds");
+	prepare_object_for_alteration(ctx, obj, NULL);
+	pdf_drop_obj(ctx, ARRAY(obj)->items[i]);
+	ARRAY(obj)->items[i] = 0;
+	ARRAY(obj)->len--;
+	memmove(ARRAY(obj)->items + i, ARRAY(obj)->items + i + 1, (ARRAY(obj)->len - i) * sizeof(pdf_obj*));
+}
+int
+pdf_array_contains(fz_context *ctx, pdf_obj *arr, pdf_obj *obj)
+{
+	int i, len;
+	len = pdf_array_len(ctx, arr);
+	for (i = 0; i < len; i++)
+		if (!pdf_objcmp(ctx, pdf_array_get(ctx, arr, i), obj))
+			return 1;
+	return 0;
+}
+int
+pdf_array_find(fz_context *ctx, pdf_obj *arr, pdf_obj *obj)
+{
+	int i, len;
+	len = pdf_array_len(ctx, arr);
+	for (i = 0; i < len; i++)
+		if (!pdf_objcmp(ctx, pdf_array_get(ctx, arr, i), obj))
+			return i;
+	return -1;
+}
+pdf_obj *pdf_new_point(fz_context *ctx, pdf_document *doc, fz_point point)
+{
+	pdf_obj *arr = pdf_new_array(ctx, doc, 2);
+	fz_try(ctx)
+	{
+		pdf_array_push_real(ctx, arr, point.x);
+		pdf_array_push_real(ctx, arr, point.y);
+	}
+	fz_catch(ctx)
+	{
+		pdf_drop_obj(ctx, arr);
+		fz_rethrow(ctx);
+	}
+	return arr;
+}
+pdf_obj *pdf_new_rect(fz_context *ctx, pdf_document *doc, fz_rect rect)
+{
+	pdf_obj *arr = pdf_new_array(ctx, doc, 4);
+	fz_try(ctx)
+	{
+		pdf_array_push_real(ctx, arr, rect.x0);
+		pdf_array_push_real(ctx, arr, rect.y0);
+		pdf_array_push_real(ctx, arr, rect.x1);
+		pdf_array_push_real(ctx, arr, rect.y1);
+	}
+	fz_catch(ctx)
+	{
+		pdf_drop_obj(ctx, arr);
+		fz_rethrow(ctx);
+	}
+	return arr;
+}
+pdf_obj *pdf_new_matrix(fz_context *ctx, pdf_document *doc, fz_matrix mtx)
+{
+	pdf_obj *arr = pdf_new_array(ctx, doc, 6);
+	fz_try(ctx)
+	{
+		pdf_array_push_real(ctx, arr, mtx.a);
+		pdf_array_push_real(ctx, arr, mtx.b);
+		pdf_array_push_real(ctx, arr, mtx.c);
+		pdf_array_push_real(ctx, arr, mtx.d);
+		pdf_array_push_real(ctx, arr, mtx.e);
+		pdf_array_push_real(ctx, arr, mtx.f);
+	}
+	fz_catch(ctx)
+	{
+		pdf_drop_obj(ctx, arr);
+		fz_rethrow(ctx);
+	}
+	return arr;
+}
+pdf_obj *pdf_new_date(fz_context *ctx, pdf_document *doc, int64_t time)
+{
+	char s[40];
+	if (!pdf_format_date(ctx, time, s, nelem(s)))
+		return NULL;
+	return pdf_new_string(ctx, s, strlen(s));
+}
+/* dicts may only have names as keys! */
+static int keyvalcmp(const void *ap, const void *bp)
+{
+	const struct keyval *a = ap;
+	const struct keyval *b = bp;
+	const char *an;
+	const char *bn;
+	/* We should never get a->k == NULL or b->k == NULL. If we
+	 * do, then they match. */
+	if (a->k < PDF_LIMIT)
+		an = PDF_NAME_LIST[(intptr_t)a->k];
+	else if (a->k >= PDF_LIMIT && a->k->kind == PDF_NAME)
+		an = NAME(a->k)->n;
+	else
+		return 0;
+	if (b->k < PDF_LIMIT)
+		bn = PDF_NAME_LIST[(intptr_t)b->k];
+	else if (b->k >= PDF_LIMIT && b->k->kind == PDF_NAME)
+		bn = NAME(b->k)->n;
+	else
+		return 0;
+	return strcmp(an, bn);
+}
+pdf_obj *
+pdf_new_dict(fz_context *ctx, pdf_document *doc, int initialcap)
+{
+	pdf_obj_dict *obj;
+	int i;
+	if (doc == NULL)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "cannot create dictionary without a document");
+	obj = Memento_label(fz_malloc(ctx, sizeof(pdf_obj_dict)), "pdf_obj(dict)");
+	obj->super.refs = 1;
+	obj->super.kind = PDF_DICT;
+	obj->super.flags = 0;
+	obj->doc = doc;
+	obj->parent_num = 0;
+	obj->len = 0;
+	obj->cap = initialcap > 1 ? initialcap : 10;
+	fz_try(ctx)
+	{
+		DICT(obj)->items = Memento_label(fz_malloc_array(ctx, DICT(obj)->cap, struct keyval), "dict_items");
+	}
+	fz_catch(ctx)
+	{
+		fz_free(ctx, obj);
+		fz_rethrow(ctx);
+	}
+	for (i = 0; i < DICT(obj)->cap; i++)
+	{
+		DICT(obj)->items[i].k = NULL;
+		DICT(obj)->items[i].v = NULL;
+	}
+	return &obj->super;
+}
+static void
+pdf_dict_grow(fz_context *ctx, pdf_obj *obj)
+{
+	int i;
+	int new_cap = (DICT(obj)->cap * 3) / 2;
+	DICT(obj)->items = fz_realloc_array(ctx, DICT(obj)->items, new_cap, struct keyval);
+	DICT(obj)->cap = new_cap;
+	for (i = DICT(obj)->len; i < DICT(obj)->cap; i++)
+	{
+		DICT(obj)->items[i].k = NULL;
+		DICT(obj)->items[i].v = NULL;
+	}
+}
+pdf_obj *
+pdf_copy_dict(fz_context *ctx, pdf_obj *obj)
+{
+	pdf_document *doc;
+	pdf_obj *dict;
+	int i, n;
+	RESOLVE(obj);
+	if (!OBJ_IS_DICT(obj))
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "not a dict (%s)", pdf_objkindstr(obj));
+	doc = DICT(obj)->doc;
+	n = pdf_dict_len(ctx, obj);
+	dict = pdf_new_dict(ctx, doc, n);
+	fz_try(ctx)
+		for (i = 0; i < n; i++)
+			pdf_dict_put(ctx, dict, pdf_dict_get_key(ctx, obj, i), pdf_dict_get_val(ctx, obj, i));
+	fz_catch(ctx)
+	{
+		pdf_drop_obj(ctx, dict);
+		fz_rethrow(ctx);
+	}
+	return dict;
+}
+int
+pdf_dict_len(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	if (!OBJ_IS_DICT(obj))
+		return 0;
+	return DICT(obj)->len;
+}
+pdf_obj *
+pdf_dict_get_key(fz_context *ctx, pdf_obj *obj, int i)
+{
+	RESOLVE(obj);
+	if (!OBJ_IS_DICT(obj))
+		return NULL;
+	if (i < 0 || i >= DICT(obj)->len)
+		return NULL;
+	return DICT(obj)->items[i].k;
+}
+pdf_obj *
+pdf_dict_get_val(fz_context *ctx, pdf_obj *obj, int i)
+{
+	RESOLVE(obj);
+	if (!OBJ_IS_DICT(obj))
+		return NULL;
+	if (i < 0 || i >= DICT(obj)->len)
+		return NULL;
+	return DICT(obj)->items[i].v;
+}
+void
+pdf_dict_put_val_null(fz_context *ctx, pdf_obj *obj, int idx)
+{
+	RESOLVE(obj);
+	if (!OBJ_IS_DICT(obj))
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "not a dict (%s)", pdf_objkindstr(obj));
+	if (idx < 0 || idx >= DICT(obj)->len)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "index out of bounds");
+	prepare_object_for_alteration(ctx, obj, NULL);
+	pdf_drop_obj(ctx, DICT(obj)->items[idx].v);
+	DICT(obj)->items[idx].v = PDF_NULL;
+}
+/* Returns 0 <= i < len for key found. Returns -1-len < i <= -1 for key
+* not found, but with insertion point -1-i. */
+static int
+pdf_dict_finds(fz_context *ctx, pdf_obj *obj, const char *key)
+{
+	int len = DICT(obj)->len;
+	if ((obj->flags & PDF_FLAGS_SORTED) && len > 0)
+	{
+		int l = 0;
+		int r = len - 1;
+		if (strcmp(pdf_to_name(ctx, DICT(obj)->items[r].k), key) < 0)
+		{
+			return -1 - (r+1);
+		}
+		while (l <= r)
+		{
+			int m = (l + r) >> 1;
+			int c = -strcmp(pdf_to_name(ctx, DICT(obj)->items[m].k), key);
+			if (c < 0)
+				r = m - 1;
+			else if (c > 0)
+				l = m + 1;
+			else
+				return m;
+		}
+		return -1 - l;
+	}
+	else
+	{
+		int i;
+		for (i = 0; i < len; i++)
+			if (strcmp(pdf_to_name(ctx, DICT(obj)->items[i].k), key) == 0)
+				return i;
+		return -1 - len;
+	}
+}
+static int
+pdf_dict_find(fz_context *ctx, pdf_obj *obj, pdf_obj *key)
+{
+	int len = DICT(obj)->len;
+	if ((obj->flags & PDF_FLAGS_SORTED) && len > 0)
+	{
+		int l = 0;
+		int r = len - 1;
+		pdf_obj *k = DICT(obj)->items[r].k;
+		if (k == key || (k >= PDF_LIMIT && strcmp(NAME(k)->n, PDF_NAME_LIST[(intptr_t)key]) < 0))
+		{
+			return -1 - (r+1);
+		}
+		while (l <= r)
+		{
+			int m = (l + r) >> 1;
+			int c;
+			k = DICT(obj)->items[m].k;
+			c = (k < PDF_LIMIT ? (char *)key-(char *)k : -strcmp(NAME(k)->n, PDF_NAME_LIST[(intptr_t)key]));
+			if (c < 0)
+				r = m - 1;
+			else if (c > 0)
+				l = m + 1;
+			else
+				return m;
+		}
+		return -1 - l;
+	}
+	else
+	{
+		int i;
+		for (i = 0; i < len; i++)
+		{
+			pdf_obj *k = DICT(obj)->items[i].k;
+			if (k < PDF_LIMIT)
+			{
+				if (k == key)
+					return i;
+			}
+			else
+			{
+				if (!strcmp(PDF_NAME_LIST[(intptr_t)key], NAME(k)->n))
+					return i;
+			}
+		}
+		return -1 - len;
+	}
+}
+pdf_obj *
+pdf_dict_gets(fz_context *ctx, pdf_obj *obj, const char *key)
+{
+	int i;
+	RESOLVE(obj);
+	if (!OBJ_IS_DICT(obj))
+		return NULL;
+	if (!key)
+		return NULL;
+	i = pdf_dict_finds(ctx, obj, key);
+	if (i >= 0)
+		return DICT(obj)->items[i].v;
+	return NULL;
+}
+pdf_obj *
+pdf_dict_getp(fz_context *ctx, pdf_obj *obj, const char *keys)
+{
+	char buf[256];
+	char *k, *e;
+	RESOLVE(obj);
+	if (!OBJ_IS_DICT(obj))
+		return NULL;
+	if (strlen(keys)+1 > 256)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "path too long");
+	strcpy(buf, keys);
+	e = buf;
+	while (*e && obj)
+	{
+		k = e;
+		while (*e != '/' && *e != '\0')
+			e++;
+		if (*e == '/')
+		{
+			*e = '\0';
+			e++;
+		}
+		obj = pdf_dict_gets(ctx, obj, k);
+	}
+	return obj;
+}
+pdf_obj *
+pdf_dict_getl(fz_context *ctx, pdf_obj *obj, ...)
+{
+	va_list keys;
+	pdf_obj *key;
+	va_start(keys, obj);
+	while (obj != NULL && (key = va_arg(keys, pdf_obj *)) != NULL)
+	{
+		obj = pdf_dict_get(ctx, obj, key);
+	}
+	va_end(keys);
+	return obj;
+}
+pdf_obj *
+pdf_dict_get(fz_context *ctx, pdf_obj *obj, pdf_obj *key)
+{
+	int i;
+	RESOLVE(obj);
+	if (!OBJ_IS_DICT(obj))
+		return NULL;
+	if (!OBJ_IS_NAME(key))
+		return NULL;
+	if (key < PDF_LIMIT)
+		i = pdf_dict_find(ctx, obj, key);
+	else
+		i = pdf_dict_finds(ctx, obj, pdf_to_name(ctx, key));
+	if (i >= 0)
+		return DICT(obj)->items[i].v;
+	return NULL;
+}
+pdf_obj *
+pdf_dict_getsa(fz_context *ctx, pdf_obj *obj, const char *key, const char *abbrev)
+{
+	pdf_obj *v;
+	v = pdf_dict_gets(ctx, obj, key);
+	if (v)
+		return v;
+	return pdf_dict_gets(ctx, obj, abbrev);
+}
+pdf_obj *
+pdf_dict_geta(fz_context *ctx, pdf_obj *obj, pdf_obj *key, pdf_obj *abbrev)
+{
+	pdf_obj *v;
+	/* ISO 32000-2:2020 (PDF 2.0) - abbreviated names take precedence. */
+	v = pdf_dict_get(ctx, obj, abbrev);
+	if (v)
+		return v;
+	return pdf_dict_get(ctx, obj, key);
+}
+static void
+pdf_dict_get_put(fz_context *ctx, pdf_obj *obj, pdf_obj *key, pdf_obj *val, pdf_obj **old_val)
+{
+	int i;
+	if (old_val)
+		*old_val = NULL;
+	RESOLVE(obj);
+	if (!OBJ_IS_DICT(obj))
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "not a dict (%s)", pdf_objkindstr(obj));
+	if (!OBJ_IS_NAME(key))
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "key is not a name (%s)", pdf_objkindstr(obj));
+	if (DICT(obj)->len > 100 && !(obj->flags & PDF_FLAGS_SORTED))
+		pdf_sort_dict(ctx, obj);
+	if (key < PDF_LIMIT)
+		i = pdf_dict_find(ctx, obj, key);
+	else
+		i = pdf_dict_finds(ctx, obj, pdf_to_name(ctx, key));
+	prepare_object_for_alteration(ctx, obj, val);
+	if (i >= 0 && i < DICT(obj)->len)
+	{
+		if (DICT(obj)->items[i].v != val)
+		{
+			pdf_obj *d = DICT(obj)->items[i].v;
+			DICT(obj)->items[i].v = pdf_keep_obj(ctx, val);
+			if (old_val)
+				*old_val = d;
+			else
+				pdf_drop_obj(ctx, d);
+		}
+	}
+	else
+	{
+		if (DICT(obj)->len + 1 > DICT(obj)->cap)
+			pdf_dict_grow(ctx, obj);
+		i = -1-i;
+		if ((obj->flags & PDF_FLAGS_SORTED) && DICT(obj)->len > 0)
+			memmove(&DICT(obj)->items[i + 1],
+					&DICT(obj)->items[i],
+					(DICT(obj)->len - i) * sizeof(struct keyval));
+		DICT(obj)->items[i].k = pdf_keep_obj(ctx, key);
+		DICT(obj)->items[i].v = pdf_keep_obj(ctx, val);
+		DICT(obj)->len ++;
+	}
+}
+void
+pdf_dict_put(fz_context *ctx, pdf_obj *obj, pdf_obj *key, pdf_obj *val)
+{
+	pdf_dict_get_put(ctx, obj, key, val, NULL);
+}
+void
+pdf_dict_put_drop(fz_context *ctx, pdf_obj *obj, pdf_obj *key, pdf_obj *val)
+{
+	fz_try(ctx)
+		pdf_dict_get_put(ctx, obj, key, val, NULL);
+	fz_always(ctx)
+		pdf_drop_obj(ctx, val);
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+}
+void
+pdf_dict_get_put_drop(fz_context *ctx, pdf_obj *obj, pdf_obj *key, pdf_obj *val, pdf_obj **old_val)
+{
+	fz_try(ctx)
+		pdf_dict_get_put(ctx, obj, key, val, old_val);
+	fz_always(ctx)
+		pdf_drop_obj(ctx, val);
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+}
+void
+pdf_dict_puts(fz_context *ctx, pdf_obj *obj, const char *key, pdf_obj *val)
+{
+	pdf_obj *keyobj;
+	RESOLVE(obj);
+	if (!OBJ_IS_DICT(obj))
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "not a dict (%s)", pdf_objkindstr(obj));
+	keyobj = pdf_new_name(ctx, key);
+	fz_try(ctx)
+		pdf_dict_put(ctx, obj, keyobj, val);
+	fz_always(ctx)
+		pdf_drop_obj(ctx, keyobj);
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+}
+void
+pdf_dict_puts_drop(fz_context *ctx, pdf_obj *obj, const char *key, pdf_obj *val)
+{
+	pdf_obj *keyobj;
+	RESOLVE(obj);
+	if (!OBJ_IS_DICT(obj))
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "not a dict (%s)", pdf_objkindstr(obj));
+	keyobj = pdf_new_name(ctx, key);
+	fz_var(keyobj);
+	fz_try(ctx)
+		pdf_dict_put(ctx, obj, keyobj, val);
+	fz_always(ctx)
+	{
+		pdf_drop_obj(ctx, keyobj);
+		pdf_drop_obj(ctx, val);
+	}
+	fz_catch(ctx)
+	{
+		fz_rethrow(ctx);
+	}
+}
+void
+pdf_dict_putp(fz_context *ctx, pdf_obj *obj, const char *keys, pdf_obj *val)
+{
+	pdf_document *doc;
+	char buf[256];
+	char *k, *e;
+	pdf_obj *cobj = NULL;
+	RESOLVE(obj);
+	if (!OBJ_IS_DICT(obj))
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "not a dict (%s)", pdf_objkindstr(obj));
+	if (strlen(keys)+1 > 256)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "path too long");
+	doc = DICT(obj)->doc;
+	strcpy(buf, keys);
+	e = buf;
+	while (*e)
+	{
+		k = e;
+		while (*e != '/' && *e != '\0')
+			e++;
+		if (*e == '/')
+		{
+			*e = '\0';
+			e++;
+		}
+		if (*e)
+		{
+			/* Not the last key in the key path. Create subdict if not already there. */
+			cobj = pdf_dict_gets(ctx, obj, k);
+			if (!pdf_is_dict(ctx, cobj))
+			{
+				cobj = pdf_new_dict(ctx, doc, 1);
+				fz_try(ctx)
+					pdf_dict_puts(ctx, obj, k, cobj);
+				fz_always(ctx)
+					pdf_drop_obj(ctx, cobj);
+				fz_catch(ctx)
+					fz_rethrow(ctx);
+			}
+			/* Move to subdict */
+			obj = cobj;
+		}
+		else
+		{
+			/* Last key. Use it to store the value */
+			/* Use val = NULL to request delete */
+			if (val)
+				pdf_dict_puts(ctx, obj, k, val);
+			else
+				pdf_dict_dels(ctx, obj, k);
+		}
+	}
+}
+void
+pdf_dict_putp_drop(fz_context *ctx, pdf_obj *obj, const char *keys, pdf_obj *val)
+{
+	fz_try(ctx)
+		pdf_dict_putp(ctx, obj, keys, val);
+	fz_always(ctx)
+		pdf_drop_obj(ctx, val);
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+}
+static void
+pdf_dict_vputl(fz_context *ctx, pdf_obj *obj, pdf_obj *val, va_list keys)
+{
+	pdf_obj *key;
+	pdf_obj *next_key;
+	pdf_obj *next_obj;
+	pdf_document *doc;
+	RESOLVE(obj);
+	if (!OBJ_IS_DICT(obj))
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "not a dict (%s)", pdf_objkindstr(obj));
+	doc = DICT(obj)->doc;
+	key = va_arg(keys, pdf_obj *);
+	if (key == NULL)
+		return;
+	while ((next_key = va_arg(keys, pdf_obj *)) != NULL)
+	{
+		next_obj = pdf_dict_get(ctx, obj, key);
+		if (next_obj == NULL)
+			goto new_obj;
+		obj = next_obj;
+		key = next_key;
+	}
+	pdf_dict_put(ctx, obj, key, val);
+	return;
+new_obj:
+	/* We have to create entries */
+	do
+	{
+		next_obj = pdf_new_dict(ctx, doc, 1);
+		pdf_dict_put_drop(ctx, obj, key, next_obj);
+		obj = next_obj;
+		key = next_key;
+	}
+	while ((next_key = va_arg(keys, pdf_obj *)) != NULL);
+	pdf_dict_put(ctx, obj, key, val);
+	return;
+}
+void
+pdf_dict_putl(fz_context *ctx, pdf_obj *obj, pdf_obj *val, ...)
+{
+	va_list keys;
+	va_start(keys, val);
+	fz_try(ctx)
+		pdf_dict_vputl(ctx, obj, val, keys);
+	fz_always(ctx)
+		va_end(keys);
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+}
+void
+pdf_dict_putl_drop(fz_context *ctx, pdf_obj *obj, pdf_obj *val, ...)
+{
+	va_list keys;
+	va_start(keys, val);
+	fz_try(ctx)
+		pdf_dict_vputl(ctx, obj, val, keys);
+	fz_always(ctx)
+	{
+		pdf_drop_obj(ctx, val);
+		va_end(keys);
+	}
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+}
+void
+pdf_dict_dels(fz_context *ctx, pdf_obj *obj, const char *key)
+{
+	int i;
+	RESOLVE(obj);
+	if (!OBJ_IS_DICT(obj))
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "not a dict (%s)", pdf_objkindstr(obj));
+	if (!key)
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "key is null");
+	prepare_object_for_alteration(ctx, obj, NULL);
+	i = pdf_dict_finds(ctx, obj, key);
+	if (i >= 0)
+	{
+		pdf_drop_obj(ctx, DICT(obj)->items[i].k);
+		pdf_drop_obj(ctx, DICT(obj)->items[i].v);
+		obj->flags &= ~PDF_FLAGS_SORTED;
+		DICT(obj)->items[i] = DICT(obj)->items[DICT(obj)->len-1];
+		DICT(obj)->len --;
+	}
+}
+void
+pdf_dict_del(fz_context *ctx, pdf_obj *obj, pdf_obj *key)
+{
+	if (!OBJ_IS_NAME(key))
+		fz_throw(ctx, FZ_ERROR_ARGUMENT, "key is not a name (%s)", pdf_objkindstr(key));
+	if (key < PDF_LIMIT)
+		pdf_dict_dels(ctx, obj, PDF_NAME_LIST[(intptr_t)key]);
+	else
+		pdf_dict_dels(ctx, obj, NAME(key)->n);
+}
+void
+pdf_sort_dict(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	if (!OBJ_IS_DICT(obj))
+		return;
+	if (!(obj->flags & PDF_FLAGS_SORTED))
+	{
+		qsort(DICT(obj)->items, DICT(obj)->len, sizeof(struct keyval), keyvalcmp);
+		obj->flags |= PDF_FLAGS_SORTED;
+	}
+}
+pdf_obj *
+pdf_deep_copy_obj(fz_context *ctx, pdf_obj *obj)
+{
+	if (obj < PDF_LIMIT)
+	{
+		return obj;
+	}
+	if (obj->kind == PDF_DICT)
+	{
+		pdf_document *doc = DICT(obj)->doc;
+		int n = pdf_dict_len(ctx, obj);
+		pdf_obj *dict = pdf_new_dict(ctx, doc, n);
+		int i;
+		fz_try(ctx)
+			for (i = 0; i < n; i++)
+			{
+				pdf_obj *obj_copy = pdf_deep_copy_obj(ctx, pdf_dict_get_val(ctx, obj, i));
+				pdf_dict_put_drop(ctx, dict, pdf_dict_get_key(ctx, obj, i), obj_copy);
+			}
+		fz_catch(ctx)
+		{
+			pdf_drop_obj(ctx, dict);
+			fz_rethrow(ctx);
+		}
+		DICT(dict)->parent_num = DICT(obj)->parent_num;
+		return dict;
+	}
+	else if (obj->kind == PDF_ARRAY)
+	{
+		pdf_document *doc = ARRAY(obj)->doc;
+		int n = pdf_array_len(ctx, obj);
+		pdf_obj *arr = pdf_new_array(ctx, doc, n);
+		int i;
+		fz_try(ctx)
+			for (i = 0; i < n; i++)
+			{
+				pdf_obj *obj_copy = pdf_deep_copy_obj(ctx, pdf_array_get(ctx, obj, i));
+				pdf_array_push_drop(ctx, arr, obj_copy);
+			}
+		fz_catch(ctx)
+		{
+			pdf_drop_obj(ctx, arr);
+			fz_rethrow(ctx);
+		}
+		ARRAY(arr)->parent_num = ARRAY(obj)->parent_num;
+		return arr;
+	}
+	else
+	{
+		return pdf_keep_obj(ctx, obj);
+	}
+}
+/* obj marking and unmarking functions - to avoid infinite recursions. */
+int
+pdf_obj_marked(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	if (obj < PDF_LIMIT)
+		return 0;
+	return !!(obj->flags & PDF_FLAGS_MARKED);
+}
+int
+pdf_mark_obj(fz_context *ctx, pdf_obj *obj)
+{
+	int marked;
+	RESOLVE(obj);
+	if (obj < PDF_LIMIT)
+		return 0;
+	marked = !!(obj->flags & PDF_FLAGS_MARKED);
+	obj->flags |= PDF_FLAGS_MARKED;
+	return marked;
+}
+void
+pdf_unmark_obj(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	if (obj < PDF_LIMIT)
+		return;
+	obj->flags &= ~PDF_FLAGS_MARKED;
+}
+int
+pdf_cycle(fz_context *ctx, pdf_cycle_list *here, pdf_cycle_list *up, pdf_obj *obj)
+{
+	int num = pdf_to_num(ctx, obj);
+	if (num > 0)
+	{
+		pdf_cycle_list *x = up;
+		while (x)
+		{
+			if (x->num == num)
+				return 1;
+			x = x->up;
+		}
+	}
+	here->up = up;
+	here->num = num;
+	return 0;
+}
+pdf_mark_bits *
+pdf_new_mark_bits(fz_context *ctx, pdf_document *doc)
+{
+	int n = pdf_xref_len(ctx, doc);
+	int nb = (n + 7) >> 3;
+	pdf_mark_bits *marks = fz_calloc(ctx, offsetof(pdf_mark_bits, bits) + nb, 1);
+	marks->len = n;
+	return marks;
+}
+void
+pdf_drop_mark_bits(fz_context *ctx, pdf_mark_bits *marks)
+{
+	fz_free(ctx, marks);
+}
+void pdf_mark_bits_reset(fz_context *ctx, pdf_mark_bits *marks)
+{
+	memset(marks->bits, 0, (marks->len + 7) >> 3);
+}
+int pdf_mark_bits_set(fz_context *ctx, pdf_mark_bits *marks, pdf_obj *obj)
+{
+	int num = pdf_to_num(ctx, obj);
+	if (num > 0 && num < marks->len)
+	{
+		int x = num >> 3;
+		int m = 1 << (num & 7);
+		if (marks->bits[x] & m)
+			return 1;
+		marks->bits[x] |= m;
+	}
+	return 0;
+}
+void pdf_mark_bits_clear(fz_context *ctx, pdf_mark_bits *marks, pdf_obj *obj)
+{
+	int num = pdf_to_num(ctx, obj);
+	if (num > 0 && num < marks->len)
+	{
+		int x = num >> 3;
+		int m = 0xff ^ (1 << (num & 7));
+		marks->bits[x] &= m;
+	}
+}
+int
+pdf_mark_list_push(fz_context *ctx, pdf_mark_list *marks, pdf_obj *obj)
+{
+	int num = pdf_to_num(ctx, obj);
+	int i;
+	/* If object is not an indirection, then no record to check.
+	 * We must still push it to allow pops to stay in sync. */
+	if (num > 0)
+	{
+		/* Note: this is slow, if the mark list is expected to be big use pdf_mark_bits instead! */
+		for (i = 0; i < marks->len; ++i)
+			if (marks->list[i] == num)
+				return 1;
+	}
+	if (marks->len == marks->max)
+	{
+		int newsize = marks->max << 1;
+		if (marks->list == marks->local_list)
+		{
+			marks->list = fz_malloc_array(ctx, newsize, int);
+			memcpy(marks->list, marks->local_list, sizeof(marks->local_list));
+		}
+		else
+			marks->list = fz_realloc_array(ctx, marks->list, newsize, int);
+		marks->max = newsize;
+	}
+	marks->list[marks->len++] = num;
+	return 0;
+}
+void
+pdf_mark_list_pop(fz_context *ctx, pdf_mark_list *marks)
+{
+	--marks->len;
+}
+int
+pdf_mark_list_check(fz_context *ctx, pdf_mark_list *marks, pdf_obj *obj)
+{
+	if (pdf_mark_list_push(ctx, marks, obj))
+		return 1;
+	pdf_mark_list_pop(ctx, marks);
+	return 0;
+}
+void
+pdf_mark_list_init(fz_context *ctx, pdf_mark_list *marks)
+{
+	marks->len = 0;
+	marks->max = nelem(marks->local_list);
+	marks->list = marks->local_list;
+}
+void
+pdf_mark_list_free(fz_context *ctx, pdf_mark_list *marks)
+{
+	if (marks->list != marks->local_list)
+		fz_free(ctx, marks->list);
+	marks->len = 0;
+	marks->max = 0;
+	marks->list = NULL;
+}
+void
+pdf_set_obj_memo(fz_context *ctx, pdf_obj *obj, int bit, int memo)
+{
+	if (obj < PDF_LIMIT)
+		return;
+	bit <<= 1;
+	obj->flags |= PDF_FLAGS_MEMO_BASE << bit;
+	if (memo)
+		obj->flags |= PDF_FLAGS_MEMO_BASE_BOOL << bit;
+	else
+		obj->flags &= ~(PDF_FLAGS_MEMO_BASE_BOOL << bit);
+}
+int
+pdf_obj_memo(fz_context *ctx, pdf_obj *obj, int bit, int *memo)
+{
+	if (obj < PDF_LIMIT)
+		return 0;
+	bit <<= 1;
+	if (!(obj->flags & (PDF_FLAGS_MEMO_BASE<<bit)))
+		return 0;
+	*memo = !!(obj->flags & (PDF_FLAGS_MEMO_BASE_BOOL<<bit));
+	return 1;
+}
+/* obj dirty bit support. */
+int pdf_obj_is_dirty(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	if (obj < PDF_LIMIT)
+		return 0;
+	return !!(obj->flags & PDF_FLAGS_DIRTY);
+}
+void pdf_dirty_obj(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	if (obj < PDF_LIMIT)
+		return;
+	obj->flags |= PDF_FLAGS_DIRTY;
+}
+void pdf_clean_obj(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	if (obj < PDF_LIMIT)
+		return;
+	obj->flags &= ~PDF_FLAGS_DIRTY;
+}
+static void
+pdf_drop_array(fz_context *ctx, pdf_obj *obj)
+{
+	int i;
+	for (i = 0; i < DICT(obj)->len; i++)
+		pdf_drop_obj(ctx, ARRAY(obj)->items[i]);
+	fz_free(ctx, DICT(obj)->items);
+	fz_free(ctx, obj);
+}
+static void
+pdf_drop_dict(fz_context *ctx, pdf_obj *obj)
+{
+	int i;
+	for (i = 0; i < DICT(obj)->len; i++) {
+		pdf_drop_obj(ctx, DICT(obj)->items[i].k);
+		pdf_drop_obj(ctx, DICT(obj)->items[i].v);
+	}
+	fz_free(ctx, DICT(obj)->items);
+	fz_free(ctx, obj);
+}
+pdf_obj *
+pdf_keep_obj(fz_context *ctx, pdf_obj *obj)
+{
+	if (obj >= PDF_LIMIT)
+		return fz_keep_imp16(ctx, obj, &obj->refs);
+	return obj;
+}
+void
+pdf_drop_obj(fz_context *ctx, pdf_obj *obj)
+{
+	if (obj >= PDF_LIMIT)
+	{
+		if (fz_drop_imp16(ctx, obj, &obj->refs))
+		{
+			if (obj->kind == PDF_ARRAY)
+				pdf_drop_array(ctx, obj);
+			else if (obj->kind == PDF_DICT)
+				pdf_drop_dict(ctx, obj);
+			else if (obj->kind == PDF_STRING)
+			{
+				fz_free(ctx, STRING(obj)->text);
+				fz_free(ctx, obj);
+			}
+			else
+				fz_free(ctx, obj);
+		}
+	}
+}
+pdf_obj *
+pdf_drop_singleton_obj(fz_context *ctx, pdf_obj *obj)
+{
+	int drop;
+	/* If an object is < PDF_LIMIT, then it's a 'common' name or
+	 * true or false. No point in dropping these as it
+	 * won't save any memory. */
+	if (obj < PDF_LIMIT)
+		return obj;
+	/* See if it's a singleton object. We can only drop if
+	 * it's a singleton object. If not, just exit leaving
+	 * everything unchanged. */
+	fz_lock(ctx, FZ_LOCK_ALLOC);
+	drop = (obj->refs == 1);
+	fz_unlock(ctx, FZ_LOCK_ALLOC);
+	if (!drop)
+		return obj;
+	/* So drop the object! */
+	if (obj->kind == PDF_ARRAY)
+		pdf_drop_array(ctx, obj);
+	else if (obj->kind == PDF_DICT)
+		pdf_drop_dict(ctx, obj);
+	else if (obj->kind == PDF_STRING)
+	{
+		fz_free(ctx, STRING(obj)->text);
+		fz_free(ctx, obj);
+	}
+	else
+		fz_free(ctx, obj);
+	return NULL;
+}
+/*
+	Recurse through the object structure setting the node's parent_num to num.
+	parent_num is used when a subobject is to be changed during a document edit.
+	The whole containing hierarchy is moved to the incremental xref section, so
+	to be later written out as an incremental file update.
+*/
+void
+pdf_set_obj_parent(fz_context *ctx, pdf_obj *obj, int num)
+{
+	int n, i;
+	if (obj < PDF_LIMIT)
+		return;
+	switch (obj->kind)
+	{
+	case PDF_ARRAY:
+		ARRAY(obj)->parent_num = num;
+		n = pdf_array_len(ctx, obj);
+		for (i = 0; i < n; i++)
+			pdf_set_obj_parent(ctx, pdf_array_get(ctx, obj, i), num);
+		break;
+	case PDF_DICT:
+		DICT(obj)->parent_num = num;
+		n = pdf_dict_len(ctx, obj);
+		for (i = 0; i < n; i++)
+			pdf_set_obj_parent(ctx, pdf_dict_get_val(ctx, obj, i), num);
+		break;
+	}
+}
+int pdf_obj_parent_num(fz_context *ctx, pdf_obj *obj)
+{
+	if (obj < PDF_LIMIT)
+		return 0;
+	switch (obj->kind)
+	{
+	case PDF_INDIRECT:
+		return REF(obj)->num;
+	case PDF_ARRAY:
+		return ARRAY(obj)->parent_num;
+	case PDF_DICT:
+		return DICT(obj)->parent_num;
+	default:
+		return 0;
+	}
+}
+/* Pretty printing objects */
+struct fmt
+{
+	char *buf; /* original static buffer */
+	char *ptr; /* buffer we're writing to, maybe dynamically reallocated */
+	size_t cap;
+	size_t len;
+	int indent;
+	int tight;
+	int ascii;
+	int col;
+	int sep;
+	int last;
+	pdf_crypt *crypt;
+	int num;
+	int gen;
+};
+static void fmt_obj(fz_context *ctx, struct fmt *fmt, pdf_obj *obj);
+static inline int iswhite(int ch)
+{
+	return
+		ch == '\000' ||
+		ch == '\011' ||
+		ch == '\012' ||
+		ch == '\014' ||
+		ch == '\015' ||
+		ch == '\040';
+}
+static inline int isdelim(int ch)
+{
+	return
+		ch == '(' || ch == ')' ||
+		ch == '<' || ch == '>' ||
+		ch == '[' || ch == ']' ||
+		ch == '{' || ch == '}' ||
+		ch == '/' ||
+		ch == '%';
+}
+static inline void fmt_putc(fz_context *ctx, struct fmt *fmt, int c)
+{
+	if (fmt->sep && !isdelim(fmt->last) && !iswhite(fmt->last) && !isdelim(c) && !iswhite(c)) {
+		fmt->sep = 0;
+		fmt_putc(ctx, fmt, ' ');
+	}
+	fmt->sep = 0;
+	if (fmt->len >= fmt->cap)
+	{
+		fmt->cap *= 2;
+		if (fmt->buf == fmt->ptr)
+		{
+			fmt->ptr = Memento_label(fz_malloc(ctx, fmt->cap), "fmt_ptr");
+			memcpy(fmt->ptr, fmt->buf, fmt->len);
+		}
+		else
+		{
+			fmt->ptr = fz_realloc(ctx, fmt->ptr, fmt->cap);
+		}
+	}
+	fmt->ptr[fmt->len] = c;
+	if (c == '\n')
+		fmt->col = 0;
+	else
+		fmt->col ++;
+	fmt->len ++;
+	fmt->last = c;
+}
+static inline void fmt_indent(fz_context *ctx, struct fmt *fmt)
+{
+	int i = fmt->indent;
+	while (i--) {
+		fmt_putc(ctx, fmt, ' ');
+		fmt_putc(ctx, fmt, ' ');
+	}
+}
+static inline void fmt_puts(fz_context *ctx, struct fmt *fmt, char *s)
+{
+	while (*s)
+		fmt_putc(ctx, fmt, *s++);
+}
+static inline void fmt_sep(fz_context *ctx, struct fmt *fmt)
+{
+	fmt->sep = 1;
+}
+static int is_binary_string(fz_context *ctx, pdf_obj *obj)
+{
+	unsigned char *s = (unsigned char *)pdf_to_str_buf(ctx, obj);
+	size_t i, n = pdf_to_str_len(ctx, obj);
+	for (i = 0; i < n; ++i)
+	{
+		if (s[i] > 126) return 1;
+		if (s[i] < 32 && (s[i] != '\t' && s[i] != '\n' && s[i] != '\r')) return 1;
+	}
+	return 0;
+}
+static int is_longer_than_hex(fz_context *ctx, pdf_obj *obj)
+{
+	unsigned char *s = (unsigned char *)pdf_to_str_buf(ctx, obj);
+	size_t i, n = pdf_to_str_len(ctx, obj);
+	size_t m = 0;
+	for (i = 0; i < n; ++i)
+	{
+		if (s[i] > 126)
+			m += 4;
+		else if (s[i] == 0)
+			m += 4;
+		else if (strchr("\n\r\t\b\f()\\", s[i]))
+			m += 2;
+		else if (s[i] < 32)
+			m += 4;
+		else
+			m += 1;
+	}
+	return m > (n * 2);
+}
+static void fmt_str_out(fz_context *ctx, void *fmt_, const unsigned char *s, size_t n)
+{
+	struct fmt *fmt = (struct fmt *)fmt_;
+	int c;
+	size_t i;
+	for (i = 0; i < n; i++)
+	{
+		c = (unsigned char)s[i];
+		if (c == '\n')
+			fmt_puts(ctx, fmt, "\\n");
+		else if (c == '\r')
+			fmt_puts(ctx, fmt, "\\r");
+		else if (c == '\t')
+			fmt_puts(ctx, fmt, "\\t");
+		else if (c == '\b')
+			fmt_puts(ctx, fmt, "\\b");
+		else if (c == '\f')
+			fmt_puts(ctx, fmt, "\\f");
+		else if (c == '(')
+			fmt_puts(ctx, fmt, "\\(");
+		else if (c == ')')
+			fmt_puts(ctx, fmt, "\\)");
+		else if (c == '\\')
+			fmt_puts(ctx, fmt, "\\\\");
+		else if (c < 32 || c >= 127) {
+			fmt_putc(ctx, fmt, '\\');
+			fmt_putc(ctx, fmt, '0' + ((c / 64) & 7));
+			fmt_putc(ctx, fmt, '0' + ((c / 8) & 7));
+			fmt_putc(ctx, fmt, '0' + ((c) & 7));
+		}
+		else
+			fmt_putc(ctx, fmt, c);
+	}
+}
+static void fmt_str(fz_context *ctx, struct fmt *fmt, pdf_obj *obj)
+{
+	unsigned char *s = (unsigned char *)pdf_to_str_buf(ctx, obj);
+	size_t n = pdf_to_str_len(ctx, obj);
+	fmt_putc(ctx, fmt, '(');
+	pdf_encrypt_data(ctx, fmt->crypt, fmt->num, fmt->gen, fmt_str_out, fmt, s, n);
+	fmt_putc(ctx, fmt, ')');
+}
+static void fmt_hex_out(fz_context *ctx, void *arg, const unsigned char *s, size_t n)
+{
+	struct fmt *fmt = (struct fmt *)arg;
+	size_t i;
+	int b, c;
+	for (i = 0; i < n; i++) {
+		b = (unsigned char) s[i];
+		c = (b >> 4) & 0x0f;
+		fmt_putc(ctx, fmt, c < 0xA ? c + '0' : c + 'A' - 0xA);
+		c = (b) & 0x0f;
+		fmt_putc(ctx, fmt, c < 0xA ? c + '0' : c + 'A' - 0xA);
+	}
+}
+static void fmt_hex(fz_context *ctx, struct fmt *fmt, pdf_obj *obj)
+{
+	unsigned char *s = (unsigned char *)pdf_to_str_buf(ctx, obj);
+	size_t n = pdf_to_str_len(ctx, obj);
+	fmt_putc(ctx, fmt, '<');
+	pdf_encrypt_data(ctx, fmt->crypt, fmt->num, fmt->gen, fmt_hex_out, fmt, s, n);
+	fmt_putc(ctx, fmt, '>');
+}
+static void fmt_name(fz_context *ctx, struct fmt *fmt, pdf_obj *obj)
+{
+	unsigned char *s = (unsigned char *) pdf_to_name(ctx, obj);
+	int i, c;
+	fmt_putc(ctx, fmt, '/');
+	for (i = 0; s[i]; i++)
+	{
+		if (isdelim(s[i]) || iswhite(s[i]) ||
+			s[i] == '#' || s[i] < 32 || s[i] >= 127)
+		{
+			fmt_putc(ctx, fmt, '#');
+			c = (s[i] >> 4) & 0xf;
+			fmt_putc(ctx, fmt, c < 0xA ? c + '0' : c + 'A' - 0xA);
+			c = s[i] & 0xf;
+			fmt_putc(ctx, fmt, c < 0xA ? c + '0' : c + 'A' - 0xA);
+		}
+		else
+		{
+			fmt_putc(ctx, fmt, s[i]);
+		}
+	}
+	fmt->sep = 1;
+}
+static void fmt_array(fz_context *ctx, struct fmt *fmt, pdf_obj *obj)
+{
+	int i, n;
+	n = pdf_array_len(ctx, obj);
+	if (fmt->tight) {
+		fmt_putc(ctx, fmt, '[');
+		for (i = 0; i < n; i++) {
+			fmt_obj(ctx, fmt, pdf_array_get(ctx, obj, i));
+		}
+		fmt_putc(ctx, fmt, ']');
+	}
+	else {
+		fmt_putc(ctx, fmt, '[');
+		fmt->indent ++;
+		for (i = 0; i < n; i++) {
+			if (fmt->col > 60) {
+				fmt_putc(ctx, fmt, '\n');
+				fmt_indent(ctx, fmt);
+			} else {
+				fmt_putc(ctx, fmt, ' ');
+			}
+			fmt_obj(ctx, fmt, pdf_array_get(ctx, obj, i));
+		}
+		fmt->indent --;
+		fmt_putc(ctx, fmt, ' ');
+		fmt_putc(ctx, fmt, ']');
+		fmt_sep(ctx, fmt);
+	}
+}
+static int is_signature(fz_context *ctx, pdf_obj *obj)
+{
+	if (pdf_dict_get(ctx, obj, PDF_NAME(Type)) ==  PDF_NAME(Sig))
+		if (pdf_dict_get(ctx, obj, PDF_NAME(Contents)) && pdf_dict_get(ctx, obj, PDF_NAME(ByteRange)) && pdf_dict_get(ctx, obj, PDF_NAME(Filter)))
+			return 1;
+	return 0;
+}
+static void fmt_dict(fz_context *ctx, struct fmt *fmt, pdf_obj *obj)
+{
+	int i, n;
+	pdf_obj *key, *val;
+	int skip = 0;
+	pdf_obj *type = pdf_dict_get(ctx, obj, PDF_NAME(Type));
+	n = pdf_dict_len(ctx, obj);
+	/* Open the dictionary.
+	 * We spot /Type and /Subtype here so we can sent those first,
+	 * in order. The hope is this will improve compression, because
+	 * we'll be consistently sending those first. */
+	if (fmt->tight) {
+		fmt_puts(ctx, fmt, "<<");
+		if (type)
+		{
+			pdf_obj *subtype = pdf_dict_get(ctx, obj, PDF_NAME(Subtype));
+			fmt_obj(ctx, fmt, PDF_NAME(Type));
+			fmt_obj(ctx, fmt, type);
+			if (subtype)
+			{
+				fmt_obj(ctx, fmt, PDF_NAME(Subtype));
+				fmt_obj(ctx, fmt, subtype);
+				skip |= 2; /* Skip Subtype */
+			}
+			skip |= 1; /* Skip Type */
+		}
+		/* Now send all the key/value pairs except the ones we have decided to
+		 * skip. */
+		for (i = 0; i < n; i++) {
+			key = pdf_dict_get_key(ctx, obj, i);
+			if (skip)
+			{
+				if ((skip & 1) != 0 && key == PDF_NAME(Type))
+					continue;
+				if ((skip & 2) != 0 && key == PDF_NAME(Subtype))
+					continue;
+			}
+			val = pdf_dict_get_val(ctx, obj, i);
+			fmt_obj(ctx, fmt, key);
+			if (key == PDF_NAME(Contents) && is_signature(ctx, obj))
+			{
+				pdf_crypt *crypt = fmt->crypt;
+				fz_try(ctx)
+				{
+					fmt->crypt = NULL;
+					fmt_obj(ctx, fmt, val);
+				}
+				fz_always(ctx)
+					fmt->crypt = crypt;
+				fz_catch(ctx)
+					fz_rethrow(ctx);
+			}
+			else
+				fmt_obj(ctx, fmt, val);
+		}
+		fmt_puts(ctx, fmt, ">>");
+	}
+	else /* Not tight, send it simply. */
+	{
+		fmt_puts(ctx, fmt, "<<\n");
+		fmt->indent ++;
+		for (i = 0; i < n; i++) {
+			key = pdf_dict_get_key(ctx, obj, i);
+			val = pdf_dict_get_val(ctx, obj, i);
+			fmt_indent(ctx, fmt);
+			fmt_obj(ctx, fmt, key);
+			fmt_putc(ctx, fmt, ' ');
+			if (!pdf_is_indirect(ctx, val) && pdf_is_array(ctx, val))
+				fmt->indent ++;
+			if (key == PDF_NAME(Contents) && is_signature(ctx, obj))
+			{
+				pdf_crypt *crypt = fmt->crypt;
+				fz_try(ctx)
+				{
+					fmt->crypt = NULL;
+					fmt_obj(ctx, fmt, val);
+				}
+				fz_always(ctx)
+					fmt->crypt = crypt;
+				fz_catch(ctx)
+					fz_rethrow(ctx);
+			}
+			else
+				fmt_obj(ctx, fmt, val);
+			fmt_putc(ctx, fmt, '\n');
+			if (!pdf_is_indirect(ctx, val) && pdf_is_array(ctx, val))
+				fmt->indent --;
+		}
+		fmt->indent --;
+		fmt_indent(ctx, fmt);
+		fmt_puts(ctx, fmt, ">>");
+	}
+}
+static void fmt_obj(fz_context *ctx, struct fmt *fmt, pdf_obj *obj)
+{
+	char buf[256];
+	if (obj == PDF_NULL)
+	{
+		fmt_puts(ctx, fmt, "null");
+		fmt->sep = 1;
+		return;
+	}
+	else if (obj == PDF_TRUE)
+	{
+		fmt_puts(ctx, fmt, "true");
+		fmt->sep = 1;
+		return;
+	}
+	else if (obj == PDF_FALSE)
+	{
+		fmt_puts(ctx, fmt, "false");
+		fmt->sep = 1;
+		return;
+	}
+	else if (pdf_is_indirect(ctx, obj))
+	{
+		int n = pdf_to_num(ctx, obj);
+		int g = pdf_to_gen(ctx, obj);
+		fz_snprintf(buf, sizeof buf, "%d %d R", n, g);
+		fmt_puts(ctx, fmt, buf);
+		fmt->sep = 1;
+		return;
+	}
+	else if (pdf_is_int(ctx, obj))
+	{
+		fz_snprintf(buf, sizeof buf, "%ld", pdf_to_int64(ctx, obj));
+		fmt_puts(ctx, fmt, buf);
+		fmt->sep = 1;
+		return;
+	}
+	else if (pdf_is_real(ctx, obj))
+	{
+		float f = pdf_to_real(ctx, obj);
+		if (f == (int)f)
+			fz_snprintf(buf, sizeof buf, "%d", (int)f);
+		else
+			fz_snprintf(buf, sizeof buf, "%g", f);
+		fmt_puts(ctx, fmt, buf);
+		fmt->sep = 1;
+		return;
+	}
+	else if (pdf_is_string(ctx, obj))
+	{
+		unsigned char *str = (unsigned char *)pdf_to_str_buf(ctx, obj);
+		if (fmt->crypt
+			|| (fmt->ascii && is_binary_string(ctx, obj))
+			|| (str[0]==0xff && str[1]==0xfe)
+			|| (str[0]==0xfe && str[1] == 0xff)
+			|| is_longer_than_hex(ctx, obj)
+			)
+			fmt_hex(ctx, fmt, obj);
+		else
+			fmt_str(ctx, fmt, obj);
+	}
+	else if (pdf_is_name(ctx, obj))
+		fmt_name(ctx, fmt, obj);
+	else if (pdf_is_array(ctx, obj))
+		fmt_array(ctx, fmt, obj);
+	else if (pdf_is_dict(ctx, obj))
+		fmt_dict(ctx, fmt, obj);
+	else
+		fmt_puts(ctx, fmt, "<unknown object>");
+}
+static char *
+pdf_sprint_encrypted_obj(fz_context *ctx, char *buf, size_t cap, size_t *len, pdf_obj *obj, int tight, int ascii, pdf_crypt *crypt, int num, int gen, int *sep)
+{
+	struct fmt fmt;
+	fmt.indent = 0;
+	fmt.col = 0;
+	fmt.sep = sep ? *sep : 0;
+	fmt.last = 0;
+	if (!buf || cap == 0)
+	{
+		fmt.cap = 1024;
+		fmt.buf = NULL;
+		fmt.ptr = Memento_label(fz_malloc(ctx, fmt.cap), "fmt_buf");
+	}
+	else
+	{
+		fmt.cap = cap;
+		fmt.buf = buf;
+		fmt.ptr = buf;
+	}
+	fmt.tight = tight;
+	fmt.ascii = ascii;
+	fmt.len = 0;
+	fmt.crypt = crypt;
+	fmt.num = num;
+	fmt.gen = gen;
+	fz_try(ctx)
+	{
+		fmt_obj(ctx, &fmt, obj);
+		if (sep)
+			*sep = fmt.sep;
+		fmt.sep = 0;
+		fmt_putc(ctx, &fmt, 0);
+	}
+	fz_catch(ctx)
+	{
+		if (!buf || cap == 0)
+			fz_free(ctx, fmt.ptr);
+		fz_rethrow(ctx);
+	}
+	return *len = fmt.len-1, fmt.ptr;
+}
+char *
+pdf_sprint_obj(fz_context *ctx, char *buf, size_t cap, size_t *len, pdf_obj *obj, int tight, int ascii)
+{
+	return pdf_sprint_encrypted_obj(ctx, buf, cap, len, obj, tight, ascii, NULL, 0, 0, NULL);
+}
+void pdf_print_encrypted_obj(fz_context *ctx, fz_output *out, pdf_obj *obj, int tight, int ascii, pdf_crypt *crypt, int num, int gen, int *sep)
+{
+	char buf[1024];
+	char *ptr;
+	size_t n;
+	ptr = pdf_sprint_encrypted_obj(ctx, buf, sizeof buf, &n, obj, tight, ascii, crypt, num, gen, sep);
+	fz_try(ctx)
+		fz_write_data(ctx, out, ptr, n);
+	fz_always(ctx)
+		if (ptr != buf)
+			fz_free(ctx, ptr);
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+}
+void pdf_print_obj(fz_context *ctx, fz_output *out, pdf_obj *obj, int tight, int ascii)
+{
+	pdf_print_encrypted_obj(ctx, out, obj, tight, ascii, NULL, 0, 0, NULL);
+}
+void pdf_debug_obj(fz_context *ctx, pdf_obj *obj)
+{
+	pdf_print_obj(ctx, fz_stddbg(ctx), pdf_resolve_indirect(ctx, obj), 0, 0);
+}
+void pdf_debug_ref(fz_context *ctx, pdf_obj *obj)
+{
+	fz_output *out = fz_stddbg(ctx);
+	pdf_print_obj(ctx, out, obj, 0, 0);
+	fz_write_byte(ctx, out, '\n');
+}
+int pdf_obj_refs(fz_context *ctx, pdf_obj *obj)
+{
+	if (obj < PDF_LIMIT)
+		return 0;
+	return obj->refs;
+}
+/* Convenience functions */
+/*
+	Uses Floyd's cycle finding algorithm, modified to avoid starting
+	the 'slow' pointer for a while.
+	https://www.geeksforgeeks.org/floyds-cycle-finding-algorithm/
+*/
+pdf_obj *
+pdf_dict_get_inheritable(fz_context *ctx, pdf_obj *node, pdf_obj *key)
+{
+	pdf_obj *slow = node;
+	int halfbeat = 11; /* Don't start moving slow pointer for a while. */
+	while (node)
+	{
+		pdf_obj *val = pdf_dict_get(ctx, node, key);
+		if (val)
+			return val;
+		node = pdf_dict_get(ctx, node, PDF_NAME(Parent));
+		if (node == slow)
+			fz_throw(ctx, FZ_ERROR_FORMAT, "cycle in resources");
+		if (--halfbeat == 0)
+		{
+			slow = pdf_dict_get(ctx, slow, PDF_NAME(Parent));
+			halfbeat = 2;
+		}
+	}
+	return NULL;
+}
+pdf_obj *
+pdf_dict_getp_inheritable(fz_context *ctx, pdf_obj *node, const char *path)
+{
+	pdf_obj *slow = node;
+	int halfbeat = 11; /* Don't start moving slow pointer for a while. */
+	while (node)
+	{
+		pdf_obj *val = pdf_dict_getp(ctx, node, path);
+		if (val)
+			return val;
+		node = pdf_dict_get(ctx, node, PDF_NAME(Parent));
+		if (node == slow)
+			fz_throw(ctx, FZ_ERROR_FORMAT, "cycle in resources");
+		if (--halfbeat == 0)
+		{
+			slow = pdf_dict_get(ctx, slow, PDF_NAME(Parent));
+			halfbeat = 2;
+		}
+	}
+	return NULL;
+}
+pdf_obj *
+pdf_dict_gets_inheritable(fz_context *ctx, pdf_obj *node, const char *key)
+{
+	pdf_obj *slow = node;
+	int halfbeat = 11; /* Don't start moving slow pointer for a while. */
+	while (node)
+	{
+		pdf_obj *val = pdf_dict_gets(ctx, node, key);
+		if (val)
+			return val;
+		node = pdf_dict_get(ctx, node, PDF_NAME(Parent));
+		if (node == slow)
+			fz_throw(ctx, FZ_ERROR_FORMAT, "cycle in resources");
+		if (--halfbeat == 0)
+		{
+			slow = pdf_dict_get(ctx, slow, PDF_NAME(Parent));
+			halfbeat = 2;
+		}
+	}
+	return NULL;
+}
+void pdf_dict_put_bool(fz_context *ctx, pdf_obj *dict, pdf_obj *key, int x)
+{
+	pdf_dict_put(ctx, dict, key, x ? PDF_TRUE : PDF_FALSE);
+}
+void pdf_dict_put_int(fz_context *ctx, pdf_obj *dict, pdf_obj *key, int64_t x)
+{
+	pdf_dict_put_drop(ctx, dict, key, pdf_new_int(ctx, x));
+}
+void pdf_dict_put_real(fz_context *ctx, pdf_obj *dict, pdf_obj *key, double x)
+{
+	pdf_dict_put_drop(ctx, dict, key, pdf_new_real(ctx, x));
+}
+void pdf_dict_put_name(fz_context *ctx, pdf_obj *dict, pdf_obj *key, const char *x)
+{
+	pdf_dict_put_drop(ctx, dict, key, pdf_new_name(ctx, x));
+}
+void pdf_dict_put_string(fz_context *ctx, pdf_obj *dict, pdf_obj *key, const char *x, size_t n)
+{
+	pdf_dict_put_drop(ctx, dict, key, pdf_new_string(ctx, x, n));
+}
+void pdf_dict_put_text_string(fz_context *ctx, pdf_obj *dict, pdf_obj *key, const char *x)
+{
+	pdf_dict_put_drop(ctx, dict, key, pdf_new_text_string(ctx, x));
+}
+void pdf_dict_put_indirect(fz_context *ctx, pdf_obj *dict, pdf_obj *key, int num)
+{
+	pdf_dict_put_drop(ctx, dict, key, pdf_new_indirect(ctx, pdf_get_bound_document(ctx, dict), num, 0));
+}
+void pdf_dict_put_point(fz_context *ctx, pdf_obj *dict, pdf_obj *key, fz_point x)
+{
+	pdf_dict_put_drop(ctx, dict, key, pdf_new_point(ctx, pdf_get_bound_document(ctx, dict), x));
+}
+void pdf_dict_put_rect(fz_context *ctx, pdf_obj *dict, pdf_obj *key, fz_rect x)
+{
+	pdf_dict_put_drop(ctx, dict, key, pdf_new_rect(ctx, pdf_get_bound_document(ctx, dict), x));
+}
+void pdf_dict_put_matrix(fz_context *ctx, pdf_obj *dict, pdf_obj *key, fz_matrix x)
+{
+	pdf_dict_put_drop(ctx, dict, key, pdf_new_matrix(ctx, pdf_get_bound_document(ctx, dict), x));
+}
+void pdf_dict_put_date(fz_context *ctx, pdf_obj *dict, pdf_obj *key, int64_t time)
+{
+	pdf_dict_put_drop(ctx, dict, key, pdf_new_date(ctx, pdf_get_bound_document(ctx, dict), time));
+}
+pdf_obj *pdf_dict_put_array(fz_context *ctx, pdf_obj *dict, pdf_obj *key, int initial)
+{
+	pdf_obj *obj = pdf_new_array(ctx, pdf_get_bound_document(ctx, dict), initial);
+	pdf_dict_put_drop(ctx, dict, key, obj);
+	return obj;
+}
+pdf_obj *pdf_dict_put_dict(fz_context *ctx, pdf_obj *dict, pdf_obj *key, int initial)
+{
+	pdf_obj *obj = pdf_new_dict(ctx, pdf_get_bound_document(ctx, dict), initial);
+	pdf_dict_put_drop(ctx, dict, key, obj);
+	return obj;
+}
+pdf_obj *pdf_dict_puts_dict(fz_context *ctx, pdf_obj *dict, const char *key, int initial)
+{
+	pdf_obj *obj = pdf_new_dict(ctx, pdf_get_bound_document(ctx, dict), initial);
+	pdf_dict_puts_drop(ctx, dict, key, obj);
+	return obj;
+}
+void pdf_array_push_bool(fz_context *ctx, pdf_obj *array, int x)
+{
+	pdf_array_push(ctx, array, x ? PDF_TRUE : PDF_FALSE);
+}
+void pdf_array_push_int(fz_context *ctx, pdf_obj *array, int64_t x)
+{
+	pdf_array_push_drop(ctx, array, pdf_new_int(ctx, x));
+}
+void pdf_array_push_real(fz_context *ctx, pdf_obj *array, double x)
+{
+	pdf_array_push_drop(ctx, array, pdf_new_real(ctx, x));
+}
+void pdf_array_push_name(fz_context *ctx, pdf_obj *array, const char *x)
+{
+	pdf_array_push_drop(ctx, array, pdf_new_name(ctx, x));
+}
+void pdf_array_push_string(fz_context *ctx, pdf_obj *array, const char *x, size_t n)
+{
+	pdf_array_push_drop(ctx, array, pdf_new_string(ctx, x, n));
+}
+void pdf_array_push_text_string(fz_context *ctx, pdf_obj *array, const char *x)
+{
+	pdf_array_push_drop(ctx, array, pdf_new_text_string(ctx, x));
+}
+pdf_obj *pdf_array_push_array(fz_context *ctx, pdf_obj *array, int initial)
+{
+	pdf_obj *obj = pdf_new_array(ctx, pdf_get_bound_document(ctx, array), initial);
+	pdf_array_push_drop(ctx, array, obj);
+	return obj;
+}
+pdf_obj *pdf_array_push_dict(fz_context *ctx, pdf_obj *array, int initial)
+{
+	pdf_obj *obj = pdf_new_dict(ctx, pdf_get_bound_document(ctx, array), initial);
+	pdf_array_push_drop(ctx, array, obj);
+	return obj;
+}
+void pdf_array_put_bool(fz_context *ctx, pdf_obj *array, int i, int x)
+{
+	pdf_array_put(ctx, array, i, x ? PDF_TRUE : PDF_FALSE);
+}
+void pdf_array_put_int(fz_context *ctx, pdf_obj *array, int i, int64_t x)
+{
+	pdf_array_put_drop(ctx, array, i, pdf_new_int(ctx, x));
+}
+void pdf_array_put_real(fz_context *ctx, pdf_obj *array, int i, double x)
+{
+	pdf_array_put_drop(ctx, array, i, pdf_new_real(ctx, x));
+}
+void pdf_array_put_name(fz_context *ctx, pdf_obj *array, int i, const char *x)
+{
+	pdf_array_put_drop(ctx, array, i, pdf_new_name(ctx, x));
+}
+void pdf_array_put_string(fz_context *ctx, pdf_obj *array, int i, const char *x, size_t n)
+{
+	pdf_array_put_drop(ctx, array, i, pdf_new_string(ctx, x, n));
+}
+void pdf_array_put_text_string(fz_context *ctx, pdf_obj *array, int i, const char *x)
+{
+	pdf_array_put_drop(ctx, array, i, pdf_new_text_string(ctx, x));
+}
+pdf_obj *pdf_array_put_array(fz_context *ctx, pdf_obj *array, int i, int initial)
+{
+	pdf_obj *obj = pdf_new_array(ctx, pdf_get_bound_document(ctx, array), initial);
+	pdf_array_put_drop(ctx, array, i, obj);
+	return obj;
+}
+pdf_obj *pdf_array_put_dict(fz_context *ctx, pdf_obj *array, int i, int initial)
+{
+	pdf_obj *obj = pdf_new_dict(ctx, pdf_get_bound_document(ctx, array), initial);
+	pdf_array_put_drop(ctx, array, i, obj);
+	return obj;
+}
+int pdf_dict_get_bool(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	return pdf_to_bool(ctx, pdf_dict_get(ctx, dict, key));
+}
+int pdf_dict_get_bool_default(fz_context *ctx, pdf_obj *dict, pdf_obj *key, int def)
+{
+	return pdf_to_bool_default(ctx, pdf_dict_get(ctx, dict, key), def);
+}
+int pdf_dict_get_int(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	return pdf_to_int(ctx, pdf_dict_get(ctx, dict, key));
+}
+int pdf_dict_get_int_default(fz_context *ctx, pdf_obj *dict, pdf_obj *key, int def)
+{
+	return pdf_to_int_default(ctx, pdf_dict_get(ctx, dict, key), def);
+}
+int64_t pdf_dict_get_int64(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	return pdf_to_int64(ctx, pdf_dict_get(ctx, dict, key));
+}
+float pdf_dict_get_real(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	return pdf_to_real(ctx, pdf_dict_get(ctx, dict, key));
+}
+float pdf_dict_get_real_default(fz_context *ctx, pdf_obj *dict, pdf_obj *key, float def)
+{
+	return pdf_to_real_default(ctx, pdf_dict_get(ctx, dict, key), def);
+}
+const char *pdf_dict_get_name(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	return pdf_to_name(ctx, pdf_dict_get(ctx, dict, key));
+}
+const char *pdf_dict_get_string(fz_context *ctx, pdf_obj *dict, pdf_obj *key, size_t *sizep)
+{
+	return pdf_to_string(ctx, pdf_dict_get(ctx, dict, key), sizep);
+}
+const char *pdf_dict_get_text_string(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	return pdf_to_text_string(ctx, pdf_dict_get(ctx, dict, key));
+}
+const char *pdf_dict_get_text_string_opt(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	pdf_obj *obj = pdf_dict_get(ctx, dict, key);
+	if (!pdf_is_string(ctx, obj))
+		return NULL;
+	return pdf_to_text_string(ctx, obj);
+}
+fz_point pdf_dict_get_point(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	return pdf_to_point(ctx, pdf_dict_get(ctx, dict, key), 0);
+}
+fz_rect pdf_dict_get_rect(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	return pdf_to_rect(ctx, pdf_dict_get(ctx, dict, key));
+}
+fz_matrix pdf_dict_get_matrix(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	return pdf_to_matrix(ctx, pdf_dict_get(ctx, dict, key));
+}
+int pdf_dict_get_inheritable_bool(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	return pdf_to_bool(ctx, pdf_dict_get_inheritable(ctx, dict, key));
+}
+int pdf_dict_get_inheritable_int(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	return pdf_to_int(ctx, pdf_dict_get_inheritable(ctx, dict, key));
+}
+int64_t pdf_dict_get_inheritable_int64(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	return pdf_to_int64(ctx, pdf_dict_get_inheritable(ctx, dict, key));
+}
+float pdf_dict_get_inheritable_real(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	return pdf_to_real(ctx, pdf_dict_get_inheritable(ctx, dict, key));
+}
+const char *pdf_dict_get_inheritable_name(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	return pdf_to_name(ctx, pdf_dict_get_inheritable(ctx, dict, key));
+}
+const char *pdf_dict_get_inheritable_string(fz_context *ctx, pdf_obj *dict, pdf_obj *key, size_t *sizep)
+{
+	return pdf_to_string(ctx, pdf_dict_get_inheritable(ctx, dict, key), sizep);
+}
+const char *pdf_dict_get_inheritable_text_string(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	return pdf_to_text_string(ctx, pdf_dict_get_inheritable(ctx, dict, key));
+}
+fz_rect pdf_dict_get_inheritable_rect(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	return pdf_to_rect(ctx, pdf_dict_get_inheritable(ctx, dict, key));
+}
+fz_matrix pdf_dict_get_inheritable_matrix(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	return pdf_to_matrix(ctx, pdf_dict_get_inheritable(ctx, dict, key));
+}
+int64_t pdf_dict_get_inheritable_date(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	return pdf_to_date(ctx, pdf_dict_get_inheritable(ctx, dict, key));
+}
+int64_t pdf_dict_get_date(fz_context *ctx, pdf_obj *dict, pdf_obj *key)
+{
+	return pdf_to_date(ctx, pdf_dict_get(ctx, dict, key));
+}
+int pdf_array_get_bool(fz_context *ctx, pdf_obj *array, int index)
+{
+	return pdf_to_bool(ctx, pdf_array_get(ctx, array, index));
+}
+int pdf_array_get_int(fz_context *ctx, pdf_obj *array, int index)
+{
+	return pdf_to_int(ctx, pdf_array_get(ctx, array, index));
+}
+float pdf_array_get_real(fz_context *ctx, pdf_obj *array, int index)
+{
+	return pdf_to_real(ctx, pdf_array_get(ctx, array, index));
+}
+const char *pdf_array_get_name(fz_context *ctx, pdf_obj *array, int index)
+{
+	return pdf_to_name(ctx, pdf_array_get(ctx, array, index));
+}
+const char *pdf_array_get_string(fz_context *ctx, pdf_obj *array, int index, size_t *sizep)
+{
+	return pdf_to_string(ctx, pdf_array_get(ctx, array, index), sizep);
+}
+const char *pdf_array_get_text_string(fz_context *ctx, pdf_obj *array, int index)
+{
+	return pdf_to_text_string(ctx, pdf_array_get(ctx, array, index));
+}
+fz_rect pdf_array_get_rect(fz_context *ctx, pdf_obj *array, int index)
+{
+	return pdf_to_rect(ctx, pdf_array_get(ctx, array, index));
+}
+fz_matrix pdf_array_get_matrix(fz_context *ctx, pdf_obj *array, int index)
+{
+	return pdf_to_matrix(ctx, pdf_array_get(ctx, array, index));
+}
+#ifndef NDEBUG
+void pdf_verify_name_table_sanity(void)
+{
+	int i;
+	for (i = PDF_ENUM_FALSE+1; i < PDF_ENUM_LIMIT-1; i++)
+	{
+		assert(strcmp(PDF_NAME_LIST[i], PDF_NAME_LIST[i+1]) < 0);
+	}
+}
+#endif

Mercurial > hgrepos > Python2 > PyMuPDF

comparison mupdf-source/source/pdf/pdf-object.c @ 2:b50eed0cc0ef upstream