--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/source/fitz/load-jbig2.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,219 @@
+// Copyright (C) 2004-2021 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 "pixmap-imp.h"
+
+#include <jbig2.h>
+
+struct info
+{
+	int width, height;
+	int xres, yres;
+	int pages;
+	fz_colorspace *cspace;
+};
+
+struct fz_jbig2_allocator
+{
+	Jbig2Allocator super;
+	fz_context *ctx;
+};
+
+static void
+error_callback(void *data, const char *msg, Jbig2Severity severity, uint32_t seg_idx)
+{
+	fz_context *ctx = data;
+	if (severity == JBIG2_SEVERITY_FATAL)
+		fz_warn(ctx, "jbig2dec error: %s (segment %u)", msg, seg_idx);
+	else if (severity == JBIG2_SEVERITY_WARNING)
+		fz_warn(ctx, "jbig2dec warning: %s (segment %u)", msg, seg_idx);
+#ifdef JBIG2_DEBUG
+	else if (severity == JBIG2_SEVERITY_INFO)
+		fz_warn(ctx, "jbig2dec info: %s (segment %u)", msg, seg_idx);
+	else if (severity == JBIG2_SEVERITY_DEBUG)
+		fz_warn(ctx, "jbig2dec debug: %s (segment %u)", msg, seg_idx);
+#endif
+}
+
+static void *fz_jbig2_alloc(Jbig2Allocator *allocator, size_t size)
+{
+	fz_context *ctx = ((struct fz_jbig2_allocator *) allocator)->ctx;
+	return fz_malloc_no_throw(ctx, size);
+}
+
+static void fz_jbig2_free(Jbig2Allocator *allocator, void *p)
+{
+	fz_context *ctx = ((struct fz_jbig2_allocator *) allocator)->ctx;
+	fz_free(ctx, p);
+}
+
+static void *fz_jbig2_realloc(Jbig2Allocator *allocator, void *p, size_t size)
+{
+	fz_context *ctx = ((struct fz_jbig2_allocator *) allocator)->ctx;
+	if (size == 0)
+	{
+		fz_free(ctx, p);
+		return NULL;
+	}
+	if (p == NULL)
+		return Memento_label(fz_malloc(ctx, size), "jbig2_realloc");
+	return Memento_label(fz_realloc_no_throw(ctx, p, size), "jbig2_realloc");
+}
+
+static fz_pixmap *
+jbig2_read_image(fz_context *ctx, struct info *jbig2, const unsigned char *buf, size_t len, int only_metadata, int subimage)
+{
+	Jbig2Ctx *jctx = NULL;
+	Jbig2Image *page = NULL;
+	struct fz_jbig2_allocator allocator;
+	fz_pixmap *pix = NULL;
+
+	allocator.super.alloc = fz_jbig2_alloc;
+	allocator.super.free = fz_jbig2_free;
+	allocator.super.realloc = fz_jbig2_realloc;
+	allocator.ctx = ctx;
+
+	fz_var(jctx);
+	fz_var(page);
+	fz_var(pix);
+
+	fz_try(ctx)
+	{
+		jctx = jbig2_ctx_new((Jbig2Allocator *) &allocator, 0, NULL, error_callback, ctx);
+		if (jctx == NULL)
+			fz_throw(ctx, FZ_ERROR_LIBRARY, "cannot create jbig2 context");
+		if (jbig2_data_in(jctx, buf, len) < 0)
+			fz_throw(ctx, FZ_ERROR_LIBRARY, "cannot decode jbig2 image");
+		if (jbig2_complete_page(jctx) < 0)
+			fz_throw(ctx, FZ_ERROR_LIBRARY, "cannot complete jbig2 image");
+
+		if (only_metadata && subimage < 0)
+		{
+			while ((page = jbig2_page_out(jctx)) != NULL)
+			{
+				jbig2_release_page(jctx, page);
+				jbig2->pages++;
+			}
+		}
+		else if (only_metadata && subimage >= 0)
+		{
+			while ((page = jbig2_page_out(jctx)) != NULL && subimage > 0)
+			{
+				jbig2_release_page(jctx, page);
+				subimage--;
+			}
+
+			if (page == NULL)
+				fz_throw(ctx, FZ_ERROR_LIBRARY, "no jbig2 image decoded");
+
+			jbig2->cspace = fz_device_gray(ctx);
+			jbig2->width = page->width;
+			jbig2->height = page->height;
+			jbig2->xres = 72;
+			jbig2->yres = 72;
+		}
+		else if (subimage >= 0)
+		{
+			while ((page = jbig2_page_out(jctx)) != NULL && subimage > 0)
+			{
+				jbig2_release_page(jctx, page);
+				subimage--;
+			}
+
+			if (page == NULL)
+				fz_throw(ctx, FZ_ERROR_LIBRARY, "no jbig2 image decoded");
+
+			jbig2->cspace = fz_device_gray(ctx);
+			jbig2->width = page->width;
+			jbig2->height = page->height;
+			jbig2->xres = 72;
+			jbig2->yres = 72;
+
+			pix = fz_new_pixmap(ctx, jbig2->cspace, jbig2->width, jbig2->height, NULL, 0);
+			fz_unpack_tile(ctx, pix, page->data, 1, 1, page->stride, 0);
+			fz_invert_pixmap(ctx, pix);
+		}
+	}
+	fz_always(ctx)
+	{
+		jbig2_release_page(jctx, page);
+		jbig2_ctx_free(jctx);
+	}
+	fz_catch(ctx)
+	{
+		fz_drop_pixmap(ctx, pix);
+		fz_rethrow(ctx);
+	}
+
+	return pix;
+}
+
+int
+fz_load_jbig2_subimage_count(fz_context *ctx, const unsigned char *buf, size_t len)
+{
+	struct info jbig2 = { 0 };
+	int subimage_count = 0;
+
+	fz_try(ctx)
+	{
+		jbig2_read_image(ctx, &jbig2, buf, len, 1, -1);
+		subimage_count = jbig2.pages;
+	}
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+
+	return subimage_count;
+}
+
+void
+fz_load_jbig2_info_subimage(fz_context *ctx, const unsigned char *buf, size_t len, int *wp, int *hp, int *xresp, int *yresp, fz_colorspace **cspacep, int subimage)
+{
+	struct info jbig2 = { 0 };
+
+	jbig2_read_image(ctx, &jbig2, buf, len, 1, subimage);
+	*cspacep = fz_keep_colorspace(ctx, jbig2.cspace);
+	*wp = jbig2.width;
+	*hp = jbig2.height;
+	*xresp = jbig2.xres;
+	*yresp = jbig2.yres;
+}
+
+fz_pixmap *
+fz_load_jbig2_subimage(fz_context *ctx, const unsigned char *buf, size_t len, int subimage)
+{
+	struct info jbig2 = { 0 };
+	return jbig2_read_image(ctx, &jbig2, buf, len, 0, subimage);
+}
+
+fz_pixmap *
+fz_load_jbig2(fz_context *ctx, const unsigned char *buf, size_t len)
+{
+	return fz_load_jbig2_subimage(ctx, buf, len, 0);
+}
+
+void
+fz_load_jbig2_info(fz_context *ctx, const unsigned char *buf, size_t len, int *wp, int *hp, int *xresp, int *yresp, fz_colorspace **cspacep)
+{
+	fz_load_jbig2_info_subimage(ctx, buf, len, wp, hp, xresp, yresp, cspacep, 0);
+}