--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/source/pdf/pdf-zugferd.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,277 @@
+// Copyright (C) 2024-2025 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"
+
+static const char *
+tag_or_text(fz_xml *x, const char *find)
+{
+	const char *text;
+	const char *f = strchr(find, ':');
+
+	/* If we find a : we have a namespace. Search for both with and
+	 * without the namespace. */
+	if (f)
+		f++;
+
+	text = fz_xml_att(x, find);
+	if (text == NULL && f)
+		text = fz_xml_att(x, f);
+	if (text == NULL)
+		text = fz_xml_text(fz_xml_down(fz_xml_find_down(x, find)));
+	if (text == NULL && f)
+		text = fz_xml_text(fz_xml_down(fz_xml_find_down(x, f)));
+
+	return text;
+}
+
+static enum pdf_zugferd_profile
+do_zugferd_profile(fz_context *ctx, pdf_document *doc, float *version, char **fname)
+{
+	pdf_obj *metadata = pdf_dict_getl(ctx, pdf_trailer(ctx, doc), PDF_NAME(Root), PDF_NAME(Metadata), NULL);
+	fz_buffer *buf;
+	fz_xml *xml = NULL;
+	fz_xml *x;
+	enum pdf_zugferd_profile ret = PDF_NOT_ZUGFERD;
+
+	if (version)
+		*version = 0;
+	if (fname)
+		*fname = NULL;
+
+	if (metadata == NULL)
+		return PDF_NOT_ZUGFERD;
+
+	buf = pdf_load_stream(ctx, metadata);
+
+	fz_var(xml);
+
+	fz_try(ctx)
+	{
+		xml = fz_parse_xml(ctx, buf, 0);
+
+		/* Version 1. */
+		x = fz_xml_find_dfs(xml, "Description", "xmlns:zf", "urn:ferd:pdfa:CrossIndustryDocument:invoice:1p0#");
+		if (x)
+		{
+			while (x)
+			{
+				/* The Version tag in the document appears to always be 1.0 */
+				const char *v = tag_or_text(x, "zf:Version");
+				const char *cl = tag_or_text(x, "zf:ConformanceLevel");
+				const char *df = tag_or_text(x, "zf:DocumentFileName");
+				const char *dt = tag_or_text(x, "zf:DocumentType");
+				if (v && dt && !strcmp(dt, "INVOICE"))
+				{
+					if (!cl)
+						fz_warn(ctx, "No conformance level specified");
+					else if (!strcmp(cl, "COMFORT"))
+						ret = PDF_ZUGFERD_COMFORT;
+					else if (!strcmp(cl, "BASIC"))
+						ret = PDF_ZUGFERD_BASIC;
+					else if (!strcmp(cl, "EXTENDED"))
+						ret = PDF_ZUGFERD_EXTENDED;
+
+					if (version)
+						*version = fz_atof(v);
+
+					if (!df)
+						fz_warn(ctx, "ZUGFeRD doc is missing filename");
+					else if (strcmp(df, "ZUGFeRD-invoice.xml"))
+						fz_warn(ctx, "ZUGFeRD doc has non-standard filename");
+					if (fname && df)
+						*fname = fz_strdup(ctx, df); /* Nothing can throw after this */
+					break;
+				}
+
+				x = fz_xml_find_next_dfs(x, "Description", "xmlns:zf", "urn:ferd:pdfa:CrossIndustryDocument:invoice:1p0#");
+			}
+			break;
+		}
+
+		/* Version 2. */
+		x = fz_xml_find_dfs(xml, "Description", "xmlns:fx", "urn:zugferd:pdfa:CrossIndustryDocument:invoice:2p0#");
+		if (x)
+		{
+			while (x)
+			{
+				const char *v = tag_or_text(x, "fx:Version");
+				const char *cl = tag_or_text(x, "fx:ConformanceLevel");
+				const char *df = tag_or_text(x, "fx:DocumentFileName");
+				const char *dt = tag_or_text(x, "fx:DocumentType");
+				if (v && dt && !strcmp(dt, "INVOICE"))
+				{
+					if (!cl)
+						fz_warn(ctx, "No conformance level specified");
+					else if (!strcmp(cl, "EN 16931"))
+						ret = PDF_ZUGFERD_COMFORT;
+					else if (!strcmp(cl, "BASIC"))
+						ret = PDF_ZUGFERD_BASIC;
+					else if (!strcmp(cl, "EXTENDED"))
+						ret = PDF_ZUGFERD_EXTENDED;
+					else if (!strcmp(cl, "BASIC WL"))
+						ret = PDF_ZUGFERD_BASIC_WL;
+					else if (!strcmp(cl, "MINIMUM"))
+						ret = PDF_ZUGFERD_MINIMUM;
+
+					if (version)
+						*version = fz_atof(v);
+
+					if (!df)
+						fz_warn(ctx, "ZUGFeRD doc is missing filename");
+					else if (strcmp(df, "zugferd-invoice.xml"))
+						fz_warn(ctx, "ZUGFeRD doc has non-standard filename");
+					if (fname && df)
+						*fname = fz_strdup(ctx, df); /* Nothing can throw after this */
+					break;
+				}
+
+				x = fz_xml_find_next_dfs(x, "Description", "xmlns:fx", "urn:zugferd:pdfa:CrossIndustryDocument:invoice:2p0#");
+			}
+			break;
+		}
+
+		/* Version 2.1 + 2.11 */
+		x = fz_xml_find_dfs(xml, "Description", "xmlns:fx", "urn:factur-x:pdfa:CrossIndustryDocument:invoice:1p0#");
+		if (x)
+		{
+			while (x)
+			{
+				const char *v = tag_or_text(x, "fx:Version");
+				const char *cl = tag_or_text(x, "fx:ConformanceLevel");
+				const char *df = tag_or_text(x, "fx:DocumentFileName");
+				const char *dt = tag_or_text(x, "fx:DocumentType");
+				if (v && dt && !strcmp(dt, "INVOICE"))
+				{
+					if (!cl)
+						fz_warn(ctx, "No conformance level specified");
+					else if (!strcmp(cl, "EN 16931"))
+						ret = PDF_ZUGFERD_COMFORT;
+					else if (!strcmp(cl, "BASIC"))
+						ret = PDF_ZUGFERD_BASIC;
+					else if (!strcmp(cl, "EXTENDED"))
+						ret = PDF_ZUGFERD_EXTENDED;
+					else if (!strcmp(cl, "BASIC WL"))
+						ret = PDF_ZUGFERD_BASIC_WL;
+					else if (!strcmp(cl, "MINIMUM"))
+						ret = PDF_ZUGFERD_MINIMUM;
+					else if (!strcmp(cl, "XRECHNUNG"))
+						ret = PDF_ZUGFERD_XRECHNUNG;
+
+					if (version)
+						*version = fz_atof(v);
+
+					if (!df)
+						fz_warn(ctx, "ZUGFeRD doc is missing filename");
+					else if (ret == PDF_ZUGFERD_XRECHNUNG && strcmp(df, "xrechnung.xml"))
+						fz_warn(ctx, "ZUGFeRD doc has non-standard filename");
+					else if (ret != PDF_ZUGFERD_XRECHNUNG && strcmp(df, "factur-x.xml"))
+						fz_warn(ctx, "ZUGFeRD doc has non-standard filename");
+					if (fname && df)
+						*fname = fz_strdup(ctx, df); /* Nothing can throw after this */
+					break;
+				}
+
+				x = fz_xml_find_next_dfs(x, "Description", "xmlns:fx", "urn:factur-x:pdfa:CrossIndustryDocument:invoice:1p0#");
+			}
+			break;
+		}
+	}
+	fz_always(ctx)
+	{
+		fz_drop_xml(ctx, xml);
+		fz_drop_buffer(ctx, buf);
+	}
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+
+	return ret;
+}
+
+enum pdf_zugferd_profile pdf_zugferd_profile(fz_context *ctx, pdf_document *doc, float *version)
+{
+	return do_zugferd_profile(ctx, doc, version, NULL);
+}
+
+fz_buffer *pdf_zugferd_xml(fz_context *ctx, pdf_document *doc)
+{
+	char *fname;
+	float version;
+	enum pdf_zugferd_profile p = do_zugferd_profile(ctx, doc, &version, &fname);
+	int count, i;
+	fz_buffer *buf = NULL;
+
+	if (p == PDF_NOT_ZUGFERD)
+	{
+		fz_free(ctx, fname);
+		return NULL;
+	}
+
+	fz_try(ctx)
+	{
+		count = pdf_count_document_associated_files(ctx, doc);
+		for (i = 0; i < count; i++)
+		{
+			pdf_obj *fs = pdf_document_associated_file(ctx, doc, i);
+			pdf_filespec_params params;
+
+			pdf_get_filespec_params(ctx, fs, &params);
+
+			if (!strcmp(fname, params.filename))
+			{
+				if (!pdf_is_embedded_file(ctx, fs))
+					fz_throw(ctx, FZ_ERROR_FORMAT, "ZUGFeRD XML was not embedded");
+
+				buf = pdf_load_embedded_file_contents(ctx, fs);
+				break;
+			}
+		}
+	}
+	fz_always(ctx)
+		fz_free(ctx, fname);
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+
+	return buf;
+}
+
+const char *
+pdf_zugferd_profile_to_string(fz_context *ctx, enum pdf_zugferd_profile profile)
+{
+	static const char *strings[] =
+	{
+		"NOT ZUGFERD",
+		"COMFORT",
+		"BASIC",
+		"EXTENDED",
+		"BASIC WL",
+		"MINIMUM",
+		"XRECHNUNG",
+		"UNKNOWN"
+	};
+
+	if (profile < PDF_NOT_ZUGFERD || profile > PDF_ZUGFERD_UNKNOWN)
+		profile = PDF_ZUGFERD_UNKNOWN;
+
+	return strings[profile];
+}