--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/source/fitz/gz-doc.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,105 @@
+// Copyright (C) 2023-2024 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"
+
+#ifndef MAX_WBITS
+#  define MAX_WBITS   15 /* 32K LZ77 window */
+#endif
+
+static fz_document *
+gz_open_document(fz_context *ctx, const fz_document_handler *handler, fz_stream *ostm, fz_stream *accel, fz_archive *dir, void *state)
+{
+	fz_stream *stm = fz_open_flated(ctx, ostm, 16 + MAX_WBITS);
+	fz_buffer *buf = NULL;
+	fz_document *doc = NULL;
+
+	fz_var(buf);
+	fz_var(doc);
+
+	fz_try(ctx)
+	{
+		buf = fz_read_all(ctx, stm, 1024);
+		/* No way to pass the magic onwards :( */
+		doc = fz_open_document_with_buffer(ctx, "application/octet-stream", buf);
+	}
+	fz_always(ctx)
+	{
+		fz_drop_stream(ctx, stm);
+		fz_drop_buffer(ctx, buf);
+	}
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+
+	return doc;
+}
+
+static const char *gz_extensions[] =
+{
+	"gz",
+	NULL
+};
+
+static const char *gz_mimetypes[] =
+{
+	"application/x-gzip-compressed",
+	NULL
+};
+
+static int
+gz_recognize_doc_content(fz_context *ctx, const fz_document_handler *handler, fz_stream *stream, fz_archive *dir, void **state, fz_document_recognize_state_free_fn **free_state)
+{
+	int ret = 0;
+	uint8_t data[10];
+
+	if (state)
+		*state = NULL;
+	if (free_state)
+		*free_state = NULL;
+
+	if (stream == NULL)
+		return 0;
+
+	fz_try(ctx)
+	{
+		fz_seek(ctx, stream, 0, SEEK_SET);
+		/* 10 byte header */
+		if (fz_read(ctx, stream, data, 10) != 10)
+			break;
+		/* We only actually check the first 3 bytes though. */
+		if (data[0] == 0x1f && data[1] == 0x8b && data[2] == 0x08)
+			ret = 100;
+	}
+	fz_catch(ctx)
+		fz_rethrow(ctx);
+
+	return ret;
+}
+
+fz_document_handler gz_document_handler =
+{
+	NULL,
+	gz_open_document,
+	gz_extensions,
+	gz_mimetypes,
+	gz_recognize_doc_content
+};