Add fz_deflate family of functions.

This gives us a friendlier interface to zlib.

Simplifies PNG output and PCLM output code.

6 files changed, 162 insertions, 24 deletions

diff --git a/include/mupdf/fitz.h b/include/mupdf/fitz.h
index 9b6d6aa9..9f697c8a 100644
--- a/include/mupdf/fitz.h
+++ b/include/mupdf/fitz.h
@@ -23,6 +23,7 @@ extern "C" {
 /* I/O */
 #include "mupdf/fitz/buffer.h"
 #include "mupdf/fitz/stream.h"
+#include "mupdf/fitz/compress.h"
 #include "mupdf/fitz/compressed-buffer.h"
 #include "mupdf/fitz/filter.h"
 #include "mupdf/fitz/output.h"
diff --git a/include/mupdf/fitz/compress.h b/include/mupdf/fitz/compress.h
new file mode 100644
index 00000000..cfd4ed1a
--- /dev/null
+++ b/include/mupdf/fitz/compress.h
@@ -0,0 +1,50 @@
+#ifndef MUPDF_FITZ_COMPRESS_H
+#define MUPDF_FITZ_COMPRESS_H
+
+#include "mupdf/fitz/system.h"
+
+typedef enum
+{
+	FZ_DEFLATE_NONE = 0,
+	FZ_DEFLATE_BEST_SPEED = 1,
+	FZ_DEFLATE_BEST = 9,
+	FZ_DEFLATE_DEFAULT = -1
+} fz_deflate_level;
+
+/*
+	fz_deflate_bound: Returns the upper bound on the
+	size of flated data of length size.
+ */
+size_t fz_deflate_bound(fz_context *ctx, size_t size);
+
+/*
+	fz_deflate: Compress source_length bytes of data starting
+	at source, into a buffer of length *destLen, starting at dest.
+	*compressed_length will be updated on exit to contain the size
+	actually used.
+ */
+void fz_deflate(fz_context *ctx, unsigned char *dest, size_t *compressed_length, const unsigned char *source, size_t source_length, fz_deflate_level level);
+
+/*
+	fz_new_deflated_data: Compress source_length bytes of data starting
+	at source, into a new memory block malloced for that purpose.
+	*compressed_length is updated on exit to contain the size used.
+	Ownership of the block is returned from this function, and the
+	caller is therefore responsible for freeing it. The block may be
+	considerably larger than is actually required. The caller is
+	free to fz_realloc it down if it wants to.
+*/
+unsigned char *fz_new_deflated_data(fz_context *ctx, size_t *compressed_length, const unsigned char *source, size_t source_length, fz_deflate_level level);
+
+/*
+	fz_new_deflated_data_from_buffer: Compress the contents of a fz_buffer into a
+	new block malloced for that purpose. *compressed_length is updated
+	on exit to contain the size used. Ownership of the block is
+	returned from this function, and the caller is therefore responsible
+	for freeing it. The block may be considerably larger than is
+	actually required. The caller is free to fz_realloc it down if it
+	wants to.
+*/
+unsigned char *fz_new_deflated_data_from_buffer(fz_context *ctx, size_t *compressed_length, fz_buffer *buffer, fz_deflate_level level);
+
+#endif
diff --git a/platform/win32/libmupdf.vcproj b/platform/win32/libmupdf.vcproj
index 02bed939..024591db 100644
--- a/platform/win32/libmupdf.vcproj
+++ b/platform/win32/libmupdf.vcproj
@@ -1545,6 +1545,10 @@
 				>
 			</File>
 			<File
+				RelativePath="..\..\source\fitz\compress.c"
+				>
+			</File>
+			<File
 				RelativePath="..\..\source\fitz\compressed-buffer.c"
 				>
 			</File>
@@ -2316,6 +2320,10 @@
 					>
 				</File>
 				<File
+					RelativePath="..\..\include\mupdf\fitz\compress.h"
+					>
+				</File>
+				<File
 					RelativePath="..\..\include\mupdf\fitz\compressed-buffer.h"
 					>
 				</File>
diff --git a/source/fitz/compress.c b/source/fitz/compress.c
new file mode 100644
index 00000000..439c461e
--- /dev/null
+++ b/source/fitz/compress.c
@@ -0,0 +1,97 @@
+#include "mupdf/fitz.h"
+
+#include <zlib.h>
+
+static void *fz_z_alloc(void *opaque, unsigned int count, unsigned int size)
+{
+	fz_context *ctx = (fz_context *)opaque;
+	size_t c = count * size;
+
+	return fz_malloc_no_throw(ctx, c);
+}
+
+static void fz_z_free(void *opaque, void *addr)
+{
+	fz_context *ctx = (fz_context *)opaque;
+
+	fz_free(ctx, addr);
+}
+
+void fz_deflate(fz_context *ctx, unsigned char *dest, size_t *destLen, const unsigned char *source, size_t sourceLen, fz_deflate_level level)
+{
+	z_stream stream;
+	int err;
+	size_t left;
+
+	left = *destLen;
+	*destLen = 0;
+
+	stream.zalloc = fz_z_alloc;
+	stream.zfree = fz_z_free;
+	stream.opaque = ctx;
+
+	err = deflateInit(&stream, (int)level);
+	if (err != Z_OK)
+		fz_throw(ctx, FZ_ERROR_GENERIC, "zlib compression failed: %d", err);
+
+	stream.next_out = dest;
+	stream.avail_out = 0;
+	stream.next_in = (z_const Bytef *)source;
+	stream.avail_in = 0;
+
+	do {
+		if (stream.avail_out == 0) {
+			stream.avail_out = left > UINT_MAX ? UINT_MAX : (uInt)left;
+			left -= stream.avail_out;
+		}
+		if (stream.avail_in == 0) {
+			stream.avail_in = sourceLen > UINT_MAX ? UINT_MAX : (uInt)sourceLen;
+			sourceLen -= stream.avail_in;
+		}
+		err = deflate(&stream, sourceLen ? Z_NO_FLUSH : Z_FINISH);
+	} while (err == Z_OK);
+
+	/* We might have problems if the compressed length > uLong sized. Tough, for now. */
+	*destLen = stream.total_out;
+	deflateEnd(&stream);
+	if (err != Z_STREAM_END)
+		fz_throw(ctx, FZ_ERROR_GENERIC, "Zlib failure: %d", err);
+}
+
+unsigned char *fz_new_deflated_data(fz_context *ctx, size_t *compressed_length, const unsigned char *source, size_t source_length, fz_deflate_level level)
+{
+	size_t bound = fz_deflate_bound(ctx, source_length);
+	unsigned char *cdata = fz_malloc(ctx, bound);
+	*compressed_length = 0;
+
+	fz_try(ctx)
+		fz_deflate(ctx, cdata, &bound, source, source_length, level);
+	fz_catch(ctx)
+	{
+		fz_free(ctx, cdata);
+		fz_rethrow(ctx);
+	}
+
+	*compressed_length = bound;
+	return cdata;
+}
+
+unsigned char *fz_new_deflated_data_from_buffer(fz_context *ctx, size_t *compressed_length, fz_buffer *buffer, fz_deflate_level level)
+{
+	unsigned char *data;
+	size_t size = fz_buffer_storage(ctx, buffer, &data);
+
+	if (size == 0 || data == NULL)
+	{
+		*compressed_length = 0;
+		return NULL;
+	}
+
+	return fz_new_deflated_data(ctx, compressed_length, data, size, level);
+}
+
+size_t fz_deflate_bound(fz_context *ctx, size_t size)
+{
+	/* Copied from zlib to account for size_t vs uLong */
+	return size + (size >> 12) + (size >> 14) + (size >> 25) + 13;
+}
diff --git a/source/fitz/output-pclm.c b/source/fitz/output-pclm.c
index 52f673a1..0d1f728c 100644
--- a/source/fitz/output-pclm.c
+++ b/source/fitz/output-pclm.c
@@ -122,7 +122,7 @@ pclm_write_header(fz_context *ctx, fz_band_writer *writer_, const fz_colorspace
 	fz_free(ctx, writer->stripbuf);
 	fz_free(ctx, writer->compbuf);
 	writer->stripbuf = fz_malloc(ctx, w * sh * n);
-	writer->complen = compressBound(w * sh * n);
+	writer->complen = fz_deflate_bound(ctx, w * sh * n);
 	writer->compbuf = fz_malloc(ctx, writer->complen);
 
 	/* Send the file header on the first page */
@@ -193,9 +193,7 @@ flush_strip(fz_context *ctx, pclm_band_writer *writer, int fill)
 	if (writer->options.compress)
 	{
 		uLongf destLen = writer->complen;
-		int err = compress(writer->compbuf, &destLen, data, (uLongf)len);
-		if (err != Z_OK)
-			fz_throw(ctx, FZ_ERROR_GENERIC, "cannot compress strip: %d", err);
+		fz_deflate(ctx, writer->compbuf, &destLen, data, len, FZ_DEFLATE_DEFAULT);
 		len = destLen;
 		data = writer->compbuf;
 	}
diff --git a/source/fitz/output-png.c b/source/fitz/output-png.c
index 38bfa778..d21bc59b 100644
--- a/source/fitz/output-png.c
+++ b/source/fitz/output-png.c
@@ -86,34 +86,18 @@ static void
 png_write_icc(fz_context *ctx, png_band_writer *writer, const fz_colorspace *cs)
 {
 	fz_output *out = writer->super.out;
-	int size;
+	size_t size, csize;
 	fz_buffer *buffer = fz_icc_data_from_icc_colorspace(ctx, cs);
-	unsigned char *data;
 	unsigned char *pos, *cdata, *chunk = NULL;
-	uLong bound;
-	uLongf csize;
-	uLong long_size;
-	int t;
 
-	long_size = (uLong)fz_buffer_storage(ctx, buffer, &data);
+	/* Deflate the profile */
+	cdata = fz_new_deflated_data_from_buffer(ctx, &csize, buffer, FZ_DEFLATE_DEFAULT);
 
-	if (!data)
+	if (!cdata)
 		return;
 
-	/* Deflate the profile */
-	bound = compressBound(long_size);
-	cdata = fz_malloc(ctx, bound);
-	csize = (uLongf)bound;
-	t = compress(cdata, &csize, data, long_size);
-	if (t != Z_OK)
-	{
-		fz_free(ctx, cdata);
-		fz_throw(ctx, FZ_ERROR_GENERIC, "cannot deflate icc buffer");
-	}
 	size = csize + strlen("MuPDF Profile") + 2;
 
-	fz_var(cdata);
-
 	fz_try(ctx)
 	{
 		chunk = fz_calloc(ctx, size, 1);