1 files changed, 97 insertions, 0 deletions
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;
+}