3 files changed, 84 insertions, 4 deletions

diff --git a/source/fitz/compressed-buffer.c b/source/fitz/compressed-buffer.c
index e62feee0..b25709d9 100644
--- a/source/fitz/compressed-buffer.c
+++ b/source/fitz/compressed-buffer.c
@@ -14,11 +14,16 @@ fz_free_compressed_buffer(fz_context *ctx, fz_compressed_buffer *buf)
 }
 
 fz_stream *
-fz_open_image_decomp_stream(fz_context *ctx, fz_compressed_buffer *buffer, int *l2factor)
+fz_open_image_decomp_stream_from_buffer(fz_context *ctx, fz_compressed_buffer *buffer, int *l2factor)
 {
 	fz_stream *chain = fz_open_buffer(ctx, buffer->buffer);
-	fz_compression_params *params = &buffer->params;
 
+	return fz_open_image_decomp_stream(ctx, chain, &buffer->params, l2factor);
+}
+
+fz_stream *
+fz_open_image_decomp_stream(fz_context *ctx, fz_stream *chain, fz_compression_params *params, int *l2factor)
+{
 	switch (params->type)
 	{
 	case FZ_IMAGE_FAX:
@@ -63,7 +68,7 @@ fz_open_compressed_buffer(fz_context *ctx, fz_compressed_buffer *buffer)
 {
 	int l2factor = 0;
 
-	return fz_open_image_decomp_stream(ctx, buffer, &l2factor);
+	return fz_open_image_decomp_stream_from_buffer(ctx, buffer, &l2factor);
 }
 
 unsigned int
diff --git a/source/fitz/filter-leech.c b/source/fitz/filter-leech.c
new file mode 100644
index 00000000..321e31d7
--- /dev/null
+++ b/source/fitz/filter-leech.c
@@ -0,0 +1,75 @@
+#include "mupdf/fitz.h"
+
+#include <zlib.h>
+
+typedef struct fz_leech_s fz_leech;
+
+struct fz_leech_s
+{
+	fz_stream *chain;
+	fz_buffer *buffer;
+};
+
+static int
+next_leech(fz_stream *stm, int max)
+{
+	fz_leech *state = stm->state;
+	fz_buffer *buffer = state->buffer;
+	int n = fz_available(state->chain, max);
+
+	if (n > max)
+		n = max;
+
+	while (buffer->cap < buffer->len + n)
+	{
+		fz_grow_buffer(stm->ctx, state->buffer);
+	}
+	memcpy(buffer->data + buffer->len, state->chain->rp, n);
+	stm->rp = buffer->data + buffer->len;
+	stm->wp = buffer->data + buffer->len + n;
+	state->chain->rp += n;
+	buffer->len += n;
+
+	if (n == 0)
+		return EOF;
+	return *stm->rp++;
+}
+
+static void
+close_leech(fz_context *ctx, void *state_)
+{
+	fz_leech *state = (fz_leech *)state_;
+
+	fz_close(state->chain);
+	fz_free(ctx, state);
+}
+
+static fz_stream *
+rebind_leech(fz_stream *s)
+{
+	fz_leech *state = s->state;
+	return state->chain;
+}
+
+fz_stream *
+fz_open_leecher(fz_stream *chain, fz_buffer *buffer)
+{
+	fz_leech *state = NULL;
+	fz_context *ctx = chain->ctx;
+
+	fz_var(state);
+
+	fz_try(ctx)
+	{
+		state = fz_malloc_struct(ctx, fz_leech);
+		state->chain = chain;
+		state->buffer = buffer;
+	}
+	fz_catch(ctx)
+	{
+		fz_free(ctx, state);
+		fz_close(chain);
+		fz_rethrow(ctx);
+	}
+	return fz_new_stream(ctx, state, next_leech, close_leech, rebind_leech);
+}
diff --git a/source/fitz/image.c b/source/fitz/image.c
index 54889b1c..3ee5f88d 100644
--- a/source/fitz/image.c
+++ b/source/fitz/image.c
@@ -280,7 +280,7 @@ fz_image_get_pixmap(fz_context *ctx, fz_image *image, int w, int h)
 		break;
 	default:
 		native_l2factor = l2factor;
-		stm = fz_open_image_decomp_stream(ctx, image->buffer, &native_l2factor);
+		stm = fz_open_image_decomp_stream_from_buffer(ctx, image->buffer, &native_l2factor);
 
 		indexed = fz_colorspace_is_indexed(image->colorspace);
 		tile = fz_decomp_image_from_stream(ctx, stm, image, indexed, l2factor, native_l2factor);