1 files changed, 75 insertions, 0 deletions
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);
+}