1 files changed, 67 insertions, 0 deletions
diff --git a/filter/rld.c b/filter/rld.c
new file mode 100644
index 00000000..a66e0f94
--- /dev/null
+++ b/filter/rld.c
@@ -0,0 +1,67 @@
+#include <fitz.h>
+
+fz_error *
+fz_newrld(fz_filter **fp, fz_obj *params)
+{
+	FZ_NEWFILTER(fz_filter, f, rld);
+	return nil;
+}
+
+void
+fz_freerld(fz_filter *rld)
+{
+	fz_free(rld);
+}
+
+fz_error *
+fz_processrld(fz_filter *filter, fz_buffer *in, fz_buffer *out)
+{
+	int run, i;
+	unsigned char c;
+
+	while (1)
+	{
+		if (in->rp == in->wp)
+			return fz_ioneedin;
+
+		if (out->wp == out->ep)
+			return fz_ioneedout;
+
+		run = *in->rp++;
+
+		if (run == 128) {
+			out->eof = 1;
+			return fz_iodone;
+		}
+
+		else if (run < 128) {
+			run = run + 1;
+			if (in->rp + run > in->wp) {
+				in->rp --;
+				return fz_ioneedin;
+			}
+			if (out->wp + run > out->ep) {
+				in->rp --;
+				return fz_ioneedout;
+			}
+			for (i = 0; i < run; i++)
+				*out->wp++ = *in->rp++;
+		}
+
+		else if (run > 128) {
+			run = 257 - run;
+			if (in->rp + 1 > in->wp) {
+				in->rp --;
+				return fz_ioneedin;
+			}
+			if (out->wp + run > out->ep) {
+				in->rp --;
+				return fz_ioneedout;
+			}
+			c = *in->rp++;
+			for (i = 0; i < run; i++)
+				*out->wp++ = c;
+		}
+	}
+}
+