1 files changed, 54 insertions, 0 deletions
diff --git a/fitz/filt_null.c b/fitz/filt_null.c
new file mode 100644
index 00000000..601ed815
--- /dev/null
+++ b/fitz/filt_null.c
@@ -0,0 +1,54 @@
+#include "fitz-base.h"
+#include "fitz-stream.h"
+
+typedef struct fz_nullfilter_s fz_nullfilter;
+
+struct fz_nullfilter_s
+{
+	fz_filter super;
+	int len;
+	int cur;
+};
+
+fz_error *
+fz_newnullfilter(fz_filter **fp, int len)
+{
+	FZ_NEWFILTER(fz_nullfilter, f, nullfilter);
+	f->len = len;
+	f->cur = 0;
+	return fz_okay;
+}
+
+void
+fz_dropnullfilter(fz_filter *f)
+{
+}
+
+fz_error *
+fz_processnullfilter(fz_filter *filter, fz_buffer *in, fz_buffer *out)
+{
+	fz_nullfilter *f = (fz_nullfilter*)filter;
+	int n;
+
+	n = MIN(in->wp - in->rp, out->ep - out->wp);
+	if (f->len >= 0)
+	    n = MIN(n, f->len - f->cur);
+
+	if (n)
+	{
+		memcpy(out->wp, in->rp, n);
+		in->rp += n;
+		out->wp += n;
+		f->cur += n;
+	}
+
+	if (f->cur == f->len)
+		return fz_iodone;
+	if (in->rp == in->wp)
+		return fz_ioneedin;
+	if (out->wp == out->ep)
+		return fz_ioneedout;
+
+	return fz_throw("braindead programmer trapped in nullfilter");
+}
+