1 files changed, 92 insertions, 0 deletions
diff --git a/Imaging/libImaging/PackDecode.c b/Imaging/libImaging/PackDecode.c
new file mode 100644
index 0000000..267aa85
--- /dev/null
+++ b/Imaging/libImaging/PackDecode.c
@@ -0,0 +1,92 @@
+/*
+ * The Python Imaging Library.
+ * $Id: PackDecode.c 2134 2004-10-06 08:55:20Z fredrik $
+ *
+ * decoder for PackBits image data.
+ *
+ * history:
+ *	96-04-19 fl	Created
+ *
+ * Copyright (c) Fredrik Lundh 1996.
+ * Copyright (c) Secret Labs AB 1997.
+ *
+ * See the README file for information on usage and redistribution.
+ */
+
+
+#include "Imaging.h"
+
+int
+ImagingPackbitsDecode(Imaging im, ImagingCodecState state,
+		      UINT8* buf, int bytes)
+{
+    UINT8 n;
+    UINT8* ptr;
+    int i;
+
+    ptr = buf;
+
+    for (;;) {
+
+	if (bytes < 1)
+	    return ptr - buf;
+
+	if (ptr[0] & 0x80) {
+
+	    if (ptr[0] == 0x80) {
+		/* Nop */
+		ptr++; bytes--;
+		continue;
+	    }
+
+	    /* Run */
+	    if (bytes < 2)
+		return ptr - buf;
+
+	    for (n = 257 - ptr[0]; n > 0; n--) {
+		if (state->x >= state->bytes) {
+		    /* state->errcode = IMAGING_CODEC_OVERRUN; */
+		    break;
+		}
+		state->buffer[state->x++] = ptr[1];
+	    }
+
+	    ptr += 2; bytes -= 2;
+
+	} else {
+
+	    /* Literal */
+	    n = ptr[0]+2;
+
+	    if (bytes < n)
+		return ptr - buf;
+
+	    for (i = 1; i < n; i++) {
+		if (state->x >= state->bytes) {
+		    /* state->errcode = IMAGING_CODEC_OVERRUN; */
+		    break;
+		}
+		state->buffer[state->x++] = ptr[i];
+	    }
+
+	    ptr += n; bytes -= n;
+
+	}
+
+	if (state->x >= state->bytes) {
+
+	    /* Got a full line, unpack it */
+	    state->shuffle((UINT8*) im->image[state->y + state->yoff] +
+			   state->xoff * im->pixelsize, state->buffer,
+			   state->xsize);
+
+	    state->x = 0;
+
+	    if (++state->y >= state->ysize) {
+		/* End of file (errcode = 0) */
+		return -1;
+	    }
+	}
+
+    }
+}