1 files changed, 148 insertions, 0 deletions
diff --git a/Imaging/libImaging/PcxEncode.c b/Imaging/libImaging/PcxEncode.c
new file mode 100644
index 0000000..2c9d250
--- /dev/null
+++ b/Imaging/libImaging/PcxEncode.c
@@ -0,0 +1,148 @@
+/*
+ * The Python Imaging Library.
+ * $Id: PcxEncode.c 2134 2004-10-06 08:55:20Z fredrik $
+ *
+ * encoder for PCX data
+ *
+ * history:
+ * 99-02-07 fl	created
+ *
+ * Copyright (c) Fredrik Lundh 1999.
+ * Copyright (c) Secret Labs AB 1999.
+ *
+ * See the README file for information on usage and redistribution.
+ */
+
+
+#include "Imaging.h"
+
+enum { INIT, FETCH, ENCODE };
+
+/* we're reusing "ystep" to store the last value */
+#define LAST ystep
+
+int
+ImagingPcxEncode(Imaging im, ImagingCodecState state, UINT8* buf, int bytes)
+{
+    UINT8* ptr;
+    int this;
+
+    ptr = buf;
+
+    if (!state->state) {
+
+        /* sanity check */
+        if (state->xsize <= 0 || state->ysize <= 0) {
+            state->errcode = IMAGING_CODEC_END;
+            return 0;
+        }
+
+	state->bytes = (state->xsize*state->bits + 7) / 8;
+        state->state = FETCH;
+
+    }
+
+    for (;;)
+
+        switch (state->state) {
+        case FETCH:
+
+            /* get a line of data */
+            if (state->y >= state->ysize) {
+                state->errcode = IMAGING_CODEC_END;
+                return ptr - buf;
+            }
+
+            state->shuffle(state->buffer,
+                           (UINT8*) im->image[state->y + state->yoff] +
+                           state->xoff * im->pixelsize, state->xsize);
+
+            state->y++;
+
+            state->count = 1;
+            state->LAST = state->buffer[0];
+
+            state->x = 1;
+
+            state->state = ENCODE;
+            /* fall through */
+
+        case ENCODE:
+
+            /* compress this line */
+
+            /* when we arrive here, "count" contains the number of
+               bytes having the value of "LAST" that we've already
+               seen */
+
+            while (state->x < state->bytes) {
+
+                if (state->count == 63) {
+
+                    /* this run is full; flush it */
+                    if (bytes < 2)
+                        return ptr - buf;
+                    *ptr++ = 0xff;
+                    *ptr++ = state->LAST;
+                    bytes -= 2;
+
+                    state->count = 0;
+
+                }
+
+                this = state->buffer[state->x];
+
+                if (this == state->LAST) {
+
+                    /* extend the current run */
+                    state->x++;
+                    state->count++;
+
+                } else {
+
+                    /* start a new run */
+                    if (state->count == 1 && (state->LAST < 0xc0)) {
+                        if (bytes < 1)
+                            return ptr - buf;
+                        *ptr++ = state->LAST;
+                        bytes--;
+                    } else {
+                        if (state->count > 0) {
+                            if (bytes < 2)
+                                return ptr - buf;
+                            *ptr++ = 0xc0 | state->count;
+                            *ptr++ = state->LAST;
+                            bytes -= 2;
+                        }
+                    }
+
+                    state->LAST = this;
+                    state->count = 1;
+
+                    state->x++;
+
+                }
+            }
+
+            /* end of line; flush the current run */
+            if (state->count == 1 && (state->LAST < 0xc0)) {
+                if (bytes < 1)
+                    return ptr - buf;
+                *ptr++ = state->LAST;
+                bytes--;
+            } else {
+                if (state->count > 0) {
+                    if (bytes < 2)
+                        return ptr - buf;
+                    *ptr++ = 0xc0 | state->count;
+                    *ptr++ = state->LAST;
+                    bytes -= 2;
+                }
+            }
+
+            /* read next line */
+            state->state = FETCH;
+            break;
+
+        }
+}