Factorize out code used for MS RLE format decoding in different decoders.

Originally committed as revision 15356 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 254 insertions, 0 deletions

diff --git a/libavcodec/msrledec.c b/libavcodec/msrledec.c
new file mode 100644
index 0000000000..f44b8b6d12
--- /dev/null
+++ b/libavcodec/msrledec.c
@@ -0,0 +1,254 @@
+/*
+ * Micrsoft RLE Decoder
+ * Copyright (C) 2008 Konstantin Shishkov
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file msrledec.c
+ * MS RLE Decoder based on decoder by Mike Melanson and my own for TSCC
+ * For more information about the MS RLE format, visit:
+ *   http://www.multimedia.cx/msrle.txt
+ */
+
+#include "avcodec.h"
+
+#define FETCH_NEXT_STREAM_BYTE() \
+    if (stream_ptr >= data_size) \
+    { \
+      av_log(avctx, AV_LOG_ERROR, " MS RLE: stream ptr just went out of bounds (1)\n"); \
+      return -1; \
+    } \
+    stream_byte = data[stream_ptr++];
+
+static int msrle_decode_pal4(AVCodecContext *avctx, AVPicture *pic,
+                              const uint8_t *data, int data_size)
+{
+    int stream_ptr = 0;
+    unsigned char rle_code;
+    unsigned char extra_byte, odd_pixel;
+    unsigned char stream_byte;
+    int pixel_ptr = 0;
+    int row_dec = pic->linesize[0];
+    int row_ptr = (avctx->height - 1) * row_dec;
+    int frame_size = row_dec * avctx->height;
+    int i;
+
+    while (row_ptr >= 0) {
+        FETCH_NEXT_STREAM_BYTE();
+        rle_code = stream_byte;
+        if (rle_code == 0) {
+            /* fetch the next byte to see how to handle escape code */
+            FETCH_NEXT_STREAM_BYTE();
+            if (stream_byte == 0) {
+                /* line is done, goto the next one */
+                row_ptr -= row_dec;
+                pixel_ptr = 0;
+            } else if (stream_byte == 1) {
+                /* decode is done */
+                return 0;
+            } else if (stream_byte == 2) {
+                /* reposition frame decode coordinates */
+                FETCH_NEXT_STREAM_BYTE();
+                pixel_ptr += stream_byte;
+                FETCH_NEXT_STREAM_BYTE();
+                row_ptr -= stream_byte * row_dec;
+        } else {
+            // copy pixels from encoded stream
+            odd_pixel =  stream_byte & 1;
+            rle_code = (stream_byte + 1) / 2;
+            extra_byte = rle_code & 0x01;
+            if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
+                (row_ptr < 0)) {
+                av_log(avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
+                return -1;
+            }
+
+            for (i = 0; i < rle_code; i++) {
+                if (pixel_ptr >= avctx->width)
+                    break;
+                FETCH_NEXT_STREAM_BYTE();
+                pic->data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
+                pixel_ptr++;
+                if (i + 1 == rle_code && odd_pixel)
+                    break;
+                if (pixel_ptr >= avctx->width)
+                    break;
+                pic->data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
+                pixel_ptr++;
+            }
+
+            // if the RLE code is odd, skip a byte in the stream
+            if (extra_byte)
+              stream_ptr++;
+            }
+        } else {
+            // decode a run of data
+            if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
+                (row_ptr < 0)) {
+                av_log(avctx, AV_LOG_ERROR, " MS RLE: frame ptr just went out of bounds (1)\n");
+                return -1;
+            }
+            FETCH_NEXT_STREAM_BYTE();
+            for (i = 0; i < rle_code; i++) {
+                if (pixel_ptr >= avctx->width)
+                    break;
+                if ((i & 1) == 0)
+                    pic->data[0][row_ptr + pixel_ptr] = stream_byte >> 4;
+                else
+                    pic->data[0][row_ptr + pixel_ptr] = stream_byte & 0x0F;
+                pixel_ptr++;
+            }
+        }
+    }
+
+    /* one last sanity check on the way out */
+    if (stream_ptr < data_size) {
+        av_log(avctx, AV_LOG_ERROR, " MS RLE: ended frame decode with bytes left over (%d < %d)\n",
+            stream_ptr, data_size);
+        return -1;
+    }
+
+    return 0;
+}
+
+
+static int msrle_decode_8_16_24_32(AVCodecContext *avctx, AVPicture *pic, int depth,
+                                    const uint8_t *data, int srcsize)
+{
+    uint8_t *output, *output_end;
+    const uint8_t* src = data;
+    int p1, p2, line=avctx->height, pos=0, i;
+    uint16_t pix16;
+    uint32_t pix32;
+
+    output = pic->data[0] + (avctx->height - 1) * pic->linesize[0];
+    output_end = pic->data[0] + (avctx->height) * pic->linesize[0];
+    while(src < data + srcsize) {
+        p1 = *src++;
+        if(p1 == 0) { //Escape code
+            p2 = *src++;
+            if(p2 == 0) { //End-of-line
+                output = pic->data[0] + (--line) * pic->linesize[0];
+                if (line < 0)
+                    return -1;
+                pos = 0;
+                continue;
+            } else if(p2 == 1) { //End-of-picture
+                return 0;
+            } else if(p2 == 2) { //Skip
+                p1 = *src++;
+                p2 = *src++;
+                line -= p2;
+                if (line < 0)
+                    return -1;
+                pos += p1;
+                output = pic->data[0] + line * pic->linesize[0] + pos * (depth >> 3);
+                continue;
+            }
+            // Copy data
+            if (output + p2 * (depth >> 3) > output_end) {
+                src += p2 * (depth >> 3);
+                continue;
+            }
+            if ((depth == 8) || (depth == 24)) {
+                for(i = 0; i < p2 * (depth >> 3); i++) {
+                    *output++ = *src++;
+                }
+                // RLE8 copy is actually padded - and runs are not!
+                if(depth == 8 && (p2 & 1)) {
+                    src++;
+                }
+            } else if (depth == 16) {
+                for(i = 0; i < p2; i++) {
+                    pix16 = AV_RL16(src);
+                    src += 2;
+                    *(uint16_t*)output = pix16;
+                    output += 2;
+                }
+            } else if (depth == 32) {
+                for(i = 0; i < p2; i++) {
+                    pix32 = AV_RL32(src);
+                    src += 4;
+                    *(uint32_t*)output = pix32;
+                    output += 4;
+                }
+            }
+            pos += p2;
+        } else { //Run of pixels
+            int pix[4]; //original pixel
+            switch(depth){
+            case  8: pix[0] = *src++;
+                     break;
+            case 16: pix16 = AV_RL16(src);
+                     src += 2;
+                     *(uint16_t*)pix = pix16;
+                     break;
+            case 24: pix[0] = *src++;
+                     pix[1] = *src++;
+                     pix[2] = *src++;
+                     break;
+            case 32: pix32 = AV_RL32(src);
+                     src += 4;
+                     *(uint32_t*)pix = pix32;
+                     break;
+            }
+            if (output + p1 * (depth >> 3) > output_end)
+                continue;
+            for(i = 0; i < p1; i++) {
+                switch(depth){
+                case  8: *output++ = pix[0];
+                         break;
+                case 16: *(uint16_t*)output = pix16;
+                         output += 2;
+                         break;
+                case 24: *output++ = pix[0];
+                         *output++ = pix[1];
+                         *output++ = pix[2];
+                         break;
+                case 32: *(uint32_t*)output = pix32;
+                         output += 4;
+                         break;
+                }
+            }
+            pos += p1;
+        }
+    }
+
+    av_log(avctx, AV_LOG_WARNING, "MS RLE warning: no End-of-picture code\n");
+    return 0;
+}
+
+
+int ff_msrle_decode(AVCodecContext *avctx, AVPicture *pic, int depth,
+                    const uint8_t* data, int data_size)
+{
+    switch(depth){
+    case  4:
+        return msrle_decode_pal4(avctx, pic, data, data_size);
+    case  8:
+    case 16:
+    case 24:
+    case 32:
+        return msrle_decode_8_16_24_32(avctx, pic, depth, data, data_size);
+    default:
+        av_log(avctx, AV_LOG_ERROR, "Unknown depth %d\n", depth);
+        return -1;
+    }
+}
+