targa: convert to bytestream2.

Also remove some write-only variables or write-only variable
assignments, remove internal colorspace conversion to native
endianness (that can be done by swscale much more efficiently),
and some cosmetics.

libavcodec/targa.c

@@ -27,83 +27,76 @@
 
 typedef struct TargaContext {
     AVFrame picture;
+    GetByteContext gb;
 
-    int width, height;
-    int bpp;
     int color_type;
     int compression_type;
 } TargaContext;
 
-#define CHECK_BUFFER_SIZE(buf, buf_end, needed, where) \
-    if(needed > buf_end - buf){ \
-        av_log(avctx, AV_LOG_ERROR, "Problem: unexpected end of data while reading " where "\n"); \
-        return -1; \
-    } \
-
-static int targa_decode_rle(AVCodecContext *avctx, TargaContext *s, const uint8_t *src, int src_size, uint8_t *dst, int w, int h, int stride, int bpp)
+static int targa_decode_rle(AVCodecContext *avctx, TargaContext *s,
+                            uint8_t *dst, int w, int h, int stride, int bpp)
 {
-    int i, x, y;
+    int x, y;
     int depth = (bpp + 1) >> 3;
     int type, count;
     int diff;
-    const uint8_t *src_end = src + src_size;
 
     diff = stride - w * depth;
     x = y = 0;
-    while(y < h){
-        CHECK_BUFFER_SIZE(src, src_end, 1, "image type");
-        type = *src++;
+    while (y < h) {
+        if (bytestream2_get_bytes_left(&s->gb) <= 0) {
+            av_log(avctx, AV_LOG_ERROR,
+                   "Ran ouf of data before end-of-image\n");
+            return AVERROR_INVALIDDATA;
+        }
+        type  = bytestream2_get_byteu(&s->gb);
         count = (type & 0x7F) + 1;
         type &= 0x80;
-        if((x + count > w) && (x + count + 1 > (h - y) * w)){
-            av_log(avctx, AV_LOG_ERROR, "Packet went out of bounds: position (%i,%i) size %i\n", x, y, count);
-            return -1;
+        if (x + count > w && x + count + 1 > (h - y) * w) {
+            av_log(avctx, AV_LOG_ERROR,
+                   "Packet went out of bounds: position (%i,%i) size %i\n",
+                   x, y, count);
+            return AVERROR_INVALIDDATA;
         }
-        if(type){
-            CHECK_BUFFER_SIZE(src, src_end, depth, "image data");
-        }else{
-            CHECK_BUFFER_SIZE(src, src_end, count * depth, "image data");
-        }
-        for(i = 0; i < count; i++){
-            switch(depth){
-            case 1:
-                *dst = *src;
-                break;
-            case 2:
-                *((uint16_t*)dst) = AV_RL16(src);
-                break;
-            case 3:
-                dst[0] = src[0];
-                dst[1] = src[1];
-                dst[2] = src[2];
-                break;
-            case 4:
-                *((uint32_t*)dst) = AV_RL32(src);
-                break;
-            }
-            dst += depth;
-            if(!type)
-                src += depth;
-
-            x++;
-            if(x == w){
-                x = 0;
-                y++;
-                dst += diff;
-            }
+        if (!type) {
+            do {
+                int n  = FFMIN(count, w - x);
+                bytestream2_get_buffer(&s->gb, dst, n * depth);
+                count -= n;
+                dst   += n * depth;
+                x     += n;
+                if (x == w) {
+                    x    = 0;
+                    y++;
+                    dst += diff;
+                }
+            } while (count > 0);
+        } else {
+            uint8_t tmp[4];
+            bytestream2_get_buffer(&s->gb, tmp, depth);
+            do {
+                int n  = FFMIN(count, w - x);
+                count -= n;
+                x     += n;
+                do {
+                    memcpy(dst, tmp, depth);
+                    dst += depth;
+                } while (--n);
+                if (x == w) {
+                    x    = 0;
+                    y++;
+                    dst += diff;
+                }
+            } while (count > 0);
         }
-        if(type)
-            src += depth;
     }
-    return src_size;
+    return 0;
 }
 
 static int decode_frame(AVCodecContext *avctx,
                         void *data, int *data_size,
                         AVPacket *avpkt)
 {
-    const uint8_t *buf = avpkt->data;
-    const uint8_t *buf_end = avpkt->data + avpkt->size;
     TargaContext * const s = avctx->priv_data;
     AVFrame *picture = data;
     AVFrame * const p = &s->picture;
@@ -112,44 +105,41 @@ static int decode_frame(AVCodecContext *avctx,
     int idlen, compr, y, w, h, bpp, flags;
     int first_clr, colors, csize;
 
+    bytestream2_init(&s->gb, avpkt->data, avpkt->size);
+
     /* parse image header */
-    CHECK_BUFFER_SIZE(buf, buf_end, 18, "header");
-    idlen = *buf++;
-    buf++; /* pal */
-    compr = *buf++;
-    first_clr = AV_RL16(buf); buf += 2;
-    colors = AV_RL16(buf); buf += 2;
-    csize = *buf++;
-    buf += 2; /* x */
-    y = AV_RL16(buf); buf += 2;
-    w = AV_RL16(buf); buf += 2;
-    h = AV_RL16(buf); buf += 2;
-    bpp = *buf++;
-    flags = *buf++;
-    //skip identifier if any
-    CHECK_BUFFER_SIZE(buf, buf_end, idlen, "identifiers");
-    buf += idlen;
-    s->bpp = bpp;
-    s->width = w;
-    s->height = h;
-    switch(s->bpp){
+    idlen     = bytestream2_get_byte(&s->gb);
+    bytestream2_skip(&s->gb, 1); /* pal */
+    compr     = bytestream2_get_byte(&s->gb);
+    first_clr = bytestream2_get_le16(&s->gb);
+    colors    = bytestream2_get_le16(&s->gb);
+    csize     = bytestream2_get_byte(&s->gb);
+    bytestream2_skip(&s->gb, 4); /* 2: x, 2: y */
+    w         = bytestream2_get_le16(&s->gb);
+    h         = bytestream2_get_le16(&s->gb);
+    bpp       = bytestream2_get_byte(&s->gb);
+    flags     = bytestream2_get_byte(&s->gb);
+    // skip identifier if any
+    bytestream2_skip(&s->gb, idlen);
+
+    switch(bpp){
     case 8:
         avctx->pix_fmt = ((compr & (~TGA_RLE)) == TGA_BW) ? PIX_FMT_GRAY8 : PIX_FMT_PAL8;
         break;
     case 15:
-        avctx->pix_fmt = PIX_FMT_RGB555;
+        avctx->pix_fmt = PIX_FMT_RGB555LE;
         break;
     case 16:
-        avctx->pix_fmt = PIX_FMT_RGB555;
+        avctx->pix_fmt = PIX_FMT_RGB555LE;
         break;
     case 24:
         avctx->pix_fmt = PIX_FMT_BGR24;
         break;
     case 32:
-        avctx->pix_fmt = PIX_FMT_RGB32;
+        avctx->pix_fmt = PIX_FMT_BGRA;
         break;
     default:
-        av_log(avctx, AV_LOG_ERROR, "Bit depth %i is not supported\n", s->bpp);
+        av_log(avctx, AV_LOG_ERROR, "Bit depth %i is not supported\n", bpp);
         return -1;
     }
 
@@ -187,23 +177,27 @@ static int decode_frame(AVCodecContext *avctx,
             return -1;
         }
         pal_size = colors * pal_sample_size;
-        CHECK_BUFFER_SIZE(buf, buf_end, pal_size, "color table");
         if(avctx->pix_fmt != PIX_FMT_PAL8)//should not occur but skip palette anyway
-            buf += pal_size;
+            bytestream2_skip(&s->gb, pal_size);
         else{
             int t;
             uint32_t *pal = ((uint32_t *)p->data[1]) + first_clr;
 
+            if (bytestream2_get_bytes_left(&s->gb) < pal_size) {
+                av_log(avctx, AV_LOG_ERROR,
+                       "Not enough data to read palette\n");
+                return AVERROR_INVALIDDATA;
+            }
             switch (pal_sample_size) {
             case 3:
                 /* RGB24 */
                 for (t = 0; t < colors; t++)
-                    *pal++ = bytestream_get_le24(&buf);
+                    *pal++ = bytestream2_get_le24u(&s->gb);
                 break;
             case 2:
                 /* RGB555 */
                 for (t = 0; t < colors; t++) {
-                    uint32_t v = bytestream_get_le16(&buf);
+                    uint32_t v = bytestream2_get_le16u(&s->gb);
                     v = ((v & 0x7C00) <<  9) |
                         ((v & 0x03E0) <<  6) |
                         ((v & 0x001F) <<  3);
@@ -216,34 +210,23 @@ static int decode_frame(AVCodecContext *avctx,
             p->palette_has_changed = 1;
         }
     }
-    if((compr & (~TGA_RLE)) == TGA_NODATA)
-        memset(p->data[0], 0, p->linesize[0] * s->height);
-    else{
+    if ((compr & (~TGA_RLE)) == TGA_NODATA) {
+        memset(p->data[0], 0, p->linesize[0] * h);
+    } else {
         if(compr & TGA_RLE){
-            int res = targa_decode_rle(avctx, s, buf, buf_end - buf, dst, avctx->width, avctx->height, stride, bpp);
+            int res = targa_decode_rle(avctx, s, dst, w, h, stride, bpp);
             if (res < 0)
-                return -1;
-            buf += res;
-        }else{
-            size_t img_size = s->width * ((s->bpp + 1) >> 3);
-            CHECK_BUFFER_SIZE(buf, buf_end, img_size, "image data");
-            for(y = 0; y < s->height; y++){
-#if HAVE_BIGENDIAN
-                int x;
-                if((s->bpp + 1) >> 3 == 2){
-                    uint16_t *dst16 = (uint16_t*)dst;
-                    for(x = 0; x < s->width; x++)
-                        dst16[x] = AV_RL16(buf + x * 2);
-                }else if((s->bpp + 1) >> 3 == 4){
-                    uint32_t *dst32 = (uint32_t*)dst;
-                    for(x = 0; x < s->width; x++)
-                        dst32[x] = AV_RL32(buf + x * 4);
-                }else
-#endif
-                    memcpy(dst, buf, img_size);
-
+                return res;
+        } else {
+            size_t img_size = w * ((bpp + 1) >> 3);
+            if (bytestream2_get_bytes_left(&s->gb) < img_size * h) {
+                av_log(avctx, AV_LOG_ERROR,
+                       "Not enough data available for image\n");
+                return AVERROR_INVALIDDATA;
+            }
+            for (y = 0; y < h; y++) {
+                bytestream2_get_bufferu(&s->gb, dst, img_size);
                 dst += stride;
-                buf += img_size;
             }
         }
     }