Distinguish between non-coded blocks and decode errors in rtjpeg's get_block

[frescor/ffmpeg.git] / libavcodec / rtjpeg.c

diff --git a/libavcodec/rtjpeg.c b/libavcodec/rtjpeg.c
index 8e5082023655fcfa83c7cf70330450f5b56ab403..4c48f25b2cde26b58e30146b40f471b82d5a9c0d 100644 (file)
--- a/libavcodec/rtjpeg.c
+++ b/libavcodec/rtjpeg.c
@@ -18,8 +18,8 @@
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
-#include "common.h"
-#include "bitstream.h"
+#include "libavutil/common.h"
+#include "get_bits.h"
 #include "dsputil.h"
 #include "rtjpeg.h"
 
@@ -38,13 +38,14 @@
  * \param block where data is written to
  * \param scan array containing the mapping stream address -> block position
  * \param quant quantization factors
+ * \return 0 means the block is not coded, < 0 means an error occurred.
  *
  * Note: GetBitContext is used to make the code simpler, since all data is
  * aligned this could be done faster in a different way, e.g. as it is done
- * in MPlayer libmpcodecs/native/RTjpegN.c
+ * in MPlayer libmpcodecs/native/rtjpegn.c.
  */
-static inline int get_block(GetBitContext *gb, DCTELEM *block, uint8_t *scan,
-                            uint32_t *quant) {
+static inline int get_block(GetBitContext *gb, DCTELEM *block, const uint8_t *scan,
+                            const uint32_t *quant) {
     int coeff, i, n;
     int8_t ac;
     uint8_t dc = get_bits(gb, 8);
@@ -55,6 +56,9 @@ static inline int get_block(GetBitContext *gb, DCTELEM *block, uint8_t *scan,
 
     // number of non-zero coefficients
     coeff = get_bits(gb, 6);
+    if (get_bits_count(gb) + (coeff << 1) >= gb->size_in_bits)
+        return -1;
+
     // normally we would only need to clear the (63 - coeff) last values,
     // but since we do not know where they are we just clear the whole block
     memset(block, 0, 64 * sizeof(DCTELEM));
@@ -69,6 +73,8 @@ static inline int get_block(GetBitContext *gb, DCTELEM *block, uint8_t *scan,
 
     // 4 bits per coefficient
     ALIGN(4);
+    if (get_bits_count(gb) + (coeff << 2) >= gb->size_in_bits)
+        return -1;
     while (coeff) {
         ac = get_sbits(gb, 4);
         if (ac == -8)
@@ -78,6 +84,8 @@ static inline int get_block(GetBitContext *gb, DCTELEM *block, uint8_t *scan,
 
     // 8 bits per coefficient
     ALIGN(8);
+    if (get_bits_count(gb) + (coeff << 3) >= gb->size_in_bits)
+        return -1;
     while (coeff) {
         ac = get_sbits(gb, 8);
         PUT_COEFF(ac);
@@ -97,32 +105,32 @@ static inline int get_block(GetBitContext *gb, DCTELEM *block, uint8_t *scan,
  * \return number of bytes consumed from the input buffer
  */
 int rtjpeg_decode_frame_yuv420(RTJpegContext *c, AVFrame *f,
-                               uint8_t *buf, int buf_size) {
-    DECLARE_ALIGNED_16(DCTELEM, block[64]);
+                               const uint8_t *buf, int buf_size) {
     GetBitContext gb;
     int w = c->w / 16, h = c->h / 16;
     int x, y;
-    void *y1 = f->data[0], *y2 = f->data[0] + 8 * f->linesize[0];
-    void *u = f->data[1], *v = f->data[2];
+    uint8_t *y1 = f->data[0], *y2 = f->data[0] + 8 * f->linesize[0];
+    uint8_t *u = f->data[1], *v = f->data[2];
     init_get_bits(&gb, buf, buf_size * 8);
     for (y = 0; y < h; y++) {
         for (x = 0; x < w; x++) {
-            if (get_block(&gb, block, c->scan, c->lquant))
+            DCTELEM *block = c->block;
+            if (get_block(&gb, block, c->scan, c->lquant) > 0)
                 c->dsp->idct_put(y1, f->linesize[0], block);
             y1 += 8;
-            if (get_block(&gb, block, c->scan, c->lquant))
+            if (get_block(&gb, block, c->scan, c->lquant) > 0)
                 c->dsp->idct_put(y1, f->linesize[0], block);
             y1 += 8;
-            if (get_block(&gb, block, c->scan, c->lquant))
+            if (get_block(&gb, block, c->scan, c->lquant) > 0)
                 c->dsp->idct_put(y2, f->linesize[0], block);
             y2 += 8;
-            if (get_block(&gb, block, c->scan, c->lquant))
+            if (get_block(&gb, block, c->scan, c->lquant) > 0)
                 c->dsp->idct_put(y2, f->linesize[0], block);
             y2 += 8;
-            if (get_block(&gb, block, c->scan, c->cquant))
+            if (get_block(&gb, block, c->scan, c->cquant) > 0)
                 c->dsp->idct_put(u, f->linesize[1], block);
             u += 8;
-            if (get_block(&gb, block, c->scan, c->cquant))
+            if (get_block(&gb, block, c->scan, c->cquant) > 0)
                 c->dsp->idct_put(v, f->linesize[2], block);
             v += 8;
         }
@@ -147,7 +155,7 @@ int rtjpeg_decode_frame_yuv420(RTJpegContext *c, AVFrame *f,
  */
 void rtjpeg_decode_init(RTJpegContext *c, DSPContext *dsp,
                         int width, int height,
-                        uint32_t *lquant, uint32_t *cquant) {
+                        const uint32_t *lquant, const uint32_t *cquant) {
     int i;
     c->dsp = dsp;
     for (i = 0; i < 64; i++) {