[FFmpeg-devel] [PATCH v2 04/15] avcodec/adpcm: Fix undefined left shifts of negative numbers

[Andreas Rheinhardt]

Affected the adpcm-afc, adpcm-dtk, adpcm-ea-1, adpcm-ea-2, adpcm-ima-oki,
adpcm-ea-maxis-xa, adpcm-ea-r1, adpcm-ea-r2, adpcm-ea-r3 and adpcm-thp
FATE-tests.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
---
 libavcodec/adpcm.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/libavcodec/adpcm.c b/libavcodec/adpcm.c
index 7f2ebfc99d..a0c5b6a42a 100644
--- a/libavcodec/adpcm.c
+++ b/libavcodec/adpcm.c
@@ -342,7 +342,7 @@ static inline int16_t adpcm_ima_oki_expand_nibble(ADPCMChannelStatus *c, int nib
     c->predictor = av_clip_intp2(predictor, 11);
     c->step_index = step_index;
 
-    return c->predictor << 4;
+    return c->predictor * (1 << 4);
 }
 
 static inline int16_t adpcm_ct_expand_nibble(ADPCMChannelStatus *c, int8_t nibble)
@@ -1279,8 +1279,8 @@ static int adpcm_decode_frame(AVCodecContext *avctx, void *data,
 
             for (count2 = 0; count2 < 28; count2++) {
                 byte = bytestream2_get_byteu(&gb);
-                next_left_sample  = sign_extend(byte >> 4, 4) << shift_left;
-                next_right_sample = sign_extend(byte,      4) << shift_right;
+                next_left_sample  = sign_extend(byte >> 4, 4) * (1 << shift_left);
+                next_right_sample = sign_extend(byte,      4) * (1 << shift_right);
 
                 next_left_sample = (next_left_sample +
                     (current_left_sample * coeff1l) +
@@ -1319,7 +1319,7 @@ static int adpcm_decode_frame(AVCodecContext *avctx, void *data,
             if (st) byte[1] = bytestream2_get_byteu(&gb);
             for(i = 4; i >= 0; i-=4) { /* Pairwise samples LL RR (st) or LL LL (mono) */
                 for(channel = 0; channel < avctx->channels; channel++) {
-                    int sample = sign_extend(byte[channel] >> i, 4) << shift[channel];
+                    int sample = sign_extend(byte[channel] >> i, 4) * (1 << shift[channel]);
                     sample = (sample +
                              c->status[channel].sample1 * coeff[channel][0] +
                              c->status[channel].sample2 * coeff[channel][1] + 0x80) >> 8;
@@ -1380,11 +1380,12 @@ static int adpcm_decode_frame(AVCodecContext *avctx, void *data,
 
                     for (count2=0; count2<28; count2++) {
                         if (count2 & 1)
-                            next_sample = sign_extend(byte,    4) << shift;
+                            next_sample = sign_extend(byte,      4);
                         else {
                             byte = bytestream2_get_byte(&gb);
-                            next_sample = sign_extend(byte >> 4, 4) << shift;
+                            next_sample = sign_extend(byte >> 4, 4);
                         }
+                        next_sample *= 1 << shift;
 
                         next_sample += (current_sample  * coeff1) +
                                        (previous_sample * coeff2);
@@ -1595,8 +1596,8 @@ static int adpcm_decode_frame(AVCodecContext *avctx, void *data,
                         sampledat = sign_extend(byte >> 4, 4);
                     }
 
-                    sampledat = ((prev1 * factor1 + prev2 * factor2) +
-                                 ((sampledat * scale) << 11)) >> 11;
+                    sampledat = ((prev1 * factor1 + prev2 * factor2) >> 11) +
+                                sampledat * scale;
                     *samples = av_clip_int16(sampledat);
                     prev2 = prev1;
                     prev1 = *samples++;
@@ -1673,7 +1674,7 @@ static int adpcm_decode_frame(AVCodecContext *avctx, void *data,
                     }
 
                     sampledat = ((c->status[ch].sample1 * factor1
-                                + c->status[ch].sample2 * factor2) >> 11) + (sampledat << exp);
+                                + c->status[ch].sample2 * factor2) >> 11) + sampledat * (1 << exp);
                     *samples = av_clip_int16(sampledat);
                     c->status[ch].sample2 = c->status[ch].sample1;
                     c->status[ch].sample1 = *samples++;
@@ -1720,7 +1721,7 @@ static int adpcm_decode_frame(AVCodecContext *avctx, void *data,
                     else
                         sampledat = sign_extend(byte >> 4, 4);
 
-                    sampledat = (((sampledat << 12) >> (header & 0xf)) << 6) + prev;
+                    sampledat = ((sampledat * (1 << 12)) >> (header & 0xf)) * (1 << 6) + prev;
                     *samples++ = av_clip_int16(sampledat >> 6);
                     c->status[channel].sample2 = c->status[channel].sample1;
                     c->status[channel].sample1 = sampledat;
-- 
2.20.1