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authorRamiro Polla <ramiro.polla@gmail.com>2008-08-14 03:58:05 +0000
committerRamiro Polla <ramiro.polla@gmail.com>2008-08-14 03:58:05 +0000
commita7cc783d711f0f47eb748a33b55d0c4f57ac1840 (patch)
tree4127268c5cfa5d1eae5bcf30a942fc22ee113dad /libavcodec
parent3c9769a008e1a7e5a33307139b3c19b642cea141 (diff)
downloadffmpeg-a7cc783d711f0f47eb748a33b55d0c4f57ac1840.tar.gz
mlp: split simple inline function that xors 4 bytes into one.
Originally committed as revision 14747 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec')
-rw-r--r--libavcodec/mlp.c3
-rw-r--r--libavcodec/mlp.h8
-rw-r--r--libavcodec/mlpdec.c5
3 files changed, 10 insertions, 6 deletions
diff --git a/libavcodec/mlp.c b/libavcodec/mlp.c
index f2a0276574..2ac2e658f1 100644
--- a/libavcodec/mlp.c
+++ b/libavcodec/mlp.c
@@ -110,8 +110,7 @@ uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size)
for (; buf < buf_end - 3; buf += 4)
scratch ^= *((const uint32_t*)buf);
- scratch ^= scratch >> 16;
- scratch ^= scratch >> 8;
+ scratch = xor_32_to_8(scratch);
for (; buf < buf_end; buf++)
scratch ^= *buf;
diff --git a/libavcodec/mlp.h b/libavcodec/mlp.h
index dc6856727a..a434cd1a22 100644
--- a/libavcodec/mlp.h
+++ b/libavcodec/mlp.h
@@ -107,4 +107,12 @@ int ff_mlp_init_crc2D(AVCodecParserContext *s);
void ff_mlp_init_crc();
+/** XOR four bytes into one. */
+static inline uint8_t xor_32_to_8(uint32_t value)
+{
+ value ^= value >> 16;
+ value ^= value >> 8;
+ return value;
+}
+
#endif /* FFMPEG_MLP_H */
diff --git a/libavcodec/mlpdec.c b/libavcodec/mlpdec.c
index d44c9b0b29..421abdece1 100644
--- a/libavcodec/mlpdec.c
+++ b/libavcodec/mlpdec.c
@@ -364,10 +364,7 @@ static int read_restart_header(MLPDecodeContext *m, GetBitContext *gbp,
lossless_check = get_bits(gbp, 8);
if (substr == m->max_decoded_substream
&& s->lossless_check_data != 0xffffffff) {
- tmp = s->lossless_check_data;
- tmp ^= tmp >> 16;
- tmp ^= tmp >> 8;
- tmp &= 0xff;
+ tmp = xor_32_to_8(s->lossless_check_data);
if (tmp != lossless_check)
av_log(m->avctx, AV_LOG_WARNING,
"Lossless check failed - expected %02x, calculated %02x.\n",