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adler32: avoid "too big" check in the inner loop

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Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2012-02-03 22:18:05 +01:00
parent 25f35df115
commit 7f8027b76f
1 changed files with 10 additions and 4 deletions
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14
libavutil/adler32.c
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@ -23,6 +23,7 @@
#include "config.h" #include "config.h"
#include "adler32.h" #include "adler32.h"
#include "common.h"
#define BASE 65521L /* largest prime smaller than 65536 */ #define BASE 65521L /* largest prime smaller than 65536 */
@ -37,17 +38,22 @@ unsigned long av_adler32_update(unsigned long adler, const uint8_t * buf,
unsigned long s2 = adler >> 16; unsigned long s2 = adler >> 16;
while (len > 0) { while (len > 0) {
unsigned len2 = FFMIN((len-1) & ~15, 2048);
if (len2) {
len -= len2;
#if CONFIG_SMALL #if CONFIG_SMALL
while (len > 4 && s2 < (1U << 31)) { while (len2 >= 4) {
DO4(buf); DO4(buf);
len -= 4; len2 -= 4;
} }
#else #else
while (len > 16 && s2 < (1U << 31)) { while (len2 >= 16) {
DO16(buf); DO16(buf);
len -= 16; len2 -= 16;
} }
#endif #endif
}
DO1(buf); len--; DO1(buf); len--;
s1 %= BASE; s1 %= BASE;
s2 %= BASE; s2 %= BASE;