MdeModulePkg BrotliLib: Fix the regression logic issue in loop

In V2, change logic to avoid use mtf[-1] style to get value.

Roll back to previous logic, and use point + offset to get byte value.

Cc: Bell Song <binx.song@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Liming Gao <liming.gao@intel.com>
Reviewed-by: Bell Song <binx.song@intel.com>
(cherry picked from commit 2c8d2545f5)
This commit is contained in:
Liming Gao
2017-04-14 00:13:06 +08:00
parent fc3ce2f30c
commit 321ec73af7

View File

@ -855,6 +855,7 @@ static BROTLI_NOINLINE void InverseMoveToFrontTransform(
uint32_t i = 4;
uint32_t upper_bound = state->mtf_upper_bound;
uint8_t* mtf = &state->mtf[4]; /* Make mtf[-1] addressable. */
uint8_t* mtft = &state->mtf[3];
/* Load endian-aware constant. */
const uint8_t b0123[4] = {0, 1, 2, 3};
uint32_t pattern;
@ -875,10 +876,10 @@ static BROTLI_NOINLINE void InverseMoveToFrontTransform(
uint8_t value = mtf[index];
upper_bound |= (uint32_t)v[i];
v[i] = value;
mtf[-1] = value;
while (index > 0) {
mtft[0] = value;
while (index >= 0) {
mtft[index + 1] = mtft[index];
index--;
mtf[index + 1] = mtf[index];
}
}
/* Remember amount of elements to be reinitialized. */