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Merge "introduce a generic GetCoeffs() function pointer"

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This commit is contained in:
Pascal Massimino
2017-01-18 07:44:36 +00:00
committed by Gerrit Code Review
parent 749a45a520 8074b89eb3
commit 1dc82a6bba
2 changed files with 86 additions and 2 deletions
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56
src/dec/vp8.c
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@ -26,6 +26,16 @@ int WebPGetDecoderVersion(void) {
return (DEC_MAJ_VERSION << 16) | (DEC_MIN_VERSION << 8) | DEC_REV_VERSION;
}
//------------------------------------------------------------------------------
// Signature and pointer-to-function for GetCoeffs() variants below.
typedef int (*GetCoeffsFunc)(VP8BitReader* const br,
const VP8BandProbas* const prob[],
int ctx, const quant_t dq, int n, int16_t* out);
static volatile GetCoeffsFunc GetCoeffs = NULL;
static void InitGetCoeffs(void);
//------------------------------------------------------------------------------
// VP8Decoder
@ -51,6 +61,7 @@ VP8Decoder* VP8New(void) {
WebPGetWorkerInterface()->Init(&dec->worker_);
dec->ready_ = 0;
dec->num_parts_minus_one_ = 0;
InitGetCoeffs();
}
return dec;
}
@ -422,8 +433,9 @@ static int GetLargeValue(VP8BitReader* const br, const uint8_t* const p) {
}
// Returns the position of the last non-zero coeff plus one
static int GetCoeffs(VP8BitReader* const br, const VP8BandProbas* const prob[],
int ctx, const quant_t dq, int n, int16_t* out) {
static int GetCoeffsFast(VP8BitReader* const br,
const VP8BandProbas* const prob[],
int ctx, const quant_t dq, int n, int16_t* out) {
const uint8_t* p = prob[n]->probas_[ctx];
for (; n < 16; ++n) {
if (!VP8GetBit(br, p[0])) {
@ -449,6 +461,46 @@ static int GetCoeffs(VP8BitReader* const br, const VP8BandProbas* const prob[],
return 16;
}
// This version of GetCoeffs() uses VP8GetBitAlt() which is an alternate version
// of VP8GetBitAlt() targeting specific platforms.
static int GetCoeffsAlt(VP8BitReader* const br,
const VP8BandProbas* const prob[],
int ctx, const quant_t dq, int n, int16_t* out) {
const uint8_t* p = prob[n]->probas_[ctx];
for (; n < 16; ++n) {
if (!VP8GetBitAlt(br, p[0])) {
return n; // previous coeff was last non-zero coeff
}
while (!VP8GetBitAlt(br, p[1])) { // sequence of zero coeffs
p = prob[++n]->probas_[0];
if (n == 16) return 16;
}
{ // non zero coeff
const VP8ProbaArray* const p_ctx = &prob[n + 1]->probas_[0];
int v;
if (!VP8GetBitAlt(br, p[2])) {
v = 1;
p = p_ctx[1];
} else {
v = GetLargeValue(br, p);
p = p_ctx[2];
}
out[kZigzag[n]] = VP8GetSigned(br, v) * dq[n > 0];
}
}
return 16;
}
WEBP_TSAN_IGNORE_FUNCTION static void InitGetCoeffs(void) {
if (GetCoeffs == NULL) {
if (VP8GetCPUInfo != NULL && VP8GetCPUInfo(kSlowSSSE3)) {
GetCoeffs = GetCoeffsAlt;
} else {
GetCoeffs = GetCoeffsFast;
}
}
}
static WEBP_INLINE uint32_t NzCodeBits(uint32_t nz_coeffs, int nz, int dc_nz) {
nz_coeffs <<= 2;
nz_coeffs |= (nz > 3) ? 3 : (nz > 1) ? 2 : dc_nz;