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use a bit-set transforms_seen_ instead of looping

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may be useful later for instance to bypass some code
if we know we don't use the Bundle+ColorMap transform.

Change-Id: I9dc70d18165b2363ad9ede763684ef3d8eba5903
This commit is contained in:
Pascal Massimino 2012-05-24 02:04:23 -07:00
parent 18da1f53fc
commit 7f2dfc92dc
2 changed files with 7 additions and 7 deletions
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12
src/dec/vp8l.c
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@ -714,7 +714,6 @@ static int ExpandColorMap(int num_colors, VP8LTransform* const transform) {
static int ReadTransform(int* const xsize, int const* ysize,
VP8LDecoder* const dec) {
int i;
int ok = 1;
VP8LBitReader* const br = &dec->br_;
VP8LTransform* transform = &dec->transforms_[dec->next_transform_];
@ -722,19 +721,17 @@ static int ReadTransform(int* const xsize, int const* ysize,
(VP8LImageTransformType)VP8LReadBits(br, 2);
// Each transform type can only be present once in the stream.
// TODO(later): use a bit set to mark already-used transforms.
for (i = 0; i < dec->next_transform_; ++i) {
if (dec->transforms_[i].type_ == type) {
return 0; // Already there, let's not accept the second same transform.
}
if (dec->transforms_seen_ & (1U << type)) {
return 0; // Already there, let's not accept the second same transform.
}
assert(dec->next_transform_ < NUM_TRANSFORMS);
dec->transforms_seen_ |= (1U << type);
transform->type_ = type;
transform->xsize_ = *xsize;
transform->ysize_ = *ysize;
transform->data_ = NULL;
++dec->next_transform_;
assert(dec->next_transform_ <= NUM_TRANSFORMS);
switch (type) {
case PREDICTOR_TRANSFORM:
@ -808,6 +805,7 @@ void VP8LClear(VP8LDecoder* const dec) {
ClearTransform(&dec->transforms_[i]);
}
dec->next_transform_ = 0;
dec->transforms_seen_ = 0;
free(dec->rescaler_memory);
dec->rescaler_memory = NULL;

2
src/dec/vp8li.h
View File

@ -89,6 +89,8 @@ typedef struct {
int next_transform_;
VP8LTransform transforms_[NUM_TRANSFORMS];
// or'd bitset storing the transforms types.
uint32_t transforms_seen_;
uint8_t *rescaler_memory; // Working memory for rescaling work.
WebPRescaler *rescaler; // Common rescaler for all channels.