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speed up the bounds checking in FLAC__encoder_process*

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This commit is contained in:
Josh Coalson
2001-05-31 06:16:17 +00:00
parent d16370d6b4
commit ac244de474
1 changed files with 10 additions and 8 deletions
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18
src/libFLAC/encoder.c
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@@ -514,8 +514,7 @@ bool FLAC__encoder_process(FLAC__Encoder *encoder, const int32 *buf[], unsigned
int32 x, mid, side;
bool ms;
const bool ms0 = encoder->do_mid_side_stereo && encoder->channels == 2;
const int32 min_side = -((int64)1 << (encoder->bits_per_sample-1));
const int32 max_side = ((int64)1 << (encoder->bits_per_sample-1)) - 1;
const int32 limitmask = (int32)(((uint32)(-1)) >> (33-encoder->bits_per_sample));
const unsigned channels = encoder->channels, blocksize = encoder->blocksize;
assert(encoder != 0);
@@ -532,7 +531,7 @@ bool FLAC__encoder_process(FLAC__Encoder *encoder, const int32 *buf[], unsigned
}
if(ms) {
side = buf[0][j] - x; /* x still == buf[1][j] */
if(side < min_side || side > max_side) {
if(side & limitmask && ~side & limitmask) {
encoder->guts->current_frame_can_do_mid_side = false;
ms = false;
}
@@ -561,28 +560,30 @@ bool FLAC__encoder_process_interleaved(FLAC__Encoder *encoder, const int32 buf[]
{
unsigned i, j, k, channel;
int32 x, left = 0, mid, side;
const bool ms = encoder->do_mid_side_stereo && encoder->channels == 2;
const int32 min_side = -((int64)1 << (encoder->bits_per_sample-1));
const int32 max_side = ((int64)1 << (encoder->bits_per_sample-1)) - 1;
bool ms;
const bool ms0 = encoder->do_mid_side_stereo && encoder->channels == 2;
const int32 limitmask = (int32)(((uint32)(-1)) >> (33-encoder->bits_per_sample));
assert(encoder != 0);
assert(encoder->state == FLAC__ENCODER_OK);
j = k = 0;
ms = ms0 && encoder->guts->current_frame_can_do_mid_side;
do {
for(i = encoder->guts->current_sample_number; i < encoder->blocksize && j < samples; i++, j++) {
for(channel = 0; channel < encoder->channels; channel++) {
x = buf[k++];
encoder->guts->integer_signal[channel][i] = x;
encoder->guts->real_signal[channel][i] = (real)x;
if(ms && encoder->guts->current_frame_can_do_mid_side) {
if(ms) {
if(channel == 0) {
left = x;
}
else {
side = left - x;
if(side < min_side || side > max_side) {
if(side & limitmask && ~side & limitmask) {
encoder->guts->current_frame_can_do_mid_side = false;
ms = false;
}
else {
mid = (left + x) >> 1; /* NOTE: not the same as 'mid = (left + x) / 2' ! */
@@ -599,6 +600,7 @@ bool FLAC__encoder_process_interleaved(FLAC__Encoder *encoder, const int32 buf[]
if(i == encoder->blocksize) {
if(!encoder_process_frame_(encoder, false)) /* false => not last frame */
return false;
ms = ms0;
}
} while(j < samples);