void MP3StreamState::seekWithinFile(float seekNPT) {
if (fFidIsReallyASocket) return; // it's not seekable
float fileDuration = filePlayTime();
if (seekNPT < 0.0) {
seekNPT = 0.0;
} else if (seekNPT > fileDuration) {
seekNPT = fileDuration;
}
float seekFraction = seekNPT/fileDuration;
unsigned seekByteNumber;
if (fHasXingTOC) {
// The file is VBR, with a Xing TOC; use it to determine which byte to seek to:
float percent = seekFraction*100.0f;
unsigned a = (unsigned)percent;
if (a > 99) a = 99;
unsigned fa = fXingTOC[a];
unsigned fb;
if (a < 99) {
fb = fXingTOC[a+1];
} else {
fb = 256;
}
float seekByteFraction = (fa + (fb-fa)*(percent-a))/256.0f;
seekByteNumber = (unsigned)(seekByteFraction*fFileSize);
} else {
// Normal case: Treat the file as if it's CBR:
seekByteNumber = (unsigned)(seekFraction*fFileSize);
}
fseek(fFid, seekByteNumber, SEEK_SET);
}
void MP3FileSource::seekWithinFile(double seekNPT, double streamDuration) {
float fileDuration = filePlayTime();
// First, make sure that 0.0 <= seekNPT <= seekNPT + streamDuration <= fileDuration
if (seekNPT < 0.0) {
seekNPT = 0.0;
} else if (seekNPT > fileDuration) {
seekNPT = fileDuration;
}
if (streamDuration < 0.0) {
streamDuration = 0.0;
} else if (seekNPT + streamDuration > fileDuration) {
streamDuration = fileDuration - seekNPT;
}
float seekFraction = (float)seekNPT/fileDuration;
unsigned seekByteNumber = fStreamState->getByteNumberFromPositionFraction(seekFraction);
fStreamState->seekWithinFile(seekByteNumber);
fLimitNumBytesToStream = False; // by default
if (streamDuration > 0.0) {
float endFraction = (float)(seekNPT + streamDuration)/fileDuration;
unsigned endByteNumber = fStreamState->getByteNumberFromPositionFraction(endFraction);
if (endByteNumber > seekByteNumber) { // sanity check
fNumBytesToStream = endByteNumber - seekByteNumber;
fLimitNumBytesToStream = True;
}
}
}
