Don't do any audio conversion if none is necessary

This commit is contained in:
Sam Lantinga 2017-01-05 23:53:46 -08:00
parent 41be9756f0
commit 3443dc19f9

View file

@ -467,6 +467,9 @@ SDL_BuildAudioCVT(SDL_AudioCVT * cvt,
return SDL_InvalidParamError("cvt");
}
/* Make sure we zero out the audio conversion before error checking */
SDL_zerop(cvt);
/* there are no unsigned types over 16 bits, so catch this up front. */
if ((SDL_AUDIO_BITSIZE(src_fmt) > 16) && (!SDL_AUDIO_ISSIGNED(src_fmt))) {
return SDL_SetError("Invalid source format");
@ -488,7 +491,6 @@ SDL_BuildAudioCVT(SDL_AudioCVT * cvt,
#endif
/* Start off with no conversion necessary */
SDL_zerop(cvt);
cvt->src_format = src_fmt;
cvt->dst_format = dst_fmt;
cvt->needed = 0;
@ -512,17 +514,22 @@ SDL_BuildAudioCVT(SDL_AudioCVT * cvt,
(script-generated) custom converters for every data type and
it was a bloat on SDL compile times and final library size. */
/* see if we can skip float conversion entirely (just a byteswap needed). */
if ((src_rate == dst_rate) && (src_channels == dst_channels) &&
((src_fmt != dst_fmt) &&
((src_fmt & ~SDL_AUDIO_MASK_ENDIAN) == (dst_fmt & ~SDL_AUDIO_MASK_ENDIAN)))) {
cvt->filters[cvt->filter_index++] = SDL_Convert_Byteswap;
cvt->needed = 1;
return 1;
/* see if we can skip float conversion entirely. */
if (src_rate == dst_rate && src_channels == dst_channels) {
if (src_fmt == dst_fmt) {
return 0;
}
/* just a byteswap needed? */
if ((src_fmt & ~SDL_AUDIO_MASK_ENDIAN) == (dst_fmt & ~SDL_AUDIO_MASK_ENDIAN)) {
cvt->filters[cvt->filter_index++] = SDL_Convert_Byteswap;
cvt->needed = 1;
return 1;
}
}
/* Convert data types, if necessary. Updates (cvt). */
if (SDL_BuildAudioTypeCVTToFloat(cvt, src_fmt) == -1) {
if (SDL_BuildAudioTypeCVTToFloat(cvt, src_fmt) < 0) {
return -1; /* shouldn't happen, but just in case... */
}
@ -578,12 +585,12 @@ SDL_BuildAudioCVT(SDL_AudioCVT * cvt,
}
/* Do rate conversion, if necessary. Updates (cvt). */
if (SDL_BuildAudioResampleCVT(cvt, dst_channels, src_rate, dst_rate) == -1) {
if (SDL_BuildAudioResampleCVT(cvt, dst_channels, src_rate, dst_rate) < 0) {
return -1; /* shouldn't happen, but just in case... */
}
/* Move to final data type. */
if (SDL_BuildAudioTypeCVTFromFloat(cvt, dst_fmt) == -1) {
if (SDL_BuildAudioTypeCVTFromFloat(cvt, dst_fmt) < 0) {
return -1; /* shouldn't happen, but just in case... */
}