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decoder/dsf: eliminate temporary buffer

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Convert into a second buffer that gets passed to decoder_data()
without copying back to the first buffer.
This commit is contained in:
Max Kellermann 2014-08-21 17:11:48 +02:00
parent a756cd9565
commit 74cdc0005a
1 changed files with 7 additions and 12 deletions
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19
src/decoder/plugins/DsfDecoderPlugin.cxx
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@ -39,8 +39,6 @@
#include "tag/TagHandler.hxx" #include "tag/TagHandler.hxx"
#include "Log.hxx" #include "Log.hxx"
#include <string.h>
static constexpr unsigned DSF_BLOCK_SIZE = 4096; static constexpr unsigned DSF_BLOCK_SIZE = 4096;
struct DsfMetaData { struct DsfMetaData {
@ -197,22 +195,17 @@ bit_reverse_buffer(uint8_t *p, uint8_t *end)
* order. * order.
*/ */
static void static void
dsf_to_pcm_order(uint8_t *dest, size_t nrbytes) dsf_to_pcm_order(uint8_t *dest, const uint8_t *src, size_t nrbytes)
{ {
uint8_t scratch[DSF_BLOCK_SIZE * 2];
assert(nrbytes <= sizeof(scratch));
for (size_t i = 0, j = 0; i < nrbytes; i += 2) { for (size_t i = 0, j = 0; i < nrbytes; i += 2) {
scratch[i] = *(dest+j); dest[i] = src[j];
j++; j++;
} }
for (size_t i = 1, j = 0; i < nrbytes; i += 2) { for (size_t i = 1, j = 0; i < nrbytes; i += 2) {
scratch[i] = *(dest + DSF_BLOCK_SIZE + j); dest[i] = src[DSF_BLOCK_SIZE + j];
j++; j++;
} }
memcpy(dest, scratch, nrbytes);
} }
/** /**
@ -250,9 +243,11 @@ dsf_decode_chunk(Decoder &decoder, InputStream &is,
if (bitreverse) if (bitreverse)
bit_reverse_buffer(buffer, buffer + nbytes); bit_reverse_buffer(buffer, buffer + nbytes);
dsf_to_pcm_order(buffer, nbytes); uint8_t interleaved_buffer[DSF_BLOCK_SIZE * 2];
dsf_to_pcm_order(interleaved_buffer, buffer, nbytes);
const auto cmd = decoder_data(decoder, is, buffer, nbytes, const auto cmd = decoder_data(decoder, is,
interleaved_buffer, nbytes,
sample_rate / 1000); sample_rate / 1000);
switch (cmd) { switch (cmd) {
case DecoderCommand::NONE: case DecoderCommand::NONE: