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authorMax Kellermann <max@duempel.org>2011-10-09 12:37:32 +0200
committerMax Kellermann <max@duempel.org>2011-10-10 10:24:06 +0200
commit20c6159c041cc5ec644c51009503cf6801b6fcab (patch)
tree55e38810c32ca6059bafd61578705172feb299e2
parenta47e9d1a4b5bd6b999eaec33624d7c96a29f24e6 (diff)
downloadmpd-20c6159c041cc5ec644c51009503cf6801b6fcab.tar.gz
mpd-20c6159c041cc5ec644c51009503cf6801b6fcab.tar.xz
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pcm_dither: pass an "end" pointer instead of a sample count
This is easier and more efficient to loop on, because only two variables get modified (src and dest).
-rw-r--r--src/pcm_dither.c10
-rw-r--r--src/pcm_dither.h6
-rw-r--r--src/pcm_format.c17
-rw-r--r--test/test_pcm_dither.c4
4 files changed, 16 insertions, 21 deletions
diff --git a/src/pcm_dither.c b/src/pcm_dither.c
index a75b07e5d..4811946c8 100644
--- a/src/pcm_dither.c
+++ b/src/pcm_dither.c
@@ -72,10 +72,9 @@ pcm_dither_sample_24_to_16(int32_t sample, struct pcm_dither *dither)
void
pcm_dither_24_to_16(struct pcm_dither *dither,
- int16_t *dest, const int32_t *src,
- unsigned num_samples)
+ int16_t *dest, const int32_t *src, const int32_t *src_end)
{
- while (num_samples-- > 0)
+ while (src < src_end)
*dest++ = pcm_dither_sample_24_to_16(*src++, dither);
}
@@ -87,9 +86,8 @@ pcm_dither_sample_32_to_16(int32_t sample, struct pcm_dither *dither)
void
pcm_dither_32_to_16(struct pcm_dither *dither,
- int16_t *dest, const int32_t *src,
- unsigned num_samples)
+ int16_t *dest, const int32_t *src, const int32_t *src_end)
{
- while (num_samples-- > 0)
+ while (src < src_end)
*dest++ = pcm_dither_sample_32_to_16(*src++, dither);
}
diff --git a/src/pcm_dither.h b/src/pcm_dither.h
index 5ba4d7bb4..046dea21e 100644
--- a/src/pcm_dither.h
+++ b/src/pcm_dither.h
@@ -36,12 +36,10 @@ pcm_dither_24_init(struct pcm_dither *dither)
void
pcm_dither_24_to_16(struct pcm_dither *dither,
- int16_t *dest, const int32_t *src,
- unsigned num_samples);
+ int16_t *dest, const int32_t *src, const int32_t *src_end);
void
pcm_dither_32_to_16(struct pcm_dither *dither,
- int16_t *dest, const int32_t *src,
- unsigned num_samples);
+ int16_t *dest, const int32_t *src, const int32_t *src_end);
#endif
diff --git a/src/pcm_format.c b/src/pcm_format.c
index 21459f0f4..148cd70ed 100644
--- a/src/pcm_format.c
+++ b/src/pcm_format.c
@@ -35,18 +35,16 @@ pcm_convert_8_to_16(int16_t *out, const int8_t *in,
static void
pcm_convert_24_to_16(struct pcm_dither *dither,
- int16_t *out, const int32_t *in,
- unsigned num_samples)
+ int16_t *out, const int32_t *in, const int32_t *in_end)
{
- pcm_dither_24_to_16(dither, out, in, num_samples);
+ pcm_dither_24_to_16(dither, out, in, in_end);
}
static void
pcm_convert_32_to_16(struct pcm_dither *dither,
- int16_t *out, const int32_t *in,
- unsigned num_samples)
+ int16_t *out, const int32_t *in, const int32_t *in_end)
{
- pcm_dither_32_to_16(dither, out, in, num_samples);
+ pcm_dither_32_to_16(dither, out, in, in_end);
}
static int32_t *
@@ -63,6 +61,7 @@ pcm_convert_to_16(struct pcm_buffer *buffer, struct pcm_dither *dither,
enum sample_format src_format, const void *src,
size_t src_size, size_t *dest_size_r)
{
+ const void *src_end = (const char *)src + src_size;
unsigned num_samples;
int16_t *dest;
int32_t *dest32;
@@ -95,7 +94,7 @@ pcm_convert_to_16(struct pcm_buffer *buffer, struct pcm_dither *dither,
/* convert to 16 bit in-place */
*dest_size_r = num_samples * sizeof(*dest);
pcm_convert_24_to_16(dither, dest, dest32,
- num_samples);
+ dest32 + num_samples);
return dest;
case SAMPLE_FORMAT_S24_P32:
@@ -105,7 +104,7 @@ pcm_convert_to_16(struct pcm_buffer *buffer, struct pcm_dither *dither,
pcm_convert_24_to_16(dither, dest,
(const int32_t *)src,
- num_samples);
+ (const int32_t *)src_end);
return dest;
case SAMPLE_FORMAT_S32:
@@ -115,7 +114,7 @@ pcm_convert_to_16(struct pcm_buffer *buffer, struct pcm_dither *dither,
pcm_convert_32_to_16(dither, dest,
(const int32_t *)src,
- num_samples);
+ (const int32_t *)src_end);
return dest;
}
diff --git a/test/test_pcm_dither.c b/test/test_pcm_dither.c
index 889c61ccd..44d105207 100644
--- a/test/test_pcm_dither.c
+++ b/test/test_pcm_dither.c
@@ -48,7 +48,7 @@ test_pcm_dither_24(void)
int16_t dest[N];
- pcm_dither_24_to_16(&dither, dest, src, N);
+ pcm_dither_24_to_16(&dither, dest, src, src + N);
for (unsigned i = 0; i < N; ++i) {
g_assert_cmpint(dest[i], >=, (src[i] >> 8) - 8);
@@ -70,7 +70,7 @@ test_pcm_dither_32(void)
int16_t dest[N];
- pcm_dither_32_to_16(&dither, dest, src, N);
+ pcm_dither_32_to_16(&dither, dest, src, src + N);
for (unsigned i = 0; i < N; ++i) {
g_assert_cmpint(dest[i], >=, (src[i] >> 16) - 8);