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authorMax Kellermann <max@duempel.org>2013-01-31 22:43:28 +0100
committerMax Kellermann <max@duempel.org>2013-01-31 22:54:10 +0100
commitf2491c88c86707cc35c7dfc30a1b5a0a29886540 (patch)
treed7b2079f3122aa486b8717c916b596c421944f82 /src/PcmDither.cxx
parent1b175025fecb1c10e6719d4ab79c188d473fccc4 (diff)
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PcmDither: convert struct to a class
Diffstat (limited to 'src/PcmDither.cxx')
-rw-r--r--src/PcmDither.cxx40
1 files changed, 19 insertions, 21 deletions
diff --git a/src/PcmDither.cxx b/src/PcmDither.cxx
index e18119082..2560a1aa3 100644
--- a/src/PcmDither.cxx
+++ b/src/PcmDither.cxx
@@ -21,11 +21,9 @@
#include "PcmDither.hxx"
#include "PcmPrng.hxx"
-static int16_t
-pcm_dither_sample_24_to_16(int32_t sample, struct pcm_dither *dither)
+inline int16_t
+PcmDither::Dither24To16(int_fast32_t sample)
{
- int32_t output, rnd;
-
enum {
from_bits = 24,
to_bits = 16,
@@ -37,18 +35,18 @@ pcm_dither_sample_24_to_16(int32_t sample, struct pcm_dither *dither)
MAX = ONE - 1
};
- sample += dither->error[0] - dither->error[1] + dither->error[2];
+ sample += error[0] - error[1] + error[2];
- dither->error[2] = dither->error[1];
- dither->error[1] = dither->error[0] / 2;
+ error[2] = error[1];
+ error[1] = error[0] / 2;
/* round */
- output = sample + round;
+ int_fast32_t output = sample + round;
- rnd = pcm_prng(dither->random);
- output += (rnd & mask) - (dither->random & mask);
+ int_fast32_t rnd = pcm_prng(random);
+ output += (rnd & mask) - (random & mask);
- dither->random = rnd;
+ random = rnd;
/* clip */
if (output > MAX) {
@@ -65,29 +63,29 @@ pcm_dither_sample_24_to_16(int32_t sample, struct pcm_dither *dither)
output &= ~mask;
- dither->error[0] = sample - output;
+ error[0] = sample - output;
return (int16_t)(output >> scale_bits);
}
void
-pcm_dither_24_to_16(struct pcm_dither *dither,
- int16_t *dest, const int32_t *src, const int32_t *src_end)
+PcmDither::Dither24To16(int16_t *dest, const int32_t *src,
+ const int32_t *src_end)
{
while (src < src_end)
- *dest++ = pcm_dither_sample_24_to_16(*src++, dither);
+ *dest++ = Dither24To16(*src++);
}
-static int16_t
-pcm_dither_sample_32_to_16(int32_t sample, struct pcm_dither *dither)
+inline int16_t
+PcmDither::Dither32To16(int_fast32_t sample)
{
- return pcm_dither_sample_24_to_16(sample >> 8, dither);
+ return Dither24To16(sample >> 8);
}
void
-pcm_dither_32_to_16(struct pcm_dither *dither,
- int16_t *dest, const int32_t *src, const int32_t *src_end)
+PcmDither::Dither32To16(int16_t *dest, const int32_t *src,
+ const int32_t *src_end)
{
while (src < src_end)
- *dest++ = pcm_dither_sample_32_to_16(*src++, dither);
+ *dest++ = Dither32To16(*src++);
}