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alac: eliminate 2 unneeded local variables in bastardized_rice_decompress()

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x_modified is just unnecessary, and final_val can be removed by simplifying
the unsigned-to-signed conversion.
This commit is contained in:
Justin Ruggles 2012-07-09 10:53:28 -04:00
parent 6fd8a28b59
commit 7e6593e977
1 changed files with 7 additions and 16 deletions
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23
libavcodec/alac.c
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@ -110,32 +110,23 @@ static void bastardized_rice_decompress(ALACContext *alac,
int sign_modifier = 0; int sign_modifier = 0;
for (output_count = 0; output_count < output_size; output_count++) { for (output_count = 0; output_count < output_size; output_count++) {
int32_t x; int x, k;
int32_t x_modified;
int32_t final_val;
/* standard rice encoding */
int k; /* size of extra bits */
/* read k, that is bits as is */ /* read k, that is bits as is */
k = av_log2((history >> 9) + 3); k = av_log2((history >> 9) + 3);
k = FFMIN(k, alac->rice_limit); k = FFMIN(k, alac->rice_limit);
x = decode_scalar(&alac->gb, k, readsamplesize); x = decode_scalar(&alac->gb, k, readsamplesize);
x += sign_modifier;
x_modified = sign_modifier + x;
final_val = (x_modified + 1) / 2;
if (x_modified & 1) final_val *= -1;
output_buffer[output_count] = final_val;
sign_modifier = 0; sign_modifier = 0;
output_buffer[output_count] = (x >> 1) ^ -(x & 1);
/* now update the history */ /* now update the history */
if (x_modified > 0xffff) if (x > 0xffff)
history = 0xffff; history = 0xffff;
else else
history += x_modified * rice_history_mult - history += x * rice_history_mult -
((history * rice_history_mult) >> 9); ((history * rice_history_mult) >> 9);
/* special case: there may be compressed blocks of 0 */ /* special case: there may be compressed blocks of 0 */
if ((history < 128) && (output_count+1 < output_size)) { if ((history < 128) && (output_count+1 < output_size)) {