548b4dd5f2
Removing redundant 'extern' keywords and parentheses, fixing indentation, making variable names lower case, using short expressions x *= c instead of x = x * c, minor code simplifications. Change-Id: If6a25fcf306d1db26e90d27e3c24a32735c607de
129 lines
2.8 KiB
C
129 lines
2.8 KiB
C
/*
|
|
* Copyright (c) 2010 The WebM project authors. All Rights Reserved.
|
|
*
|
|
* Use of this source code is governed by a BSD-style license
|
|
* that can be found in the LICENSE file in the root of the source
|
|
* tree. An additional intellectual property rights grant can be found
|
|
* in the file PATENTS. All contributing project authors may
|
|
* be found in the AUTHORS file in the root of the source tree.
|
|
*/
|
|
|
|
|
|
#include "vp9/decoder/vp9_dboolhuff.h"
|
|
#include "vpx_ports/mem.h"
|
|
#include "vpx_mem/vpx_mem.h"
|
|
|
|
int vp9_start_decode(BOOL_DECODER *br,
|
|
const unsigned char *source,
|
|
unsigned int source_sz) {
|
|
br->user_buffer_end = source + source_sz;
|
|
br->user_buffer = source;
|
|
br->value = 0;
|
|
br->count = -8;
|
|
br->range = 255;
|
|
|
|
if (source_sz && !source)
|
|
return 1;
|
|
|
|
/* Populate the buffer */
|
|
vp9_bool_decoder_fill(br);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
void vp9_bool_decoder_fill(BOOL_DECODER *br) {
|
|
const unsigned char *bufptr = br->user_buffer;
|
|
const unsigned char *bufend = br->user_buffer_end;
|
|
VP9_BD_VALUE value = br->value;
|
|
int count = br->count;
|
|
int shift = VP9_BD_VALUE_SIZE - 8 - (count + 8);
|
|
int loop_end = 0;
|
|
int bits_left = (int)((bufend - bufptr)*CHAR_BIT);
|
|
int x = shift + CHAR_BIT - bits_left;
|
|
|
|
if (x >= 0) {
|
|
count += VP9_LOTS_OF_BITS;
|
|
loop_end = x;
|
|
}
|
|
|
|
if (x < 0 || bits_left) {
|
|
while (shift >= loop_end) {
|
|
count += CHAR_BIT;
|
|
value |= (VP9_BD_VALUE)*bufptr++ << shift;
|
|
shift -= CHAR_BIT;
|
|
}
|
|
}
|
|
|
|
br->user_buffer = bufptr;
|
|
br->value = value;
|
|
br->count = count;
|
|
}
|
|
|
|
|
|
static int get_unsigned_bits(unsigned num_values) {
|
|
int cat = 0;
|
|
if (num_values <= 1)
|
|
return 0;
|
|
num_values--;
|
|
while (num_values > 0) {
|
|
cat++;
|
|
num_values >>= 1;
|
|
}
|
|
return cat;
|
|
}
|
|
|
|
int vp9_inv_recenter_nonneg(int v, int m) {
|
|
if (v > (m << 1))
|
|
return v;
|
|
else if ((v & 1) == 0)
|
|
return (v >> 1) + m;
|
|
else
|
|
return m - ((v + 1) >> 1);
|
|
}
|
|
|
|
int vp9_decode_uniform(BOOL_DECODER *br, int n) {
|
|
int v;
|
|
int l = get_unsigned_bits(n);
|
|
int m = (1 << l) - n;
|
|
if (!l) return 0;
|
|
v = decode_value(br, l - 1);
|
|
if (v < m)
|
|
return v;
|
|
else
|
|
return (v << 1) - m + decode_value(br, 1);
|
|
}
|
|
|
|
int vp9_decode_term_subexp(BOOL_DECODER *br, int k, int num_syms) {
|
|
int i = 0, mk = 0, word;
|
|
while (1) {
|
|
int b = (i ? k + i - 1 : k);
|
|
int a = (1 << b);
|
|
if (num_syms <= mk + 3 * a) {
|
|
word = vp9_decode_uniform(br, num_syms - mk) + mk;
|
|
break;
|
|
} else {
|
|
if (decode_value(br, 1)) {
|
|
i++;
|
|
mk += a;
|
|
} else {
|
|
word = decode_value(br, b) + mk;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
return word;
|
|
}
|
|
|
|
int vp9_decode_unsigned_max(BOOL_DECODER *br, int max) {
|
|
int data = 0, bit = 0, lmax = max;
|
|
|
|
while (lmax) {
|
|
data |= decode_bool(br, 128) << bit++;
|
|
lmax >>= 1;
|
|
}
|
|
if (data > max)
|
|
return max;
|
|
return data;
|
|
}
|