vl_vlc.h revision 19bcd21ed151cf1716f2f87dff0f712231aa2ce7 
1/**************************************************************************
2 *
3 * Copyright 2011 Christian König.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28#ifndef vl_vlc_h
29#define vl_vlc_h
30
31#include <assert.h>
32
33#include "pipe/p_compiler.h"
34
35#include "util/u_math.h"
36#include "util/u_pointer.h"
37
38struct vl_vlc
39{
40   uint64_t buffer;
41   unsigned valid_bits;
42   uint32_t *data;
43   uint32_t *end;
44};
45
46struct vl_vlc_entry
47{
48   int8_t length;
49   int8_t value;
50};
51
52struct vl_vlc_compressed
53{
54   uint16_t bitcode;
55   struct vl_vlc_entry entry;
56};
57
58static INLINE void
59vl_vlc_init_table(struct vl_vlc_entry *dst, unsigned dst_size, const struct vl_vlc_compressed *src, unsigned src_size)
60{
61   unsigned i, bits = util_logbase2(dst_size);
62
63   for (i=0;i<dst_size;++i) {
64      dst[i].length = 0;
65      dst[i].value = 0;
66   }
67
68   for(; src_size > 0; --src_size, ++src) {
69      for(i=0; i<(1 << (bits - src->entry.length)); ++i)
70         dst[src->bitcode >> (16 - bits) | i] = src->entry;
71   }
72}
73
74static INLINE void
75vl_vlc_fillbits(struct vl_vlc *vlc)
76{
77   if (vlc->valid_bits < 32) {
78      uint32_t value = *vlc->data;
79
80      //assert(vlc->data <= vlc->end);
81
82#ifndef PIPE_ARCH_BIG_ENDIAN
83      value = util_bswap32(value);
84#endif
85
86      vlc->buffer |= (uint64_t)value << (32 - vlc->valid_bits);
87      ++vlc->data;
88      vlc->valid_bits += 32;
89   }
90}
91
92static INLINE void
93vl_vlc_init(struct vl_vlc *vlc, const uint8_t *data, unsigned len)
94{
95   assert(vlc);
96   assert(data && len);
97
98   vlc->buffer = 0;
99   vlc->valid_bits = 0;
100
101   /* align the data pointer */
102   while (pointer_to_uintptr(data) & 3) {
103      vlc->buffer |= (uint64_t)*data << (56 - vlc->valid_bits);
104      ++data;
105      --len;
106      vlc->valid_bits += 8;
107   }
108   vlc->data = (uint32_t*)data;
109   vlc->end = (uint32_t*)(data + len);
110
111   vl_vlc_fillbits(vlc);
112   vl_vlc_fillbits(vlc);
113}
114
115static INLINE unsigned
116vl_vlc_bits_left(struct vl_vlc *vlc)
117{
118   signed bytes_left = ((uint8_t*)vlc->end)-((uint8_t*)vlc->data);
119   return bytes_left * 8 + vlc->valid_bits;
120}
121
122static INLINE unsigned
123vl_vlc_peekbits(struct vl_vlc *vlc, unsigned num_bits)
124{
125   //assert(vlc->valid_bits >= num_bits);
126
127   return vlc->buffer >> (64 - num_bits);
128}
129
130static INLINE void
131vl_vlc_eatbits(struct vl_vlc *vlc, unsigned num_bits)
132{
133   //assert(vlc->valid_bits > num_bits);
134
135   vlc->buffer <<= num_bits;
136   vlc->valid_bits -= num_bits;
137}
138
139static INLINE unsigned
140vl_vlc_get_uimsbf(struct vl_vlc *vlc, unsigned num_bits)
141{
142   unsigned value;
143
144   //assert(vlc->valid_bits >= num_bits);
145
146   value = vlc->buffer >> (64 - num_bits);
147   vl_vlc_eatbits(vlc, num_bits);
148
149   return value;
150}
151
152static INLINE signed
153vl_vlc_get_simsbf(struct vl_vlc *vlc, unsigned num_bits)
154{
155   signed value;
156
157   //assert(vlc->valid_bits >= num_bits);
158
159   value = ((int64_t)vlc->buffer) >> (64 - num_bits);
160   vl_vlc_eatbits(vlc, num_bits);
161
162   return value;
163}
164
165static INLINE int8_t
166vl_vlc_get_vlclbf(struct vl_vlc *vlc, const struct vl_vlc_entry *tbl, unsigned num_bits)
167{
168   tbl += vl_vlc_peekbits(vlc, num_bits);
169   vl_vlc_eatbits(vlc, tbl->length);
170   return tbl->value;
171}
172
173#endif /* vl_vlc_h */
174