src/gallium/auxiliary/vl/vl_vlc.h

   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
  38 struct vl_vlc
  39 {
  40    uint64_t buffer;
  41    unsigned valid_bits;
  42    uint32_t *data;
  43    uint32_t *end;
  44 };
  45
  46 struct vl_vlc_entry
  47 {
  48    int8_t length;
  49    int8_t value;
  50 };
  51
  52 struct vl_vlc_compressed
  53 {
  54    uint16_t bitcode;
  55    struct vl_vlc_entry entry;
  56 };
  57
  58 static INLINE void
  59 vl_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
  74 static INLINE void
  75 vl_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
  92 static INLINE void
  93 vl_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
 115 static INLINE unsigned
 116 vl_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
 122 static INLINE unsigned
 123 vl_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
 130 static INLINE void
 131 vl_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
 139 static INLINE unsigned
 140 vl_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
 152 static INLINE signed
 153 vl_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
 165 static INLINE int8_t
 166 vl_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 */