| 1 | /*************************************************************************** |
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| 2 | * Copyright (c) 2006, Broadcom Corporation |
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| 3 | * All Rights Reserved |
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| 4 | * Confidential Property of Broadcom Corporation |
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| 5 | * |
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| 6 | * THIS SOFTWARE MAY ONLY BE USED SUBJECT TO AN EXECUTED SOFTWARE LICENSE |
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| 7 | * AGREEMENT BETWEEN THE USER AND BROADCOM. YOU HAVE NO RIGHT TO USE OR |
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| 8 | * EXPLOIT THIS MATERIAL EXCEPT SUBJECT TO THE TERMS OF SUCH AN AGREEMENT. |
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| 9 | * |
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| 10 | * $brcm_Workfile: biobits.c $ |
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| 11 | * $brcm_Revision: 2 $ |
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| 12 | * $brcm_Date: 8/31/06 9:45a $ |
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| 13 | * |
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| 14 | * Module Description: |
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| 15 | * |
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| 16 | * Bit stream utility |
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| 17 | * |
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| 18 | * Revision History: |
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| 19 | * |
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| 20 | * $brcm_Log: /BSEAV/lib/asf/biobits.c $ |
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| 21 | * |
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| 22 | * 2 8/31/06 9:45a vsilyaev |
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| 23 | * PR 23826: Fixed bub in end of vector condition |
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| 24 | * |
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| 25 | * 1 7/28/06 4:09p vsilyaev |
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| 26 | * PR 22578: Bitstream utility |
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| 27 | * |
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| 28 | * |
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| 29 | *******************************************************************************/ |
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| 30 | #include "bstd.h" |
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| 31 | #include "biobits.h" |
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| 32 | |
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| 33 | BDBG_MODULE(biobits); |
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| 34 | |
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| 35 | void |
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| 36 | bio_bitstream_init(bio_bitstream *bs, bio_cursor *cursor) |
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| 37 | { |
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| 38 | bs->cursor = cursor; |
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| 39 | bs->cache = 0; |
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| 40 | bs->cache_pos = -1; /* invalid */ |
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| 41 | } |
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| 42 | |
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| 43 | void |
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| 44 | bio_bitstream_dump(bio_bitstream *bs) |
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| 45 | { |
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| 46 | BSTD_UNUSED(bs); |
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| 47 | BDBG_WRN(("bio_bitstream: cache %#x cache_pos %d", bs->cache, bs->cache_pos)); |
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| 48 | return; |
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| 49 | } |
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| 50 | |
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| 51 | bool |
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| 52 | bio_bitstream_eof(bio_bitstream *bs) |
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| 53 | { |
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| 54 | return bs->cache_pos == -1 && bio_cursor_eof(bs->cursor); |
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| 55 | } |
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| 56 | |
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| 57 | static int |
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| 58 | bio_bitstream_refill(bio_bitstream *bs) |
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| 59 | { |
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| 60 | bio_cursor *c = bs->cursor; |
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| 61 | |
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| 62 | BDBG_ASSERT(bs->cache_pos==-1); |
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| 63 | #if B_IOVEC_FAST |
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| 64 | if (c->left>=4) { |
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| 65 | bs->cache = (uint32_t)c->cursor[3] | |
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| 66 | ((uint32_t)(c->cursor[2])<<8) | |
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| 67 | ((uint32_t)(c->cursor[1])<<16) | |
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| 68 | ((uint32_t)(c->cursor[0])<<24); |
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| 69 | bs->cache_pos=31; |
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| 70 | c->cursor += 4; |
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| 71 | c->left -= 4; |
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| 72 | return 0; |
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| 73 | } |
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| 74 | #endif |
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| 75 | { |
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| 76 | int next; |
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| 77 | uint32_t cache; |
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| 78 | |
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| 79 | next = bio_cursor_next(c); |
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| 80 | if (next==BIO_EOF) { |
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| 81 | return BIO_EOF; |
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| 82 | } |
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| 83 | cache = (uint32_t)next; |
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| 84 | next = bio_cursor_next(c); |
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| 85 | if (next==BIO_EOF) { |
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| 86 | bs->cache = cache; |
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| 87 | bs->cache_pos = 7; |
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| 88 | return 0; |
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| 89 | } |
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| 90 | cache = (cache << 8) | (uint32_t)next; |
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| 91 | |
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| 92 | next = bio_cursor_next(c); |
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| 93 | if (next==BIO_EOF) { |
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| 94 | bs->cache = cache; |
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| 95 | bs->cache_pos = 15; |
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| 96 | return 0; |
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| 97 | } |
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| 98 | cache = (cache << 8) | (uint32_t)next; |
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| 99 | |
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| 100 | next = bio_cursor_next(c); |
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| 101 | if (next==BIO_EOF) { |
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| 102 | bs->cache = cache; |
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| 103 | bs->cache_pos = 23; |
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| 104 | return 0; |
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| 105 | } |
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| 106 | bs->cache = (cache << 8) | (uint32_t)next; |
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| 107 | bs->cache_pos = 31; |
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| 108 | } |
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| 109 | return 0; |
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| 110 | } |
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| 111 | |
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| 112 | int |
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| 113 | bio_bitstream_show(bio_bitstream *bs) |
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| 114 | { |
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| 115 | int bit; |
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| 116 | |
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| 117 | if(bs->cache_pos==-1) { |
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| 118 | if (bio_bitstream_refill(bs)==BIO_EOF) { |
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| 119 | return BIO_EOF; |
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| 120 | } |
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| 121 | } |
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| 122 | bit = (bs->cache >> bs->cache_pos)&1; |
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| 123 | return bit; |
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| 124 | } |
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| 125 | |
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| 126 | int |
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| 127 | bio_bitstream_bit(bio_bitstream *bs) |
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| 128 | { |
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| 129 | int bit; |
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| 130 | |
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| 131 | bit = bio_bitstream_show(bs); |
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| 132 | if (bit!=BIO_EOF) { |
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| 133 | bs->cache_pos--; |
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| 134 | } |
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| 135 | return bit; |
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| 136 | } |
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| 137 | |
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| 138 | int |
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| 139 | bio_bitstream_drop(bio_bitstream *bs) |
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| 140 | { |
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| 141 | return bio_bitstream_bit(bs); |
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| 142 | } |
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| 143 | |
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| 144 | unsigned |
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| 145 | bio_bitstream_bits(bio_bitstream *bs, unsigned nbits) |
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| 146 | { |
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| 147 | uint32_t bits; |
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| 148 | int pos; |
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| 149 | |
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| 150 | BDBG_ASSERT(nbits<=31); |
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| 151 | BDBG_ASSERT(nbits>0); |
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| 152 | pos = bs->cache_pos - nbits; |
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| 153 | nbits--; |
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| 154 | if( bs->cache_pos>=(int)nbits) { |
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| 155 | bits = bs->cache >> (bs->cache_pos-nbits) & ((uint32_t)(-1)>>(31-nbits)); |
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| 156 | bs->cache_pos = pos; |
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| 157 | } else { |
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| 158 | for(bits=0;;) { |
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| 159 | bits |= (unsigned) bio_bitstream_bit(bs); |
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| 160 | if (nbits==0) { |
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| 161 | break; |
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| 162 | } |
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| 163 | nbits--; |
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| 164 | bits <<=1; |
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| 165 | } |
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| 166 | } |
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| 167 | return bits; |
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| 168 | } |
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| 169 | |
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| 170 | void |
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| 171 | bio_bitstream_drop_bits(bio_bitstream *bs, unsigned nbits) |
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| 172 | { |
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| 173 | bio_bitstream_bits(bs, nbits); |
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| 174 | return; |
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| 175 | } |
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| 176 | |
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