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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 8619 | maxcodehac | 1 | /* |
| 2 | jbig2dec |
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| 3 | |||
| 4 | Copyright (C) 2001 Artifex Software, Inc. |
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| 5 | |||
| 6 | This software is provided AS-IS with no warranty, |
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| 7 | either express or implied. |
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| 8 | |||
| 9 | This software is distributed under license and may not |
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| 10 | be copied, modified or distributed except as expressly |
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| 11 | authorized under the terms of the license contained in |
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| 12 | the file LICENSE in this distribution. |
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| 13 | |||
| 14 | For further licensing information refer to http://artifex.com/ or |
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| 15 | contact Artifex Software, Inc., 7 Mt. Lassen Drive - Suite A-134, |
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| 16 | San Rafael, CA 94903, U.S.A., +1(415)492-9861. |
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| 17 | */ |
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| 18 | |||
| 19 | /* Annex A */ |
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| 20 | |||
| 21 | #ifdef HAVE_CONFIG_H |
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| 22 | #include "config.h" |
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| 23 | #endif |
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| 24 | #include "os_types.h" |
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| 25 | |||
| 26 | #include |
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| 27 | #include |
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| 28 | |||
| 29 | #include "jbig2.h" |
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| 30 | #include "jbig2_priv.h" |
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| 31 | #include "jbig2_arith.h" |
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| 32 | #include "jbig2_arith_int.h" |
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| 33 | |||
| 34 | struct _Jbig2ArithIntCtx { |
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| 35 | Jbig2ArithCx IAx[512]; |
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| 36 | }; |
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| 37 | |||
| 38 | Jbig2ArithIntCtx * |
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| 39 | jbig2_arith_int_ctx_new(Jbig2Ctx *ctx) |
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| 40 | { |
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| 41 | Jbig2ArithIntCtx *result = jbig2_new(ctx, Jbig2ArithIntCtx, 1); |
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| 42 | |||
| 43 | memset(result->IAx, 0, sizeof(result->IAx)); |
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| 44 | |||
| 45 | return result; |
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| 46 | } |
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| 47 | |||
| 48 | /* A.2 */ |
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| 49 | /* Return value: -1 on error, 0 on normal value, 1 on OOB return. */ |
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| 50 | int |
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| 51 | jbig2_arith_int_decode(Jbig2ArithIntCtx *ctx, Jbig2ArithState *as, |
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| 52 | int32_t *p_result) |
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| 53 | { |
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| 54 | Jbig2ArithCx *IAx = ctx->IAx; |
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| 55 | int PREV = 1; |
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| 56 | int S, V; |
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| 57 | int bit; |
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| 58 | int n_tail, offset; |
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| 59 | int i; |
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| 60 | |||
| 61 | S = jbig2_arith_decode(as, &IAx[PREV]); |
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| 62 | PREV = (PREV << 1) | S; |
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| 63 | |||
| 64 | bit = jbig2_arith_decode(as, &IAx[PREV]); |
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| 65 | PREV = (PREV << 1) | bit; |
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| 66 | if (bit) |
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| 67 | { |
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| 68 | bit = jbig2_arith_decode(as, &IAx[PREV]); |
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| 69 | PREV = (PREV << 1) | bit; |
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| 70 | |||
| 71 | if (bit) |
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| 72 | { |
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| 73 | bit = jbig2_arith_decode(as, &IAx[PREV]); |
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| 74 | PREV = (PREV << 1) | bit; |
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| 75 | |||
| 76 | if (bit) |
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| 77 | { |
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| 78 | bit = jbig2_arith_decode(as, &IAx[PREV]); |
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| 79 | PREV = (PREV << 1) | bit; |
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| 80 | |||
| 81 | if (bit) |
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| 82 | { |
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| 83 | bit = jbig2_arith_decode(as, &IAx[PREV]); |
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| 84 | PREV = (PREV << 1) | bit; |
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| 85 | |||
| 86 | if (bit) |
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| 87 | { |
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| 88 | n_tail = 32; |
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| 89 | offset = 4436; |
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| 90 | } |
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| 91 | else |
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| 92 | { |
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| 93 | n_tail = 12; |
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| 94 | offset = 340; |
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| 95 | } |
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| 96 | } |
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| 97 | else |
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| 98 | { |
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| 99 | n_tail = 8; |
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| 100 | offset = 84; |
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| 101 | } |
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| 102 | } |
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| 103 | else |
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| 104 | { |
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| 105 | n_tail = 6; |
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| 106 | offset = 20; |
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| 107 | } |
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| 108 | } |
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| 109 | else |
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| 110 | { |
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| 111 | n_tail = 4; |
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| 112 | offset = 4; |
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| 113 | } |
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| 114 | } |
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| 115 | else |
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| 116 | { |
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| 117 | n_tail = 2; |
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| 118 | offset = 0; |
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| 119 | } |
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| 120 | |||
| 121 | V = 0; |
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| 122 | for (i = 0; i < n_tail; i++) |
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| 123 | { |
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| 124 | bit = jbig2_arith_decode(as, &IAx[PREV]); |
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| 125 | PREV = ((PREV << 1) & 511) | (PREV & 256) | bit; |
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| 126 | V = (V << 1) | bit; |
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| 127 | } |
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| 128 | |||
| 129 | V += offset; |
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| 130 | V = S ? -V : V; |
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| 131 | *p_result = V; |
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| 132 | return S && V == 0 ? 1 : 0; |
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| 133 | } |
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| 134 | |||
| 135 | void |
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| 136 | jbig2_arith_int_ctx_free(Jbig2Ctx *ctx, Jbig2ArithIntCtx *iax) |
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| 137 | { |
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| 138 | jbig2_free(ctx->allocator, iax); |
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| 139 | } |