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69 lines
2.3 KiB
C
69 lines
2.3 KiB
C
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// Copyright 2013 Google Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// Lookup tables to map prefix codes to value ranges. This is used during
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// decoding of the block lengths, literal insertion lengths and copy lengths.
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#ifndef BROTLI_DEC_PREFIX_H_
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#define BROTLI_DEC_PREFIX_H_
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// Represents the range of values belonging to a prefix code:
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// [offset, offset + 2^nbits)
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struct PrefixCodeRange {
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int offset;
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int nbits;
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};
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static const struct PrefixCodeRange kBlockLengthPrefixCode[] = {
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{ 1, 2}, { 5, 2}, { 9, 2}, { 13, 2},
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{ 17, 3}, { 25, 3}, { 33, 3}, { 41, 3},
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{ 49, 4}, { 65, 4}, { 81, 4}, { 97, 4},
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{ 113, 5}, { 145, 5}, { 177, 5}, { 209, 5},
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{ 241, 6}, { 305, 6}, { 369, 7}, { 497, 8},
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{ 753, 9}, { 1265, 10}, {2289, 11}, {4337, 12},
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{8433, 13}, {16625, 24}
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};
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static const struct PrefixCodeRange kInsertLengthPrefixCode[] = {
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{ 0, 0}, { 1, 0}, { 2, 0}, { 3, 0},
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{ 4, 0}, { 5, 0}, { 6, 1}, { 8, 1},
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{ 10, 2}, { 14, 2}, { 18, 3}, { 26, 3},
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{ 34, 4}, { 50, 4}, { 66, 5}, { 98, 5},
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{ 130, 6}, { 194, 7}, { 322, 8}, { 578, 9},
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{1090, 10}, {2114, 12}, {6210, 14}, {22594, 24},
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};
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static const struct PrefixCodeRange kCopyLengthPrefixCode[] = {
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{ 2, 0}, { 3, 0}, { 4, 0}, { 5, 0},
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{ 6, 0}, { 7, 0}, { 8, 0}, { 9, 0},
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{ 10, 1}, { 12, 1}, { 14, 2}, { 18, 2},
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{ 22, 3}, { 30, 3}, { 38, 4}, { 54, 4},
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{ 70, 5}, { 102, 5}, { 134, 6}, { 198, 7},
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{326, 8}, { 582, 9}, {1094, 10}, {2118, 24},
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};
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static const int kInsertAndCopyRangeLut[9] = {
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0, 1, 4, 2, 3, 6, 5, 7, 8,
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};
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static const int kInsertRangeLut[9] = {
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0, 0, 1, 1, 0, 2, 1, 2, 2,
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};
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static const int kCopyRangeLut[9] = {
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0, 1, 0, 1, 2, 0, 2, 1, 2,
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};
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#endif // BROTLI_DEC_PREFIX_H_
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