openvcdiff | 311c714 | 2008-08-26 19:29:25 +0000 | [diff] [blame] | 1 | // Copyright 2008 Google Inc. |
| 2 | // Author: Lincoln Smith |
| 3 | // |
| 4 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | // you may not use this file except in compliance with the License. |
| 6 | // You may obtain a copy of the License at |
| 7 | // |
| 8 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | // |
| 10 | // Unless required by applicable law or agreed to in writing, software |
| 11 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | // See the License for the specific language governing permissions and |
| 14 | // limitations under the License. |
| 15 | |
| 16 | #include <config.h> |
| 17 | #include "instruction_map.h" |
openvcdiff | 28db807 | 2008-10-10 23:29:11 +0000 | [diff] [blame^] | 18 | #include <string.h> // memset |
openvcdiff | 311c714 | 2008-08-26 19:29:25 +0000 | [diff] [blame] | 19 | #include "addrcache.h" |
| 20 | #include "vcdiff_defs.h" |
| 21 | |
| 22 | namespace open_vcdiff { |
| 23 | |
| 24 | // VCDiffInstructionMap members and methods |
| 25 | |
| 26 | VCDiffInstructionMap* VCDiffInstructionMap::default_instruction_map = NULL; |
| 27 | |
| 28 | VCDiffInstructionMap* VCDiffInstructionMap::GetDefaultInstructionMap() { |
| 29 | if (!default_instruction_map) { |
| 30 | default_instruction_map = new VCDiffInstructionMap( |
| 31 | VCDiffCodeTableData::kDefaultCodeTableData, |
| 32 | VCDiffAddressCache::DefaultLastMode()); |
| 33 | } |
| 34 | return default_instruction_map; |
| 35 | } |
| 36 | |
| 37 | static unsigned char FindMaxSize( |
| 38 | const unsigned char size_array[VCDiffCodeTableData::kCodeTableSize]) { |
| 39 | unsigned char max_size = size_array[0]; |
| 40 | for (int i = 1; i < VCDiffCodeTableData::kCodeTableSize; ++i) { |
| 41 | if (size_array[i] > max_size) { |
| 42 | max_size = size_array[i]; |
| 43 | } |
| 44 | } |
| 45 | return max_size; |
| 46 | } |
| 47 | |
| 48 | static void ClearSizeOpcodeArray(int length, OpcodeOrNone* array) { |
| 49 | for (int i = 0; i < length; ++i) { |
| 50 | array[i] = kNoOpcode; |
| 51 | } |
| 52 | } |
| 53 | |
| 54 | static OpcodeOrNone* NewSizeOpcodeArray(int length) { |
| 55 | OpcodeOrNone* array = new OpcodeOrNone[length]; |
| 56 | ClearSizeOpcodeArray(length, array); |
| 57 | return array; |
| 58 | } |
| 59 | |
| 60 | VCDiffInstructionMap::FirstInstructionMap::FirstInstructionMap( |
| 61 | int num_insts_and_modes, |
| 62 | int max_size_1) |
| 63 | : num_instruction_type_modes_(num_insts_and_modes), |
| 64 | max_size_1_(max_size_1) { |
| 65 | first_opcodes_ = new OpcodeOrNone*[num_instruction_type_modes_]; |
| 66 | for (int i = 0; i < num_instruction_type_modes_; ++i) { |
| 67 | // There must be at least (max_size_1_ + 1) elements in first_opcodes_ |
| 68 | // because the element first_opcodes[max_size_1_] will be referenced. |
| 69 | first_opcodes_[i] = NewSizeOpcodeArray(max_size_1_ + 1); |
| 70 | } |
| 71 | } |
| 72 | |
| 73 | VCDiffInstructionMap::FirstInstructionMap::~FirstInstructionMap() { |
| 74 | for (int i = 0; i < num_instruction_type_modes_; ++i) { |
| 75 | delete[] first_opcodes_[i]; |
| 76 | } |
| 77 | delete[] first_opcodes_; |
| 78 | } |
| 79 | |
| 80 | VCDiffInstructionMap::SecondInstructionMap::SecondInstructionMap( |
| 81 | int num_insts_and_modes, |
| 82 | int max_size_2) |
| 83 | : num_instruction_type_modes_(num_insts_and_modes), |
| 84 | max_size_2_(max_size_2) { |
| 85 | memset(second_opcodes_, 0, sizeof(second_opcodes_)); |
| 86 | } |
| 87 | |
| 88 | |
| 89 | VCDiffInstructionMap::SecondInstructionMap::~SecondInstructionMap() { |
| 90 | for (int opcode = 0; opcode < VCDiffCodeTableData::kCodeTableSize; ++opcode) { |
| 91 | if (second_opcodes_[opcode] != NULL) { |
| 92 | for (int inst_mode = 0; |
| 93 | inst_mode < num_instruction_type_modes_; |
| 94 | ++inst_mode) { |
| 95 | // No need to check for NULL |
| 96 | delete[] second_opcodes_[opcode][inst_mode]; |
| 97 | } |
| 98 | delete[] second_opcodes_[opcode]; |
| 99 | } |
| 100 | } |
| 101 | } |
| 102 | |
| 103 | void VCDiffInstructionMap::SecondInstructionMap::Add( |
| 104 | unsigned char first_opcode, |
| 105 | unsigned char inst, |
| 106 | unsigned char size, |
| 107 | unsigned char mode, |
| 108 | unsigned char second_opcode) { |
| 109 | OpcodeOrNone**& inst_mode_array = second_opcodes_[first_opcode]; |
| 110 | if (!inst_mode_array) { |
| 111 | inst_mode_array = new OpcodeOrNone*[num_instruction_type_modes_]; |
| 112 | memset(inst_mode_array, |
| 113 | 0, |
| 114 | num_instruction_type_modes_ * sizeof(inst_mode_array[0])); |
| 115 | } |
| 116 | OpcodeOrNone*& size_array = inst_mode_array[inst + mode]; |
| 117 | if (!size_array) { |
| 118 | // There must be at least (max_size_2_ + 1) elements in size_array |
| 119 | // because the element size_array[max_size_2_] will be referenced. |
| 120 | size_array = NewSizeOpcodeArray(max_size_2_ + 1); |
| 121 | } |
| 122 | if (size_array[size] == kNoOpcode) { |
| 123 | size_array[size] = second_opcode; |
| 124 | } |
| 125 | } |
| 126 | |
| 127 | OpcodeOrNone VCDiffInstructionMap::SecondInstructionMap::Lookup( |
| 128 | unsigned char first_opcode, |
| 129 | unsigned char inst, |
| 130 | unsigned char size, |
| 131 | unsigned char mode) const { |
| 132 | if (size > max_size_2_) { |
| 133 | return kNoOpcode; |
| 134 | } |
| 135 | const OpcodeOrNone* const * const inst_mode_array = |
| 136 | second_opcodes_[first_opcode]; |
| 137 | if (!inst_mode_array) { |
| 138 | return kNoOpcode; |
| 139 | } |
| 140 | int inst_mode = (inst == VCD_COPY) ? (inst + mode) : inst; |
| 141 | const OpcodeOrNone* const size_array = inst_mode_array[inst_mode]; |
| 142 | if (!size_array) { |
| 143 | return kNoOpcode; |
| 144 | } |
| 145 | return size_array[size]; |
| 146 | } |
| 147 | |
| 148 | // Because a constructor should never fail, the caller must already |
| 149 | // have run ValidateCodeTable() against the code table data. |
| 150 | // |
| 151 | VCDiffInstructionMap::VCDiffInstructionMap( |
| 152 | const VCDiffCodeTableData& code_table_data, |
| 153 | unsigned char max_mode) |
| 154 | : first_instruction_map_(VCD_LAST_INSTRUCTION_TYPE + max_mode + 1, |
| 155 | FindMaxSize(code_table_data.size1)), |
| 156 | second_instruction_map_(VCD_LAST_INSTRUCTION_TYPE + max_mode + 1, |
| 157 | FindMaxSize(code_table_data.size2)) { |
| 158 | // First pass to fill up first_instruction_map_ |
| 159 | for (int opcode = 0; opcode < VCDiffCodeTableData::kCodeTableSize; ++opcode) { |
| 160 | if (code_table_data.inst2[opcode] == VCD_NOOP) { |
| 161 | // Single instruction. If there is more than one opcode for the same |
| 162 | // inst, mode, and size, then the lowest-numbered opcode will always |
| 163 | // be used by the encoder, because of the descending loop. |
| 164 | first_instruction_map_.Add(code_table_data.inst1[opcode], |
| 165 | code_table_data.size1[opcode], |
| 166 | code_table_data.mode1[opcode], |
| 167 | opcode); |
| 168 | } else if (code_table_data.inst1[opcode] == VCD_NOOP) { |
| 169 | // An unusual case where inst1 == NOOP and inst2 == ADD, RUN, or COPY. |
| 170 | // This is valid under the standard, but unlikely to be used. |
| 171 | // Add it to the first instruction map as if inst1 and inst2 were swapped. |
| 172 | first_instruction_map_.Add(code_table_data.inst2[opcode], |
| 173 | code_table_data.size2[opcode], |
| 174 | code_table_data.mode2[opcode], |
| 175 | opcode); |
| 176 | } |
| 177 | } |
| 178 | // Second pass to fill up second_instruction_map_ (depends on first pass) |
| 179 | for (int opcode = 0; opcode < VCDiffCodeTableData::kCodeTableSize; ++opcode) { |
| 180 | if ((code_table_data.inst1[opcode] != VCD_NOOP) && |
| 181 | (code_table_data.inst2[opcode] != VCD_NOOP)) { |
| 182 | // Double instruction. Find the corresponding single instruction opcode |
| 183 | const OpcodeOrNone single_opcode = |
| 184 | LookupFirstOpcode(code_table_data.inst1[opcode], |
| 185 | code_table_data.size1[opcode], |
| 186 | code_table_data.mode1[opcode]); |
| 187 | if (single_opcode == kNoOpcode) continue; // No single opcode found |
| 188 | second_instruction_map_.Add(static_cast<unsigned char>(single_opcode), |
| 189 | code_table_data.inst2[opcode], |
| 190 | code_table_data.size2[opcode], |
| 191 | code_table_data.mode2[opcode], |
| 192 | opcode); |
| 193 | } |
| 194 | } |
| 195 | } |
| 196 | |
| 197 | }; // namespace open_vcdiff |