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Diffstat (limited to 'sdch/open-vcdiff/src/instruction_map.cc')
| -rw-r--r-- | sdch/open-vcdiff/src/instruction_map.cc | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/sdch/open-vcdiff/src/instruction_map.cc b/sdch/open-vcdiff/src/instruction_map.cc new file mode 100644 index 0000000..12cb811 --- /dev/null +++ b/sdch/open-vcdiff/src/instruction_map.cc @@ -0,0 +1,197 @@ +// Copyright 2008 Google Inc. +// Author: Lincoln Smith +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include <config.h> +#include "instruction_map.h" +#include <string.h> // memset +#include "addrcache.h" +#include "vcdiff_defs.h" + +namespace open_vcdiff { + +// VCDiffInstructionMap members and methods + +VCDiffInstructionMap* VCDiffInstructionMap::default_instruction_map = NULL; + +VCDiffInstructionMap* VCDiffInstructionMap::GetDefaultInstructionMap() { + if (!default_instruction_map) { + default_instruction_map = new VCDiffInstructionMap( + VCDiffCodeTableData::kDefaultCodeTableData, + VCDiffAddressCache::DefaultLastMode()); + } + return default_instruction_map; +} + +static unsigned char FindMaxSize( + const unsigned char size_array[VCDiffCodeTableData::kCodeTableSize]) { + unsigned char max_size = size_array[0]; + for (int i = 1; i < VCDiffCodeTableData::kCodeTableSize; ++i) { + if (size_array[i] > max_size) { + max_size = size_array[i]; + } + } + return max_size; +} + +static void ClearSizeOpcodeArray(int length, OpcodeOrNone* array) { + for (int i = 0; i < length; ++i) { + array[i] = kNoOpcode; + } +} + +static OpcodeOrNone* NewSizeOpcodeArray(int length) { + OpcodeOrNone* array = new OpcodeOrNone[length]; + ClearSizeOpcodeArray(length, array); + return array; +} + +VCDiffInstructionMap::FirstInstructionMap::FirstInstructionMap( + int num_insts_and_modes, + int max_size_1) + : num_instruction_type_modes_(num_insts_and_modes), + max_size_1_(max_size_1) { + first_opcodes_ = new OpcodeOrNone*[num_instruction_type_modes_]; + for (int i = 0; i < num_instruction_type_modes_; ++i) { + // There must be at least (max_size_1_ + 1) elements in first_opcodes_ + // because the element first_opcodes[max_size_1_] will be referenced. + first_opcodes_[i] = NewSizeOpcodeArray(max_size_1_ + 1); + } +} + +VCDiffInstructionMap::FirstInstructionMap::~FirstInstructionMap() { + for (int i = 0; i < num_instruction_type_modes_; ++i) { + delete[] first_opcodes_[i]; + } + delete[] first_opcodes_; +} + +VCDiffInstructionMap::SecondInstructionMap::SecondInstructionMap( + int num_insts_and_modes, + int max_size_2) + : num_instruction_type_modes_(num_insts_and_modes), + max_size_2_(max_size_2) { + memset(second_opcodes_, 0, sizeof(second_opcodes_)); +} + + +VCDiffInstructionMap::SecondInstructionMap::~SecondInstructionMap() { + for (int opcode = 0; opcode < VCDiffCodeTableData::kCodeTableSize; ++opcode) { + if (second_opcodes_[opcode] != NULL) { + for (int inst_mode = 0; + inst_mode < num_instruction_type_modes_; + ++inst_mode) { + // No need to check for NULL + delete[] second_opcodes_[opcode][inst_mode]; + } + delete[] second_opcodes_[opcode]; + } + } +} + +void VCDiffInstructionMap::SecondInstructionMap::Add( + unsigned char first_opcode, + unsigned char inst, + unsigned char size, + unsigned char mode, + unsigned char second_opcode) { + OpcodeOrNone**& inst_mode_array = second_opcodes_[first_opcode]; + if (!inst_mode_array) { + inst_mode_array = new OpcodeOrNone*[num_instruction_type_modes_]; + memset(inst_mode_array, + 0, + num_instruction_type_modes_ * sizeof(inst_mode_array[0])); + } + OpcodeOrNone*& size_array = inst_mode_array[inst + mode]; + if (!size_array) { + // There must be at least (max_size_2_ + 1) elements in size_array + // because the element size_array[max_size_2_] will be referenced. + size_array = NewSizeOpcodeArray(max_size_2_ + 1); + } + if (size_array[size] == kNoOpcode) { + size_array[size] = second_opcode; + } +} + +OpcodeOrNone VCDiffInstructionMap::SecondInstructionMap::Lookup( + unsigned char first_opcode, + unsigned char inst, + unsigned char size, + unsigned char mode) const { + if (size > max_size_2_) { + return kNoOpcode; + } + const OpcodeOrNone* const * const inst_mode_array = + second_opcodes_[first_opcode]; + if (!inst_mode_array) { + return kNoOpcode; + } + int inst_mode = (inst == VCD_COPY) ? (inst + mode) : inst; + const OpcodeOrNone* const size_array = inst_mode_array[inst_mode]; + if (!size_array) { + return kNoOpcode; + } + return size_array[size]; +} + +// Because a constructor should never fail, the caller must already +// have run ValidateCodeTable() against the code table data. +// +VCDiffInstructionMap::VCDiffInstructionMap( + const VCDiffCodeTableData& code_table_data, + unsigned char max_mode) + : first_instruction_map_(VCD_LAST_INSTRUCTION_TYPE + max_mode + 1, + FindMaxSize(code_table_data.size1)), + second_instruction_map_(VCD_LAST_INSTRUCTION_TYPE + max_mode + 1, + FindMaxSize(code_table_data.size2)) { + // First pass to fill up first_instruction_map_ + for (int opcode = 0; opcode < VCDiffCodeTableData::kCodeTableSize; ++opcode) { + if (code_table_data.inst2[opcode] == VCD_NOOP) { + // Single instruction. If there is more than one opcode for the same + // inst, mode, and size, then the lowest-numbered opcode will always + // be used by the encoder, because of the descending loop. + first_instruction_map_.Add(code_table_data.inst1[opcode], + code_table_data.size1[opcode], + code_table_data.mode1[opcode], + opcode); + } else if (code_table_data.inst1[opcode] == VCD_NOOP) { + // An unusual case where inst1 == NOOP and inst2 == ADD, RUN, or COPY. + // This is valid under the standard, but unlikely to be used. + // Add it to the first instruction map as if inst1 and inst2 were swapped. + first_instruction_map_.Add(code_table_data.inst2[opcode], + code_table_data.size2[opcode], + code_table_data.mode2[opcode], + opcode); + } + } + // Second pass to fill up second_instruction_map_ (depends on first pass) + for (int opcode = 0; opcode < VCDiffCodeTableData::kCodeTableSize; ++opcode) { + if ((code_table_data.inst1[opcode] != VCD_NOOP) && + (code_table_data.inst2[opcode] != VCD_NOOP)) { + // Double instruction. Find the corresponding single instruction opcode + const OpcodeOrNone single_opcode = + LookupFirstOpcode(code_table_data.inst1[opcode], + code_table_data.size1[opcode], + code_table_data.mode1[opcode]); + if (single_opcode == kNoOpcode) continue; // No single opcode found + second_instruction_map_.Add(static_cast<unsigned char>(single_opcode), + code_table_data.inst2[opcode], + code_table_data.size2[opcode], + code_table_data.mode2[opcode], + opcode); + } + } +} + +}; // namespace open_vcdiff |