Index: sdch/open_vcdiff/depot/opensource/open-vcdiff/src/decodetable.h |
=================================================================== |
--- sdch/open_vcdiff/depot/opensource/open-vcdiff/src/decodetable.h (revision 2678) |
+++ sdch/open_vcdiff/depot/opensource/open-vcdiff/src/decodetable.h (working copy) |
@@ -1,152 +0,0 @@ |
-// 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. |
- |
-#ifndef OPEN_VCDIFF_DECODETABLE_H_ |
-#define OPEN_VCDIFF_DECODETABLE_H_ |
- |
-#include <config.h> |
-#include <stdint.h> // int32_t |
-#include <cstddef> // NULL |
-#include <memory> // auto_ptr |
-#include "codetable.h" // VCDiffInstructi... |
-#include "logging.h" |
- |
-namespace open_vcdiff { |
- |
-// This class is used by the decoder. It can use a standard or |
-// non-standard code table, and will translate the opcodes in the code table |
-// into delta instructions. |
-// |
-// NOT threadsafe. |
-// |
-class VCDiffCodeTableReader { |
- public: |
- // When constructed, the object will be set up to use the default code table. |
- // If a non-default code table is to be used, then UseCodeTable() |
- // should be called after the VCDiffCodeTableReader has been constructed. |
- // In any case, the Init() method must be called before GetNextInstruction() |
- // may be used. |
- // |
- VCDiffCodeTableReader(); |
- |
- // Sets up a non-standard code table. The caller |
- // may free the memory occupied by the argument code table after |
- // passing it to this method, because the argument code table |
- // allocates space to store a copy of it. |
- // UseCodeTable() may be called either before or after calling Init(). |
- // Returns true if the code table was accepted, or false if the |
- // argument did not appear to be a valid code table. |
- // |
- bool UseCodeTable(const VCDiffCodeTableData& code_table_data, |
- unsigned char max_mode); |
- |
- // Defines the buffer containing the instructions and sizes. |
- // This method must be called before GetNextInstruction() may be used. |
- // Init() may be called any number of times to reset the state of |
- // the object. |
- // |
- void Init(const char** instructions_and_sizes, |
- const char* instructions_and_sizes_end) { |
- instructions_and_sizes_ = instructions_and_sizes; |
- instructions_and_sizes_end_ = instructions_and_sizes_end; |
- last_instruction_start_ = NULL; |
- pending_second_instruction_ = kNoOpcode; |
- last_pending_second_instruction_ = kNoOpcode; |
- } |
- |
- // Updates the pointers to the buffer containing the instructions and sizes, |
- // but leaves the rest of the reader state intact, so that (for example) |
- // any pending second instruction or unread instruction will still be |
- // read when requested. NOTE: UnGetInstruction() will not work immediately |
- // after using UpdatePointers(); GetNextInstruction() must be called first. |
- // |
- void UpdatePointers(const char** instructions_and_sizes, |
- const char* instructions_and_sizes_end) { |
- instructions_and_sizes_ = instructions_and_sizes; |
- instructions_and_sizes_end_ = instructions_and_sizes_end; |
- last_instruction_start_ = *instructions_and_sizes; |
- // pending_second_instruction_ is unchanged |
- last_pending_second_instruction_ = pending_second_instruction_; |
- } |
- |
- // Returns the next instruction from the stream of opcodes, |
- // or VCD_INSTRUCTION_END_OF_DATA if the end of the opcode stream is reached, |
- // or VCD_INSTRUCTION_ERROR if an error occurred. |
- // In the first of these cases, increments *instructions_and_sizes_ |
- // past the values it reads, and populates *size |
- // with the corresponding size for the returned instruction; |
- // otherwise, the value of *size is undefined, and is not |
- // guaranteed to be preserved. |
- // If the instruction returned is VCD_COPY, *mode will |
- // be populated with the copy mode; otherwise, the value of *mode |
- // is undefined, and is not guaranteed to be preserved. |
- // Any occurrences of VCD_NOOP in the opcode stream |
- // are skipped over and ignored, not returned. |
- // If Init() was not called before calling this method, then |
- // VCD_INSTRUCTION_ERROR will be returned. |
- // |
- VCDiffInstructionType GetNextInstruction(int32_t* size, unsigned char* mode); |
- |
- // Puts a single instruction back onto the front of the |
- // instruction stream. The next call to GetNextInstruction() |
- // will return the same value that was returned by the last |
- // call. Calling UnGetInstruction() more than once before calling |
- // GetNextInstruction() will have no additional effect; you can |
- // only rewind one instruction. |
- // |
- void UnGetInstruction() { |
- if (last_instruction_start_) { |
- if (last_instruction_start_ > *instructions_and_sizes_) { |
- LOG(DFATAL) << "Internal error: last_instruction_start past end of " |
- "instructions_and_sizes in UnGetInstruction" << LOG_ENDL; |
- } |
- *instructions_and_sizes_ = last_instruction_start_; |
- if ((pending_second_instruction_ != kNoOpcode) && |
- (last_pending_second_instruction_ != kNoOpcode)) { |
- LOG(DFATAL) << "Internal error: two pending instructions in a row " |
- "in UnGetInstruction" << LOG_ENDL; |
- } |
- pending_second_instruction_ = last_pending_second_instruction_; |
- } |
- } |
- |
- private: |
- // A pointer to the code table. This is the object that will be used |
- // to interpret opcodes in GetNextInstruction(). |
- const VCDiffCodeTableData* code_table_data_; |
- |
- // If the default code table is not being used, then space for the |
- // code table data will be allocated using this pointer and freed |
- // when the VCDiffCodeTableReader is destroyed. This will keep the |
- // code that uses the object from having to worry about memory |
- // management for the non-standard code table, whose contents have |
- // been read as part of the encoded data file/stream. |
- // |
- std::auto_ptr<VCDiffCodeTableData> non_default_code_table_data_; |
- |
- const char** instructions_and_sizes_; |
- const char* instructions_and_sizes_end_; |
- const char* last_instruction_start_; |
- OpcodeOrNone pending_second_instruction_; |
- OpcodeOrNone last_pending_second_instruction_; |
- |
- // Making these private avoids implicit copy constructor & assignment operator |
- VCDiffCodeTableReader(const VCDiffCodeTableReader&); |
- void operator=(const VCDiffCodeTableReader&); |
-}; |
- |
-}; // namespace open_vcdiff |
- |
-#endif // OPEN_VCDIFF_DECODETABLE_H_ |