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257d6e8156
It is not necessary to check for null pointers after new. Simplify also two delete operations which were missing in the previous commit. Signed-off-by: Stefan Weil <sw@weilnetz.de>
148 lines
3.2 KiB
C++
148 lines
3.2 KiB
C++
/**********************************************************************
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* File: cached_file.pp
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* Description: Implementation of an Cached File Class
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* Author: Ahmad Abdulkader
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* Created: 2007
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*
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* (C) Copyright 2008, Google Inc.
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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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** http://www.apache.org/licenses/LICENSE-2.0
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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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**********************************************************************/
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#include <string>
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#include <stdlib.h>
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#include <cstring>
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#include "cached_file.h"
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namespace tesseract {
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CachedFile::CachedFile(string file_name) {
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file_name_ = file_name;
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buff_ = NULL;
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buff_pos_ = 0;
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buff_size_ = 0;
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file_pos_ = 0;
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file_size_ = 0;
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fp_ = NULL;
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}
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CachedFile::~CachedFile() {
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if (fp_ != NULL) {
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fclose(fp_);
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fp_ = NULL;
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}
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if (buff_ != NULL) {
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delete []buff_;
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buff_ = NULL;
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}
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}
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// free buffers and init vars
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bool CachedFile::Open() {
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if (fp_ != NULL) {
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return true;
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}
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fp_ = fopen(file_name_.c_str(), "rb");
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if (fp_ == NULL) {
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return false;
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}
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// seek to the end
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fseek(fp_, 0, SEEK_END);
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// get file size
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file_size_ = ftell(fp_);
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if (file_size_ < 1) {
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return false;
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}
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// rewind again
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rewind(fp_);
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// alloc memory for buffer
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buff_ = new unsigned char[kCacheSize];
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// init counters
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buff_size_ = 0;
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buff_pos_ = 0;
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file_pos_ = 0;
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return true;
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}
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// add a new sample
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int CachedFile::Read(void *read_buff, int bytes) {
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int read_bytes = 0;
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unsigned char *buff = (unsigned char *)read_buff;
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// do we need to read beyond the buffer
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if ((buff_pos_ + bytes) > buff_size_) {
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// copy as much bytes from the current buffer if any
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int copy_bytes = buff_size_ - buff_pos_;
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if (copy_bytes > 0) {
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memcpy(buff, buff_ + buff_pos_, copy_bytes);
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buff += copy_bytes;
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bytes -= copy_bytes;
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read_bytes += copy_bytes;
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}
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// determine how much to read
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buff_size_ = kCacheSize;
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if ((file_pos_ + buff_size_) > file_size_) {
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buff_size_ = static_cast<int>(file_size_ - file_pos_);
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}
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// EOF ?
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if (buff_size_ <= 0 || bytes > buff_size_) {
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return read_bytes;
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}
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// read the first chunck
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if (fread(buff_, 1, buff_size_, fp_) != buff_size_) {
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return read_bytes;
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}
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buff_pos_ = 0;
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file_pos_ += buff_size_;
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}
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memcpy(buff, buff_ + buff_pos_, bytes);
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read_bytes += bytes;
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buff_pos_ += bytes;
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return read_bytes;
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}
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long CachedFile::Size() {
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if (fp_ == NULL && Open() == false) {
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return 0;
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}
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return file_size_;
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}
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long CachedFile::Tell() {
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if (fp_ == NULL && Open() == false) {
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return 0;
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}
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return file_pos_ - buff_size_ + buff_pos_;
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}
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bool CachedFile::eof() {
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if (fp_ == NULL && Open() == false) {
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return true;
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}
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return (file_pos_ - buff_size_ + buff_pos_) >= file_size_;
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}
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} // namespace tesseract
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