/src/im/gpinyin/share/utf16reader.cpp

  1/*
  2 * Copyright (C) 2009 The Android Open Source Project
  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
 17#include "../include/utf16reader.h"
 18
 19namespace ime_pinyin {
 20
 21#define MIN_BUF_LEN 128
 22#define MAX_BUF_LEN 65535
 23
 24Utf16Reader::Utf16Reader() {
 25  fp_ = NULL;
 26  buffer_ = NULL;
 27  buffer_total_len_ = 0;
 28  buffer_next_pos_ = 0;
 29  buffer_valid_len_ = 0;
 30}
 31
 32Utf16Reader::~Utf16Reader() {
 33  if (NULL != fp_)
 34    fclose(fp_);
 35
 36  if (NULL != buffer_)
 37    delete [] buffer_;
 38}
 39
 40
 41bool Utf16Reader::open(const char* filename, unsigned buffer_len) {
 42  if (filename == NULL)
 43    return false;
 44
 45  if (buffer_len < MIN_BUF_LEN)
 46    buffer_len = MIN_BUF_LEN;
 47  else if (buffer_len > MAX_BUF_LEN)
 48    buffer_len = MAX_BUF_LEN;
 49
 50  buffer_total_len_ = buffer_len;
 51
 52  if (NULL != buffer_)
 53    delete [] buffer_;
 54  buffer_ = new char16[buffer_total_len_];
 55  if (NULL == buffer_)
 56    return false;
 57
 58  if ((fp_ = fopen(filename, "rb")) == NULL)
 59    return false;
 60
 61  // the UTF16 file header, skip
 62  char16 header;
 63  if (fread(&header, sizeof(header), 1, fp_) != 1 || header != 0xfeff) {
 64    fclose(fp_);
 65    fp_ = NULL;
 66    return false;
 67  }
 68
 69  return true;
 70}
 71
 72char16* Utf16Reader::readline(char16* read_buf, unsigned max_len) {
 73  if (NULL == fp_ || NULL == read_buf || 0 == max_len)
 74    return NULL;
 75
 76  unsigned ret_len = 0;
 77
 78  do {
 79    if (buffer_valid_len_ == 0) {
 80      buffer_next_pos_ = 0;
 81      buffer_valid_len_ = fread(buffer_, sizeof(char16),
 82                                buffer_total_len_, fp_);
 83      if (buffer_valid_len_ == 0) {
 84        if (0 == ret_len)
 85          return NULL;
 86        read_buf[ret_len] = (char16)'\0';
 87        return read_buf;
 88      }
 89    }
 90
 91    for (unsigned i = 0; i < buffer_valid_len_; i++) {
 92      if (i == max_len - 1 ||
 93          buffer_[buffer_next_pos_ + i] == (char16)'\n') {
 94        if (ret_len + i > 0 && read_buf[ret_len + i - 1] == (char16)'\r') {
 95          read_buf[ret_len + i - 1] = (char16)'\0';
 96        } else {
 97          read_buf[ret_len + i] = (char16)'\0';
 98        }
 99
100        i++;
101        buffer_next_pos_ += i;
102        buffer_valid_len_ -= i;
103        if (buffer_next_pos_ == buffer_total_len_) {
104          buffer_next_pos_ = 0;
105          buffer_valid_len_ = 0;
106        }
107        return read_buf;
108      } else {
109        read_buf[ret_len + i] = buffer_[buffer_next_pos_ + i];
110      }
111    }
112
113    ret_len += buffer_valid_len_;
114    buffer_valid_len_ = 0;
115  } while (true);
116
117  // Never reach here
118  return NULL;
119}
120
121bool Utf16Reader::close() {
122  if (NULL != fp_)
123    fclose(fp_);
124  fp_ = NULL;
125
126  if (NULL != buffer_)
127    delete [] buffer_;
128  buffer_ = NULL;
129  return true;
130}
131}  // namespace ime_pinyin