1 | // Copyright 2012 Google Inc. All Rights Reserved.
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2 | //
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3 | // Licensed under the Apache License, Version 2.0 (the "License"); you
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4 | // may not use this file except in compliance with the License. You
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5 | // may obtain a copy of the License at
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6 | //
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7 | // http://www.apache.org/licenses/LICENSE-2.0
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8 | //
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9 | // Unless required by applicable law or agreed to in writing, software
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10 | // distributed under the License is distributed on an "AS IS" BASIS,
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11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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12 | // implied. See the License for the specific language governing
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13 | // permissions and limitations under the License.
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14 |
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15 | #ifndef WEBGL_LOADER_STREAM_H_
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16 | #define WEBGL_LOADER_STREAM_H_
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17 |
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18 | #include <stdio.h>
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19 | #include <string>
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20 | #include <vector>
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21 |
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22 | #include "base.h"
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23 |
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24 | namespace webgl_loader {
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25 |
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26 | // An abstract interface to allow appending bytes to various streams.
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27 | class ByteSinkInterface {
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28 | public:
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29 | virtual void Put(char c) = 0;
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30 | virtual size_t PutN(const char* data, size_t len) = 0;
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31 | virtual ~ByteSinkInterface() { }
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32 |
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33 | protected:
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34 | ByteSinkInterface() { }
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35 |
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36 | private:
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37 | // Disallow copy and assignment.
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38 | ByteSinkInterface(const ByteSinkInterface&);
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39 | void operator=(const ByteSinkInterface&);
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40 | };
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41 |
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42 | // None of the concrete implementations actually own the backing data.
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43 | // They should be safe to copy.
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44 |
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45 | class NullSink : public ByteSinkInterface {
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46 | public:
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47 | NullSink() { }
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48 |
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49 | virtual void Put(char) { }
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50 |
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51 | virtual size_t PutN(const char*, size_t len) { return len; }
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52 | };
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53 |
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54 | class FileSink : public ByteSinkInterface {
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55 | public:
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56 | // |fp| is unowned and must not be NULL.
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57 | explicit FileSink(FILE* fp)
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58 | : fp_(fp) {
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59 | }
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60 |
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61 | virtual void Put(char c) {
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62 | PutChar(c, fp_);
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63 | }
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64 |
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65 | virtual size_t PutN(const char* data, size_t len) {
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66 | return fwrite(data, 1, len, fp_);
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67 | }
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68 |
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69 | private:
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70 | FILE *fp_; // unowned.
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71 | };
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72 |
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73 | class VectorSink : public ByteSinkInterface {
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74 | public:
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75 | // |vec| is unowned and must not be NULL.
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76 | explicit VectorSink(std::vector<char>* vec)
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77 | : vec_(vec) {
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78 | }
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79 |
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80 | virtual void Put(char c) {
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81 | vec_->push_back(c);
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82 | }
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83 |
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84 | virtual size_t PutN(const char* data, size_t len) {
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85 | vec_->insert(vec_->end(), data, data + len);
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86 | return len;
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87 | }
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88 |
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89 | private:
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90 | std::vector<char>* vec_; // unowned.
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91 | };
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92 |
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93 | class StringSink : public ByteSinkInterface {
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94 | public:
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95 | // |str| is unowned and must not be NULL.
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96 | explicit StringSink(std::string* str)
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97 | : str_(str) {
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98 | DCHECK(str != NULL);
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99 | }
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100 |
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101 | virtual void Put(char c) {
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102 | str_->push_back(c);
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103 | }
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104 |
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105 | virtual size_t PutN(const char* data, size_t len) {
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106 | str_->append(data, len);
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107 | return len;
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108 | }
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109 |
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110 | private:
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111 | std::string* str_; // unowned.
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112 | };
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113 |
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114 | class ByteHistogramSink : public ByteSinkInterface {
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115 | public:
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116 | // |sink| in unowned and must not be NULL.
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117 | explicit ByteHistogramSink(ByteSinkInterface* sink)
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118 | : sink_(sink) {
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119 | memset(histo_, 0, sizeof(histo_));
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120 | }
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121 |
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122 | virtual void Put(char c) {
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123 | histo_[static_cast<uint8>(c)]++;
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124 | sink_->Put(c);
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125 | }
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126 |
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127 | virtual size_t PutN(const char* data, size_t len) {
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128 | const char* const end = data + len;
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129 | for (const char* iter = data; iter != end; ++iter) {
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130 | histo_[static_cast<uint8>(*iter)]++;
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131 | }
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132 | return sink_->PutN(data, len);
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133 | }
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134 |
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135 | const size_t* histo() const {
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136 | return histo_;
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137 | }
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138 |
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139 | private:
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140 | size_t histo_[256];
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141 | ByteSinkInterface* sink_; // unowned.
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142 | };
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143 |
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144 | // TODO: does it make sense to have a global enum? How should
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145 | // new BufferedInput implementations define new error codes?
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146 | enum ErrorCode {
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147 | kNoError = 0,
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148 | kEndOfFile = 1,
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149 | kFileError = 2, // TODO: translate errno.
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150 | };
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151 |
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152 | // Adapted from ryg's BufferedStream abstraction:
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153 | // http://fgiesen.wordpress.com/2011/11/21/buffer-centric-io/
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154 | class BufferedInput {
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155 | public:
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156 | typedef ErrorCode (*Refiller)(BufferedInput*);
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157 |
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158 | BufferedInput(Refiller refiller = RefillZeroes)
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159 | : cursor(NULL),
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160 | begin_(NULL),
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161 | end_(NULL),
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162 | refiller_(refiller),
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163 | error_(kNoError) {
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164 | }
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165 |
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166 | // InitFromMemory.
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167 | BufferedInput(const char* data, size_t length)
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168 | : cursor(data),
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169 | begin_(data),
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170 | end_(data + length),
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171 | refiller_(RefillEndOfFile),
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172 | error_(kNoError) {
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173 | }
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174 |
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175 | const char* begin() const {
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176 | return begin_;
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177 | }
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178 |
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179 | const char* end() const {
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180 | return end_;
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181 | }
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182 |
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183 | const char* cursor;
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184 |
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185 | ErrorCode error() const {
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186 | DCHECK(begin() <= cursor);
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187 | DCHECK(cursor <= end());
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188 | return error_;
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189 | }
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190 |
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191 | ErrorCode Refill() {
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192 | DCHECK(begin() <= cursor);
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193 | DCHECK(cursor <= end());
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194 | if (cursor == end()) {
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195 | error_ = refiller_(this);
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196 | }
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197 | return error_;
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198 | }
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199 |
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200 | protected:
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201 | static ErrorCode RefillZeroes(BufferedInput* bi) {
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202 | static const char kZeroes[64] = { 0 };
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203 | bi->cursor = kZeroes;
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204 | bi->begin_ = kZeroes;
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205 | bi->end_ = kZeroes + sizeof(kZeroes);
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206 | return bi->error_;
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207 | }
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208 |
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209 | static ErrorCode RefillEndOfFile(BufferedInput* bi) {
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210 | return bi->fail(kEndOfFile);
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211 | }
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212 |
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213 | ErrorCode fail(ErrorCode why) {
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214 | error_ = why;
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215 | refiller_ = RefillZeroes;
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216 | return Refill();
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217 | }
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218 |
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219 | const char* begin_;
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220 | const char* end_;
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221 | Refiller refiller_;
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222 | ErrorCode error_;
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223 |
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224 | private:
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225 | // Disallow copy and assign.
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226 | BufferedInput(const BufferedInput&);
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227 | void operator=(const BufferedInput&);
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228 | };
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229 |
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230 | class BufferedInputStream : public BufferedInput {
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231 | public:
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232 | BufferedInputStream(FILE* fp, char* buf, size_t size)
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233 | : BufferedInput(RefillFread),
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234 | fp_(fp),
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235 | buf_(buf),
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236 | size_(size) {
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237 | DCHECK(buf != NULL);
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238 | // Disable buffering since we're doing it ourselves.
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239 | // TODO check error.
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240 | setvbuf(fp_, NULL, _IONBF, 0);
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241 | cursor = buf;
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242 | begin_ = buf;
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243 | end_ = buf;
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244 | }
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245 | protected:
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246 | // TODO: figure out how to automate this casting pattern.
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247 | static ErrorCode RefillFread(BufferedInput* bi) {
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248 | return static_cast<BufferedInputStream*>(bi)->DoRefillFread();
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249 | }
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250 | private:
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251 | ErrorCode DoRefillFread() {
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252 | const size_t bytes_read = fread(buf_, 1, size_, fp_);
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253 | cursor = begin_;
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254 | end_ = begin_ + bytes_read;
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255 | if (bytes_read < size_) {
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256 | if (feof(fp_)) {
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257 | refiller_ = RefillEndOfFile;
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258 | } else if (ferror(fp_)) {
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259 | return fail(kFileError);
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260 | }
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261 | }
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262 | return kNoError;
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263 | }
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264 |
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265 | FILE* fp_;
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266 | char* buf_;
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267 | size_t size_;
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268 | };
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269 |
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270 | } // namespace webgl_loader
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271 |
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272 | #endif // WEBGL_LOADER_STREAM_H_
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