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      1 // Copyright 2009 Google Inc.
      2 // Author: James deBoer
      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 #include <config.h>
     17 #include <stdio.h>
     18 #include <string.h>
     19 #include <sstream>
     20 #include <string>
     21 #include "jsonwriter.h"
     22 #include "google/output_string.h"
     23 
     24 namespace open_vcdiff {
     25 
     26 JSONCodeTableWriter::JSONCodeTableWriter()
     27   : output_called_(false) {}
     28 JSONCodeTableWriter::~JSONCodeTableWriter() {}
     29 
     30 bool JSONCodeTableWriter::Init(size_t /*dictionary_size*/) {
     31   output_ = "[";
     32   target_length_ = 0;
     33   return true;
     34 }
     35 
     36 void JSONCodeTableWriter::Output(OutputStringInterface* out) {
     37   output_called_ = true;
     38   out->append(output_.data(), output_.size());
     39   output_ = "";
     40   target_length_ = 0;
     41 }
     42 
     43 void JSONCodeTableWriter::FinishEncoding(OutputStringInterface* out) {
     44   if (output_called_) {
     45     out->append("]", 1);
     46   }
     47 }
     48 
     49 void JSONCodeTableWriter::JSONEscape(const char* data,
     50                                      size_t size,
     51                                      string* out) {
     52   for (size_t i = 0; i < size; ++i) {
     53     const char c = data[i];
     54     switch (c) {
     55       case '"': out->append("\\\"", 2); break;
     56       case '\\': out->append("\\\\", 2); break;
     57       case '\b': out->append("\\b", 2); break;
     58       case '\f': out->append("\\f", 2); break;
     59       case '\n': out->append("\\n", 2); break;
     60       case '\r': out->append("\\r", 2); break;
     61       case '\t': out->append("\\t", 2); break;
     62       default:
     63         // encode zero as unicode, also all control codes.
     64         if (c < 32 || c >= 127) {
     65           char unicode_code[8] = "";
     66           snprintf(unicode_code, sizeof(unicode_code), "\\u%04x", c);
     67           out->append(unicode_code, strlen(unicode_code));
     68         } else {
     69           out->push_back(c);
     70         }
     71     }
     72   }
     73 }
     74 
     75 void JSONCodeTableWriter::Add(const char* data, size_t size) {
     76   output_.push_back('\"');
     77   JSONEscape(data, size, &output_);
     78   output_.append("\",", 2);
     79   target_length_ += size;
     80 }
     81 
     82 void JSONCodeTableWriter::Copy(int32_t offset, size_t size) {
     83   std::ostringstream copy_code;
     84   copy_code << offset << "," << size << ",";
     85   output_.append(copy_code.str());
     86   target_length_ += size;
     87 }
     88 
     89 void JSONCodeTableWriter::Run(size_t size, unsigned char byte) {
     90   output_.push_back('\"');
     91   output_.append(string(size, byte).data(), size);
     92   output_.append("\",", 2);
     93   target_length_ += size;
     94 }
     95 
     96 size_t JSONCodeTableWriter::target_length() const {
     97   return target_length_;
     98 }
     99 
    100 void JSONCodeTableWriter::WriteHeader(OutputStringInterface *,
    101                                       VCDiffFormatExtensionFlags) {
    102   // The JSON format does not need a header.
    103 }
    104 
    105 }  // namespace open_vcdiff
    106