src/json.cc

// Copyright 2021 Google Inc. All Rights Reserved.
//
// 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.

#include "json.h"

#include <cstdio>
#include <string>

void EncodeAppendJSONString(std::string* out, StringPiece in) {
  const char hex_digits[] = "0123456789abcdef";
  for (auto c : in) {
    switch (c) {
    case '\b':
      out->append("\\b");
      break;
    case '\f':
      out->append("\\f");
      break;
    case '\n':
      out->append("\\n");
      break;
    case '\r':
      out->append("\\r");
      break;
    case '\t':
      out->append("\\t");
      break;
    case '\\':
      out->append("\\\\");
      break;
    case '"':
      out->append("\\\"");
      break;
    default:
      if (0x0 <= c && c < 0x20) {  // non-printable chars.
        out->append("\\u00");
        out->push_back(hex_digits[c >> 4]);
        out->push_back(hex_digits[c & 0xf]);
      } else {
        out->push_back(c);
      }
    }
  }
}

std::string EncodeJSONString(StringPiece in) {
  std::string out;
  out.reserve(in.size() * 1.2);
  EncodeAppendJSONString(&out, in);
  return out;
}

void PrintJSONString(StringPiece in) {
  std::string out = EncodeJSONString(in);
  fwrite(out.c_str(), 1, out.length(), stdout);
}