xapian-applications/omega/jsonescape.cc

   1 /* @file jsonescape.cc
   2  * @brief JSON escape a string
   3  */
   4 /* Copyright (C) 2013 Olly Betts
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to
   8  * deal in the Software without restriction, including without limitation the
   9  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
  10  * sell copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  22  * IN THE SOFTWARE.
  23  */
  24
  25 #include <config.h>
  26
  27 #include "jsonescape.h"
  28
  29 #include <cstdio>
  30 #include <string>
  31
  32 #include <xapian.h>
  33
  34 using namespace std;
  35
  36 enum { UNI = 0, CLR = 1 };
  37
  38 static const char json_tab['"' + 1] = {
  39     UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, // 0-7
  40     'b', 't', 'n', UNI, 'f', 'r', UNI, UNI, // 8-15
  41     UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, // 16-23
  42     UNI, UNI, UNI, UNI, UNI, UNI, UNI, UNI, // 24-31
  43     CLR, CLR, '"'
  44 };
  45
  46 void
  47 json_escape(string &s)
  48 {
  49     string r;
  50     for (Xapian::Utf8Iterator i(s); i != Xapian::Utf8Iterator(); ++i) {
  51         unsigned int ch = *i;
  52         if (ch >= 128) {
  53             Xapian::Unicode::append_utf8(r, ch);
  54             continue;
  55         }
  56         if (ch > '"') {
  57             if (ch != '\\') {
  58                 r += ch;
  59                 continue;
  60             }
  61         } else {
  62             unsigned char t = json_tab[ch];
  63             if (t == CLR) {
  64                 r += ch;
  65                 continue;
  66             }
  67             if (t == UNI) {
  68                 char buf[7];
  69                 sprintf(buf, "\\u00%02x", ch);
  70                 r.append(buf, 6);
  71                 continue;
  72             }
  73             ch = t;
  74         }
  75         char buf[2] = {'\\', char(ch)};
  76         r.append(buf, 2);
  77     }
  78     swap(s, r);
  79 }