base/strings/string_split.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/strings/string_split.h"
   6
   7 #include "base/logging.h"
   8 #include "base/strings/string_util.h"
   9 #include "base/strings/utf_string_conversions.h"
  10 #include "base/third_party/icu/icu_utf.h"
  11
  12 namespace base {
  13
  14 template<typename STR>
  15 static void SplitStringT(const STR& str,
  16                          const typename STR::value_type s,
  17                          bool trim_whitespace,
  18                          std::vector<STR>* r) {
  19   r->clear();
  20   size_t last = 0;
  21   size_t c = str.size();
  22   for (size_t i = 0; i <= c; ++i) {
  23     if (i == c || str[i] == s) {
  24       STR tmp(str, last, i - last);
  25       if (trim_whitespace)
  26         TrimWhitespace(tmp, TRIM_ALL, &tmp);
  27       // Avoid converting an empty or all-whitespace source string into a vector
  28       // of one empty string.
  29       if (i != c || !r->empty() || !tmp.empty())
  30         r->push_back(tmp);
  31       last = i + 1;
  32     }
  33   }
  34 }
  35
  36 void SplitString(const string16& str,
  37                  char16 c,
  38                  std::vector<string16>* r) {
  39   DCHECK(CBU16_IS_SINGLE(c));
  40   SplitStringT(str, c, true, r);
  41 }
  42
  43 void SplitString(const std::string& str,
  44                  char c,
  45                  std::vector<std::string>* r) {
  46 #if CHAR_MIN < 0
  47   DCHECK(c >= 0);
  48 #endif
  49   DCHECK(c < 0x7F);
  50   SplitStringT(str, c, true, r);
  51 }
  52
  53 bool SplitStringIntoKeyValues(
  54     const std::string& line,
  55     char key_value_delimiter,
  56     std::string* key, std::vector<std::string>* values) {
  57   key->clear();
  58   values->clear();
  59
  60   // Find the key string.
  61   size_t end_key_pos = line.find_first_of(key_value_delimiter);
  62   if (end_key_pos == std::string::npos) {
  63     DVLOG(1) << "cannot parse key from line: " << line;
  64     return false;    // no key
  65   }
  66   key->assign(line, 0, end_key_pos);
  67
  68   // Find the values string.
  69   std::string remains(line, end_key_pos, line.size() - end_key_pos);
  70   size_t begin_values_pos = remains.find_first_not_of(key_value_delimiter);
  71   if (begin_values_pos == std::string::npos) {
  72     DVLOG(1) << "cannot parse value from line: " << line;
  73     return false;   // no value
  74   }
  75   std::string values_string(remains, begin_values_pos,
  76                             remains.size() - begin_values_pos);
  77
  78   // Construct the values vector.
  79   values->push_back(values_string);
  80   return true;
  81 }
  82
  83 bool SplitStringIntoKeyValuePairs(const std::string& line,
  84                                   char key_value_delimiter,
  85                                   char key_value_pair_delimiter,
  86                                   StringPairs* key_value_pairs) {
  87   key_value_pairs->clear();
  88
  89   std::vector<std::string> pairs;
  90   SplitString(line, key_value_pair_delimiter, &pairs);
  91
  92   bool success = true;
  93   for (size_t i = 0; i < pairs.size(); ++i) {
  94     // Empty pair. SplitStringIntoKeyValues is more strict about an empty pair
  95     // line, so continue with the next pair.
  96     if (pairs[i].empty())
  97       continue;
  98
  99     std::string key;
 100     std::vector<std::string> value;
 101     if (!SplitStringIntoKeyValues(pairs[i],
 102                                   key_value_delimiter,
 103                                   &key, &value)) {
 104       // Don't return here, to allow for keys without associated
 105       // values; just record that our split failed.
 106       success = false;
 107     }
 108     DCHECK_LE(value.size(), 1U);
 109     key_value_pairs->push_back(
 110         make_pair(key, value.empty() ? std::string() : value[0]));
 111   }
 112   return success;
 113 }
 114
 115 template <typename STR>
 116 static void SplitStringUsingSubstrT(const STR& str,
 117                                     const STR& s,
 118                                     std::vector<STR>* r) {
 119   r->clear();
 120   typename STR::size_type begin_index = 0;
 121   while (true) {
 122     const typename STR::size_type end_index = str.find(s, begin_index);
 123     if (end_index == STR::npos) {
 124       const STR term = str.substr(begin_index);
 125       STR tmp;
 126       TrimWhitespace(term, TRIM_ALL, &tmp);
 127       r->push_back(tmp);
 128       return;
 129     }
 130     const STR term = str.substr(begin_index, end_index - begin_index);
 131     STR tmp;
 132     TrimWhitespace(term, TRIM_ALL, &tmp);
 133     r->push_back(tmp);
 134     begin_index = end_index + s.size();
 135   }
 136 }
 137
 138 void SplitStringUsingSubstr(const string16& str,
 139                             const string16& s,
 140                             std::vector<string16>* r) {
 141   SplitStringUsingSubstrT(str, s, r);
 142 }
 143
 144 void SplitStringUsingSubstr(const std::string& str,
 145                             const std::string& s,
 146                             std::vector<std::string>* r) {
 147   SplitStringUsingSubstrT(str, s, r);
 148 }
 149
 150 void SplitStringDontTrim(const string16& str,
 151                          char16 c,
 152                          std::vector<string16>* r) {
 153   DCHECK(CBU16_IS_SINGLE(c));
 154   SplitStringT(str, c, false, r);
 155 }
 156
 157 void SplitStringDontTrim(const std::string& str,
 158                          char c,
 159                          std::vector<std::string>* r) {
 160   DCHECK(IsStringUTF8(str));
 161 #if CHAR_MIN < 0
 162   DCHECK(c >= 0);
 163 #endif
 164   DCHECK(c < 0x7F);
 165   SplitStringT(str, c, false, r);
 166 }
 167
 168 template<typename STR>
 169 void SplitStringAlongWhitespaceT(const STR& str, std::vector<STR>* result) {
 170   result->clear();
 171   const size_t length = str.length();
 172   if (!length)
 173     return;
 174
 175   bool last_was_ws = false;
 176   size_t last_non_ws_start = 0;
 177   for (size_t i = 0; i < length; ++i) {
 178     switch (str[i]) {
 179       // HTML 5 defines whitespace as: space, tab, LF, line tab, FF, or CR.
 180       case L' ':
 181       case L'\t':
 182       case L'\xA':
 183       case L'\xB':
 184       case L'\xC':
 185       case L'\xD':
 186         if (!last_was_ws) {
 187           if (i > 0) {
 188             result->push_back(
 189                 str.substr(last_non_ws_start, i - last_non_ws_start));
 190           }
 191           last_was_ws = true;
 192         }
 193         break;
 194
 195       default:  // Not a space character.
 196         if (last_was_ws) {
 197           last_was_ws = false;
 198           last_non_ws_start = i;
 199         }
 200         break;
 201     }
 202   }
 203   if (!last_was_ws) {
 204     result->push_back(
 205         str.substr(last_non_ws_start, length - last_non_ws_start));
 206   }
 207 }
 208
 209 void SplitStringAlongWhitespace(const string16& str,
 210                                 std::vector<string16>* result) {
 211   SplitStringAlongWhitespaceT(str, result);
 212 }
 213
 214 void SplitStringAlongWhitespace(const std::string& str,
 215                                 std::vector<std::string>* result) {
 216   SplitStringAlongWhitespaceT(str, result);
 217 }
 218
 219 }  // namespace base