root/base/strings/string_split.cc

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DEFINITIONS

This source file includes following definitions.
  1. SplitStringT
  2. SplitStringIntoKeyValue
  3. SplitStringUsingSubstrT
  4. SplitStringAlongWhitespaceT
  5. SplitString
  6. SplitString
  7. SplitStringIntoKeyValuePairs
  8. SplitStringUsingSubstr
  9. SplitStringUsingSubstr
  10. SplitStringDontTrim
  11. SplitStringDontTrim
  12. SplitStringAlongWhitespace
  13. SplitStringAlongWhitespace

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/strings/string_split.h"

#include "base/logging.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "base/third_party/icu/icu_utf.h"

namespace base {

namespace {

template <typename STR>
void SplitStringT(const STR& str,
                  const typename STR::value_type s,
                  bool trim_whitespace,
                  std::vector<STR>* r) {
  r->clear();
  size_t last = 0;
  size_t c = str.size();
  for (size_t i = 0; i <= c; ++i) {
    if (i == c || str[i] == s) {
      STR tmp(str, last, i - last);
      if (trim_whitespace)
        TrimWhitespace(tmp, TRIM_ALL, &tmp);
      // Avoid converting an empty or all-whitespace source string into a vector
      // of one empty string.
      if (i != c || !r->empty() || !tmp.empty())
        r->push_back(tmp);
      last = i + 1;
    }
  }
}

bool SplitStringIntoKeyValue(const std::string& line,
                             char key_value_delimiter,
                             std::string* key,
                             std::string* value) {
  key->clear();
  value->clear();

  // Find the delimiter.
  size_t end_key_pos = line.find_first_of(key_value_delimiter);
  if (end_key_pos == std::string::npos) {
    DVLOG(1) << "cannot find delimiter in: " << line;
    return false;    // no delimiter
  }
  key->assign(line, 0, end_key_pos);

  // Find the value string.
  std::string remains(line, end_key_pos, line.size() - end_key_pos);
  size_t begin_value_pos = remains.find_first_not_of(key_value_delimiter);
  if (begin_value_pos == std::string::npos) {
    DVLOG(1) << "cannot parse value from line: " << line;
    return false;   // no value
  }
  value->assign(remains, begin_value_pos, remains.size() - begin_value_pos);
  return true;
}

template <typename STR>
void SplitStringUsingSubstrT(const STR& str,
                                    const STR& s,
                                    std::vector<STR>* r) {
  r->clear();
  typename STR::size_type begin_index = 0;
  while (true) {
    const typename STR::size_type end_index = str.find(s, begin_index);
    if (end_index == STR::npos) {
      const STR term = str.substr(begin_index);
      STR tmp;
      TrimWhitespace(term, TRIM_ALL, &tmp);
      r->push_back(tmp);
      return;
    }
    const STR term = str.substr(begin_index, end_index - begin_index);
    STR tmp;
    TrimWhitespace(term, TRIM_ALL, &tmp);
    r->push_back(tmp);
    begin_index = end_index + s.size();
  }
}

template<typename STR>
void SplitStringAlongWhitespaceT(const STR& str, std::vector<STR>* result) {
  result->clear();
  const size_t length = str.length();
  if (!length)
    return;

  bool last_was_ws = false;
  size_t last_non_ws_start = 0;
  for (size_t i = 0; i < length; ++i) {
    switch (str[i]) {
      // HTML 5 defines whitespace as: space, tab, LF, line tab, FF, or CR.
      case L' ':
      case L'\t':
      case L'\xA':
      case L'\xB':
      case L'\xC':
      case L'\xD':
        if (!last_was_ws) {
          if (i > 0) {
            result->push_back(
                str.substr(last_non_ws_start, i - last_non_ws_start));
          }
          last_was_ws = true;
        }
        break;

      default:  // Not a space character.
        if (last_was_ws) {
          last_was_ws = false;
          last_non_ws_start = i;
        }
        break;
    }
  }
  if (!last_was_ws) {
    result->push_back(
        str.substr(last_non_ws_start, length - last_non_ws_start));
  }
}

}  // namespace

void SplitString(const string16& str,
                 char16 c,
                 std::vector<string16>* r) {
  DCHECK(CBU16_IS_SINGLE(c));
  SplitStringT(str, c, true, r);
}

void SplitString(const std::string& str,
                 char c,
                 std::vector<std::string>* r) {
#if CHAR_MIN < 0
  DCHECK(c >= 0);
#endif
  DCHECK(c < 0x7F);
  SplitStringT(str, c, true, r);
}

bool SplitStringIntoKeyValuePairs(const std::string& line,
                                  char key_value_delimiter,
                                  char key_value_pair_delimiter,
                                  StringPairs* key_value_pairs) {
  key_value_pairs->clear();

  std::vector<std::string> pairs;
  SplitString(line, key_value_pair_delimiter, &pairs);

  bool success = true;
  for (size_t i = 0; i < pairs.size(); ++i) {
    // Don't add empty pairs into the result.
    if (pairs[i].empty())
      continue;

    std::string key;
    std::string value;
    if (!SplitStringIntoKeyValue(pairs[i], key_value_delimiter, &key, &value)) {
      // Don't return here, to allow for pairs without associated
      // value or key; just record that the split failed.
      success = false;
    }
    key_value_pairs->push_back(make_pair(key, value));
  }
  return success;
}

void SplitStringUsingSubstr(const string16& str,
                            const string16& s,
                            std::vector<string16>* r) {
  SplitStringUsingSubstrT(str, s, r);
}

void SplitStringUsingSubstr(const std::string& str,
                            const std::string& s,
                            std::vector<std::string>* r) {
  SplitStringUsingSubstrT(str, s, r);
}

void SplitStringDontTrim(const string16& str,
                         char16 c,
                         std::vector<string16>* r) {
  DCHECK(CBU16_IS_SINGLE(c));
  SplitStringT(str, c, false, r);
}

void SplitStringDontTrim(const std::string& str,
                         char c,
                         std::vector<std::string>* r) {
  DCHECK(IsStringUTF8(str));
#if CHAR_MIN < 0
  DCHECK(c >= 0);
#endif
  DCHECK(c < 0x7F);
  SplitStringT(str, c, false, r);
}

void SplitStringAlongWhitespace(const string16& str,
                                std::vector<string16>* result) {
  SplitStringAlongWhitespaceT(str, result);
}

void SplitStringAlongWhitespace(const std::string& str,
                                std::vector<std::string>* result) {
  SplitStringAlongWhitespaceT(str, result);
}

}  // namespace base

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