blob: e23ce3fa039a087b3cd902aab55a18520599d9ae [file] [log] [blame]
// 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/third_party/icu/icu_utf.h"
namespace base {
namespace {
// PieceToOutputType converts a StringPiece as needed to a given output type,
// which is either the same type of StringPiece (a NOP) or the corresponding
// non-piece string type.
//
// The default converter is a NOP, it works when the OutputType is the
// correct StringPiece.
template<typename Str, typename OutputType>
OutputType PieceToOutputType(BasicStringPiece<Str> piece) {
return piece;
}
template<> // Convert StringPiece to std::string
std::string PieceToOutputType<std::string, std::string>(StringPiece piece) {
return piece.as_string();
}
template<> // Convert StringPiece16 to string16.
string16 PieceToOutputType<string16, string16>(StringPiece16 piece) {
return piece.as_string();
}
// Returns either the ASCII or UTF-16 whitespace.
template<typename Str> BasicStringPiece<Str> WhitespaceForType();
template<> StringPiece16 WhitespaceForType<string16>() {
return kWhitespaceUTF16;
}
template<> StringPiece WhitespaceForType<std::string>() {
return kWhitespaceASCII;
}
// Optimize the single-character case to call find() on the string instead,
// since this is the common case and can be made faster. This could have been
// done with template specialization too, but would have been less clear.
//
// There is no corresponding FindFirstNotOf because StringPiece already
// implements these different versions that do the optimized searching.
size_t FindFirstOf(StringPiece piece, char c, size_t pos) {
return piece.find(c, pos);
}
size_t FindFirstOf(StringPiece16 piece, char16 c, size_t pos) {
return piece.find(c, pos);
}
size_t FindFirstOf(StringPiece piece, StringPiece one_of, size_t pos) {
return piece.find_first_of(one_of, pos);
}
size_t FindFirstOf(StringPiece16 piece, StringPiece16 one_of, size_t pos) {
return piece.find_first_of(one_of, pos);
}
// General string splitter template. Can take 8- or 16-bit input, can produce
// the corresponding string or StringPiece output, and can take single- or
// multiple-character delimiters.
//
// DelimiterType is either a character (Str::value_type) or a string piece of
// multiple characters (BasicStringPiece<Str>). StringPiece has a version of
// find for both of these cases, and the single-character version is the most
// common and can be implemented faster, which is why this is a template.
template<typename Str, typename OutputStringType, typename DelimiterType>
static std::vector<OutputStringType> SplitStringT(
BasicStringPiece<Str> str,
DelimiterType delimiter,
WhitespaceHandling whitespace,
SplitResult result_type) {
std::vector<OutputStringType> result;
if (str.empty())
return result;
size_t start = 0;
while (start != Str::npos) {
size_t end = FindFirstOf(str, delimiter, start);
BasicStringPiece<Str> piece;
if (end == Str::npos) {
piece = str.substr(start);
start = Str::npos;
} else {
piece = str.substr(start, end - start);
start = end + 1;
}
if (whitespace == TRIM_WHITESPACE)
piece = TrimString(piece, WhitespaceForType<Str>(), TRIM_ALL);
if (result_type == SPLIT_WANT_ALL || !piece.empty())
result.push_back(PieceToOutputType<Str, OutputStringType>(piece));
}
return result;
}
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();
}
}
} // namespace
std::vector<std::string> SplitString(StringPiece input,
StringPiece separators,
WhitespaceHandling whitespace,
SplitResult result_type) {
if (separators.size() == 1) {
return SplitStringT<std::string, std::string, char>(
input, separators[0], whitespace, result_type);
}
return SplitStringT<std::string, std::string, StringPiece>(
input, separators, whitespace, result_type);
}
std::vector<string16> SplitString(StringPiece16 input,
StringPiece16 separators,
WhitespaceHandling whitespace,
SplitResult result_type) {
if (separators.size() == 1) {
return SplitStringT<string16, string16, char16>(
input, separators[0], whitespace, result_type);
}
return SplitStringT<string16, string16, StringPiece16>(
input, separators, whitespace, result_type);
}
std::vector<StringPiece> SplitStringPiece(StringPiece input,
StringPiece separators,
WhitespaceHandling whitespace,
SplitResult result_type) {
if (separators.size() == 1) {
return SplitStringT<std::string, StringPiece, char>(
input, separators[0], whitespace, result_type);
}
return SplitStringT<std::string, StringPiece, StringPiece>(
input, separators, whitespace, result_type);
}
std::vector<StringPiece16> SplitStringPiece(StringPiece16 input,
StringPiece16 separators,
WhitespaceHandling whitespace,
SplitResult result_type) {
if (separators.size() == 1) {
return SplitStringT<string16, StringPiece16, char16>(
input, separators[0], whitespace, result_type);
}
return SplitStringT<string16, StringPiece16, StringPiece16>(
input, separators, whitespace, result_type);
}
void SplitString(const string16& str,
char16 c,
std::vector<string16>* result) {
DCHECK(CBU16_IS_SINGLE(c));
*result = SplitStringT<string16, string16, char16>(
str, c, TRIM_WHITESPACE, SPLIT_WANT_ALL);
// Backward-compat hack: The old SplitString implementation would keep
// empty substrings, for example:
// "a,,b" -> ["a", "", "b"]
// "a, ,b" -> ["a", "", "b"]
// which the current code also does. But the old one would discard them when
// the only result was that empty string:
// " " -> []
// In the latter case, our new code will give [""]
if (result->size() == 1 && (*result)[0].empty())
result->clear();
}
void SplitString(const std::string& str,
char c,
std::vector<std::string>* result) {
#if CHAR_MIN < 0
DCHECK_GE(c, 0);
#endif
DCHECK_LT(c, 0x7F);
*result = SplitStringT<std::string, std::string, char>(
str, c, TRIM_WHITESPACE, SPLIT_WANT_ALL);
// Backward-compat hack, see above.
if (result->size() == 1 && (*result)[0].empty())
result->clear();
}
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(StringPiece16 str,
char16 c,
std::vector<string16>* result) {
DCHECK(CBU16_IS_SINGLE(c));
*result = SplitStringT<string16, string16, char16>(
str, c, KEEP_WHITESPACE, SPLIT_WANT_ALL);
}
void SplitStringDontTrim(StringPiece str,
char c,
std::vector<std::string>* result) {
#if CHAR_MIN < 0
DCHECK_GE(c, 0);
#endif
DCHECK_LT(c, 0x7F);
*result = SplitStringT<std::string, std::string, char>(
str, c, KEEP_WHITESPACE, SPLIT_WANT_ALL);
}
void SplitStringAlongWhitespace(const string16& str,
std::vector<string16>* result) {
*result = SplitStringT<string16, string16, StringPiece16>(
str, StringPiece16(kWhitespaceASCIIAs16),
TRIM_WHITESPACE, SPLIT_WANT_NONEMPTY);
}
void SplitStringAlongWhitespace(const std::string& str,
std::vector<std::string>* result) {
*result = SplitStringT<std::string, std::string, StringPiece>(
str, StringPiece(kWhitespaceASCII),
TRIM_WHITESPACE, SPLIT_WANT_NONEMPTY);
}
} // namespace base