// 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 <stddef.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 AppendStringKeyValue(StringPiece input,
char delimiter,
StringPairs* result) {
// Always append a new item regardless of success (it might be empty). The
// below code will copy the strings directly into the result pair.
result->resize(result->size() + 1);
auto& result_pair = result->back();
// Find the delimiter.
size_t end_key_pos = input.find_first_of(delimiter);
if (end_key_pos == std::string::npos) {
DVLOG(1) << "cannot find delimiter in: " << input;
return false; // No delimiter.
}
input.substr(0, end_key_pos).CopyToString(&result_pair.first);
// Find the value string.
StringPiece remains = input.substr(end_key_pos, input.size() - end_key_pos);
size_t begin_value_pos = remains.find_first_not_of(delimiter);
if (begin_value_pos == StringPiece::npos) {
DVLOG(1) << "cannot parse value from input: " << input;
return false; // No value.
}
remains.substr(begin_value_pos, remains.size() - begin_value_pos)
.CopyToString(&result_pair.second);
return true;
}
template <typename Str, typename OutputStringType>
void SplitStringUsingSubstrT(BasicStringPiece<Str> input,
BasicStringPiece<Str> delimiter,
WhitespaceHandling whitespace,
SplitResult result_type,
std::vector<OutputStringType>* result) {
using Piece = BasicStringPiece<Str>;
using size_type = typename Piece::size_type;
result->clear();
for (size_type begin_index = 0, end_index = 0; end_index != Piece::npos;
begin_index = end_index + delimiter.size()) {
end_index = input.find(delimiter, begin_index);
Piece term = end_index == Piece::npos
? input.substr(begin_index)
: input.substr(begin_index, end_index - begin_index);
if (whitespace == TRIM_WHITESPACE)
term = TrimString(term, WhitespaceForType<Str>(), TRIM_ALL);
if (result_type == SPLIT_WANT_ALL || !term.empty())
result->push_back(PieceToOutputType<Str, OutputStringType>(term));
}
}
} // 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);
}
bool SplitStringIntoKeyValuePairs(StringPiece input,
char key_value_delimiter,
char key_value_pair_delimiter,
StringPairs* key_value_pairs) {
key_value_pairs->clear();
std::vector<StringPiece> pairs = SplitStringPiece(
input, std::string(1, key_value_pair_delimiter),
TRIM_WHITESPACE, SPLIT_WANT_NONEMPTY);
key_value_pairs->reserve(pairs.size());
bool success = true;
for (const StringPiece& pair : pairs) {
if (!AppendStringKeyValue(pair, key_value_delimiter, key_value_pairs)) {
// Don't return here, to allow for pairs without associated
// value or key; just record that the split failed.
success = false;
}
}
return success;
}
void SplitStringUsingSubstr(StringPiece16 input,
StringPiece16 delimiter,
std::vector<string16>* result) {
SplitStringUsingSubstrT(input, delimiter, TRIM_WHITESPACE, SPLIT_WANT_ALL,
result);
}
void SplitStringUsingSubstr(StringPiece input,
StringPiece delimiter,
std::vector<std::string>* result) {
SplitStringUsingSubstrT(input, delimiter, TRIM_WHITESPACE, SPLIT_WANT_ALL,
result);
}
std::vector<StringPiece16> SplitStringPieceUsingSubstr(
StringPiece16 input,
StringPiece16 delimiter,
WhitespaceHandling whitespace,
SplitResult result_type) {
std::vector<StringPiece16> result;
SplitStringUsingSubstrT(input, delimiter, whitespace, result_type, &result);
return result;
}
std::vector<StringPiece> SplitStringPieceUsingSubstr(
StringPiece input,
StringPiece delimiter,
WhitespaceHandling whitespace,
SplitResult result_type) {
std::vector<StringPiece> result;
SplitStringUsingSubstrT(input, delimiter, whitespace, result_type, &result);
return result;
}
} // namespace base