base/strings/string_split.cc - chromium/src - Git at Google

 // 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) {
   return SplitStringIntoKeyValuePairsUsingSubstr(
       input, key_value_delimiter, StringPiece(&key_value_pair_delimiter, 1),
       key_value_pairs);
 }

 bool SplitStringIntoKeyValuePairsUsingSubstr(
     StringPiece input,
     char key_value_delimiter,
     StringPiece key_value_pair_delimiter,
     StringPairs* key_value_pairs) {
   key_value_pairs->clear();

   std::vector<StringPiece> pairs = SplitStringPieceUsingSubstr(
       input, 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;
 }

 std::vector<string16> SplitStringUsingSubstr(StringPiece16 input,
                                              StringPiece16 delimiter,
                                              WhitespaceHandling whitespace,
                                              SplitResult result_type) {
   std::vector<string16> result;
   SplitStringUsingSubstrT(input, delimiter, whitespace, result_type, &result);
   return result;
 }

 std::vector<std::string> SplitStringUsingSubstr(StringPiece input,
                                                 StringPiece delimiter,
                                                 WhitespaceHandling whitespace,
                                                 SplitResult result_type) {
   std::vector<std::string> result;
   SplitStringUsingSubstrT(input, delimiter, whitespace, result_type, &result);
   return 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
	// 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) {
	return SplitStringIntoKeyValuePairsUsingSubstr(
	input, key_value_delimiter, StringPiece(&key_value_pair_delimiter, 1),
	key_value_pairs);
	}

	bool SplitStringIntoKeyValuePairsUsingSubstr(
	StringPiece input,
	char key_value_delimiter,
	StringPiece key_value_pair_delimiter,
	StringPairs* key_value_pairs) {
	key_value_pairs->clear();

	std::vector<StringPiece> pairs = SplitStringPieceUsingSubstr(
	input, 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;
	}

	std::vector<string16> SplitStringUsingSubstr(StringPiece16 input,
	StringPiece16 delimiter,
	WhitespaceHandling whitespace,
	SplitResult result_type) {
	std::vector<string16> result;
	SplitStringUsingSubstrT(input, delimiter, whitespace, result_type, &result);
	return result;
	}

	std::vector<std::string> SplitStringUsingSubstr(StringPiece input,
	StringPiece delimiter,
	WhitespaceHandling whitespace,
	SplitResult result_type) {
	std::vector<std::string> result;
	SplitStringUsingSubstrT(input, delimiter, whitespace, result_type, &result);
	return 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