Add new SplitString backend.

base/strings/string_util.cc

Index: base/strings/string_util.cc
diff --git a/base/strings/string_util.cc b/base/strings/string_util.cc
index cc7769343b5a592a2d081c89e3203dc82be8f720..540fc0948439e18276502d65c1211e1372bc3130 100644
--- a/base/strings/string_util.cc
+++ b/base/strings/string_util.cc
@@ -21,6 +21,7 @@
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/memory/singleton.h"
+#include "base/strings/string_split.h"
 #include "base/strings/utf_string_conversion_utils.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/third_party/icu/icu_utf.h"
@@ -193,29 +194,33 @@ bool RemoveChars(const std::string& input,
   return ReplaceChars(input, remove_chars.as_string(), std::string(), output);
 }
 
-template<typename STR>
-TrimPositions TrimStringT(const STR& input,
-                          const STR& trim_chars,
+template<typename Str>
+TrimPositions TrimStringT(const Str& input,
+                          BasicStringPiece<Str> trim_chars,
                           TrimPositions positions,
-                          STR* output) {
-  // Find the edges of leading/trailing whitespace as desired.
+                          Str* output) {
+  // Find the edges of leading/trailing whitespace as desired. Need to use
+  // a StringPiece version of input to be able to call find* on it with the
+  // StringPiece version of trim_chars (normally the trim_chars will be a
+  // constant so avoid making a copy).
+  BasicStringPiece<Str> input_piece(input);
   const size_t last_char = input.length() - 1;
   const size_t first_good_char = (positions & TRIM_LEADING) ?
-      input.find_first_not_of(trim_chars) : 0;
+      input_piece.find_first_not_of(trim_chars) : 0;
   const size_t last_good_char = (positions & TRIM_TRAILING) ?
-      input.find_last_not_of(trim_chars) : last_char;
+      input_piece.find_last_not_of(trim_chars) : last_char;
 
-  // When the string was all whitespace, report that we stripped off whitespace
-  // from whichever position the caller was interested in.  For empty input, we
-  // stripped no whitespace, but we still need to clear |output|.
+  // When the string was all trimmed, report that we stripped off characters
+  // from whichever position the caller was interested in. For empty input, we
+  // stripped no characters, but we still need to clear |output|.
   if (input.empty() ||
-      (first_good_char == STR::npos) || (last_good_char == STR::npos)) {
+      (first_good_char == Str::npos) || (last_good_char == Str::npos)) {
     bool input_was_empty = input.empty();  // in case output == &input
     output->clear();
     return input_was_empty ? TRIM_NONE : positions;
   }
 
-  // Trim the whitespace.
+  // Trim.
   *output =
       input.substr(first_good_char, last_good_char - first_good_char + 1);
 
@@ -226,17 +231,38 @@ TrimPositions TrimStringT(const STR& input,
 }
 
 bool TrimString(const string16& input,
-                const base::StringPiece16& trim_chars,
+                base::StringPiece16 trim_chars,
                 string16* output) {
-  return TrimStringT(input, trim_chars.as_string(), TRIM_ALL, output) !=
-      TRIM_NONE;
+  return TrimStringT(input, trim_chars, TRIM_ALL, output) != TRIM_NONE;
 }
 
 bool TrimString(const std::string& input,
-                const base::StringPiece& trim_chars,
+                base::StringPiece trim_chars,
                 std::string* output) {
-  return TrimStringT(input, trim_chars.as_string(), TRIM_ALL, output) !=
-      TRIM_NONE;
+  return TrimStringT(input, trim_chars, TRIM_ALL, output) != TRIM_NONE;
+}
+
+template<typename Str>
+BasicStringPiece<Str> TrimStringPieceT(BasicStringPiece<Str> input,
+                                       BasicStringPiece<Str> trim_chars,
+                                       TrimPositions positions) {
+  size_t begin = (positions & TRIM_LEADING) ?
+      input.find_first_not_of(trim_chars) : 0;
+  size_t end = (positions & TRIM_TRAILING) ?
+      input.find_last_not_of(trim_chars) + 1 : input.size();
+  return input.substr(begin, end - begin);
+}
+
+StringPiece16 TrimString(StringPiece16 input,
+                         const base::StringPiece16& trim_chars,
+                         TrimPositions positions) {
+  return TrimStringPieceT(input, trim_chars, positions);
+}
+
+StringPiece TrimString(StringPiece input,
+                       const base::StringPiece& trim_chars,
+                       TrimPositions positions) {
+  return TrimStringPieceT(input, trim_chars, positions);
 }
 
 void TruncateUTF8ToByteSize(const std::string& input,
@@ -278,14 +304,13 @@ void TruncateUTF8ToByteSize(const std::string& input,
 TrimPositions TrimWhitespace(const string16& input,
                              TrimPositions positions,
                              string16* output) {
-  return TrimStringT(input, base::string16(kWhitespaceUTF16), positions,
-                     output);
+  return TrimStringT(input, StringPiece16(kWhitespaceUTF16), positions, output);
 }
 
 TrimPositions TrimWhitespaceASCII(const std::string& input,
                                   TrimPositions positions,
                                   std::string* output) {
-  return TrimStringT(input, std::string(kWhitespaceASCII), positions, output);
+  return TrimStringT(input, StringPiece(kWhitespaceASCII), positions, output);
 }
 
 // This function is only for backward-compatibility.
@@ -696,44 +721,28 @@ void ReplaceSubstringsAfterOffset(std::string* str,
                                  true);  // replace all instances
 }
 
-
-template<typename STR>
-static size_t TokenizeT(const STR& str,
-                        const STR& delimiters,
-                        std::vector<STR>* tokens) {
-  tokens->clear();
-
-  size_t start = str.find_first_not_of(delimiters);
-  while (start != STR::npos) {
-    size_t end = str.find_first_of(delimiters, start + 1);
-    if (end == STR::npos) {
-      tokens->push_back(str.substr(start));
-      break;
-    } else {
-      tokens->push_back(str.substr(start, end - start));
-      start = str.find_first_not_of(delimiters, end + 1);
-    }
-  }
-
+size_t Tokenize(const base::string16& str,
+                const base::string16& delimiters,
+                std::vector<base::string16>* tokens) {
+  *tokens = base::SplitString(
+      str, delimiters, base::KEEP_WHITESPACE, base::SPLIT_WANT_NONEMPTY);
   return tokens->size();
 }
 
-size_t Tokenize(const string16& str,
-                const string16& delimiters,
-                std::vector<string16>* tokens) {
-  return TokenizeT(str, delimiters, tokens);
-}
-
 size_t Tokenize(const std::string& str,
                 const std::string& delimiters,
                 std::vector<std::string>* tokens) {
-  return TokenizeT(str, delimiters, tokens);
+  *tokens = base::SplitString(
+      str, delimiters, base::KEEP_WHITESPACE, base::SPLIT_WANT_NONEMPTY);
+  return tokens->size();
 }
 
 size_t Tokenize(const base::StringPiece& str,
                 const base::StringPiece& delimiters,
                 std::vector<base::StringPiece>* tokens) {
-  return TokenizeT(str, delimiters, tokens);
+  *tokens = base::SplitStringPiece(
+      str, delimiters, base::KEEP_WHITESPACE, base::SPLIT_WANT_NONEMPTY);
+  return tokens->size();
 }
 
 template<typename STR>