Chromium Base库中常用的功能

按模块划分

String

base/strings/string_util.h

// Removes characters in |trim_chars| from the beginning and end of |input|.
// The 8-bit version only works on 8-bit characters, not UTF-8. Returns true if
// any characters were removed.
//
// It is safe to use the same variable for both |input| and |output| (this is
// the normal usage to trim in-place).
BASE_EXPORT bool TrimString(StringPiece16 input,
                            StringPiece16 trim_chars,
                            std::u16string* output);

去除首尾或首或尾指定子串。

相比folly::trim 易用性更好。

// Replaces characters in |replace_chars| from anywhere in |input| with
// |replace_with|.  Each character in |replace_chars| will be replaced with
// the |replace_with| string.  Returns true if any characters were replaced.
// |replace_chars| must be null-terminated.
// NOTE: Safe to use the same variable for both |input| and |output|.
BASE_EXPORT bool ReplaceChars(StringPiece16 input,
                              StringPiece16 replace_chars,
                              StringPiece16 replace_with,
                              std::u16string* output);

替换字符串中的指定子串。

// Converts the given string to it's ASCII-lowercase equivalent.
BASE_EXPORT std::string ToLowerASCII(StringPiece str);
BASE_EXPORT std::u16string ToLowerASCII(StringPiece16 str);

// Converts the given string to it's ASCII-uppercase equivalent.
BASE_EXPORT std::string ToUpperASCII(StringPiece str);
BASE_EXPORT std::u16string ToUpperASCII(StringPiece16 str);

大小写转换。

// Indicates case sensitivity of comparisons. Only ASCII case insensitivity
// is supported. Full Unicode case-insensitive conversions would need to go in
// base/i18n so it can use ICU.
//
// If you need to do Unicode-aware case-insensitive StartsWith/EndsWith, it's
// best to call base::i18n::ToLower() or base::i18n::FoldCase() (see
// base/i18n/case_conversion.h for usage advice) on the arguments, and then use
// the results to a case-sensitive comparison.
enum class CompareCase {
  SENSITIVE,
  INSENSITIVE_ASCII,
};

BASE_EXPORT bool StartsWith(
    StringPiece str,
    StringPiece search_for,
    CompareCase case_sensitivity = CompareCase::SENSITIVE);
BASE_EXPORT bool EndsWith(
    StringPiece str,
    StringPiece search_for,
    CompareCase case_sensitivity = CompareCase::SENSITIVE);

判断字符串是否以某子串起始或结束。

base/strings/string_split.h

// Split the given string on ANY of the given separators, returning copies of
// the result.
//
// Note this is inverse of JoinString() defined in string_util.h.
//
// To split on either commas or semicolons, keeping all whitespace:
//
//   std::vector<std::string> tokens = base::SplitString(
//       input, ",;", base::KEEP_WHITESPACE, base::SPLIT_WANT_ALL);
[[nodiscard]] BASE_EXPORT std::vector<std::string> SplitString(
    StringPiece input,
    StringPiece separators,
    WhitespaceHandling whitespace,
    SplitResult result_type);

分割字符串进vector。