string_number_conversions.h (8618B)
1 // Copyright 2012 The Chromium Authors 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef BASE_STRINGS_STRING_NUMBER_CONVERSIONS_H_ 6 #define BASE_STRINGS_STRING_NUMBER_CONVERSIONS_H_ 7 8 #include <stddef.h> 9 #include <stdint.h> 10 11 #include <string> 12 #include <vector> 13 14 #include "base/base_export.h" 15 #include "base/containers/span.h" 16 #include "base/strings/string_piece.h" 17 #include "build/build_config.h" 18 19 // ---------------------------------------------------------------------------- 20 // IMPORTANT MESSAGE FROM YOUR SPONSOR 21 // 22 // Please do not add "convenience" functions for converting strings to integers 23 // that return the value and ignore success/failure. That encourages people to 24 // write code that doesn't properly handle the error conditions. 25 // 26 // DO NOT use these functions in any UI unless it's NOT localized on purpose. 27 // Instead, use base::MessageFormatter for a complex message with numbers 28 // (integer, float, double) embedded or base::Format{Number,Double,Percent} to 29 // just format a single number/percent. Note that some languages use native 30 // digits instead of ASCII digits while others use a group separator or decimal 31 // point different from ',' and '.'. Using these functions in the UI would lead 32 // numbers to be formatted in a non-native way. 33 // ---------------------------------------------------------------------------- 34 35 namespace base { 36 37 // Number -> string conversions ------------------------------------------------ 38 39 // Ignores locale! see warning above. 40 BASE_EXPORT std::string NumberToString(int value); 41 BASE_EXPORT std::u16string NumberToString16(int value); 42 BASE_EXPORT std::string NumberToString(unsigned int value); 43 BASE_EXPORT std::u16string NumberToString16(unsigned int value); 44 BASE_EXPORT std::string NumberToString(long value); 45 BASE_EXPORT std::u16string NumberToString16(long value); 46 BASE_EXPORT std::string NumberToString(unsigned long value); 47 BASE_EXPORT std::u16string NumberToString16(unsigned long value); 48 BASE_EXPORT std::string NumberToString(long long value); 49 BASE_EXPORT std::u16string NumberToString16(long long value); 50 BASE_EXPORT std::string NumberToString(unsigned long long value); 51 BASE_EXPORT std::u16string NumberToString16(unsigned long long value); 52 BASE_EXPORT std::string NumberToString(double value); 53 BASE_EXPORT std::u16string NumberToString16(double value); 54 55 // String -> number conversions ------------------------------------------------ 56 57 // Perform a best-effort conversion of the input string to a numeric type, 58 // setting |*output| to the result of the conversion. Returns true for 59 // "perfect" conversions; returns false in the following cases: 60 // - Overflow. |*output| will be set to the maximum value supported 61 // by the data type. 62 // - Underflow. |*output| will be set to the minimum value supported 63 // by the data type. 64 // - Trailing characters in the string after parsing the number. |*output| 65 // will be set to the value of the number that was parsed. 66 // - Leading whitespace in the string before parsing the number. |*output| will 67 // be set to the value of the number that was parsed. 68 // - No characters parseable as a number at the beginning of the string. 69 // |*output| will be set to 0. 70 // - Empty string. |*output| will be set to 0. 71 // WARNING: Will write to |output| even when returning false. 72 // Read the comments above carefully. 73 BASE_EXPORT bool StringToInt(StringPiece input, int* output); 74 BASE_EXPORT bool StringToInt(StringPiece16 input, int* output); 75 76 BASE_EXPORT bool StringToUint(StringPiece input, unsigned* output); 77 BASE_EXPORT bool StringToUint(StringPiece16 input, unsigned* output); 78 79 BASE_EXPORT bool StringToInt64(StringPiece input, int64_t* output); 80 BASE_EXPORT bool StringToInt64(StringPiece16 input, int64_t* output); 81 82 BASE_EXPORT bool StringToUint64(StringPiece input, uint64_t* output); 83 BASE_EXPORT bool StringToUint64(StringPiece16 input, uint64_t* output); 84 85 BASE_EXPORT bool StringToSizeT(StringPiece input, size_t* output); 86 BASE_EXPORT bool StringToSizeT(StringPiece16 input, size_t* output); 87 88 // For floating-point conversions, only conversions of input strings in decimal 89 // form are defined to work. Behavior with strings representing floating-point 90 // numbers in hexadecimal, and strings representing non-finite values (such as 91 // NaN and inf) is undefined. Otherwise, these behave the same as the integral 92 // variants. This expects the input string to NOT be specific to the locale. 93 // If your input is locale specific, use ICU to read the number. 94 // WARNING: Will write to |output| even when returning false. 95 // Read the comments here and above StringToInt() carefully. 96 BASE_EXPORT bool StringToDouble(StringPiece input, double* output); 97 BASE_EXPORT bool StringToDouble(StringPiece16 input, double* output); 98 99 // Hex encoding ---------------------------------------------------------------- 100 101 // Returns a hex string representation of a binary buffer. The returned hex 102 // string will be in upper case. This function does not check if |size| is 103 // within reasonable limits since it's written with trusted data in mind. If 104 // you suspect that the data you want to format might be large, the absolute 105 // max size for |size| should be is 106 // std::numeric_limits<size_t>::max() / 2 107 BASE_EXPORT std::string HexEncode(const void* bytes, size_t size); 108 BASE_EXPORT std::string HexEncode(base::span<const uint8_t> bytes); 109 110 // Appends a hex representation of `byte`, as two uppercase (by default) 111 // characters, to `output`. This is a useful primitive in larger conversion 112 // routines. 113 inline void AppendHexEncodedByte(uint8_t byte, 114 std::string& output, 115 bool uppercase = true) { 116 static constexpr char kHexCharsUpper[] = {'0', '1', '2', '3', '4', '5', 117 '6', '7', '8', '9', 'A', 'B', 118 'C', 'D', 'E', 'F'}; 119 static constexpr char kHexCharsLower[] = {'0', '1', '2', '3', '4', '5', 120 '6', '7', '8', '9', 'a', 'b', 121 'c', 'd', 'e', 'f'}; 122 const char* const hex_chars = uppercase ? kHexCharsUpper : kHexCharsLower; 123 output.append({hex_chars[byte >> 4], hex_chars[byte & 0xf]}); 124 } 125 126 // Best effort conversion, see StringToInt above for restrictions. 127 // Will only successful parse hex values that will fit into |output|, i.e. 128 // -0x80000000 < |input| < 0x7FFFFFFF. 129 BASE_EXPORT bool HexStringToInt(StringPiece input, int* output); 130 131 // Best effort conversion, see StringToInt above for restrictions. 132 // Will only successful parse hex values that will fit into |output|, i.e. 133 // 0x00000000 < |input| < 0xFFFFFFFF. 134 // The string is not required to start with 0x. 135 BASE_EXPORT bool HexStringToUInt(StringPiece input, uint32_t* output); 136 137 // Best effort conversion, see StringToInt above for restrictions. 138 // Will only successful parse hex values that will fit into |output|, i.e. 139 // -0x8000000000000000 < |input| < 0x7FFFFFFFFFFFFFFF. 140 BASE_EXPORT bool HexStringToInt64(StringPiece input, int64_t* output); 141 142 // Best effort conversion, see StringToInt above for restrictions. 143 // Will only successful parse hex values that will fit into |output|, i.e. 144 // 0x0000000000000000 < |input| < 0xFFFFFFFFFFFFFFFF. 145 // The string is not required to start with 0x. 146 BASE_EXPORT bool HexStringToUInt64(StringPiece input, uint64_t* output); 147 148 // Similar to the previous functions, except that output is a vector of bytes. 149 // |*output| will contain as many bytes as were successfully parsed prior to the 150 // error. There is no overflow, but input.size() must be evenly divisible by 2. 151 // Leading 0x or +/- are not allowed. 152 BASE_EXPORT bool HexStringToBytes(StringPiece input, 153 std::vector<uint8_t>* output); 154 155 // Same as HexStringToBytes, but for an std::string. 156 BASE_EXPORT bool HexStringToString(StringPiece input, std::string* output); 157 158 // Decodes the hex string |input| into a presized |output|. The output buffer 159 // must be sized exactly to |input.size() / 2| or decoding will fail and no 160 // bytes will be written to |output|. Decoding an empty input is also 161 // considered a failure. When decoding fails due to encountering invalid input 162 // characters, |output| will have been filled with the decoded bytes up until 163 // the failure. 164 BASE_EXPORT bool HexStringToSpan(StringPiece input, base::span<uint8_t> output); 165 166 } // namespace base 167 168 #if BUILDFLAG(IS_WIN) 169 #include "base/strings/string_number_conversions_win.h" 170 #endif 171 172 #endif // BASE_STRINGS_STRING_NUMBER_CONVERSIONS_H_