// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef BASE_STRINGS_STRING_NUMBER_CONVERSIONS_H_
#define BASE_STRINGS_STRING_NUMBER_CONVERSIONS_H_

#include <stddef.h>
#include <stdint.h>

#include <string>
#include <string_view>
#include <vector>

#include "polyfills/base/base_export.h"
#include "base/compiler_specific.h"
#include "base/containers/span.h"
#include "build/build_config.h"

// ----------------------------------------------------------------------------
// IMPORTANT MESSAGE FROM YOUR SPONSOR
//
// Please do not add "convenience" functions for converting strings to integers
// that return the value and ignore success/failure. That encourages people to
// write code that doesn't properly handle the error conditions.
//
// DO NOT use these functions in any UI unless it's NOT localized on purpose.
// Instead, use gurl_base::MessageFormatter for a complex message with numbers
// (integer, float, double) embedded or gurl_base::Format{Number,Double,Percent} to
// just format a single number/percent. Note that some languages use native
// digits instead of ASCII digits while others use a group separator or decimal
// point different from ',' and '.'. Using these functions in the UI would lead
// numbers to be formatted in a non-native way.
// ----------------------------------------------------------------------------

namespace gurl_base {

// Number -> string conversions ------------------------------------------------

// Ignores locale! see warning above.
BASE_EXPORT std::string NumberToString(int value);
BASE_EXPORT std::u16string NumberToString16(int value);
BASE_EXPORT std::string NumberToString(unsigned int value);
BASE_EXPORT std::u16string NumberToString16(unsigned int value);
BASE_EXPORT std::string NumberToString(long value);
BASE_EXPORT std::u16string NumberToString16(long value);
BASE_EXPORT std::string NumberToString(unsigned long value);
BASE_EXPORT std::u16string NumberToString16(unsigned long value);
BASE_EXPORT std::string NumberToString(long long value);
BASE_EXPORT std::u16string NumberToString16(long long value);
BASE_EXPORT std::string NumberToString(unsigned long long value);
BASE_EXPORT std::u16string NumberToString16(unsigned long long value);

// Returns a string that contains a full representation of `value`.
BASE_EXPORT std::string NumberToString(double value);
BASE_EXPORT std::u16string NumberToString16(double value);

// Returns a string that contains a representation of `value` expressed with
// exactly `digits` digits after the decimal point.
BASE_EXPORT std::string NumberToStringWithFixedPrecision(double value,
                                                         int digits);
BASE_EXPORT std::u16string NumberToString16WithFixedPrecision(double value,
                                                              int digits);

// String -> number conversions ------------------------------------------------

// Perform a best-effort conversion of the input string to a numeric type,
// setting `*output` to the result of the conversion.  Returns true for
// "perfect" conversions; returns false in the following cases:
//  - Overflow. `*output` will be set to the maximum value supported
//    by the data type.
//  - Underflow. `*output` will be set to the minimum value supported
//    by the data type.
//  - Trailing characters in the string after parsing the number.  `*output`
//    will be set to the value of the number that was parsed.
//  - Leading whitespace in the string before parsing the number. `*output` will
//    be set to the value of the number that was parsed.
//  - No characters parseable as a number at the beginning of the string.
//    `*output` will be set to 0.
//  - Empty string.  `*output` will be set to 0.
// WARNING: Will write to `output` even when returning false.
//          Read the comments above carefully.
BASE_EXPORT bool StringToInt(std::string_view input, int* output);
BASE_EXPORT bool StringToInt(std::u16string_view input, int* output);

BASE_EXPORT bool StringToUint(std::string_view input, unsigned* output);
BASE_EXPORT bool StringToUint(std::u16string_view input, unsigned* output);

BASE_EXPORT bool StringToInt64(std::string_view input, int64_t* output);
BASE_EXPORT bool StringToInt64(std::u16string_view input, int64_t* output);

BASE_EXPORT bool StringToUint64(std::string_view input, uint64_t* output);
BASE_EXPORT bool StringToUint64(std::u16string_view input, uint64_t* output);

BASE_EXPORT bool StringToSizeT(std::string_view input, size_t* output);
BASE_EXPORT bool StringToSizeT(std::u16string_view input, size_t* output);

// For floating-point conversions, only conversions of input strings in decimal
// form are defined to work.  Behavior with strings representing floating-point
// numbers in hexadecimal, and strings representing non-finite values (such as
// NaN and inf) is undefined.  Otherwise, these behave the same as the integral
// variants.  This expects the input string to NOT be specific to the locale.
// If your input is locale specific, use ICU to read the number.
// WARNING: Will write to `output` even when returning false.
//          Read the comments here and above StringToInt() carefully.
BASE_EXPORT bool StringToDouble(std::string_view input, double* output);
BASE_EXPORT bool StringToDouble(std::u16string_view input, double* output);

// Hex encoding ----------------------------------------------------------------

// Returns a hex string representation of a binary buffer. The returned hex
// string will be in upper case. This function does not check if `size` is
// within reasonable limits since it's written with trusted data in mind.  If
// you suspect that the data you want to format might be large, the absolute
// max size for `size` should be is
//   std::numeric_limits<size_t>::max() / 2
BASE_EXPORT std::string HexEncode(gurl_base::span<const uint8_t> bytes);
BASE_EXPORT std::string HexEncode(std::string_view chars);
// TODO(crbug.com/40284755): The pointer-based overload should be removed.
BASE_EXPORT std::string HexEncode(const void* bytes, size_t size);

// Behaves like the above, but returns the hex string in lower case.
BASE_EXPORT std::string HexEncodeLower(gurl_base::span<const uint8_t> bytes);
BASE_EXPORT std::string HexEncodeLower(std::string_view chars);

// Appends a hex representation of `byte`, as two uppercase (by default)
// characters, to `output`. This is a useful primitive in larger conversion
// routines.
inline void AppendHexEncodedByte(uint8_t byte,
                                 std::string& output,
                                 bool uppercase = true) {
  static constexpr char kHexCharsUpper[] = {'0', '1', '2', '3', '4', '5',
                                            '6', '7', '8', '9', 'A', 'B',
                                            'C', 'D', 'E', 'F'};
  static constexpr char kHexCharsLower[] = {'0', '1', '2', '3', '4', '5',
                                            '6', '7', '8', '9', 'a', 'b',
                                            'c', 'd', 'e', 'f'};
  const char* const hex_chars = uppercase ? kHexCharsUpper : kHexCharsLower;
  output.append(
      {UNSAFE_TODO(hex_chars[byte >> 4]), UNSAFE_TODO(hex_chars[byte & 0xf])});
}

// Best effort conversion, see StringToInt above for restrictions.
// Will only successful parse hex values that will fit into `output`, i.e.
// -0x8000'0000 < `input` < 0x7FFF'FFFF.
BASE_EXPORT bool HexStringToInt(std::string_view input, int* output);

// Best effort conversion, see StringToInt above for restrictions.
// Will only successful parse hex values that will fit into `output`, i.e.
// 0x0000'0000 < `input` < 0xFFFF'FFFF.
// The string is not required to start with "0x".
BASE_EXPORT bool HexStringToUInt(std::string_view input, uint32_t* output);

// Best effort conversion, see StringToInt above for restrictions.
// Will only successful parse hex values that will fit into `output`, i.e.
// -0x8000'0000'0000'0000 < `input` < 0x7FFF'FFFF'FFFF'FFFF.
BASE_EXPORT bool HexStringToInt64(std::string_view input, int64_t* output);

// Best effort conversion, see StringToInt above for restrictions.
// Will only successful parse hex values that will fit into `output`, i.e.
// 0x0000'0000'0000'0000 < `input` < 0xFFFF'FFFF'FFFF'FFFF.
// The string is not required to start with "0x".
BASE_EXPORT bool HexStringToUInt64(std::string_view input, uint64_t* output);

// Similar to the previous functions, except that output is a vector of bytes.
// `*output` will contain as many bytes as were successfully parsed prior to the
// error.  There is no overflow, but input.size() must be evenly divisible by 2.
// Leading "0x" or +/- are not allowed.
BASE_EXPORT bool HexStringToBytes(std::string_view input,
                                  std::vector<uint8_t>* output);

// Same as HexStringToBytes, but for an std::string.
BASE_EXPORT bool HexStringToString(std::string_view input, std::string* output);

// Decodes the hex string `input` into a presized `output`. The output buffer
// must be sized exactly to `input.size() / 2` or decoding will fail and no
// bytes will be written to `output`. Decoding an empty input is also
// considered a failure. When decoding fails due to encountering invalid input
// characters, `output` will have been filled with the decoded bytes up until
// the failure.
BASE_EXPORT bool HexStringToSpan(std::string_view input,
                                 gurl_base::span<uint8_t> output);

}  // namespace base

#if BUILDFLAG(IS_WIN)

#endif

#endif  // BASE_STRINGS_STRING_NUMBER_CONVERSIONS_H_