text: /*
   *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree. An additional intellectual property rights grant can be found
   *  in the file PATENTS.  All contributing project authors may
   *  be found in the AUTHORS file in the root of the source tree.
   */
  
  #ifndef RTC_BASE_STRING_ENCODE_H_
  #define RTC_BASE_STRING_ENCODE_H_
  
  #include <stddef.h>
  
  #include <string>
  #include <type_traits>
  #include <vector>
  
  #include "absl/strings/string_view.h"
  #include "absl/types/optional.h"
  #include "rtc_base/checks.h"
  #include "rtc_base/string_to_number.h"
  
  namespace rtc {
  
  //////////////////////////////////////////////////////////////////////
  // String Encoding Utilities
  //////////////////////////////////////////////////////////////////////
  
  std::string hex_encode(const std::string& str);
  std::string hex_encode(const char* source, size_t srclen);
  std::string hex_encode_with_delimiter(const char* source,
                                        size_t srclen,
                                        char delimiter);
  
  // hex_decode converts ascii hex to binary.
  size_t hex_decode(char* buffer,
                    size_t buflen,
                    const char* source,
                    size_t srclen);
  
  // hex_decode, assuming that there is a delimiter between every byte
  // pair.
  // `delimiter` == 0 means no delimiter
  // If the buffer is too short or the data is invalid, we return 0.
  size_t hex_decode_with_delimiter(char* buffer,
                                   size_t buflen,
                                   const char* source,
                                   size_t srclen,
                                   char delimiter);
  
  // Helper functions for hex_decode.
  size_t hex_decode(char* buffer, size_t buflen, const std::string& source);
  size_t hex_decode_with_delimiter(char* buffer,
                                   size_t buflen,
                                   const std::string& source,
                                   char delimiter);
  
  // Joins the source vector of strings into a single string, with each
  // field in source being separated by delimiter. No trailing delimiter is added.
  std::string join(const std::vector<std::string>& source, char delimiter);
  
  // Splits the source string into multiple fields separated by delimiter,
  // with duplicates of delimiter creating empty fields.
  size_t split(absl::string_view source,
               char delimiter,
               std::vector<std::string>* fields);
  
  // Splits the source string into multiple fields separated by delimiter,
  // with duplicates of delimiter ignored.  Trailing delimiter ignored.
  size_t tokenize(absl::string_view source,
                  char delimiter,
                  std::vector<std::string>* fields);
  
  // Extract the first token from source as separated by delimiter, with
  // duplicates of delimiter ignored. Return false if the delimiter could not be
  // found, otherwise return true.
  bool tokenize_first(absl::string_view source,
                      const char delimiter,
                      std::string* token,
                      std::string* rest);
  
  // Convert arbitrary values to/from a string.
  // TODO(jonasolsson): Remove these when absl::StrCat becomes available.
  std::string ToString(bool b);
  
  std::string ToString(const char* s);
  std::string ToString(std::string t);
  
  std::string ToString(short s);
  std::string ToString(unsigned short s);
  std::string ToString(int s);
  std::string ToString(unsigned int s);
  std::string ToString(long int s);
  std::string ToString(unsigned long int s);
  std::string ToString(long long int s);
  std::string ToString(unsigned long long int s);
  
  std::string ToString(double t);
  std::string ToString(long double t);
  
  std::string ToString(const void* p);
  
  template <typename T,
            typename std::enable_if<std::is_arithmetic<T>::value &&
                                        !std::is_same<T, bool>::value,
                                    int>::type = 0>
  static bool FromString(const std::string& s, T* t) {
    RTC_DCHECK(t);
    absl::optional<T> result = StringToNumber<T>(s);
  
    if (result)
      *t = *result;
  
    return result.has_value();
  }
  
  bool FromString(const std::string& s, bool* b);
  
  template <typename T>
  static inline T FromString(const std::string& str) {
    T val;
    FromString(str, &val);
    return val;
  }
  
  //////////////////////////////////////////////////////////////////////
  
  }  // namespace rtc
  
  #endif  // RTC_BASE_STRING_ENCODE_H__
  