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 WEBRTC_BASE_STRINGENCODE_H_
  #define WEBRTC_BASE_STRINGENCODE_H_
  
  #include <sstream>
  #include <string>
  #include <vector>
  
  #include "webrtc/base/checks.h"
  
  namespace rtc {
  
  //////////////////////////////////////////////////////////////////////
  // String Encoding Utilities
  //////////////////////////////////////////////////////////////////////
  
  // Convert an unsigned value to it's utf8 representation.  Returns the length
  // of the encoded string, or 0 if the encoding is longer than buflen - 1.
  size_t utf8_encode(char* buffer, size_t buflen, unsigned long value);
  // Decode the utf8 encoded value pointed to by source.  Returns the number of
  // bytes used by the encoding, or 0 if the encoding is invalid.
  size_t utf8_decode(const char* source, size_t srclen, unsigned long* value);
  
  // Escaping prefixes illegal characters with the escape character.  Compact, but
  // illegal characters still appear in the string.
  size_t escape(char * buffer, size_t buflen,
                const char * source, size_t srclen,
                const char * illegal, char escape);
  // Note: in-place unescaping (buffer == source) is allowed.
  size_t unescape(char * buffer, size_t buflen,
                  const char * source, size_t srclen,
                  char escape);
  
  // Encoding replaces illegal characters with the escape character and 2 hex
  // chars, so it's a little less compact than escape, but completely removes
  // illegal characters.  note that hex digits should not be used as illegal
  // characters.
  size_t encode(char * buffer, size_t buflen,
                const char * source, size_t srclen,
                const char * illegal, char escape);
  // Note: in-place decoding (buffer == source) is allowed.
  size_t decode(char * buffer, size_t buflen,
                const char * source, size_t srclen,
                char escape);
  
  // Returns a list of characters that may be unsafe for use in the name of a
  // file, suitable for passing to the 'illegal' member of escape or encode.
  const char* unsafe_filename_characters();
  
  // url_encode is an encode operation with a predefined set of illegal characters
  // and escape character (for use in URLs, obviously).
  size_t url_encode(char * buffer, size_t buflen,
                    const char * source, size_t srclen);
  // Note: in-place decoding (buffer == source) is allowed.
  size_t url_decode(char * buffer, size_t buflen,
                    const char * source, size_t srclen);
  
  // html_encode prevents data embedded in html from containing markup.
  size_t html_encode(char * buffer, size_t buflen,
                     const char * source, size_t srclen);
  // Note: in-place decoding (buffer == source) is allowed.
  size_t html_decode(char * buffer, size_t buflen,
                     const char * source, size_t srclen);
  
  // xml_encode makes data suitable for inside xml attributes and values.
  size_t xml_encode(char * buffer, size_t buflen,
                    const char * source, size_t srclen);
  // Note: in-place decoding (buffer == source) is allowed.
  size_t xml_decode(char * buffer, size_t buflen,
                    const char * source, size_t srclen);
  
  // Convert an unsigned value from 0 to 15 to the hex character equivalent...
  char hex_encode(unsigned char val);
  // ...and vice-versa.
  bool hex_decode(char ch, unsigned char* val);
  
  // hex_encode shows the hex representation of binary data in ascii.
  size_t hex_encode(char* buffer, size_t buflen,
                    const char* source, size_t srclen);
  
  // hex_encode, but separate each byte representation with a delimiter.
  // |delimiter| == 0 means no delimiter
  // If the buffer is too short, we return 0
  size_t hex_encode_with_delimiter(char* buffer, size_t buflen,
                                   const char* source, size_t srclen,
                                   char delimiter);
  
  // Helper functions for hex_encode.
  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);
  
  // Apply any suitable string transform (including the ones above) to an STL
  // string.  Stack-allocated temporary space is used for the transformation,
  // so value and source may refer to the same string.
  typedef size_t (*Transform)(char * buffer, size_t buflen,
                              const char * source, size_t srclen);
  size_t transform(std::string& value, size_t maxlen, const std::string& source,
                   Transform t);
  
  // Return the result of applying transform t to source.
  std::string s_transform(const std::string& source, Transform t);
  
  // Convenience wrappers.
  inline std::string s_url_encode(const std::string& source) {
    return s_transform(source, url_encode);
  }
  inline std::string s_url_decode(const std::string& source) {
    return s_transform(source, url_decode);
  }
  
  // Splits the source string into multiple fields separated by delimiter,
  // with duplicates of delimiter creating empty fields.
  size_t split(const std::string& 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(const std::string& source, char delimiter,
                  std::vector<std::string>* fields);
  
  // Tokenize and append the tokens to fields. Return the new size of fields.
  size_t tokenize_append(const std::string& 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. A substring in
  // between the start_mark and the end_mark is treated as a single field. Return
  // the size of fields. For example, if source is "filename
  // \"/Library/Application Support/media content.txt\"", delimiter is ' ', and
  // the start_mark and end_mark are '"', this method returns two fields:
  // "filename" and "/Library/Application Support/media content.txt".
  size_t tokenize(const std::string& source, char delimiter, char start_mark,
                  char end_mark, 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(const std::string& source,
                      const char delimiter,
                      std::string* token,
                      std::string* rest);
  
  // Safe sprintf to std::string
  //void sprintf(std::string& value, size_t maxlen, const char * format, ...)
  //     PRINTF_FORMAT(3);
  
  // Convert arbitrary values to/from a string.
  
  template <class T>
  static bool ToString(const T &t, std::string* s) {
    DCHECK(s);
    std::ostringstream oss;
    oss << std::boolalpha << t;
    *s = oss.str();
    return !oss.fail();
  }
  
  template <class T>
  static bool FromString(const std::string& s, T* t) {
    DCHECK(t);
    std::istringstream iss(s);
    iss >> std::boolalpha >> *t;
    return !iss.fail();
  }
  
  // Inline versions of the string conversion routines.
  
  template<typename T>
  static inline std::string ToString(const T& val) {
    std::string str; ToString(val, &str); return str;
  }
  
  template<typename T>
  static inline T FromString(const std::string& str) {
    T val; FromString(str, &val); return val;
  }
  
  template<typename T>
  static inline T FromString(const T& defaultValue, const std::string& str) {
    T val(defaultValue); FromString(str, &val); return val;
  }
  
  // simple function to strip out characters which shouldn't be
  // used in filenames
  char make_char_safe_for_filename(char c);
  
  //////////////////////////////////////////////////////////////////////
  
  }  // namespace rtc
  
  #endif  // WEBRTC_BASE_STRINGENCODE_H__
  