Base64.hh

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#ifndef COSA_BASE64_HH
#define COSA_BASE64_HH

#include "Cosa/Types.h"
#include "Cosa/IOStream.hh"

class Base64 {
public:
  static int encode(char* dest, const void* src, size_t size);

  static int encode_P(char* dest, const void* src, size_t size);

  static int encode(IOStream::Device* dest, const void* src, size_t size);

  static int encode_P(IOStream::Device* dest, const void* src, size_t size);

  static int decode(void* dest, const char* src, size_t size);

private:
  static const char PAD = '=';

  union base64_t {
    uint8_t d[3];
    struct {
      uint8_t c0:6;
      uint8_t c1:6;
      uint8_t c2:6;
      uint8_t c3:6;
    };
  };

  static const char ENCODE[] PROGMEM;

  static char encode(uint8_t bits)
    __attribute__((always_inline))
  {
    return (pgm_read_byte(&ENCODE[bits]));
  }

  static const char DECODE[] PROGMEM;

  static uint8_t decode(char c)
    __attribute__((always_inline))
  {
    if (UNLIKELY(c < 43 || c > 122)) return (0);
    uint8_t bits = pgm_read_byte(&DECODE[c - 43]);
    return (bits == '$' ? 0 : bits - 62);
  }
};

#endif