nybbler.cc

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// ======================================================================
//
// nybbler: Half-byte manipulations
//
// ======================================================================

#include "cetlib/nybbler.h"

using cet::nybbler;

typedef unsigned char uchar;
typedef std::string string;

// ======================================================================

string
nybbler::as_hex() const
{
  string r(s_.size() * 2, 'x');

  string::iterator t = r.begin();
  for (string::const_iterator b = s_.begin(), e = s_.end(); b != e; ++b) {
    *t++ = to_hex(msn(*b));
    *t++ = to_hex(lsn(*b));
  }

  return r;
}

string
nybbler::as_char() const
{
  string r(s_.size() / 2, 'x');

  string::const_iterator f = s_.begin();
  for (string::iterator t = r.begin(), e = r.end(); t != e; ++t) {
    *t = to_nyb(*f++) << 4;
    *t |= to_nyb(*f++);
  }

  return r;
}

uchar
nybbler::msn(char ch)
{
  return (uchar(ch) >> 4) & 0xF;
}

uchar
nybbler::lsn(char ch)
{
  return uchar(ch) & 0xF;
}

char
nybbler::to_hex(uchar nyb)
{
  switch (nyb) {
  case 0u:
  case 1u:
  case 2u:
  case 3u:
  case 4u:
  case 5u:
  case 6u:
  case 7u:
  case 8u:
  case 9u:
    return '0' + nyb;
  case 10u:
  case 11u:
  case 12u:
  case 13u:
  case 14u:
  case 15u:
    return 'A' + nyb - 10u;
  default:
    return '?';
  }
}

uchar
nybbler::to_nyb(char hex)
{
  switch (hex) {
  case '0':
  case '1':
  case '2':
  case '3':
  case '4':
  case '5':
  case '6':
  case '7':
  case '8':
  case '9':
    return hex - '0';
  case 'a':
  case 'b':
  case 'c':
  case 'd':
  case 'e':
  case 'f':
    return hex - 'a' + 10;
  case 'A':
  case 'B':
  case 'C':
  case 'D':
  case 'E':
  case 'F':
    return hex - 'A' + 10;
  default:
    return '?';
  }
}

nybbler&
nybbler::operator<<(string const& s)
{
  s_ = s;
  return *this;
}

// ======================================================================