lib/cpp/src/protocol/TBase64Utils.cpp

// Copyright (c) 2006- Facebook
// Distributed under the Thrift Software License
//
// See accompanying file LICENSE or visit the Thrift site at:
// http://developers.facebook.com/thrift/

#include "TBase64Utils.h"

#include <boost/static_assert.hpp>

using std::string;

namespace facebook { namespace thrift { namespace protocol {


static const uint8_t *kBase64EncodeTable = (const uint8_t *)
  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

void  base64_encode(const uint8_t *in, uint32_t len, uint8_t *buf) {
  buf[0] = kBase64EncodeTable[(in[0] >> 2) & 0x3F];
  if (len == 3) {
    buf[1] = kBase64EncodeTable[((in[0] << 4) + (in[1] >> 4)) & 0x3f];
    buf[2] = kBase64EncodeTable[((in[1] << 2) + (in[2] >> 6)) & 0x3f];
    buf[3] = kBase64EncodeTable[in[2] & 0x3f];
  } else if (len == 2) {
    buf[1] = kBase64EncodeTable[((in[0] << 4) + (in[1] >> 4)) & 0x3f];
    buf[2] = kBase64EncodeTable[(in[1] << 2) & 0x3f];
  } else  { // len == 1
    buf[1] = kBase64EncodeTable[(in[0] << 4) & 0x3f];
  }
}

static const uint8_t kBase64DecodeTable[128] ={
  -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
  -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
  -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,62,-1,-1,-1,63,
  52,53,54,55,56,57,58,59,60,61,-1,-1,-1,-1,-1,-1,
  -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,
  15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1,
  -1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,
  41,42,43,44,45,46,47,48,49,50,51,-1,-1,-1,-1,-1
};

void base64_decode(uint8_t *buf, uint32_t len) {
  buf[0] = (kBase64DecodeTable[buf[0]] << 2) |
           (kBase64DecodeTable[buf[1]] >> 4);
  if (len > 2) {
    buf[1] = ((kBase64DecodeTable[buf[1]] << 4) & 0xf0) |
              (kBase64DecodeTable[buf[2]] >> 2);
    if (len > 3) {
      buf[2] = ((kBase64DecodeTable[buf[2]] << 6) & 0xc0) |
                (kBase64DecodeTable[buf[3]]);
    }
  }
}


}}} // facebook::thrift::protocol