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//*********************************************************************
//* Base64 - a simple base64 encoder and decoder.
//*
//* Copyright (c) 1999, Bob Withers - bwit@pobox.com
//*
//* This code may be freely used for any purpose, either personal
//* or commercial, provided the authors copyright notice remains
//* intact.
//*
//* Enhancements by Stanley Yamane:
//* o reverse lookup table for the decode function
//* o reserve string buffer space in advance
//*
//*********************************************************************
#include "talk/base/base64.h"
using std::string;
namespace talk_base {
static const char fillchar = '=';
static const string::size_type np = string::npos;
const string Base64::Base64Table(
// 0000000000111111111122222222223333333333444444444455555555556666
// 0123456789012345678901234567890123456789012345678901234567890123
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/");
// Decode Table gives the index of any valid base64 character in the
// Base64 table
// 65 == A, 97 == a, 48 == 0, 43 == +, 47 == /
const string::size_type Base64::DecodeTable[] = {
// 0 1 2 3 4 5 6 7 8 9
np,np,np,np,np,np,np,np,np,np, // 0 - 9
np,np,np,np,np,np,np,np,np,np, //10 -19
np,np,np,np,np,np,np,np,np,np, //20 -29
np,np,np,np,np,np,np,np,np,np, //30 -39
np,np,np,62,np,np,np,63,52,53, //40 -49
54,55,56,57,58,59,60,61,np,np, //50 -59
np,np,np,np,np, 0, 1, 2, 3, 4, //60 -69
5, 6, 7, 8, 9,10,11,12,13,14, //70 -79
15,16,17,18,19,20,21,22,23,24, //80 -89
25,np,np,np,np,np,np,26,27,28, //90 -99
29,30,31,32,33,34,35,36,37,38, //100 -109
39,40,41,42,43,44,45,46,47,48, //110 -119
49,50,51,np,np,np,np,np,np,np, //120 -129
np,np,np,np,np,np,np,np,np,np, //130 -139
np,np,np,np,np,np,np,np,np,np, //140 -149
np,np,np,np,np,np,np,np,np,np, //150 -159
np,np,np,np,np,np,np,np,np,np, //160 -169
np,np,np,np,np,np,np,np,np,np, //170 -179
np,np,np,np,np,np,np,np,np,np, //180 -189
np,np,np,np,np,np,np,np,np,np, //190 -199
np,np,np,np,np,np,np,np,np,np, //200 -209
np,np,np,np,np,np,np,np,np,np, //210 -219
np,np,np,np,np,np,np,np,np,np, //220 -229
np,np,np,np,np,np,np,np,np,np, //230 -239
np,np,np,np,np,np,np,np,np,np, //240 -249
np,np,np,np,np,np //250 -256
};
string Base64::encodeFromArray(const char * data, size_t len) {
size_t i;
char c;
string ret;
ret.reserve(len * 2);
for (i = 0; i < len; ++i) {
c = (data[i] >> 2) & 0x3f;
ret.append(1, Base64Table[c]);
c = (data[i] << 4) & 0x3f;
if (++i < len) {
c |= (data[i] >> 4) & 0x0f;
}
ret.append(1, Base64Table[c]);
if (i < len) {
c = (data[i] << 2) & 0x3f;
if (++i < len) {
c |= (data[i] >> 6) & 0x03;
}
ret.append(1, Base64Table[c]);
} else {
++i;
ret.append(1, fillchar);
}
if (i < len) {
c = data[i] & 0x3f;
ret.append(1, Base64Table[c]);
} else {
ret.append(1, fillchar);
}
}
return(ret);
}
string Base64::encode(const string& data) {
string::size_type i;
char c;
string::size_type len = data.length();
string ret;
ret.reserve(len * 2);
for (i = 0; i < len; ++i) {
c = (data[i] >> 2) & 0x3f;
ret.append(1, Base64Table[c]);
c = (data[i] << 4) & 0x3f;
if (++i < len) {
c |= (data[i] >> 4) & 0x0f;
}
ret.append(1, Base64Table[c]);
if (i < len) {
c = (data[i] << 2) & 0x3f;
if (++i < len) {
c |= (data[i] >> 6) & 0x03;
}
ret.append(1, Base64Table[c]);
} else {
++i;
ret.append(1, fillchar);
}
if (i < len) {
c = data[i] & 0x3f;
ret.append(1, Base64Table[c]);
} else {
ret.append(1, fillchar);
}
}
return(ret);
}
string Base64::decode(const string& data) {
string::size_type i;
char c;
char c1;
string::size_type len = data.length();
string ret;
ret.reserve(len);
for (i = 0; i < len; ++i) {
do {
c = static_cast<char>(DecodeTable[static_cast<unsigned char>(data[i])]);
} while (c == np && ++i < len);
++i;
do {
c1 = static_cast<char>(DecodeTable[static_cast<unsigned char>(data[i])]);
} while (c == np && ++i < len);
c = (c << 2) | ((c1 >> 4) & 0x3);
ret.append(1, c);
if (++i < len) {
c = data[i];
if (fillchar == c) {
break;
}
do {
c = static_cast<char>(DecodeTable[static_cast<unsigned char>(data[i])]);
} while (c == np && ++i < len);
c1 = ((c1 << 4) & 0xf0) | ((c >> 2) & 0xf);
ret.append(1, c1);
}
if (++i < len) {
c1 = data[i];
if (fillchar == c1) {
break;
}
do {
c1 = static_cast<char>(DecodeTable[static_cast<unsigned char>(data[i])]);
} while (c == np && ++i < len);
c = ((c << 6) & 0xc0) | c1;
ret.append(1, c);
}
}
return(ret);
}
} // namespace talk_base
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