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#include "osl/misc/base64.h"
#include "osl/stl/vector.h"
#include <boost/foreach.hpp>
std::string osl::misc::
base64Encode(boost::dynamic_bitset<> src)
{
if (src.empty())
return "";
const size_t bits_to_add = 6 - src.size()%6;
if (bits_to_add < 6)
{
for (size_t i=0; i<bits_to_add; ++i)
{
src.push_back(0ul); // this appends to the most significant bit
src <<= 1; // Instead, append to the least significant bit
}
}
assert(src.size()%6 == 0);
assert(src.size()/6 > 0);
vector<char> dst(src.size()/6, 0);
const boost::dynamic_bitset<> mask(src.size(), 63ul);
for (size_t i=0; i<dst.size(); ++i)
{
const unsigned long c = ((src >> i*6) & mask).to_ulong();
assert (c <= 63);
if (/*0 <= c &&*/ c <= 25) // A..Z
dst[dst.size()-1-i] = static_cast<char>(c+65);
else if (26 <= c && c <= 51) // a..z
dst[dst.size()-1-i] = static_cast<char>(c+97-26);
else if (52 <= c && c <= 61) // 0..9
dst[dst.size()-1-i] = static_cast<char>(c+48-52);
else if (c == 62)
dst[dst.size()-1-i] = '-'; // for URL instread of '+'
else if (c == 63)
dst[dst.size()-1-i] = '_'; // for URL instread of '/'
else
{
assert(false);
return "";
}
}
const size_t char_to_add = 4 - dst.size()%4;
if (char_to_add < 4)
{
for (size_t i=0; i<char_to_add; ++i)
dst.push_back('=');
}
return std::string(dst.begin(), dst.end());
}
boost::dynamic_bitset<> osl::misc::
base64Decode(std::string src)
{
if (src.empty() || src.size()%4 != 0)
return boost::dynamic_bitset<>(0);
{
int count = 0;
while (src[src.size()-1] == '=')
{
src.erase(src.end()-1);
++count;
}
if (count >= 4)
return boost::dynamic_bitset<>(0);
}
const size_t dst_size = src.size()*6;
const size_t redundant = dst_size%8;
boost::dynamic_bitset<> dst(dst_size, 0ul);
BOOST_FOREACH(char c, src)
{
unsigned long tmp = 0;
if (48 <= c && c <= 48+9) // 0..9
tmp = c -48+52;
else if (65 <= c && c <= 65+25) // A..Z
tmp = c - 65;
else if (97 <= c && c <= 97+25) // a..z
tmp = c -97+26;
else if (c == '-')
tmp = 62;
else if (c == '_')
tmp = 63;
else
{
assert(false);
return boost::dynamic_bitset<>(0);
}
assert(/*0 <= tmp &&*/ tmp <= 63);
const boost::dynamic_bitset<> mask(dst_size, tmp);
dst = (dst << 6) | mask;
}
if (redundant > 0)
{
dst >>= redundant;
dst.resize(dst.size()-redundant);
}
return dst;
}
// ;;; Local Variables:
// ;;; mode:c++
// ;;; c-basic-offset:2
// ;;; End:
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