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//
// $Id$
//
//
// Original author: Darren Kessner <darren@proteowizard.org>
//
// Copyright 2005 Louis Warschaw Prostate Cancer Center
// Cedars Sinai Medical Center, Los Angeles, California 90048
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#define PWIZ_SOURCE
#include "Base64.hpp"
#include "pwiz/utility/misc/Std.hpp"
#include <cmath>
namespace pwiz {
namespace util {
namespace {
typedef unsigned char byte;
char charTable[64] =
{
'A','B','C','D','E','F','G','H','I','J',
'K','L','M','N','O','P','Q','R','S','T',
'U','V','W','X','Y','Z','a','b','c','d',
'e','f','g','h','i','j','k','l','m','n',
'o','p','q','r','s','t','u','v','w','x',
'y','z','0','1','2','3','4','5','6','7',
'8','9', '+','/'
};
char byteTable[256];
bool byteTableInitialized = false;
void initializeByteTable()
{
for (size_t i=0; i<64; i++)
byteTable[static_cast<int>(charTable[i])] = static_cast<char>(i);
byteTableInitialized = true;
}
} // namespace
PWIZ_API_DECL size_t Base64::binaryToTextSize(size_t byteCount)
{
return (size_t)ceil(byteCount/3.) * 4;
}
PWIZ_API_DECL size_t Base64::binaryToText(const void* from, size_t byteCount, char* to)
{
byte* it = (byte*)from;
byte* end = it + byteCount;
size_t written = 0;
while (it!=end)
{
int int24bit = 0;
int paddingCount = 0;
// construct 24-bit integer from 3 bytes
for (int i=0; i<3; i++)
{
if (it!=end)
int24bit |= *it++<<((2-i)*8);
else
paddingCount++;
}
// write out 4 characters
for (int i=3; i>=0; i--)
{
to[i] = charTable[int24bit & 0x3F];
int24bit >>= 6;
}
// fixup for padding
if (paddingCount > 0)
to[3] = '=';
if (paddingCount > 1)
to[2] = '=';
to += 4;
written += 4;
}
return written;
}
PWIZ_API_DECL size_t Base64::textToBinarySize(size_t charCount)
{
return (size_t)ceil(charCount/4.) * 3;
}
PWIZ_API_DECL size_t Base64::textToBinary(const char* from, size_t charCount, void* to)
{
if (!byteTableInitialized)
initializeByteTable();
byte* it = (byte*)from;
byte* end = it + charCount;
byte* result = (byte*)to;
size_t written = 0;
while (it!=end)
{
int int24bit = 0;
int paddingCount = 0;
// construct 24-bit integer from 4 characters
for (int i=0; i<4 && it!=end; i++, it++)
{
if (*it != '=')
{
int24bit |= byteTable[*it]<<((3-i)*6);
}
else
paddingCount++;
}
// write out bytes
for (int i=0; i<3-paddingCount; i++)
{
byte temp = static_cast<byte>(int24bit>>((2-i)*8));
*result++ = temp;
int24bit ^= temp<<((2-i)*8);
written++;
}
}
return written;
}
} // namespace util
} // namespace pwiz
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