base64.cpp

各种加密算法的源代码

#include "base64.h"

static const int MAX_LINE_LENGTH = 72;

static const byte vec[] =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const byte padding = '=';
       
Base64Encoder::Base64Encoder(BufferedTransformation *outQueue)
    : Filter(outQueue)
{
    inBufSize=0;
    lineLength=0;
}

void Base64Encoder::LineBreak()
{
    outQueue->Put('\r');
    outQueue->Put('\n');
    lineLength=0;
}

void Base64Encoder::EncodeQuantum()
{
    byte out;

    out=(inBuf[0] & 0xFC) >> 2;
    outQueue->Put(vec[out]);

    out=((inBuf[0] & 0x03) << 4) | (inBuf[1] >> 4);
    outQueue->Put(vec[out]);

    out=((inBuf[1] & 0x0F) << 2) | (inBuf[2] >> 6);
    outQueue->Put(inBufSize > 1 ? vec[out] : padding);

    out=inBuf[2] & 0x3F;
    outQueue->Put(inBufSize > 2 ? vec[out] : padding);

    inBufSize=0;
    lineLength+=4;

    if (lineLength>=MAX_LINE_LENGTH)
        LineBreak();
}

void Base64Encoder::Put(const byte *inString, unsigned int length)
{
    while (length--)
        Base64Encoder::Put(*inString++);
}

void Base64Encoder::InputFinished()
{
    if (inBufSize)
    {
        for (int i=inBufSize;i<3;i++)
            inBuf[i]=0;
        EncodeQuantum();
    }

    if (lineLength) // force a line break unless the current line is empty
        LineBreak();
}

Base64Decoder::Base64Decoder(BufferedTransformation *outQueue)
    : Filter(outQueue)
{
    inBufSize=0;
}

void Base64Decoder::DecodeQuantum()
{
    byte out;

    out = (inBuf[0] << 2) | (inBuf[1] >> 4);
    outQueue->Put(out);

    out = (inBuf[1] << 4) | (inBuf[2] >> 2);
    if (inBufSize > 2) outQueue->Put(out);

    out = (inBuf[2] << 6) | inBuf[3];
    if (inBufSize > 3) outQueue->Put(out);

    inBufSize=0;
}

int Base64Decoder::ConvToNumber(byte inByte)
{
    if (inByte >= 'A' && inByte <= 'Z')
        return (inByte - 'A');

    if (inByte >= 'a' && inByte <= 'z')
        return (inByte - 'a' + 26);

    if (inByte >= '0' && inByte <= '9')
        return (inByte - '0' + 52);

    if (inByte == '+')
        return (62);

    if (inByte == '/')
        return (63);

    return (-1);
}

void Base64Decoder::Put(const byte *inString, unsigned int length)
{
    while (length--)
        Base64Decoder::Put(*inString++);
}

void Base64Decoder::InputFinished()
{
    if (inBufSize)
    {
        for (int i=inBufSize;i<4;i++)
            inBuf[i]=0;
        DecodeQuantum();
    }
}