i2pd/base64.cpp

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2013-12-10 13:08:35 +00:00
#include <stdlib.h>
#include "base64.h"
namespace i2p
{
namespace data
{
static void iT64Build(void);
/*
*
* BASE64 Substitution Table
* -------------------------
*
* Direct Substitution Table
*/
static char T64[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', '-', '~'
};
/*
* Reverse Substitution Table (built in run time)
*/
static char iT64[256];
static int isFirstTime = 1;
/*
* Padding
*/
static char P64 = '=';
/*
*
* ByteStreamToBase64
* ------------------
*
* Converts binary encoded data to BASE64 format.
*
*/
size_t /* Number of bytes in the encoded buffer */
ByteStreamToBase64 (
const uint8_t * InBuffer, /* Input buffer, binary data */
size_t InCount, /* Number of bytes in the input buffer */
char * OutBuffer, /* output buffer */
size_t len /* length of output buffer */
)
{
unsigned char * ps;
unsigned char * pd;
unsigned char acc_1;
unsigned char acc_2;
int i;
int n;
int m;
size_t outCount;
ps = (unsigned char *)InBuffer;
n = InCount/3;
m = InCount%3;
if (!m)
outCount = 4*n;
else
outCount = 4*(n+1);
if (outCount > len) return -1;
pd = (unsigned char *)OutBuffer;
for ( i = 0; i<n; i++ ){
acc_1 = *ps++;
acc_2 = (acc_1<<4)&0x30;
acc_1 >>= 2; /* base64 digit #1 */
*pd++ = T64[acc_1];
acc_1 = *ps++;
acc_2 |= acc_1 >> 4; /* base64 digit #2 */
*pd++ = T64[acc_2];
acc_1 &= 0x0f;
acc_1 <<=2;
acc_2 = *ps++;
acc_1 |= acc_2>>6; /* base64 digit #3 */
*pd++ = T64[acc_1];
acc_2 &= 0x3f; /* base64 digit #4 */
*pd++ = T64[acc_2];
}
if ( m == 1 ){
acc_1 = *ps++;
acc_2 = (acc_1<<4)&0x3f; /* base64 digit #2 */
acc_1 >>= 2; /* base64 digit #1 */
*pd++ = T64[acc_1];
*pd++ = T64[acc_2];
*pd++ = P64;
*pd++ = P64;
}
else if ( m == 2 ){
acc_1 = *ps++;
acc_2 = (acc_1<<4)&0x3f;
acc_1 >>= 2; /* base64 digit #1 */
*pd++ = T64[acc_1];
acc_1 = *ps++;
acc_2 |= acc_1 >> 4; /* base64 digit #2 */
*pd++ = T64[acc_2];
acc_1 &= 0x0f;
acc_1 <<=2; /* base64 digit #3 */
*pd++ = T64[acc_1];
*pd++ = P64;
}
return outCount;
}
/*
*
* Base64ToByteStream
* ------------------
*
* Converts BASE64 encoded data to binary format. If input buffer is
* not properly padded, buffer of negative length is returned
*
*/
size_t /* Number of output bytes */
Base64ToByteStream (
const char * InBuffer, /* BASE64 encoded buffer */
size_t InCount, /* Number of input bytes */
uint8_t * OutBuffer, /* output buffer length */
size_t len /* length of output buffer */
)
{
unsigned char * ps;
unsigned char * pd;
unsigned char acc_1;
unsigned char acc_2;
int i;
int n;
int m;
size_t outCount;
if (isFirstTime) iT64Build();
n = InCount/4;
m = InCount%4;
if (!m)
outCount = 3*n;
else {
outCount = 0;
return -1;
}
ps = (unsigned char *)(InBuffer + InCount - 1);
while ( *ps-- == P64 ) outCount--;
ps = (unsigned char *)InBuffer;
if (outCount > len) return -1;
pd = (unsigned char *)OutBuffer;
for ( i = 0; i < n; i++ ){
acc_1 = iT64[*ps++];
acc_2 = iT64[*ps++];
acc_1 <<= 2;
acc_1 |= acc_2>>4;
*pd++ = acc_1;
acc_2 <<= 4;
acc_1 = iT64[*ps++];
acc_2 |= acc_1 >> 2;
*pd++ = acc_2;
acc_2 = iT64[*ps++];
acc_2 |= acc_1 << 6;
*pd++ = acc_2;
}
return outCount;
}
/*
*
* iT64
* ----
* Reverse table builder. P64 character is replaced with 0
*
*
*/
static void iT64Build()
{
int i;
isFirstTime = 0;
for ( i=0; i<256; i++ ) iT64[i] = -1;
for ( i=0; i<64; i++ ) iT64[(int)T64[i]] = i;
iT64[(int)P64] = 0;
}
size_t Base32ToByteStream (const char * inBuf, size_t len, uint8_t * outBuf, size_t outLen)
{
int tmp = 0, bits = 0;
size_t ret = 0;
for (size_t i = 0; i < len; i++)
{
char ch = inBuf[i];
if (ch >= '2' && ch <= '7') // digit
ch = (ch - '2') + 26; // 26 means a-z
else if (ch >= 'a' && ch <= 'z')
ch = ch - 'a'; // a = 0
else
return 0; // unexpected character
tmp |= ch;
bits += 5;
if (bits >= 8)
{
if (ret >= outLen) return ret;
outBuf[ret] = tmp >> (bits - 8);
bits -= 8;
ret++;
}
tmp <<= 5;
}
return ret;
}
}
}