i2pd/libi2pd/Base.cpp
2023-10-30 08:10:17 -04:00

342 lines
6.8 KiB
C++

/*
* Copyright (c) 2013-2023, The PurpleI2P Project
*
* This file is part of Purple i2pd project and licensed under BSD3
*
* See full license text in LICENSE file at top of project tree
*/
#include <stdlib.h>
#include <string.h>
#include "Base.h"
namespace i2p
{
namespace data
{
static const char T32[32] =
{
'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', '2', '3', '4', '5', '6', '7',
};
const char * GetBase32SubstitutionTable ()
{
return T32;
}
bool IsBase32 (char ch)
{
return (ch >= 'a' && ch <= 'z') || (ch >= '2' && ch <= '7');
}
static void iT64Build(void);
/*
*
* BASE64 Substitution Table
* -------------------------
*
* Direct Substitution Table
*/
static const 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', '-', '~'
};
const char * GetBase64SubstitutionTable ()
{
return T64;
}
bool IsBase64 (char ch)
{
return (ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z') || (ch >= '0' && ch <= '9') || ch == '-' || ch == '~';
}
/*
* 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 ByteStreamToBase64 ( /* Number of bytes in the encoded buffer */
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 0;
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 Base64ToByteStream ( /* Number of output bytes */
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 (InCount && !m)
outCount = 3 * n;
else
return 0;
if(*InBuffer == P64)
return 0;
ps = (unsigned char *)(InBuffer + InCount - 1);
while ( *ps-- == P64 )
outCount--;
ps = (unsigned char *)InBuffer;
if (outCount > len)
return 0;
pd = OutBuffer;
auto endOfOutBuffer = OutBuffer + outCount;
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;
if (pd >= endOfOutBuffer)
break;
acc_2 <<= 4;
acc_1 = iT64[*ps++];
acc_2 |= acc_1 >> 2;
*pd++ = acc_2;
if (pd >= endOfOutBuffer)
break;
acc_2 = iT64[*ps++];
acc_2 |= acc_1 << 6;
*pd++ = acc_2;
}
return outCount;
}
size_t Base64EncodingBufferSize (const size_t input_size)
{
auto d = div (input_size, 3);
if (d.rem)
d.quot++;
return 4 * d.quot;
}
std::string ToBase64Standard (const std::string& in)
{
auto len = Base64EncodingBufferSize (in.length ());
char * str = new char[len + 1];
auto l = ByteStreamToBase64 ((const uint8_t *)in.c_str (), in.length (), str, len);
str[l] = 0;
// replace '-' by '+' and '~' by '/'
for (size_t i = 0; i < l; i++)
if (str[i] == '-')
str[i] = '+';
else if (str[i] == '~')
str[i] = '/';
std::string s(str);
delete[] str;
return s;
}
/*
*
* 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)
{
unsigned 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;
}
size_t ByteStreamToBase32 (const uint8_t * inBuf, size_t len, char * outBuf, size_t outLen)
{
size_t ret = 0, pos = 1;
unsigned int bits = 8, tmp = inBuf[0];
while (ret < outLen && (bits > 0 || pos < len))
{
if (bits < 5)
{
if (pos < len)
{
tmp <<= 8;
tmp |= inBuf[pos] & 0xFF;
pos++;
bits += 8;
}
else // last byte
{
tmp <<= (5 - bits);
bits = 5;
}
}
bits -= 5;
int ind = (tmp >> bits) & 0x1F;
outBuf[ret] = (ind < 26) ? (ind + 'a') : ((ind - 26) + '2');
ret++;
}
return ret;
}
}
}