Telodendria/src/Base64.c

244 lines
5.1 KiB
C

/*
* Copyright (C) 2022 Jordan Bancino <@jordan:bancino.net>
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation files
* (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge,
* publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include <Base64.h>
#include <stdlib.h>
static const char Base64EncodeMap[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const int Base64DecodeMap[] = {
62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58,
59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5,
6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28,
29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42,
43, 44, 45, 46, 47, 48, 49, 50, 51
};
size_t
Base64EncodedSize(size_t inputSize)
{
size_t size = inputSize;
if (inputSize % 3)
{
size += 3 - (inputSize % 3);
}
size /= 3;
size *= 4;
return size;
}
size_t
Base64DecodedSize(const char *base64, size_t len)
{
size_t ret;
size_t i;
if (!base64)
{
return 0;
}
ret = len / 4 * 3;
for (i = len; i > 0; i--)
{
if (base64[i] == '=')
{
ret--;
}
else
{
break;
}
}
return ret;
}
char *
Base64Encode(const char *input, size_t len)
{
char *out;
size_t outLen;
size_t i, j, v;
if (!input || !len)
{
return NULL;
}
outLen = Base64EncodedSize(len);
out = malloc(outLen + 1);
if (!out)
{
return NULL;
}
out[outLen] = '\0';
for (i = 0, j = 0; i < len; i += 3, j += 4)
{
v = input[i];
v = i + 1 < len ? v << 8 | input[i + 1] : v << 8;
v = i + 2 < len ? v << 8 | input[i + 2] : v << 8;
out[j] = Base64EncodeMap[(v >> 18) & 0x3F];
out[j + 1] = Base64EncodeMap[(v >> 12) & 0x3F];
if (i + 1 < len)
{
out[j + 2] = Base64EncodeMap[(v >> 6) & 0x3F];
}
else
{
out[j + 2] = '=';
}
if (i + 2 < len)
{
out[j + 3] = Base64EncodeMap[v & 0x3F];
}
else
{
out[j + 3] = '=';
}
}
return out;
}
static int
Base64IsValidChar(char c)
{
return (c >= '0' && c <= '9') ||
(c >= 'A' && c <= 'Z') ||
(c >= 'a' && c <= 'z') ||
(c == '+') ||
(c == '/') ||
(c == '=');
}
char *
Base64Decode(const char *input, size_t len)
{
size_t i, j;
int v;
size_t outLen;
char *out;
if (!input)
{
return NULL;
}
outLen = Base64DecodedSize(input, len);
if (len % 4)
{
/* Invalid length; must have incorrect padding */
return NULL;
}
/* Scan for invalid characters. */
for (i = 0; i < len; i++)
{
if (!Base64IsValidChar(input[i]))
{
return NULL;
}
}
out = malloc(outLen + 1);
if (!out)
{
return NULL;
}
out[outLen] = '\0';
for (i = 0, j = 0; i < len; i += 4, j += 3)
{
v = Base64DecodeMap[input[i] - 43];
v = (v << 6) | Base64DecodeMap[input[i + 1] - 43];
v = input[i + 2] == '=' ? v << 6 : (v << 6) | Base64DecodeMap[input[i + 2] - 43];
v = input[i + 3] == '=' ? v << 6 : (v << 6) | Base64DecodeMap[input[i + 3] - 43];
out[j] = (v >> 16) & 0xFF;
if (input[i + 2] != '=')
out[j + 1] = (v >> 8) & 0xFF;
if (input[i + 3] != '=')
out[j + 2] = v & 0xFF;
}
return out;
}
extern void
Base64Unpad(char *base64, size_t length)
{
if (!base64)
{
return;
}
while (base64[length - 1] == '=')
{
length--;
}
base64[length] = '\0';
}
extern int
Base64Pad(char **base64Ptr, size_t length)
{
char *tmp;
size_t newSize;
size_t i;
if (length % 4 == 0)
{
return length; /* Success: no padding needed */
}
newSize = length + (4 - (length % 4));
tmp = realloc(*base64Ptr, newSize + 100);;
if (!tmp)
{
return 0; /* Memory error */
}
*base64Ptr = tmp;
for (i = length; i < newSize; i++)
{
(*base64Ptr)[i] = '=';
}
(*base64Ptr)[newSize] = '\0';
return newSize;
}