mirror of
https://github.com/fastfetch-cli/fastfetch.git
synced 2026-09-13 02:42:09 +02:00
李通洲
113 lines
2.8 KiB
C
113 lines
2.8 KiB
C
#include "base64.h"
|
|
|
|
// https://github.com/kostya/benchmarks/blob/master/base64/test-nolib.c#L145
|
|
void ffBase64EncodeRaw(uint32_t size, const char *str, uint32_t *out_size, char *output)
|
|
{
|
|
static const char chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
|
|
char *out = output;
|
|
const char *ends = str + (size - size % 3);
|
|
while (str != ends)
|
|
{
|
|
uint32_t n = __builtin_bswap32(*(uint32_t *)str);
|
|
*out++ = chars[(n >> 26) & 63];
|
|
*out++ = chars[(n >> 20) & 63];
|
|
*out++ = chars[(n >> 14) & 63];
|
|
*out++ = chars[(n >> 8) & 63];
|
|
str += 3;
|
|
}
|
|
|
|
if (size % 3 == 1)
|
|
{
|
|
uint64_t n = (uint64_t)*str << 16;
|
|
*out++ = chars[(n >> 18) & 63];
|
|
*out++ = chars[(n >> 12) & 63];
|
|
*out++ = '=';
|
|
*out++ = '=';
|
|
}
|
|
else if (size % 3 == 2)
|
|
{
|
|
uint64_t n = (uint64_t)*str++ << 16;
|
|
n |= (uint64_t)*str << 8;
|
|
*out++ = chars[(n >> 18) & 63];
|
|
*out++ = chars[(n >> 12) & 63];
|
|
*out++ = chars[(n >> 6) & 63];
|
|
*out++ = '=';
|
|
}
|
|
*out = '\0';
|
|
*out_size = (uint32_t)(out - output);
|
|
}
|
|
|
|
static uint8_t decode_table[256];
|
|
|
|
void init_decode_table()
|
|
{
|
|
uint8_t ch = 0;
|
|
do
|
|
{
|
|
int32_t code = -1;
|
|
if (ch >= 'A' && ch <= 'Z')
|
|
code = ch - 0x41;
|
|
if (ch >= 'a' && ch <= 'z')
|
|
code = ch - 0x47;
|
|
if (ch >= '0' && ch <= '9')
|
|
code = ch + 0x04;
|
|
if (ch == '+' || ch == '-')
|
|
code = 0x3E;
|
|
if (ch == '/' || ch == '_')
|
|
code = 0x3F;
|
|
decode_table[ch] = (uint8_t) code;
|
|
} while (ch++ < 0xFF);
|
|
}
|
|
|
|
#define next_char(x) uint8_t x = decode_table[(uint8_t) *str++];
|
|
|
|
bool ffBase64DecodeRaw(uint32_t size, const char *str, uint32_t *out_size, char *output)
|
|
{
|
|
if (*(uint64_t*) decode_table == 0)
|
|
init_decode_table();
|
|
|
|
char *out = output;
|
|
while (size > 0 && (str[size - 1] == '\n' || str[size - 1] == '\r' || str[size - 1] == '='))
|
|
size--;
|
|
|
|
const char *ends = str + size - 4;
|
|
while (true)
|
|
{
|
|
if (str > ends)
|
|
break;
|
|
while (*str == '\n' || *str == '\r')
|
|
str++;
|
|
|
|
if (str > ends)
|
|
break;
|
|
next_char(a);
|
|
next_char(b);
|
|
next_char(c);
|
|
next_char(d);
|
|
|
|
*out++ = (char)(a << 2 | b >> 4);
|
|
*out++ = (char)(b << 4 | c >> 2);
|
|
*out++ = (char)(c << 6 | d >> 0);
|
|
}
|
|
|
|
uint8_t mod = (uint8_t) (ends - str + 4) % 4;
|
|
if (mod == 2)
|
|
{
|
|
next_char(a);
|
|
next_char(b);
|
|
*out++ = (char)(a << 2 | b >> 4);
|
|
}
|
|
else if (mod == 3)
|
|
{
|
|
next_char(a);
|
|
next_char(b);
|
|
next_char(c);
|
|
*out++ = (char)(a << 2 | b >> 4);
|
|
*out++ = (char)(b << 4 | c >> 2);
|
|
}
|
|
|
|
*out = '\0';
|
|
*out_size = (uint32_t) (out - output);
|
|
return true;
|
|
}
|