mirror of
https://github.com/git/git.git
synced 2024-12-01 05:54:16 +08:00
addaacab07
This code is arguably pretty hot, if you use binary patches of course. This patch helps gcc generate both smaller and faster code especially in the error free path. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
141 lines
2.9 KiB
C
141 lines
2.9 KiB
C
#include "cache.h"
|
|
|
|
#undef DEBUG_85
|
|
|
|
#ifdef DEBUG_85
|
|
#define say(a) fprintf(stderr, a)
|
|
#define say1(a,b) fprintf(stderr, a, b)
|
|
#define say2(a,b,c) fprintf(stderr, a, b, c)
|
|
#else
|
|
#define say(a) do {} while(0)
|
|
#define say1(a,b) do {} while(0)
|
|
#define say2(a,b,c) do {} while(0)
|
|
#endif
|
|
|
|
static const char en85[] = {
|
|
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
|
|
'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',
|
|
'!', '#', '$', '%', '&', '(', ')', '*', '+', '-',
|
|
';', '<', '=', '>', '?', '@', '^', '_', '`', '{',
|
|
'|', '}', '~'
|
|
};
|
|
|
|
static char de85[256];
|
|
static void prep_base85(void)
|
|
{
|
|
int i;
|
|
if (de85['Z'])
|
|
return;
|
|
for (i = 0; i < ARRAY_SIZE(en85); i++) {
|
|
int ch = en85[i];
|
|
de85[ch] = i + 1;
|
|
}
|
|
}
|
|
|
|
int decode_85(char *dst, char *buffer, int len)
|
|
{
|
|
prep_base85();
|
|
|
|
say2("decode 85 <%.*s>", len/4*5, buffer);
|
|
while (len) {
|
|
unsigned acc = 0;
|
|
int de, cnt = 4;
|
|
unsigned char ch;
|
|
do {
|
|
ch = *buffer++;
|
|
de = de85[ch];
|
|
if (--de < 0)
|
|
return error("invalid base85 alphabet %c", ch);
|
|
acc = acc * 85 + de;
|
|
} while (--cnt);
|
|
ch = *buffer++;
|
|
de = de85[ch];
|
|
if (--de < 0)
|
|
return error("invalid base85 alphabet %c", ch);
|
|
/*
|
|
* Detect overflow. The largest
|
|
* 5-letter possible is "|NsC0" to
|
|
* encode 0xffffffff, and "|NsC" gives
|
|
* 0x03030303 at this point (i.e.
|
|
* 0xffffffff = 0x03030303 * 85).
|
|
*/
|
|
if (0x03030303 < acc ||
|
|
0xffffffff - de < (acc *= 85))
|
|
error("invalid base85 sequence %.5s", buffer-5);
|
|
acc += de;
|
|
say1(" %08x", acc);
|
|
|
|
cnt = (len < 4) ? len : 4;
|
|
len -= cnt;
|
|
do {
|
|
acc = (acc << 8) | (acc >> 24);
|
|
*dst++ = acc;
|
|
} while (--cnt);
|
|
}
|
|
say("\n");
|
|
|
|
return 0;
|
|
}
|
|
|
|
void encode_85(char *buf, unsigned char *data, int bytes)
|
|
{
|
|
prep_base85();
|
|
|
|
say("encode 85");
|
|
while (bytes) {
|
|
unsigned acc = 0;
|
|
int cnt;
|
|
for (cnt = 24; cnt >= 0; cnt -= 8) {
|
|
int ch = *data++;
|
|
acc |= ch << cnt;
|
|
if (--bytes == 0)
|
|
break;
|
|
}
|
|
say1(" %08x", acc);
|
|
for (cnt = 4; cnt >= 0; cnt--) {
|
|
int val = acc % 85;
|
|
acc /= 85;
|
|
buf[cnt] = en85[val];
|
|
}
|
|
buf += 5;
|
|
}
|
|
say("\n");
|
|
|
|
*buf = 0;
|
|
}
|
|
|
|
#ifdef DEBUG_85
|
|
int main(int ac, char **av)
|
|
{
|
|
char buf[1024];
|
|
|
|
if (!strcmp(av[1], "-e")) {
|
|
int len = strlen(av[2]);
|
|
encode_85(buf, av[2], len);
|
|
if (len <= 26) len = len + 'A' - 1;
|
|
else len = len + 'a' - 26 + 1;
|
|
printf("encoded: %c%s\n", len, buf);
|
|
return 0;
|
|
}
|
|
if (!strcmp(av[1], "-d")) {
|
|
int len = *av[2];
|
|
if ('A' <= len && len <= 'Z') len = len - 'A' + 1;
|
|
else len = len - 'a' + 26 + 1;
|
|
decode_85(buf, av[2]+1, len);
|
|
printf("decoded: %.*s\n", len, buf);
|
|
return 0;
|
|
}
|
|
if (!strcmp(av[1], "-t")) {
|
|
char t[4] = { -1,-1,-1,-1 };
|
|
encode_85(buf, t, 4);
|
|
printf("encoded: D%s\n", buf);
|
|
return 0;
|
|
}
|
|
}
|
|
#endif
|