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bird/lib/strtoul.c
Maria Matejka 2915e711f7 Custom number parser to speed up config parsing
The glibc's generic parser is slow due to its versatility. Specialized
parsers for base-10 and base-16 are much faster and we don't use other
bases.
2019-02-25 23:28:36 +01:00

62 lines
1.1 KiB
C

/*
* BIRD Library -- Parse numbers
*
* (c) 2019 Maria Matejka <mq@jmq.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#include "nest/bird.h"
#include "lib/string.h"
#include <errno.h>
#define ULI_MAX_DIV10 (UINT64_MAX / 10)
#define ULI_MAX_MOD10 (UINT64_MAX % 10)
u64
bstrtoul10(const char *str, char **end)
{
u64 out = 0;
for (*end = (char *) str; (**end >= '0') && (**end <= '9'); (*end)++) {
u64 digit = **end - '0';
if ((out > ULI_MAX_DIV10) ||
(out == ULI_MAX_DIV10) && (digit > ULI_MAX_MOD10)) {
errno = ERANGE;
return UINT64_MAX;
}
out *= 10;
out += (**end) - '0';
}
return out;
}
u64
bstrtoul16(const char *str, char **end)
{
u64 out = 0;
for (int i=0; i<=(64/4); i++) {
switch (str[i]) {
case '0' ... '9':
out *= 16;
out += str[i] - '0';
break;
case 'a' ... 'f':
out *= 16;
out += str[i] + 10 - 'a';
break;
case 'A' ... 'F':
out *= 16;
out += str[i] + 10 - 'A';
break;
default:
*end = (char *) &(str[i]);
return out;
}
}
errno = ERANGE;
return UINT64_MAX;
}