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Replace use of strcmp_len() with new mem_eq_token().

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The strcmp_len() function was somewhat misconceived, since we're
only using it to test whether a length+extent string is equal to a
NUL-terminated string or not.  By simplifying it and making it
inlined, we should be able to make it a little faster.

(It *does* show up in profiles.)

Closes ticket 28856.
This commit is contained in:
Nick Mathewson 2018-12-17 09:03:04 -05:00
parent f8dac5c900
commit a0fad3981e
1 changed files with 16 additions and 5 deletions
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21
src/feature/dirparse/parsecommon.c
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@ -15,6 +15,7 @@
#include "lib/string/printf.h"
#include "lib/memarea/memarea.h"
#include "lib/crypt_ops/crypto_rsa.h"
#include "lib/ctime/di_ops.h"
#include <string.h>
@ -251,6 +252,16 @@ token_check_object(memarea_t *area, const char *kwd,
return tok;
}
/** Return true iff the <b>memlen</b>-byte chunk of memory at
* <b>memlen</b> is the same length as <b>token</b>, and their
* contents are equal. */
static bool
mem_eq_token(const void *mem, size_t memlen, const char *token)
{
size_t len = strlen(token);
return memlen == len && fast_memeq(mem, token, len);
}
/** Helper function: read the next token from *s, advance *s to the end of the
* token, and return the parsed token. Parse *<b>s</b> according to the list
* of tokens in <b>table</b>.
@ -290,7 +301,7 @@ get_next_token(memarea_t *area,
next = find_whitespace_eos(*s, eol);
if (!strcmp_len(*s, "opt", next-*s)) {
if (mem_eq_token(*s, next-*s, "opt")) {
/* Skip past an "opt" at the start of the line. */
*s = eat_whitespace_eos_no_nl(next, eol);
next = find_whitespace_eos(*s, eol);
@ -301,7 +312,7 @@ get_next_token(memarea_t *area,
/* Search the table for the appropriate entry. (I tried a binary search
* instead, but it wasn't any faster.) */
for (i = 0; table[i].t ; ++i) {
if (!strcmp_len(*s, table[i].t, next-*s)) {
if (mem_eq_token(*s, next-*s, table[i].t)) {
/* We've found the keyword. */
kwd = table[i].t;
tok->tp = table[i].v;
@ -354,7 +365,7 @@ get_next_token(memarea_t *area,
obstart = *s; /* Set obstart to start of object spec */
if (eol - *s <= 16 || memchr(*s+11,'\0',eol-*s-16) || /* no short lines, */
strcmp_len(eol-5, "-----", 5) || /* nuls or invalid endings */
!mem_eq_token(eol-5, 5, "-----") || /* nuls or invalid endings */
(eol-*s) > MAX_UNPARSED_OBJECT_SIZE) { /* name too long */
RET_ERR("Malformed object: bad begin line");
}
@ -373,8 +384,8 @@ get_next_token(memarea_t *area,
eol = eos;
/* Validate the ending tag, which should be 9 + NAME + 5 + eol */
if ((size_t)(eol-next) != 9+obname_len+5 ||
strcmp_len(next+9, tok->object_type, obname_len) ||
strcmp_len(eol-5, "-----", 5)) {
!mem_eq_token(next+9, obname_len, tok->object_type) ||
!mem_eq_token(eol-5, 5, "-----")) {
tor_snprintf(ebuf, sizeof(ebuf), "Malformed object: mismatched end tag %s",
tok->object_type);
ebuf[sizeof(ebuf)-1] = '\0';