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parsedate: parse strings without using sscanf()

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- sscanf is slow and complex, avoid it
- give up already if the string is 12 bytes or longer as no valid string
  can be that long
- this can now be done without copy

Closes #10547
This commit is contained in:
Daniel Stenberg 2023-02-17 10:04:31 +01:00
parent cbf5717615
commit ba9a4e9bd8
No known key found for this signature in database
GPG Key ID: 5CC908FDB71E12C2
1 changed files with 50 additions and 48 deletions
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74
lib/parsedate.c
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@ -212,56 +212,55 @@ static int checkday(const char *check, size_t len)
{
int i;
const char * const *what;
bool found = FALSE;
if(len > 3)
what = &weekday[0];
else
else if(len == 3)
what = &Curl_wkday[0];
else
return -1; /* too short */
for(i = 0; i<7; i++) {
if(strcasecompare(check, what[0])) {
found = TRUE;
break;
}
size_t ilen = strlen(what[0]);
if((ilen == len) &&
strncasecompare(check, what[0], len))
return i;
what++;
}
return found?i:-1;
return -1;
}
static int checkmonth(const char *check)
static int checkmonth(const char *check, size_t len)
{
int i;
const char * const *what;
bool found = FALSE;
const char * const *what = &Curl_month[0];
if(len != 3)
return -1; /* not a month */
what = &Curl_month[0];
for(i = 0; i<12; i++) {
if(strcasecompare(check, what[0])) {
found = TRUE;
break;
}
if(strncasecompare(check, what[0], 3))
return i;
what++;
}
return found?i:-1; /* return the offset or -1, no real offset is -1 */
return -1; /* return the offset or -1, no real offset is -1 */
}
/* return the time zone offset between GMT and the input one, in number
of seconds or -1 if the timezone wasn't found/legal */
static int checktz(const char *check)
static int checktz(const char *check, size_t len)
{
unsigned int i;
const struct tzinfo *what;
bool found = FALSE;
const struct tzinfo *what = tz;
if(len > 4) /* longer than any valid timezone */
return -1;
what = tz;
for(i = 0; i< sizeof(tz)/sizeof(tz[0]); i++) {
if(strcasecompare(check, what->name)) {
found = TRUE;
break;
}
size_t ilen = strlen(what->name);
if((ilen == len) &&
strncasecompare(check, what->name, len))
return what->offset*60;
what++;
}
return found?what->offset*60:-1;
return -1;
}
static void skip(const char **date)
@ -305,6 +304,9 @@ static time_t time2epoch(int sec, int min, int hour,
* PARSEDATE_SOONER - time underflow at the low end of time_t
*/
/* Wednesday is the longest name this parser knows about */
#define NAME_LEN 12
static int parsedate(const char *date, time_t *output)
{
time_t t = 0;
@ -327,32 +329,32 @@ static int parsedate(const char *date, time_t *output)
if(ISALPHA(*date)) {
/* a name coming up */
char buf[32]="";
size_t len;
if(sscanf(date, "%31[ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz]", buf))
len = strlen(buf);
else
len = 0;
size_t len = 0;
const char *p = date;
while(ISALPHA(*p) && (len < NAME_LEN)) {
p++;
len++;
}
if(len != NAME_LEN) {
if(wdaynum == -1) {
wdaynum = checkday(buf, len);
wdaynum = checkday(date, len);
if(wdaynum != -1)
found = TRUE;
}
if(!found && (monnum == -1)) {
monnum = checkmonth(buf);
monnum = checkmonth(date, len);
if(monnum != -1)
found = TRUE;
}
if(!found && (tzoff == -1)) {
/* this just must be a time zone string */
tzoff = checktz(buf);
tzoff = checktz(date, len);
if(tzoff != -1)
found = TRUE;
}
}
if(!found)
return PARSEDATE_FAIL; /* bad string */