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Improve documentation of ParseDateTime(). Reorder tests to prevent

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writing one more value into return arrays than will fit.  This is
potentially a stack smash, though I do not think it is a problem in
current uses of the routine, since a failure return causes elog anyway.
This commit is contained in:
Tom Lane 2003-08-05 18:30:21 +00:00
parent 9d41073f04
commit 630684d3a1
2 changed files with 39 additions and 24 deletions
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57
src/backend/utils/adt/datetime.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/datetime.c,v 1.111 2003/08/05 17:39:19 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/adt/datetime.c,v 1.112 2003/08/05 18:30:21 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -700,6 +700,19 @@ TrimTrailingZeros(char *str)
/* ParseDateTime()
* Break string into tokens based on a date/time context.
* Returns 0 if successful, -1 if bogus input detected.
*
* timestr - the input string
* lowstr - workspace for field string storage (must be large enough for
* a copy of the input string, including trailing null)
* field[] - pointers to field strings are returned in this array
* ftype[] - field type indicators are returned in this array
* maxfields - dimensions of the above two arrays
* *numfields - set to the actual number of fields detected
*
* The fields extracted from the input are stored as separate, null-terminated
* strings in the workspace at lowstr. Any text is converted to lower case.
*
* Several field types are assigned:
* DTK_NUMBER - digits and (possibly) a decimal point
* DTK_DATE - digits and two delimiters, or digits and text
@ -707,22 +720,33 @@ TrimTrailingZeros(char *str)
* DTK_STRING - text (no digits)
* DTK_SPECIAL - leading "+" or "-" followed by text
* DTK_TZ - leading "+" or "-" followed by digits
*
* Note that some field types can hold unexpected items:
* DTK_NUMBER can hold date fields (yy.ddd)
* DTK_STRING can hold months (January) and time zones (PST)
* DTK_DATE can hold Posix time zones (GMT-8)
*/
int
ParseDateTime(char *timestr, char *lowstr,
ParseDateTime(const char *timestr, char *lowstr,
char **field, int *ftype, int maxfields, int *numfields)
{
int nf = 0;
char *cp = timestr;
const char *cp = timestr;
char *lp = lowstr;
/* outer loop through fields */
while (*cp != '\0')
{
/* Ignore spaces between fields */
if (isspace((unsigned char) *cp))
{
cp++;
continue;
}
/* Record start of current field */
if (nf >= maxfields)
return -1;
field[nf] = lp;
/* leading digit? then date or time */
@ -745,13 +769,13 @@ ParseDateTime(char *timestr, char *lowstr,
else if ((*cp == '-') || (*cp == '/') || (*cp == '.'))
{
/* save delimiting character to use later */
char *dp = cp;
char delim = *cp;
*lp++ = *cp++;
/* second field is all digits? then no embedded text month */
if (isdigit((unsigned char) *cp))
{
ftype[nf] = ((*dp == '.') ? DTK_NUMBER : DTK_DATE);
ftype[nf] = ((delim == '.') ? DTK_NUMBER : DTK_DATE);
while (isdigit((unsigned char) *cp))
*lp++ = *cp++;
@ -759,18 +783,18 @@ ParseDateTime(char *timestr, char *lowstr,
* insist that the delimiters match to get a
* three-field date.
*/
if (*cp == *dp)
if (*cp == delim)
{
ftype[nf] = DTK_DATE;
*lp++ = *cp++;
while (isdigit((unsigned char) *cp) || (*cp == *dp))
while (isdigit((unsigned char) *cp) || (*cp == delim))
*lp++ = *cp++;
}
}
else
{
ftype[nf] = DTK_DATE;
while (isalnum((unsigned char) *cp) || (*cp == *dp))
while (isalnum((unsigned char) *cp) || (*cp == delim))
*lp++ = tolower((unsigned char) *cp++);
}
}
@ -809,20 +833,14 @@ ParseDateTime(char *timestr, char *lowstr,
*/
if ((*cp == '-') || (*cp == '/') || (*cp == '.'))
{
char *dp = cp;
char delim = *cp;
ftype[nf] = DTK_DATE;
*lp++ = *cp++;
while (isdigit((unsigned char) *cp) || (*cp == *dp))
while (isdigit((unsigned char) *cp) || (*cp == delim))
*lp++ = *cp++;
}
}
/* skip leading spaces */
else if (isspace((unsigned char) *cp))
{
cp++;
continue;
}
/* sign? then special or numeric timezone */
else if ((*cp == '+') || (*cp == '-'))
{
@ -851,12 +869,11 @@ ParseDateTime(char *timestr, char *lowstr,
else
return -1;
}
/* ignore punctuation but use as delimiter */
/* ignore other punctuation but use as delimiter */
else if (ispunct((unsigned char) *cp))
{
cp++;
continue;
}
/* otherwise, something is not right... */
else
@ -865,14 +882,12 @@ ParseDateTime(char *timestr, char *lowstr,
/* force in a delimiter after each field */
*lp++ = '\0';
nf++;
if (nf > MAXDATEFIELDS)
return -1;
}
*numfields = nf;
return 0;
} /* ParseDateTime() */
}
/* DecodeDateTime()

4
src/include/utils/datetime.h
View File

@ -9,7 +9,7 @@
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: datetime.h,v 1.43 2003/08/04 02:40:15 momjian Exp $
* $Id: datetime.h,v 1.44 2003/08/05 18:30:21 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -277,7 +277,7 @@ extern void GetCurrentTimeUsec(struct tm * tm, fsec_t *fsec, int *tzp);
extern void j2date(int jd, int *year, int *month, int *day);
extern int date2j(int year, int month, int day);
extern int ParseDateTime(char *timestr, char *lowstr,
extern int ParseDateTime(const char *timestr, char *lowstr,
char **field, int *ftype,
int maxfields, int *numfields);
extern int DecodeDateTime(char **field, int *ftype,