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Minor improvements to stringinfo package to make it more

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robust, since it's about to get used much more heavily.
This commit is contained in:
Tom Lane
1999-08-31 01:28:37 +00:00
parent f4add18557
commit 130e372b5d
5 changed files with 48 additions and 46 deletions
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59
src/backend/lib/stringinfo.c
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@ -8,7 +8,7 @@
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: stringinfo.c,v 1.20 1999/07/17 20:16:59 momjian Exp $
* $Id: stringinfo.c,v 1.21 1999/08/31 01:28:25 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -17,7 +17,6 @@
#include "postgres.h"
#include "lib/stringinfo.h"
#ifdef NOT_USED
/*
* makeStringInfo
*
@ -36,7 +35,6 @@ makeStringInfo(void)
return res;
}
#endif
/*
* initStringInfo
@ -49,7 +47,7 @@ initStringInfo(StringInfo str)
{
int size = 256; /* initial default buffer size */
str->data = palloc(size);
str->data = (char *) palloc(size);
if (str->data == NULL)
elog(ERROR,
"initStringInfo: Out of memory (%d bytes requested)", size);
@ -68,7 +66,6 @@ static void
enlargeStringInfo(StringInfo str, int needed)
{
int newlen;
char *newdata;
needed += str->len + 1; /* total space required now */
if (needed <= str->maxlen)
@ -84,15 +81,11 @@ enlargeStringInfo(StringInfo str, int needed)
while (needed > newlen)
newlen = 2 * newlen;
newdata = palloc(newlen);
if (newdata == NULL)
str->data = (char *) repalloc(str->data, newlen);
if (str->data == NULL)
elog(ERROR,
"enlargeStringInfo: Out of memory (%d bytes requested)", newlen);
"enlargeStringInfo: Out of memory (%d bytes requested)", newlen);
/* OK, transfer data into new buffer, and release old buffer */
memcpy(newdata, str->data, str->len + 1);
pfree(str->data);
str->data = newdata;
str->maxlen = newlen;
}
@ -103,29 +96,41 @@ enlargeStringInfo(StringInfo str, int needed)
* and append it to whatever is already in str. More space is allocated
* to str if necessary. This is sort of like a combination of sprintf and
* strcat.
*
* CAUTION: the current implementation has a 1K limit on the amount of text
* generated in a single call (not on the total string length).
*/
void
appendStringInfo(StringInfo str, const char *fmt,...)
{
va_list args;
char buffer[1024];
int buflen;
int avail,
nprinted;
Assert(str != NULL);
va_start(args, fmt);
buflen = vsnprintf(buffer, sizeof(buffer), fmt, args);
va_end(args);
/* Make more room if needed */
enlargeStringInfo(str, buflen);
/* OK, append the data, including the trailing null */
memcpy(str->data + str->len, buffer, buflen + 1);
str->len += buflen;
for (;;)
{
/*----------
* Try to format the given string into the available space;
* but if there's hardly any space, don't bother trying,
* just fall through to enlarge the buffer first.
*----------
*/
avail = str->maxlen - str->len - 1;
if (avail > 16)
{
va_start(args, fmt);
nprinted = vsnprintf(str->data + str->len, avail,
fmt, args);
va_end(args);
if (nprinted < avail-1)
{
/* Success. Note nprinted does not include trailing null. */
str->len += nprinted;
break;
}
}
/* Double the buffer size and try again. */
enlargeStringInfo(str, str->maxlen);
}
}
/*------------------------