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/*-------------------------------------------------------------------------
*
* stringinfo.c
*
* StringInfo provides an indefinitely-extensible string data type.
* It can be used to buffer either ordinary C strings (null-terminated text)
* or arbitrary binary data. All storage is allocated with palloc().
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: stringinfo.c,v 1.17 1999/05/26 12:55:14 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include <stdio.h>
#include <string.h>
#include "postgres.h"
#include "lib/stringinfo.h"
#ifdef NOT_USED
/*
* makeStringInfo
*
* Create an empty 'StringInfoData' & return a pointer to it.
*/
StringInfo
makeStringInfo(void)
{
StringInfo res;
res = (StringInfo) palloc(sizeof(StringInfoData));
if (res == NULL)
elog(ERROR, "makeStringInfo: Out of memory");
initStringInfo(res);
return res;
}
#endif
/*
* initStringInfo
*
* Initialize a StringInfoData struct (with previously undefined contents)
* to describe an empty string.
*/
void
initStringInfo(StringInfo str)
{
int size = 256; /* initial default buffer size */
str->data = palloc(size);
if (str->data == NULL)
elog(ERROR,
"initStringInfo: Out of memory (%d bytes requested)", size);
str->maxlen = size;
str->len = 0;
str->data[0] = '\0';
}
/*
* enlargeStringInfo
*
* Internal routine: make sure there is enough space for 'needed' more bytes
* ('needed' does not include the terminating null).
*/
static void
enlargeStringInfo(StringInfo str, int needed)
{
int newlen;
char *newdata;
needed += str->len + 1; /* total space required now */
if (needed <= str->maxlen)
return; /* got enough space already */
/*
* We don't want to allocate just a little more space with each
* append; for efficiency, double the buffer size each time it
* overflows. Actually, we might need to more than double it if
* 'needed' is big...
*/
newlen = 2 * str->maxlen;
while (needed > newlen)
newlen = 2 * newlen;
newdata = palloc(newlen);
if (newdata == NULL)
elog(ERROR,
"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;
}
/*
* appendStringInfo
*
* Format text data under the control of fmt (an sprintf-like format string)
* 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;
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;
}
/*------------------------
* appendStringInfoChar
* Append a single byte to str.
* Like appendStringInfo(str, "%c", ch) but much faster.
*/
void
appendStringInfoChar(StringInfo str, char ch)
{
Assert(str != NULL);
/* Make more room if needed */
enlargeStringInfo(str, 1);
/* OK, append the character */
str->data[str->len] = ch;
str->len++;
str->data[str->len] = '\0';
}
/*
* appendBinaryStringInfo
*
* Append arbitrary binary data to a StringInfo, allocating more space
* if necessary.
*/
void
appendBinaryStringInfo(StringInfo str, const char *data, int datalen)
{
Assert(str != NULL);
/* Make more room if needed */
enlargeStringInfo(str, datalen);
/* OK, append the data */
memcpy(str->data + str->len, data, datalen);
str->len += datalen;
/*
* Keep a trailing null in place, even though it's probably useless
* for binary data...
*/
str->data[str->len] = '\0';
}
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