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127 lines
3.0 KiB
C
127 lines
3.0 KiB
C
/*-------------------------------------------------------------------------
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*
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* stringinfo.c--
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* These are routines that can be used to write informations to a string,
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* without having to worry about string lengths, space allocation etc.
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* Ideally the interface should look like the file i/o interface,
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/lib/stringinfo.c,v 1.8 1998/01/07 15:32:19 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include <string.h>
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#include <postgres.h>
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#include <nodes/pg_list.h>
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#include <lib/stringinfo.h>
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/*---------------------------------------------------------------------
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* makeStringInfo
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*
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* Create a StringInfoData & return a pointer to it.
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*
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*---------------------------------------------------------------------
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*/
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StringInfo
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makeStringInfo()
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{
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StringInfo res;
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long size;
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res = (StringInfo) palloc(sizeof(StringInfoData));
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if (res == NULL)
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{
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elog(ABORT, "makeStringInfo: Out of memory!");
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}
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size = 100;
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res->data = palloc(size);
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if (res->data == NULL)
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{
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elog(ABORT,
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"makeStringInfo: Out of memory! (%ld bytes requested)", size);
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}
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res->maxlen = size;
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res->len = 0;
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/*
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* NOTE: we must initialize `res->data' to the empty string because we
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* use 'strcat' in 'appendStringInfo', which of course it always
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* expects a null terminated string.
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*/
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res->data[0] = '\0';
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return (res);
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}
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/*---------------------------------------------------------------------
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* appendStringInfo
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*
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* append to the current 'StringInfo' a new string.
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* If there is not enough space in the current 'data', then reallocate
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* some more...
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*
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* NOTE: if we reallocate space, we pfree the old one!
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*---------------------------------------------------------------------
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*/
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void
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appendStringInfo(StringInfo str, char *buffer)
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{
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int buflen,
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newlen;
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char *s;
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Assert(str != NULL);
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if (buffer == NULL)
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buffer = "<>";
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/*
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* do we have enough space to append the new string? (don't forget to
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* count the null string terminating char!) If no, then reallocate
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* some more.
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*/
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buflen = strlen(buffer);
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if (buflen + str->len >= str->maxlen - 1)
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{
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/*
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* how much more space to allocate ? Let's say double the current
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* space... However we must check if this is enough!
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*/
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newlen = 2 * str->len;
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while (buflen + str->len >= newlen - 1)
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{
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newlen = 2 * newlen;
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}
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/*
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* allocate enough space.
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*/
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s = palloc(newlen);
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if (s == NULL)
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{
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elog(ABORT,
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"appendStringInfo: Out of memory (%d bytes requested)",
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newlen);
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}
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memmove(s, str->data, str->len + 1);
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pfree(str->data);
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str->maxlen = newlen;
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str->data = s;
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}
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/*
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* OK, we have enough space now, append 'buffer' at the end of the
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* string & update the string length. NOTE: this is a text string
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* (i.e. printable characters) so 'strcat' will do the job (no need to
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* use 'bcopy' et all...)
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*/
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strcat(str->data, buffer);
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str->len += buflen;
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}
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