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error/notice message lengths, and number of fields per tuple. Add pqexpbuffer.c/.h, a frontend version of backend's stringinfo module. This is first step in applying Mike Ansley's long-query patches, even though he didn't do any of these particular changes...
255 lines
6.2 KiB
C
255 lines
6.2 KiB
C
/*-------------------------------------------------------------------------
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*
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* pqexpbuffer.c
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*
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* PQExpBuffer provides an indefinitely-extensible string data type.
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* It can be used to buffer either ordinary C strings (null-terminated text)
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* or arbitrary binary data. All storage is allocated with malloc().
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*
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* This module is essentially the same as the backend's StringInfo data type,
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* but it is intended for use in frontend libpq and client applications.
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* Thus, it does not rely on palloc(), elog(), nor vsnprintf().
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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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* $Header: /cvsroot/pgsql/src/interfaces/libpq/pqexpbuffer.c,v 1.1 1999/08/31 01:37:37 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "pqexpbuffer.h"
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/*
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* createPQExpBuffer
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*
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* Create an empty 'PQExpBufferData' & return a pointer to it.
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*/
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PQExpBuffer
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createPQExpBuffer(void)
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{
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PQExpBuffer res;
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res = (PQExpBuffer) malloc(sizeof(PQExpBufferData));
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if (res != NULL)
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initPQExpBuffer(res);
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return res;
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}
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/*
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* initPQExpBuffer
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*
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* Initialize a PQExpBufferData struct (with previously undefined contents)
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* to describe an empty string.
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*/
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void
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initPQExpBuffer(PQExpBuffer str)
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{
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str->data = (char *) malloc(INITIAL_EXPBUFFER_SIZE);
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if (str->data == NULL)
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{
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str->maxlen = 0;
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str->len = 0;
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}
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else
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{
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str->maxlen = INITIAL_EXPBUFFER_SIZE;
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str->len = 0;
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str->data[0] = '\0';
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}
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}
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/*------------------------
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* destroyPQExpBuffer(str);
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* free()s both the data buffer and the PQExpBufferData.
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* This is the inverse of createPQExpBuffer().
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*/
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void
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destroyPQExpBuffer(PQExpBuffer str)
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{
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if (str)
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{
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termPQExpBuffer(str);
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free(str);
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}
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}
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/*------------------------
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* termPQExpBuffer(str)
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* free()s the data buffer but not the PQExpBufferData itself.
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* This is the inverse of initPQExpBuffer().
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*/
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void
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termPQExpBuffer(PQExpBuffer str)
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{
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if (str->data)
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{
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free(str->data);
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str->data = NULL;
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}
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}
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/*------------------------
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* resetPQExpBuffer
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* Reset a PQExpBuffer to empty
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*/
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void
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resetPQExpBuffer(PQExpBuffer str)
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{
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if (str)
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{
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str->len = 0;
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if (str->data)
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str->data[0] = '\0';
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}
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}
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/*------------------------
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* enlargePQExpBuffer
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* Make sure there is enough space for 'needed' more bytes in the buffer
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* ('needed' does not include the terminating null).
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*
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* Returns 1 if OK, 0 if failed to enlarge buffer.
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*/
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int
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enlargePQExpBuffer(PQExpBuffer str, int needed)
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{
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int newlen;
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char *newdata;
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needed += str->len + 1; /* total space required now */
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if (needed <= str->maxlen)
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return 1; /* got enough space already */
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/*
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* We don't want to allocate just a little more space with each
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* append; for efficiency, double the buffer size each time it
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* overflows. Actually, we might need to more than double it if
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* 'needed' is big...
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*/
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newlen = str->maxlen ? (2 * str->maxlen) : 64;
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while (needed > newlen)
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newlen = 2 * newlen;
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newdata = (char *) realloc(str->data, newlen);
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if (newdata != NULL)
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{
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str->data = newdata;
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str->maxlen = newlen;
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return 1;
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}
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return 0;
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}
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/*------------------------
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* printfPQExpBuffer
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* Format text data under the control of fmt (an sprintf-like format string)
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* and insert it into str. More space is allocated to str if necessary.
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* This is a convenience routine that does the same thing as
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* resetPQExpBuffer() followed by appendPQExpBuffer().
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*
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* CAUTION: the frontend version of this routine WILL FAIL if the result of
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* the sprintf formatting operation exceeds 1KB of data (but the size of the
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* pre-existing string in the buffer doesn't matter). We could make it
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* support larger strings, but that requires vsnprintf() which is not
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* universally available. Currently there is no need for long strings to be
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* formatted in the frontend. We could support it, if necessary, by
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* conditionally including a vsnprintf emulation.
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*/
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void
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printfPQExpBuffer(PQExpBuffer str, const char *fmt,...)
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{
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va_list args;
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char buffer[1024];
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va_start(args, fmt);
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vsprintf(buffer, fmt, args);
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va_end(args);
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resetPQExpBuffer(str);
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appendPQExpBufferStr(str, buffer);
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}
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/*------------------------
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* appendPQExpBuffer
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*
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* Format text data under the control of fmt (an sprintf-like format string)
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* and append it to whatever is already in str. More space is allocated
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* to str if necessary. This is sort of like a combination of sprintf and
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* strcat.
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*
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* CAUTION: the frontend version of this routine WILL FAIL if the result of
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* the sprintf formatting operation exceeds 1KB of data (but the size of the
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* pre-existing string in the buffer doesn't matter). We could make it
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* support larger strings, but that requires vsnprintf() which is not
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* universally available. Currently there is no need for long strings to be
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* formatted in the frontend. We could support it, if necessary, by
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* conditionally including a vsnprintf emulation.
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*/
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void
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appendPQExpBuffer(PQExpBuffer str, const char *fmt,...)
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{
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va_list args;
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char buffer[1024];
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va_start(args, fmt);
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vsprintf(buffer, fmt, args);
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va_end(args);
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appendPQExpBufferStr(str, buffer);
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}
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/*------------------------
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* appendPQExpBufferStr
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* Append the given string to a PQExpBuffer, allocating more space
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* if necessary.
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*/
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void
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appendPQExpBufferStr(PQExpBuffer str, const char *data)
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{
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appendBinaryPQExpBuffer(str, data, strlen(data));
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}
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/*------------------------
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* appendPQExpBufferChar
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* Append a single byte to str.
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* Like appendPQExpBuffer(str, "%c", ch) but much faster.
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*/
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void
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appendPQExpBufferChar(PQExpBuffer str, char ch)
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{
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/* Make more room if needed */
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if (! enlargePQExpBuffer(str, 1))
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return;
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/* OK, append the character */
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str->data[str->len] = ch;
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str->len++;
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str->data[str->len] = '\0';
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}
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/*
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* appendBinaryPQExpBuffer
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*
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* Append arbitrary binary data to a PQExpBuffer, allocating more space
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* if necessary.
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*/
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void
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appendBinaryPQExpBuffer(PQExpBuffer str, const char *data, int datalen)
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{
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/* Make more room if needed */
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if (! enlargePQExpBuffer(str, datalen))
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return;
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/* OK, append the data */
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memcpy(str->data + str->len, data, datalen);
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str->len += datalen;
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/*
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* Keep a trailing null in place, even though it's probably useless
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* for binary data...
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*/
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str->data[str->len] = '\0';
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}
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