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/***************************************************************************
* This has been copied from:
* PostgreSQL: pgsql/src/interfaces/libpq/fe-exec.c,v
* 1.165 2004/10/21 19:28:36 tgl Exp
*
* Portions Copyright (c) 1996-2004, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
**************************************************************************/
#include <stdlib.h>
#include <ctype.h>
#include <stdio.h>
#include "compat.h"
#if USE_VERSION < 73
#define ISFIRSTOCTDIGIT(CH) ((CH) >= '0' && (CH) <= '3')
#define ISOCTDIGIT(CH) ((CH) >= '0' && (CH) <= '7')
#define OCTVAL(CH) ((CH) - '0')
/*
* PQunescapeBytea - converts the null terminated string representation
* of a bytea, strtext, into binary, filling a buffer. It returns a
* pointer to the buffer (or NULL on error), and the size of the
* buffer in retbuflen. The pointer may subsequently be used as an
* argument to the function free(3). It is the reverse of PQescapeBytea.
*
* The following transformations are made:
* \\ == ASCII 92 == \
* \ooo == a byte whose value = ooo (ooo is an octal number)
* \x == x (x is any character not matched by the above transformations)
*/
unsigned char *
PQunescapeBytea(const unsigned char *strtext, size_t *retbuflen)
{
size_t strtextlen,
buflen;
unsigned char *buffer,
*tmpbuf;
size_t i,
j;
if (strtext == NULL)
return NULL;
strtextlen = strlen(strtext);
/*
* Length of input is max length of output, but add one to avoid
* unportable malloc(0) if input is zero-length.
*/
buffer = (unsigned char *) malloc(strtextlen + 1);
if (buffer == NULL)
return NULL;
for (i = j = 0; i < strtextlen;)
{
switch (strtext[i])
{
case '\\':
i++;
if (strtext[i] == '\\')
buffer[j++] = strtext[i++];
else
{
if ((ISFIRSTOCTDIGIT(strtext[i])) &&
(ISOCTDIGIT(strtext[i + 1])) &&
(ISOCTDIGIT(strtext[i + 2])))
{
int byte;
byte = OCTVAL(strtext[i++]);
byte = (byte << 3) + OCTVAL(strtext[i++]);
byte = (byte << 3) + OCTVAL(strtext[i++]);
buffer[j++] = byte;
}
}
/*
* Note: if we see '\' followed by something that isn't a
* recognized escape sequence, we loop around having done
* nothing except advance i. Therefore the something will
* be emitted as ordinary data on the next cycle. Corner
* case: '\' at end of string will just be discarded.
*/
break;
default:
buffer[j++] = strtext[i++];
break;
}
}
buflen = j; /* buflen is the length of the dequoted
* data */
/* Shrink the buffer to be no larger than necessary */
/* +1 avoids unportable behavior when buflen==0 */
tmpbuf = realloc(buffer, buflen + 1);
/* It would only be a very brain-dead realloc that could fail, but... */
if (!tmpbuf)
{
free(buffer);
return NULL;
}
*retbuflen = buflen;
return tmpbuf;
}
#endif /* USE_VERSION < 73 */
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