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Add PQunescapeBytea libpq function.

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Everyone using libpq and bytea is probably having to invent this wheel..

Patrick Welche
This commit is contained in:
Bruce Momjian
2002-03-04 23:59:14 +00:00
parent b2aade0e4b
commit 294f0d4bd6
4 changed files with 137 additions and 25 deletions
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91
src/interfaces/libpq/fe-exec.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-exec.c,v 1.113 2001/10/25 05:50:13 momjian Exp $
* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-exec.c,v 1.114 2002/03/04 23:59:14 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -180,6 +180,95 @@ PQescapeBytea(unsigned char *bintext, size_t binlen, size_t *bytealen)
return result;
}
/*
* PQunescapeBytea - converts the null terminated string representation
* of a bytea, strtext, into binary, filling a buffer. It returns a
* pointer to the buffer which is 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 reversed:
* '\0' == ASCII 0 == \000
* '\'' == ASCII 39 == \'
* '\\' == ASCII 92 == \\
*
* States:
* 0 normal 0->1->2->3->4
* 1 \ 1->5
* 2 \0 1->6
* 3 \00
* 4 \000
* 5 \'
* 6 \\
*/
unsigned char *
PQunescapeBytea(unsigned char *strtext, size_t *retbuflen)
{
size_t buflen;
unsigned char *buffer, *sp, *bp;
unsigned int state=0;
if(strtext == NULL)return NULL;
buflen = strlen(strtext); /* will shrink, also we discover if strtext */
buffer = (unsigned char *) malloc(buflen); /* isn't NULL terminated */
if(buffer == NULL)return NULL;
for(bp = buffer, sp = strtext; *sp != '\0'; bp++, sp++)
{
switch(state)
{
case 0:
if(*sp == '\\')state=1;
*bp = *sp;
break;
case 1:
if(*sp == '\'') /* state=5 */
{ /* replace \' with 39 */
bp--;
*bp = 39;
buflen--;
state=0;
}
else if(*sp == '\\') /* state=6 */
{ /* replace \\ with 92 */
bp--;
*bp = 92;
buflen--;
state=0;
}
else
{
if(*sp == '0')state=2;
else state=0;
*bp = *sp;
}
break;
case 2:
if(*sp == '0')state=3;
else state=0;
*bp = *sp;
break;
case 3:
if(*sp == '0') /* state=4 */
{
bp -= 3;
*bp = 0;
buflen -= 3;
state=0;
}
else
{
*bp = *sp;
state=0;
}
break;
}
}
realloc(buffer,buflen);
*retbuflen=buflen;
return buffer;
}
/* ----------------
* Space management for PGresult.
*