Index: fe-exec.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/interfaces/libpq/fe-exec.c,v
retrieving revision 1.113
diff -c -r1.113 fe-exec.c
*** fe-exec.c	2001/10/25 05:50:13	1.113
--- fe-exec.c	2001/12/28 01:45:34
***************
*** 180,185 ****
--- 180,274 ----
  	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.
   *
Index: libpq-fe.h
===================================================================
RCS file: /projects/cvsroot/pgsql/src/interfaces/libpq/libpq-fe.h,v
retrieving revision 1.80
diff -c -r1.80 libpq-fe.h
*** libpq-fe.h	2001/11/08 20:37:52	1.80
--- libpq-fe.h	2001/12/28 01:45:35
***************
*** 252,257 ****
--- 252,260 ----
  extern size_t PQescapeString(char *to, const char *from, size_t length);
  extern unsigned char *PQescapeBytea(unsigned char *bintext, size_t binlen,
  			  size_t *bytealen);
+ extern unsigned char *PQunescapeBytea(unsigned char *strtext,
+ 			  size_t *retbuflen);
+ 
  
  /* Simple synchronous query */
  extern PGresult *PQexec(PGconn *conn, const char *query);
Index: libpq.sgml
===================================================================
RCS file: /projects/cvsroot/pgsql/doc/src/sgml/libpq.sgml,v
retrieving revision 1.84
diff -c -r1.84 libpq.sgml
*** libpq.sgml	2001/11/29 16:01:15	1.84
--- libpq.sgml	2001/12/28 01:47:16
***************
*** 950,955 ****
--- 950,974 ----
     character is also added.  The single quotes that must surround
     PostgreSQL string literals are not part of the result string.
    </para>
+ 
+   <para>
+    <function>PQunescapeBytea</function>
+    Converts an escaped string representation of binary data into binary
+    data - the reverse of <function>PQescapeBytea</function>.
+    <synopsis>
+     unsigned char *PQunescapeBytea(unsigned char *from, size_t *to_length);
+    </synopsis>
+ 
+    The <paramater>from</parameter> parameter points to an escaped string
+    such as might be returned by <function>PQgetvalue</function> of a
+    <type>BYTEA</type> column. <function>PQunescapeBytea</function> converts
+    this NUL terminated string representation into binary, filling a buffer.
+    It returns a pointer to the buffer which is NULL on error, and the size
+    of the buffer in <parameter>to_length</parameter>. The pointer may
+    subsequently be used as an argument to the function
+    <function>free(3)</function>.
+   </para>
+    
   </sect2>