Patch for PGunescapeBytea

--- fe-exec.c	Wed Apr 30 17:26:49 2003
+++ fe-exec.c.new	Thu May  1 19:41:38 2003
@@ -40,6 +40,7 @@
 };
 
 
+#define VAL(CH)  ((CH) - '0')
 /* Note: DONOTICE macro will work if applied to either PGconn or PGresult */
 #define DONOTICE(conn,message) \
 	((*(conn)->noticeHook) ((conn)->noticeArg, (message)))
@@ -186,29 +187,13 @@
  *		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;
+	unsigned char *buffer;
+	int i, j, byte;
 
 	if (strtext == NULL)
 		return NULL;
@@ -217,70 +202,40 @@
 	buffer = (unsigned char *) malloc(buflen);	/* isn't NULL terminated */
 	if (buffer == NULL)
 		return NULL;
-	for (bp = buffer, sp = strtext; *sp != '\0'; bp++, sp++)
+	
+	for (i = j = 0; i < buflen;)
 	{
-		switch (state)
+
+		switch (strtext[i])
 		{
-			case 0:
-				if (*sp == '\\')
-					state = 1;
-				*bp = *sp;
-				break;
-			case 1:
-				if (*sp == '\'')	/* state=5 */
-				{				/* replace \' with 39 */
-					bp--;
-					*bp = '\'';
-					buflen--;
-					state = 0;
-				}
-				else if (*sp == '\\')	/* state=6 */
-				{				/* replace \\ with 92 */
-					bp--;
-					*bp = '\\';
-					buflen--;
-					state = 0;
-				}
+			case '\\':
+				i++;
+				if (strtext[i] == '\\')
+					buffer[j++] = strtext[i++];
 				else
 				{
-					if (isdigit(*sp))
-						state = 2;
-					else
-						state = 0;
-					*bp = *sp;
+					if ((!isdigit(strtext[i])) ||
+					    (!isdigit(strtext[i+1])) ||
+					    (!isdigit(strtext[i+2])))
+						return NULL;
+
+					byte = VAL(strtext[i++]);
+					byte = (byte << 3) + VAL(strtext[i++]);	
+					buffer[j++] = (byte << 3) + VAL(strtext[i++]);
 				}
 				break;
-			case 2:
-				if (isdigit(*sp))
-					state = 3;
-				else
-					state = 0;
-				*bp = *sp;
-				break;
-			case 3:
-				if (isdigit(*sp))		/* state=4 */
-				{
-					int			v;
 
-					bp -= 3;
-					sscanf(sp - 2, "%03o", &v);
-					*bp = v;
-					buflen -= 3;
-					state = 0;
-				}
-				else
-				{
-					*bp = *sp;
-					state = 0;
-				}
-				break;
+			default:
+				buffer[j++] = strtext[i++];
 		}
 	}
-	buffer = realloc(buffer, buflen);
+
+	buffer[j] = (char)0;
+	buffer = realloc(buffer, j);
 	if (buffer == NULL)
 		return NULL;
 
-	*retbuflen = buflen;
+	*retbuflen = j;
 	return buffer;
 }

/*
 * testlibpq.c
 *		Test the C version of LIBPQ, the POSTGRES frontend library.
 *
 *
 */
#include <stdio.h>
#include "libpq-fe.h"

static void
exit_nicely(PGconn *conn)
{
	PQfinish(conn);
	exit(1);
}

int
main()
{
	char	   *pghost,
			   *pgport,
			   *pgoptions,
			   *pgtty;
	char	   *dbName;
	int			nFields;
	int			i,
				j;

	FILE	*image;
#ifdef DEBUG
	FILE	   *debug;
#endif   /* DEBUG */

	PGconn	   *conn;
	PGresult   *res;

	/*
	 * begin, by setting the parameters for a backend connection if the
	 * parameters are null, then the system will try to use reasonable
	 * defaults by looking up environment variables or, failing that,
	 * using hardwired constants
	 */
	pghost = NULL;				/* host name of the backend server */
	pgport = NULL;				/* port of the backend server */
	pgoptions = NULL;			/* special options to start up the backend
								 * server */
	pgtty = NULL;				/* debugging tty for the backend server */
	dbName = "ben";

	/* make a connection to the database */
	conn = PQsetdb(pghost, pgport, pgoptions, pgtty, dbName);

	/* check to see that the backend connection was successfully made */
	if (PQstatus(conn) == CONNECTION_BAD)
	{
		fprintf(stderr, "Connection to database '%s' failed.\n", dbName);
		fprintf(stderr, "%s", PQerrorMessage(conn));
		exit_nicely(conn);
	}

#ifdef DEBUG
	debug = fopen("/tmp/trace.out", "w");
	PQtrace(conn, debug);
#endif   /* DEBUG */

	/* start a transaction block */
	res = PQexec(conn, "BEGIN");
	if (PQresultStatus(res) != PGRES_COMMAND_OK)
	{
		fprintf(stderr, "BEGIN command failed\n");
		PQclear(res);
		exit_nicely(conn);
	}

	/*
	 * should PQclear PGresult whenever it is no longer needed to avoid
	 * memory leaks
	 */
	PQclear(res);

	/*
	 * fetch instances from the pg_database, the system catalog of
	 * databases
	 */
	res = PQexec(conn, "DECLARE myportal CURSOR FOR select picdata, location from est_houses WHERE id = 81");
	if (PQresultStatus(res) != PGRES_COMMAND_OK)
	{
		fprintf(stderr, "DECLARE CURSOR command failed\n");
		PQclear(res);
		exit_nicely(conn);
	}
	PQclear(res);

	res = PQexec(conn, "FETCH ALL in myportal");
	if (PQresultStatus(res) != PGRES_TUPLES_OK)
	{
		fprintf(stderr, "FETCH ALL command didn't return tuples properly\n");
		PQclear(res);
		exit_nicely(conn);
	}

	/* first, print out the attribute names */
	nFields = PQnfields(res);
	for (i = 0; i < nFields; i++)
		printf("%-15s", PQfname(res, i));
	printf("\n\n");

	/* next, print out the instances */
	for (i = 0; i < PQntuples(res); i++)
	{
		/* Write image to disk */
		char* bytea = PQgetvalue(res, i, 0);
		unsigned char* bytea_output;
		size_t bytea_size;
		printf("Attempting to decode bytea data...\n");
	        bytea_output = PQunescapeBytea((unsigned char*)bytea, &bytea_size);
		if (bytea_output != NULL)
		{
			printf("Writing image to disk...\n");
			image = fopen("test.jpg", "w");
			fwrite(bytea_output, bytea_size, 1, image);
			fclose(image);
			printf("Written image...\n");
			free(bytea_output, bytea_size);
		}

		for (j = 1; j < nFields; j++)
			printf("%-15s", PQgetvalue(res, i, j));
		printf("\n");
	}

	PQclear(res);

	/* close the portal */
	res = PQexec(conn, "CLOSE myportal");
	PQclear(res);

	/* end the transaction */
	res = PQexec(conn, "END");
	PQclear(res);

	/* close the connection to the database and cleanup */
	PQfinish(conn);

#ifdef DEBUG
	fclose(debug);
#endif   /* DEBUG */

	return 0;
}