Lonely Patch Seeks Long-Term Commitment to Codebase - Mailing list pgsql-patches

Hi,

I sent a patch to this list earlier this month to improve the speed of
PGunescapeBytea(). IMHO it is handicapped as it can take over a minute
to process a large amount of data, e.g. a 500Kb JPEG.

The attached patch replaces the sscanf function that causes the delay,
the code was borrowed from the PostgreSQL Python interface with
permission from the author.

Please could I have some feedback on whether the patch is likely to be
committed? Has it been rejected? Is it stuck on someone's TODO list? Was
the code unsuitable? Have I neglected some procedure, etc?

Best regards,

Ben Lamb.
--- fe-exec.c    Thu May  8 11:49:34 2003
+++ fe-exec.c.latest    Thu May  8 11:45:17 2003
@@ -180,6 +180,8 @@
     return result;
 }

+#define VAL(CH) ((CH) - '0')
+
 /*
  *        PQunescapeBytea - converts the null terminated string representation
  *        of a bytea, strtext, into binary, filling a buffer. It returns a
@@ -187,101 +189,66 @@
  *        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 == \\
+ *        The following transformations are made:
+ *        \'   == ASCII 39 == '
+ *        \\   == 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)
  *
- *        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;
+    size_t strtextlen, buflen;
+    unsigned char *buffer, *tmpbuf;
+    int i, j, byte;

-    if (strtext == NULL)
+    if (strtext == NULL) {
         return NULL;
-    buflen = strlen(strtext);    /* will shrink, also we discover if
-                                 * strtext */
-    buffer = (unsigned char *) malloc(buflen);    /* isn't NULL terminated */
+    }
+
+    strtextlen = strlen(strtext);    /* will shrink, also we discover if
+                                     * strtext isn't NULL terminated */
+    buffer = (unsigned char *)malloc(strtextlen);
     if (buffer == NULL)
         return NULL;
-    for (bp = buffer, sp = strtext; *sp != '\0'; bp++, sp++)
+
+    for (i = j = buflen = 0; i < strtextlen;)
     {
-        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])))
+                    {
+                        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);
-    if (buffer == NULL)
-        return NULL;
+    buflen = j; /* buflen is the length of the unquoted data */
+    tmpbuf = realloc(buffer, buflen);
+
+    if (!tmpbuf)
+    {
+        free(buffer);
+        return 0;
+    }

     *retbuflen = buflen;
-    return buffer;
+    return tmpbuf;
 }

 /* ----------------