[GRASS5] g.region G_usage() commented out?

[Russell Nelson]

Glynn Clements writes:
 > AFAICT, the code appears to be ensuring that the code processes the
 > entire string, and not just some initial portion of it.

But tbuf[] is filled by copying characters from buf up to the first
null.  Therefore, buf cannot contain any embedded nulls, and
strlen(buf) is going to be equal to strchr(tbuf, MARKER) - tbuf every
time.  So why not just run up to the null?  The only reason I can see
to have MARKER would be if you wanted to safely look at buf[i] and
buf[i+1] without first checking to see if buf[i] is a '\0'.  The
original code didn't do that, but ahhhh, I see that I have introduced
a potential segfault.  Revised patch, which actually is simpler and
easier to understand:

Index: src/libes/gis/ll_scan.c
===================================================================
RCS file: /home/grass/grassrepository/grass/src/libes/gis/ll_scan.c,v
retrieving revision 1.1.1.1
diff -u -r1.1.1.1 ll_scan.c
--- src/libes/gis/ll_scan.c	29 Dec 1999 15:10:30 -0000	1.1.1.1
+++ src/libes/gis/ll_scan.c	20 May 2002 13:49:13 -0000
@@ -53,13 +53,9 @@
 
 int G_llres_scan ( char *buf, double *res)
 {
-    char tbuf[100];
-
-    sprintf (tbuf, "%se", buf);
-    return scan_ll (tbuf, "we", res, 0);
+    return scan_ll (buf, NULL, res, 0);
 }
 
-#define MARKER 1
 static int scan_ll (
     char *buf,
     char *dir,
@@ -70,10 +66,6 @@
     int d,m,s;
     char ps[20], *pps;
     double p, f;
-    char tbuf[100];
-
-    sprintf (tbuf, "%s%c", buf, MARKER); /* add a marker at end of string */
-    buf = tbuf;
 
     if (sscanf (buf, "%d:%d:%d.%[0123456789]%[^\n]", &d, &m, &s, ps, h) == 5)
     {
@@ -117,13 +109,16 @@
 
     G_strip (h);
 
-    if (*result == 0.0 && *h == MARKER)
+    if (*result == 0.0 && *h == '\0')
 	return (1);
 
+    if (dir == NULL)
+        return *h == '\0';
+
     if (*h >= 'A' && *h <= 'Z') *h += 'a' - 'A';
     if (*h != dir[0] && *h != dir[1])
 	return 0;
-    if (h[1] != MARKER)
+    if (h[1] != '\0')
 	return 0;
 
     if (*h == dir[0] && *result != 0.0)


-- 
-russ nelson              http://russnelson.com | Nelson's principle: when
Crynwr sells support for free software  | PGPok | someone proposes a solution,
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