Re: [PATCH] (Minor) Bugfixes to vsprintf.c, vsscanf().

[johan verrept <johan.verrept@pandora.be>]

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johan verrept wrote:
> 
> hello,
> 
> minor bugfix for vsprintf.c, vsscanf did not discard whitespace in input:
> - when encoutering whitespace in fmt not followed by '%'
> - in conversion where result is ignored with '*'
> 
> There is another bugfix in this, don't know from who. (picked it up with uml)
> (vsscanf used to skip two characters in the fmt for a single char in the input if not in
> conversion.)
> 
> Patch against 2.4.12, I am afraid.

Attached patch is beter. Both bugs are fixed and it adds fieldwidth support for conversions with
ignored results.
Again against 2.4.12.

	J.

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--- linux-2.4.12-clean/lib/vsprintf.c	Sun Sep 16 20:26:10 2001
+++ linux-2.4.12-devel/lib/vsprintf.c	Thu Oct 18 03:06:47 2001
@@ -525,12 +525,15 @@
 	for (; *fmt; fmt++) {
 		/* skip any white space in format */
 		if (isspace(*fmt)) {
+			/* space in fmt skips all space in input */
+			while (isspace(*str)) str++;
 			continue;
 		}
 
 		/* anything that is not a conversion must match exactly */
 		if (*fmt != '%') {
-			if (*fmt++ != *str++)
+			/* Don't bump fmt because the for header will do it */
+			if (*fmt != *str++)
 				return num;
 			continue;
 		}
@@ -540,10 +543,25 @@
 		 * advance both strings to next white space
 		 */
 		if (*fmt == '*') {
-			while (!isspace(*fmt))
+			fmt++;
+			/* get fieldwidth */
+			field_width = 0xffffffffUL;
+			if (isdigit(*fmt))
+				field_width = skip_atoi(&fmt);
+
+			/* skip possible conversion qualifier */
+			if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' || *fmt == 'Z')
 				fmt++;
-			while(!isspace(*str))
+
+			/* do not skip conversion char, the for loop will do this */
+
+			/* eat all whitespace before conversion! */
+			while(isspace(*str))
+				str++;
+			while(!isspace(*str) && field_width) {
+				field_width--;
 				str++;
+			}
 			continue;
 		}