X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=interpolate.c;h=6ef53f246511a1943e375d5d5913a4ec52e2c663;hb=8e9739914972419baad820e76b44d9720ed885c2;hp=00826778fc3d760a9b001423cd9c26e7972c126f;hpb=ee4fd1adfda5b6ebde93b289227986bf884babab;p=git.git

diff --git a/interpolate.c b/interpolate.c
index 00826778f..6ef53f246 100644
--- a/interpolate.c
+++ b/interpolate.c
@@ -44,9 +44,8 @@ void interp_clear_table(struct interp *table, int ninterps)
  *        { "%%", "%"},
  *    }
  *
- * Returns 0 on a successful substitution pass that fits in result,
- * Returns a number of bytes needed to hold the full substituted
- * string otherwise.
+ * Returns the length of the substituted string (not including the final \0).
+ * Like with snprintf, if the result is >= reslen, then it overflowed.
  */
 
 unsigned long interpolate(char *result, unsigned long reslen,
@@ -61,8 +60,6 @@ unsigned long interpolate(char *result, unsigned long reslen,
 	int i;
 	char c;
 
-        memset(result, 0, reslen);
-
 	while ((c = *src)) {
 		if (c == '%') {
 			/* Try to match an interpolation string. */
@@ -76,11 +73,15 @@ unsigned long interpolate(char *result, unsigned long reslen,
 			/* Check for valid interpolation. */
 			if (i < ninterps) {
 				value = interps[i].value;
-				valuelen = strlen(value);
+				if (!value) {
+					src += namelen;
+					continue;
+				}
 
-				if (newlen + valuelen + 1 < reslen) {
+				valuelen = strlen(value);
+				if (newlen + valuelen < reslen) {
 					/* Substitute. */
-					strncpy(dest, value, valuelen);
+					memcpy(dest, value, valuelen);
 					dest += valuelen;
 				}
 				newlen += valuelen;
@@ -95,8 +96,9 @@ unsigned long interpolate(char *result, unsigned long reslen,
 		newlen++;
 	}
 
-	if (newlen + 1 < reslen)
-		return 0;
-	else
-		return newlen + 2;
+	/* XXX: the previous loop always keep room for the ending NUL,
+	   we just need to check if there was room for a NUL in the first place */
+	if (reslen > 0)
+		*dest = '\0';
+	return newlen;
 }