X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=interpolate.c;h=7f03bd99c5b66afa6cc7fa11a2430301a3042656;hb=2b6f0b0a78a713be51149f27c2c1172fe4afc9cd;hp=fb30694f4741147bba62350f704111d3afbf8133;hpb=8a3fbdd9e6c37c74b12fd0e8bd7cde8372861288;p=git.git

diff --git a/interpolate.c b/interpolate.c
index fb30694f4..7f03bd99c 100644
--- a/interpolate.c
+++ b/interpolate.c
@@ -11,8 +11,7 @@ void interp_set_entry(struct interp *table, int slot, const char *value)
 	char *oldval = table[slot].value;
 	char *newval = NULL;
 
-	if (oldval)
-		free(oldval);
+	free(oldval);
 
 	if (value)
 		newval = xstrdup(value);
@@ -44,63 +43,61 @@ void interp_clear_table(struct interp *table, int ninterps)
  *        { "%%", "%"},
  *    }
  *
- * Returns 1 on a successful substitution pass that fits in result,
- * Returns 0 on a failed or overflowing substitution pass.
+ * Returns the length of the substituted string (not including the final \0).
+ * Like with snprintf, if the result is >= reslen, then it overflowed.
  */
 
-int interpolate(char *result, int reslen,
+unsigned long interpolate(char *result, unsigned long reslen,
 		const char *orig,
 		const struct interp *interps, int ninterps)
 {
 	const char *src = orig;
 	char *dest = result;
-	int newlen = 0;
+	unsigned long newlen = 0;
 	const char *name, *value;
-	int namelen, valuelen;
+	unsigned long namelen, valuelen;
 	int i;
 	char c;
 
-        memset(result, 0, reslen);
-
-	while ((c = *src) && newlen < reslen - 1) {
+	while ((c = *src)) {
 		if (c == '%') {
 			/* Try to match an interpolation string. */
 			for (i = 0; i < ninterps; i++) {
 				name = interps[i].name;
 				namelen = strlen(name);
-				if (strncmp(src, name, namelen) == 0) {
+				if (strncmp(src, name, namelen) == 0)
 					break;
-				}
 			}
 
 			/* Check for valid interpolation. */
 			if (i < ninterps) {
 				value = interps[i].value;
-				valuelen = strlen(value);
+				if (!value) {
+					src += namelen;
+					continue;
+				}
 
-				if (newlen + valuelen < reslen - 1) {
+				valuelen = strlen(value);
+				if (newlen + valuelen < reslen) {
 					/* Substitute. */
-					strncpy(dest, value, valuelen);
-					newlen += valuelen;
+					memcpy(dest, value, valuelen);
 					dest += valuelen;
-					src += namelen;
-				} else {
-					/* Something's not fitting. */
-					return 0;
 				}
-
-			} else {
-				/* Skip bogus interpolation. */
-				*dest++ = *src++;
-				newlen++;
+				newlen += valuelen;
+				src += namelen;
+				continue;
 			}
-
-		} else {
-			/* Straight copy one non-interpolation character. */
-			*dest++ = *src++;
-			newlen++;
 		}
+		/* Straight copy one non-interpolation character. */
+		if (newlen + 1 < reslen)
+			*dest++ = *src;
+		src++;
+		newlen++;
 	}
 
-	return newlen < reslen - 1;
+	/* 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;
 }