change legacy_demangle to be more idiomatic C
the code used to be translated line-to-line from Rust iterators, change
it to be more idiomatic C and guarantee there is no weird for loop.
Fuzzing passes.
diff --git a/crates/native-c/src/demangle.c b/crates/native-c/src/demangle.c
index bb36fe4..b28baf6 100644
--- a/crates/native-c/src/demangle.c
+++ b/crates/native-c/src/demangle.c
@@ -1707,10 +1707,8 @@
if (chars_len == 0) {
return DemangleInvalid;
}
- char c = *chars++;
- chars_len--;
-
- while (c != 'E') {
+ char c;
+ while ((c = *chars) != 'E') {
// Decode an identifier element's length
if (c < '0' || c > '9') {
return DemangleInvalid;
@@ -1726,25 +1724,25 @@
return DemangleInvalid;
}
len += d;
+
+ chars++;
+ chars_len--;
if (chars_len == 0) {
return DemangleInvalid;
}
- c = *chars++;
- chars_len--;
+ c = *chars;
}
// Advance by the length
- for (size_t i = 0; i < len; i++) {
- if (chars_len == 0) {
- return DemangleInvalid;
- }
- c = *chars++;
- chars_len--;
+ if (chars_len <= len) {
+ return DemangleInvalid;
}
+ chars += len;
+ chars_len -= len;
elements++;
}
*res = (struct demangle_legacy) { inner, inner_len, elements };
- *rest = chars;
+ *rest = chars + 1;
return DemangleOk;
}
