Move symol length check out of rebinding loop (#27)
The symbol length check is loop invariant code, and so can be done
once before looping over the rebindings.
Also, replaces `str_longer` with `strnlen`.
This optimization was the work of @ocrickard in
https://github.com/facebook/fishhook/pull/26
diff --git a/fishhook.c b/fishhook.c
index 405053a..e8bec3a 100644
--- a/fishhook.c
+++ b/fishhook.c
@@ -76,15 +76,6 @@
return 0;
}
-static bool str_longer(const char *symbol, size_t len) {
- for (size_t i = 0; i <= len; i++) {
- if (symbol[i] == 0) {
- return false;
- }
- }
- return true;
-}
-
static void perform_rebinding_with_section(struct rebindings_entry *rebindings,
section_t *section,
intptr_t slide,
@@ -101,11 +92,13 @@
}
uint32_t strtab_offset = symtab[symtab_index].n_un.n_strx;
char *symbol_name = strtab + strtab_offset;
+ if (strnlen(symbol_name, 2) < 2) {
+ continue;
+ }
struct rebindings_entry *cur = rebindings;
while (cur) {
for (uint j = 0; j < cur->rebindings_nel; j++) {
- if (str_longer(symbol_name, 1) &&
- strcmp(&symbol_name[1], cur->rebindings[j].name) == 0) {
+ if (strcmp(&symbol_name[1], cur->rebindings[j].name) == 0) {
if (cur->rebindings[j].replaced != NULL &&
indirect_symbol_bindings[i] != cur->rebindings[j].replacement) {
*(cur->rebindings[j].replaced) = indirect_symbol_bindings[i];
