[libc-commits] [libc] [libc] Add inet_ntop (PR #204143)

[Jeff Bailey via libc-commits]

================
@@ -61,5 +68,160 @@ cpp::optional<in_addr_t> inet_addr(const char *cp) {
   return Endian::to_big_endian(result);
 }
 
+namespace {
+
+size_t ipv4_num_bytes(cpp::span<const uint8_t> src) {
+  size_t result = 8; // four digits, three dots and '\0'
+  for (unsigned i = 0; i < 4; ++i)
+    result += (src[i] >= 10) + (src[i] >= 100);
+  return result;
+}
+
+size_t ipv4_to_str_unchecked(cpp::span<const uint8_t> src,
+                             cpp::span<char> dst) {
+  size_t pos = 0;
----------------
kaladron wrote:

I haven't checked our std::span implementation, but doing something like this:

```c++
if (src.size() < 4 || dst.size() < 16) {
        return 0;
}
```

May allow the compiler to eliminate the bounds checks done by the span.

https://github.com/llvm/llvm-project/pull/204143