src: get rid of fp arithmetic in ParseIPv4Host

Even though most compiler should not actually emit FPU instructions, it
is unnecessary to use floating-point arithmetic for powers of 2.
Also change some signed counters to unsigned integers.
PR-URL: #46326
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: tniessen

src/node_url.cc

@@ -6,7 +6,6 @@
 #include"util-inl.h"
 
 #include<algorithm>
-#include<cmath>
 #include<cstdio>
 #include<numeric>
 #include<string>
@@ -477,19 +476,18 @@ void URLHost::ParseIPv4Host(const char* input, size_t length) {
 constchar* pointer = input;
 constchar* mark = input;
 constchar* end = pointer + length;
-int parts = 0;
+unsignedint parts = 0;
 uint32_t val = 0;
 uint64_t numbers[4];
-int tooBigNumbers = 0;
+unsignedint tooBigNumbers = 0;
 if (length == 0)
 return;
 
 while (pointer <= end) {
 constchar ch = pointer < end ? pointer[0] : kEOL;
 int64_t remaining = end - pointer - 1;
 if (ch == '.' || ch == kEOL) {
-if (++parts > static_cast<int>(arraysize(numbers)))
-return;
+if (++parts > arraysize(numbers)) return;
 if (pointer == mark)
 return;
 int64_t n = ParseIPv4Number(mark, pointer);
@@ -511,18 +509,15 @@ void URLHost::ParseIPv4Host(const char* input, size_t length) {
 // If any but the last item in numbers is greater than 255, return failure.
 // If the last item in numbers is greater than or equal to
 // 256^(5 - the number of items in numbers), return failure.
-if (tooBigNumbers > 1 ||
- (tooBigNumbers == 1 && numbers[parts - 1] <= 255) ||
- numbers[parts - 1] >= pow(256, static_cast<double>(5 - parts))) {
+if (tooBigNumbers > 1 || (tooBigNumbers == 1 && numbers[parts - 1] <= 255) ||
+ numbers[parts - 1] >= UINT64_C(1) << (8 * (5 - parts))) {
 return;
  }
 
  type_ = HostType::H_IPV4;
  val = static_cast<uint32_t>(numbers[parts - 1]);
-for (int n = 0; n < parts - 1; n++) {
-double b = 3 - n;
- val +=
-static_cast<uint32_t>(numbers[n]) * static_cast<uint32_t>(pow(256, b));
+for (unsignedint n = 0; n < parts - 1; n++) {
+ val += static_cast<uint32_t>(numbers[n]) << (8 * (3 - n));
  }
 
  value_.ipv4 = val;