Merge pull request #7234 from michtesar/fix/net-percent-encode

Fix percent encoding for bytes < 0x10

core/net/url.odin

@@ -19,7 +19,6 @@ package net
 */
 
 import "core:strings"
-import "core:strconv"
 import "core:unicode/utf8"
 import "core:encoding/hex"
 
@@ -114,6 +113,8 @@ join_url :: proc(scheme, host, path: string, queries: map[string]string, fragmen
 }
 
 percent_encode :: proc(s: string, allocator := context.allocator) -> string {
+	HEX_DIGITS_UPPER := "0123456789ABCDEF" // NOTE(michtesar): RFC 3986 §2.1
+
 	b := strings.builder_make(allocator)
 	strings.builder_grow(&b, len(s) + 16) // NOTE(tetra): A reasonable number to allow for the number of things we need to escape.
 
@@ -124,10 +125,9 @@ percent_encode :: proc(s: string, allocator := context.allocator) -> string {
 		case:
 			bytes, n := utf8.encode_rune(ch)
 			for byte in bytes[:n] {
-				buf: [2]u8 = ---
-				t := strconv.write_int(buf[:], i64(byte), 16)
-				strings.write_rune(&b, '%')
-				strings.write_string(&b, t)
+				strings.write_byte(&b, '%')
+				strings.write_byte(&b, HEX_DIGITS_UPPER[byte >> 4])
+				strings.write_byte(&b, HEX_DIGITS_UPPER[byte & 0xF])
 			}
 		}
 	}

tests/core/net/test_core_net.odin

@@ -525,6 +525,36 @@ join_url_test :: proc(t: ^testing.T) {
 	}
 }
 
+@test
+percent_encode_test :: proc(t: ^testing.T) {
+	test_cases := []struct{input, expected: string} {
+		// Bytes < 0x10 must be zero-padded to two hex digits
+		{"\n",   "%0A"},
+		{"\t",   "%09"},
+		{"\r",   "%0D"},
+		{"a\nb", "a%0Ab"},
+		{"\x00", "%00"},
+
+		// Bytes >= 0x10
+		{" ",    "%20"},
+		{"😃",   "%F0%9F%98%83"},
+
+		// Unreserved characters pass through unescaped
+		{"AZaz09-_.~", "AZaz09-_.~"},
+	}
+
+	for test in test_cases {
+		encoded := net.percent_encode(test.input)
+		defer delete(encoded)
+		testing.expectf(t, encoded == test.expected, "Expected `net.percent_encode(%q)` to return %q, got %q", test.input, test.expected, encoded)
+
+		decoded, ok := net.percent_decode(encoded)
+		defer delete(decoded)
+		testing.expectf(t, ok, "Expected `net.percent_decode(%q)` to succeed", encoded)
+		testing.expectf(t, decoded == test.input, "Expected percent-encoding roundtrip for %q, got %q", test.input, decoded)
+	}
+}
+
 @test
 test_udp_echo :: proc(t: ^testing.T) {
 	endpoint := net.Endpoint{address=net.IP4_Address{127, 0, 0, 1}, port=0}