util: remove unused IsHexNumber

The relevant unit tests have been incorporated in
uint256_tests/from_user_hex in a previous commit.

Author: stickies-v

src/test/fuzz/hex.cpp

@@ -27,7 +27,6 @@ FUZZ_TARGET(hex)
     if (IsHex(random_hex_string)) {
         assert(ToLower(random_hex_string) == hex_data);
     }
-    (void)IsHexNumber(random_hex_string);
     if (uint256::FromHex(random_hex_string)) {
         assert(random_hex_string.length() == 64);
         assert(Txid::FromHex(random_hex_string));

src/test/util_tests.cpp

@@ -432,31 +432,6 @@ BOOST_AUTO_TEST_CASE(util_IsHex)
     BOOST_CHECK(!IsHex("0x0000"));
 }
 
-BOOST_AUTO_TEST_CASE(util_IsHexNumber)
-{
-    BOOST_CHECK(IsHexNumber("0x0"));
-    BOOST_CHECK(IsHexNumber("0"));
-    BOOST_CHECK(IsHexNumber("0x10"));
-    BOOST_CHECK(IsHexNumber("10"));
-    BOOST_CHECK(IsHexNumber("0xff"));
-    BOOST_CHECK(IsHexNumber("ff"));
-    BOOST_CHECK(IsHexNumber("0xFfa"));
-    BOOST_CHECK(IsHexNumber("Ffa"));
-    BOOST_CHECK(IsHexNumber("0x00112233445566778899aabbccddeeffAABBCCDDEEFF"));
-    BOOST_CHECK(IsHexNumber("00112233445566778899aabbccddeeffAABBCCDDEEFF"));
-
-    BOOST_CHECK(!IsHexNumber(""));   // empty string not allowed
-    BOOST_CHECK(!IsHexNumber("0x")); // empty string after prefix not allowed
-    BOOST_CHECK(!IsHexNumber("0x0 ")); // no spaces at end,
-    BOOST_CHECK(!IsHexNumber(" 0x0")); // or beginning,
-    BOOST_CHECK(!IsHexNumber("0x 0")); // or middle,
-    BOOST_CHECK(!IsHexNumber(" "));    // etc.
-    BOOST_CHECK(!IsHexNumber("0x0ga")); // invalid character
-    BOOST_CHECK(!IsHexNumber("x0"));    // broken prefix
-    BOOST_CHECK(!IsHexNumber("0x0x00")); // two prefixes not allowed
-
-}
-
 BOOST_AUTO_TEST_CASE(util_seed_insecure_rand)
 {
     SeedRandomForTest(SeedRand::ZEROS);

src/util/strencodings.cpp

@@ -46,16 +46,6 @@ bool IsHex(std::string_view str)
     return (str.size() > 0) && (str.size()%2 == 0);
 }
 
-bool IsHexNumber(std::string_view str)
-{
-    if (str.substr(0, 2) == "0x") str.remove_prefix(2);
-    for (char c : str) {
-        if (HexDigit(c) < 0) return false;
-    }
-    // Return false for empty string or "0x".
-    return str.size() > 0;
-}
-
 template <typename Byte>
 std::optional<std::vector<Byte>> TryParseHex(std::string_view str)
 {

src/util/strencodings.h

@@ -70,10 +70,6 @@ std::vector<Byte> ParseHex(std::string_view hex_str)
 /* Returns true if each character in str is a hex character, and has an even
  * number of hex digits.*/
 bool IsHex(std::string_view str);
-/**
-* Return true if the string is a hex number, optionally prefixed with "0x"
-*/
-bool IsHexNumber(std::string_view str);
 std::optional<std::vector<unsigned char>> DecodeBase64(std::string_view str);
 std::string EncodeBase64(Span<const unsigned char> input);
 inline std::string EncodeBase64(Span<const std::byte> input) { return EncodeBase64(MakeUCharSpan(input)); }