utils: replace hex_to_u64 with std::from_chars

Author: oltolm

rpcs3/Crypto/key_vault.cpp

@@ -11,10 +11,10 @@ SELF_KEY::SELF_KEY(u64 ver_start, u64 ver_end, u16 rev, u32 type, const std::str
 	version_end   = ver_end;
 	revision      = rev;
 	self_type     = type;
-	hex_to_bytes(erk, e.c_str(), 0);
-	hex_to_bytes(riv, r.c_str(), 0);
-	hex_to_bytes(pub, pb.c_str(), 0);
-	hex_to_bytes(priv, pr.c_str(), 0);
+	hex_to_bytes(erk, e, 0);
+	hex_to_bytes(riv, r, 0);
+	hex_to_bytes(pub, pb, 0);
+	hex_to_bytes(priv, pr, 0);
 	curve_type = ct;
 }
 

rpcs3/Crypto/utils.cpp

@@ -7,9 +7,11 @@
 #include "sha1.h"
 #include "sha256.h"
 #include "key_vault.h"
+#include <charconv>
+#include <cstdlib>
 #include <cstring>
-#include <stdio.h>
-#include <time.h>
+#include <cstdio>
+#include <ctime>
 #include "Utilities/StrUtil.h"
 #include "Utilities/File.h"
 
@@ -21,50 +23,24 @@
 // Auxiliary functions (endian swap, xor).
 
 // Hex string conversion auxiliary functions.
-u64 hex_to_u64(const char* hex_str)
+void hex_to_bytes(unsigned char* data, std::string_view hex_str, unsigned int str_length)
 {
-	auto length = std::strlen(hex_str);
-	u64 tmp = 0;
-	u64 result = 0;
-	char c;
-
-	while (length--)
-	{
-		c = *hex_str++;
-		if((c >= '0') && (c <= '9'))
-			tmp = c - '0';
-		else if((c >= 'a') && (c <= 'f'))
-			tmp = c - 'a' + 10;
-		else if((c >= 'A') && (c <= 'F'))
-			tmp = c - 'A' + 10;
-		else
-			tmp = 0;
-		result |= (tmp << (length * 4));
-	}
-
-	return result;
-}
-
-void hex_to_bytes(unsigned char* data, const char* hex_str, unsigned int str_length)
-{
-	const auto strn_length = (str_length > 0) ? str_length : std::strlen(hex_str);
-	auto data_length = strn_length / 2;
-	char tmp_buf[3] = {0, 0, 0};
+	const auto strn_length = (str_length > 0) ? str_length : hex_str.size();
 
 	// Don't convert if the string length is odd.
 	if ((strn_length % 2) == 0)
 	{
-		while (data_length--)
+		for (size_t i = 0; i < strn_length; i += 2)
 		{
-			tmp_buf[0] = *hex_str++;
-			tmp_buf[1] = *hex_str++;
-
-			*data++ = static_cast<u8>(hex_to_u64(tmp_buf) & 0xFF);
+			const auto [ptr, err] = std::from_chars(hex_str.data() + i, hex_str.data() + i + 2, *data++, 16);
+			if (err != std::errc())
+			{
+				fmt::throw_exception("Failed to read hex string: %s", std::make_error_code(err).message());
+			}
 		}
 	}
 }
 
-
 // Crypto functions (AES128-CBC, AES128-ECB, SHA1-HMAC and AES-CMAC).
 void aescbc128_decrypt(unsigned char *key, unsigned char *iv, unsigned char *in, unsigned char *out, usz len)
 {

rpcs3/Crypto/utils.h

@@ -6,7 +6,8 @@
 
 #include "util/types.hpp"
 
-#include <stdlib.h>
+#include <cstdlib>
+#include <string_view>
 
 enum { CRYPTO_MAX_PATH = 4096 };
 
@@ -15,8 +16,7 @@ char* extract_file_name(const char* file_path, char real_file_name[CRYPTO_MAX_PA
 std::string sha256_get_hash(const char* data, usz size, bool lower_case);
 
 // Hex string conversion auxiliary functions.
-u64 hex_to_u64(const char* hex_str);
-void hex_to_bytes(unsigned char *data, const char *hex_str, unsigned int str_length);
+void hex_to_bytes(unsigned char* data, std::string_view hex_str, unsigned int str_length);
 
 // Crypto functions (AES128-CBC, AES128-ECB, SHA1-HMAC and AES-CMAC).
 void aescbc128_decrypt(unsigned char *key, unsigned char *iv, unsigned char *in, unsigned char *out, usz len);