From 15e592192773ea547d9f18f05cb357bc12d2befc Mon Sep 17 00:00:00 2001
From: orignal <i2porignal@yandex.ru>
Date: Tue, 16 Dec 2025 13:45:21 -0500
Subject: [PATCH] use std::from_chars in UrlDecode

---
 libi2pd/HTTP.cpp | 31 +++++++++++++++++++++----------
 libi2pd/HTTP.h   |  2 +-
 2 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/libi2pd/HTTP.cpp b/libi2pd/HTTP.cpp
index 8c7c8491..178ff797 100644
--- a/libi2pd/HTTP.cpp
+++ b/libi2pd/HTTP.cpp
@@ -536,21 +536,32 @@ namespace http
 		return ptr;
 	}
 
-	std::string UrlDecode(std::string_view data, bool allow_null)
+	std::string UrlDecode(std::string_view url, bool allow_null)
 	{
-		std::string decoded(data);
-		size_t pos = 0;
-		while ((pos = decoded.find('%', pos)) != std::string::npos)
+		std::string decoded;
+		decoded.reserve (url.length ());
+		size_t start = 0;
+		for (size_t i = 0; i < url.length (); i++)
 		{
-			char c = std::stol(decoded.substr(pos + 1, 2), nullptr, 16);
-			if (!c && !allow_null)
+			auto c = url[i];
+			if (c == '%')
 			{
-				pos += 3;
-				continue;
+				decoded.append (url, start, i - start); 
+				if (i + 2 <= url.length ())
+				{
+					char ch;
+					auto res = std::from_chars(url.data() + i + 1, url.data() + i + 3, ch, 16);
+					if (res.ec == std::errc())
+						decoded += ch;
+					i += 2;
+					start = i + 1;
+				}	
+				else
+					break;
 			}
-			decoded.replace(pos, 3, 1, c);
-			pos++;
 		}
+		if (start < url.length ())
+			decoded.append (url, start);
 		return decoded;
 	}
 
diff --git a/libi2pd/HTTP.h b/libi2pd/HTTP.h
index c65c1ce4..0055211b 100644
--- a/libi2pd/HTTP.h
+++ b/libi2pd/HTTP.h
@@ -160,7 +160,7 @@ namespace http
 	 * @param null If set to true - decode also %00 sequence, otherwise - skip
 	 * @return Decoded string
 	 */
-	std::string UrlDecode(std::string_view data, bool null = false);
+	std::string UrlDecode(std::string_view url, bool null = false);
 
 	/**
 	 * @brief Merge HTTP response content with Transfer-Encoding: chunked