From 31f59855b4811c6ace7ae5051f7873b602208d77 Mon Sep 17 00:00:00 2001
From: Tim Schumacher <timschumi@gmx.de>
Date: Sun, 29 Jan 2023 13:05:06 +0100
Subject: [PATCH] AK: Don't restore the stream offset when failing to read an
 LEB128

Pretty much no other read function does this, and getting rid of the
typename template parameter for the stream makes the transition to the
new AK::Stream a bit easier.
---
 AK/LEB128.h | 37 ++++++++++++-------------------------
 1 file changed, 12 insertions(+), 25 deletions(-)

diff --git a/AK/LEB128.h b/AK/LEB128.h
index f9258fd866..6f550ff26d 100644
--- a/AK/LEB128.h
+++ b/AK/LEB128.h
@@ -13,26 +13,19 @@
 namespace AK {
 
 struct LEB128 {
-    template<typename StreamT, typename ValueType = size_t>
-    static bool read_unsigned(StreamT& stream, ValueType& result)
+    template<typename ValueType = size_t>
+    static bool read_unsigned(DeprecatedInputStream& stream, ValueType& result)
     {
-        [[maybe_unused]] size_t backup_offset = 0;
-        if constexpr (requires { stream.offset(); })
-            backup_offset = stream.offset();
-        DeprecatedInputStream& input_stream { stream };
-
         result = 0;
         size_t num_bytes = 0;
         while (true) {
-            if (input_stream.unreliable_eof()) {
-                if constexpr (requires { stream.seek(backup_offset); })
-                    stream.seek(backup_offset);
-                input_stream.set_fatal_error();
+            if (stream.unreliable_eof()) {
+                stream.set_fatal_error();
                 return false;
             }
             u8 byte = 0;
-            input_stream >> byte;
-            if (input_stream.has_any_error())
+            stream >> byte;
+            if (stream.has_any_error())
                 return false;
 
             ValueType masked_byte = byte & ~(1 << 7);
@@ -53,16 +46,12 @@ struct LEB128 {
         return true;
     }
 
-    template<typename StreamT, typename ValueType = ssize_t>
-    static bool read_signed(StreamT& stream, ValueType& result)
+    template<typename ValueType = ssize_t>
+    static bool read_signed(DeprecatedInputStream& stream, ValueType& result)
     {
         // Note: We read into a u64 to simplify the parsing logic;
         //    result is range checked into ValueType after parsing.
         static_assert(sizeof(ValueType) <= sizeof(u64), "Error checking logic assumes 64 bits or less!");
-        [[maybe_unused]] size_t backup_offset = 0;
-        if constexpr (requires { stream.offset(); })
-            backup_offset = stream.offset();
-        DeprecatedInputStream& input_stream { stream };
 
         i64 temp = 0;
         size_t num_bytes = 0;
@@ -70,15 +59,13 @@ struct LEB128 {
         result = 0;
 
         do {
-            if (input_stream.unreliable_eof()) {
-                if constexpr (requires { stream.seek(backup_offset); })
-                    stream.seek(backup_offset);
-                input_stream.set_fatal_error();
+            if (stream.unreliable_eof()) {
+                stream.set_fatal_error();
                 return false;
             }
 
-            input_stream >> byte;
-            if (input_stream.has_any_error())
+            stream >> byte;
+            if (stream.has_any_error())
                 return false;
 
             // note: 64 bit assumptions!