From ea96e408fe794a2e218e4f263cb3d4209bbb9b4a Mon Sep 17 00:00:00 2001
From: Shauren <shauren.trinity@gmail.com>
Date: Sat, 3 Aug 2024 13:40:17 +0200
Subject: Core/PacketIO: Use std::string_view to read strings from ByteBuffer

(cherry picked from commit d72e91bee27f766c1f7e50640473522a07fc5389)
---
 src/server/shared/Packets/ByteBuffer.cpp | 36 +++++++++++++++++++-------------
 src/server/shared/Packets/ByteBuffer.h   |  6 +++---
 2 files changed, 24 insertions(+), 18 deletions(-)

(limited to 'src/server/shared')

diff --git a/src/server/shared/Packets/ByteBuffer.cpp b/src/server/shared/Packets/ByteBuffer.cpp
index 07a21a3e73a..a575e52bc1e 100644
--- a/src/server/shared/Packets/ByteBuffer.cpp
+++ b/src/server/shared/Packets/ByteBuffer.cpp
@@ -21,6 +21,7 @@
 #include "Log.h"
 #include "Util.h"
 #include <utf8.h>
+#include <algorithm>
 #include <sstream>
 #include <cmath>
 
@@ -33,7 +34,7 @@ ByteBufferPositionException::ByteBufferPositionException(size_t pos, size_t size
 {
 }
 
-ByteBufferInvalidValueException::ByteBufferInvalidValueException(char const* type, char const* value)
+ByteBufferInvalidValueException::ByteBufferInvalidValueException(char const* type, std::string_view value)
     : ByteBufferException(Trinity::StringFormat("Invalid {} value ({}) found in ByteBuffer", type, value))
 {
 }
@@ -54,34 +55,39 @@ ByteBuffer& ByteBuffer::operator>>(double& value)
     return *this;
 }
 
-std::string ByteBuffer::ReadCString(bool requireValidUtf8 /*= true*/)
+std::string_view ByteBuffer::ReadCString(bool requireValidUtf8 /*= true*/)
 {
-    std::string value;
-    while (rpos() < size())                         // prevent crash at wrong string format in packet
-    {
-        char c = read<char>();
-        if (c == 0)
-            break;
-        value += c;
-    }
+    if (_rpos >= size())
+        throw ByteBufferPositionException(_rpos, 1, size());
+
+    ResetBitPos();
+
+    char const* begin = reinterpret_cast<char const*>(_storage.data()) + _rpos;
+    char const* end = reinterpret_cast<char const*>(_storage.data()) + size();
+    char const* stringEnd = std::ranges::find(begin, end, '\0');
+    if (stringEnd == end)
+        throw ByteBufferPositionException(size(), 1, size());
+
+    std::string_view value(begin, stringEnd);
+    _rpos += value.length() + 1;
     if (requireValidUtf8 && !utf8::is_valid(value.begin(), value.end()))
-        throw ByteBufferInvalidValueException("string", value.c_str());
+        throw ByteBufferInvalidValueException("string", value);
     return value;
 }
 
-std::string ByteBuffer::ReadString(uint32 length, bool requireValidUtf8 /*= true*/)
+std::string_view ByteBuffer::ReadString(uint32 length, bool requireValidUtf8 /*= true*/)
 {
     if (_rpos + length > size())
         throw ByteBufferPositionException(_rpos, length, size());
 
     ResetBitPos();
     if (!length)
-        return std::string();
+        return {};
 
-    std::string value(reinterpret_cast<char const*>(&_storage[_rpos]), length);
+    std::string_view value(reinterpret_cast<char const*>(&_storage[_rpos]), length);
     _rpos += length;
     if (requireValidUtf8 && !utf8::is_valid(value.begin(), value.end()))
-        throw ByteBufferInvalidValueException("string", value.c_str());
+        throw ByteBufferInvalidValueException("string", value);
     return value;
 }
 
diff --git a/src/server/shared/Packets/ByteBuffer.h b/src/server/shared/Packets/ByteBuffer.h
index 7de0dde99e7..9233c4f5150 100644
--- a/src/server/shared/Packets/ByteBuffer.h
+++ b/src/server/shared/Packets/ByteBuffer.h
@@ -49,7 +49,7 @@ public:
 class TC_SHARED_API ByteBufferInvalidValueException : public ByteBufferException
 {
 public:
-    ByteBufferInvalidValueException(char const* type, char const* value);
+    ByteBufferInvalidValueException(char const* type, std::string_view value);
 };
 
 class TC_SHARED_API ByteBuffer
@@ -509,9 +509,9 @@ class TC_SHARED_API ByteBuffer
                 append(str, len);
         }
 
-        std::string ReadCString(bool requireValidUtf8 = true);
+        std::string_view ReadCString(bool requireValidUtf8 = true);
 
-        std::string ReadString(uint32 length, bool requireValidUtf8 = true);
+        std::string_view ReadString(uint32 length, bool requireValidUtf8 = true);
 
         uint8* contents()
         {
-- 
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