From c3b25e54f821f77153bc540c61141dad2ed78924 Mon Sep 17 00:00:00 2001
From: FlaminSarge <FlaminSarge@users.noreply.github.com>
Date: Sat, 28 Oct 2017 04:11:32 -0700
Subject: [PATCH] Add convenience logic for "offset" to Address definitions in
 GameConf (#580)

Allows for the last "read" offset for an Address to instead be "offset", which doesn't deref the addr pointer after applying the offset
Shortens the necessary coding to get a particular Address inside a function (old: store offset in a separate GameConf Offsets entry, apply the offset to the Address in SP)
---
 core/logic/GameConfigs.cpp | 30 ++++++++++++++++++++++++------
 core/logic/GameConfigs.h   |  4 +++-
 2 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/core/logic/GameConfigs.cpp b/core/logic/GameConfigs.cpp
index c5704be0..2c59400f 100644
--- a/core/logic/GameConfigs.cpp
+++ b/core/logic/GameConfigs.cpp
@@ -323,6 +323,7 @@ SMCResult CGameConfig::ReadSMC_NewSection(const SMCStates *states, const char *n
 			m_Address[0] = '\0';
 			m_AddressSignature[0] = '\0';
 			m_AddressReadCount = 0;
+			m_AddressLastIsOffset = false;
 
 			strncopy(m_Address, name, sizeof(m_Address));
 			m_ParseState = PSTATE_GAMEDEFS_ADDRESSES_ADDRESS;
@@ -430,10 +431,18 @@ SMCResult CGameConfig::ReadSMC_KeyValue(const SMCStates *states, const char *key
 			}
 		}
 	} else if (m_ParseState == PSTATE_GAMEDEFS_ADDRESSES_ADDRESS || m_ParseState == PSTATE_GAMEDEFS_ADDRESSES_ADDRESS_READ) {
-		if (strcmp(key, "read") == 0) {
+		if (strcmp(key, "read") == 0 || strcmp(key, "offset") == 0) {
 			int limit = sizeof(m_AddressRead)/sizeof(m_AddressRead[0]);
-			if (m_AddressReadCount < limit)
+			if (m_AddressLastIsOffset)
 			{
+				logger->LogError("[SM] Error parsing Address \"%s\", 'offset' entry must be the last entry (gameconf \"%s\")", m_Address, m_CurFile);
+			}
+			else if (m_AddressReadCount < limit)
+			{
+				if (strcmp(key, "offset") == 0)
+				{
+					m_AddressLastIsOffset = true;
+				}
 				m_AddressRead[m_AddressReadCount] = atoi(value);
 				m_AddressReadCount++;
 			}
@@ -637,7 +646,7 @@ SMCResult CGameConfig::ReadSMC_LeavingSection(const SMCStates *states)
 
 			if (m_Address[0] != '\0' && m_AddressSignature[0] != '\0')
 			{
-				AddressConf addrConf(m_AddressSignature, sizeof(m_AddressSignature), m_AddressReadCount, m_AddressRead);
+				AddressConf addrConf(m_AddressSignature, sizeof(m_AddressSignature), m_AddressReadCount, m_AddressRead, m_AddressLastIsOffset);
 				m_Addresses.replace(m_Address, addrConf);
 			}
 
@@ -997,12 +1006,17 @@ bool CGameConfig::GetAddress(const char *key, void **retaddr)
 		int offset = addrConf.read[i];
 
 		//NULLs in the middle of an indirection chain are bad, end NULL is ok
-		if (addr ==  NULL || reinterpret_cast<uintptr_t>(addr) < VALID_MINIMUM_MEMORY_ADDRESS)
+		if (addr == NULL || reinterpret_cast<uintptr_t>(addr) < VALID_MINIMUM_MEMORY_ADDRESS)
 		{
 			*retaddr = NULL;
 			return false;
 		}
-		addr = *(reinterpret_cast<void**>(reinterpret_cast<uint8_t*>(addr) + offset));
+		//If lastIsOffset is set and this is the last iteration of the loop, don't deref
+		if (addrConf.lastIsOffset && i == addrConf.readCount-1) {
+			addr = reinterpret_cast<void*>(reinterpret_cast<uint8_t*>(addr) + offset);
+		} else {
+			addr = *(reinterpret_cast<void**>(reinterpret_cast<uint8_t*>(addr) + offset));
+		}
 	}
 
 	*retaddr = addr;
@@ -1014,13 +1028,17 @@ static inline unsigned minOf(unsigned a, unsigned b)
 	return a <= b ? a : b;
 }
 
-CGameConfig::AddressConf::AddressConf(char *sigName, unsigned sigLength, unsigned readCount, int *read)
+CGameConfig::AddressConf::AddressConf(char *sigName, unsigned sigLength, unsigned readCount, int *read, bool lastIsOffset)
 {
 	unsigned readLimit = minOf(readCount, sizeof(this->read) / sizeof(this->read[0]));
 
 	strncopy(signatureName, sigName, sizeof(signatureName) / sizeof(signatureName[0]));
 	this->readCount = readLimit;
 	memcpy(&this->read[0], read, sizeof(this->read[0])*readLimit);
+
+	//For safety: if the readLimit isn't the same as the readCount, then the
+	//last read value was definitely discarded, so lastIsOffset should be ignored
+	this->lastIsOffset = readLimit < readCount ? false : lastIsOffset;
 }
 
 SendProp *CGameConfig::GetSendProp(const char *key)
diff --git a/core/logic/GameConfigs.h b/core/logic/GameConfigs.h
index 2ed1de50..802b9ebb 100644
--- a/core/logic/GameConfigs.h
+++ b/core/logic/GameConfigs.h
@@ -103,8 +103,9 @@ private:
 		char signatureName[64];
 		int readCount;
 		int read[8];
+		bool lastIsOffset;
 
-		AddressConf(char *sigName, unsigned sigLength, unsigned readCount, int *read);
+		AddressConf(char *sigName, unsigned sigLength, unsigned readCount, int *read, bool lastIsOffset);
 
 		AddressConf() {}
 	};
@@ -113,6 +114,7 @@ private:
 	char m_AddressSignature[64];
 	int m_AddressReadCount;
 	int m_AddressRead[8];
+	bool m_AddressLastIsOffset;
 	StringHashMap<AddressConf> m_Addresses;
 	const char *m_pEngine;
 	const char *m_pBaseEngine;