From 954fc5d5dd13ae5c4c622f40069230978e10c352 Mon Sep 17 00:00:00 2001
From: feos-tas <feos-tas@users.sf.net>
Date: Tue, 23 Jun 2015 21:04:31 +0000
Subject: [PATCH] Lua: rom.writebyte() and gethash().

---
 trunk/src/fceu.cpp       | 21 +++++++++++++++------
 trunk/src/fceu.h         |  1 +
 trunk/src/lua-engine.cpp | 32 +++++++++++++++++++++++++++++---
 3 files changed, 45 insertions(+), 9 deletions(-)

diff --git a/trunk/src/fceu.cpp b/trunk/src/fceu.cpp
index 838f4947..8aa27371 100644
--- a/trunk/src/fceu.cpp
+++ b/trunk/src/fceu.cpp
@@ -1186,8 +1186,6 @@ void FCEUXGameInterface(GI command) {
 	}
 }
 
-
-
 bool FCEUXLoad(const char *name, FCEUFILE *fp) {
 	//read ines header
 	iNES_HEADER head;
@@ -1239,11 +1237,22 @@ bool FCEUXLoad(const char *name, FCEUFILE *fp) {
 	return true;
 }
 
-
 uint8 FCEU_ReadRomByte(uint32 i) {
 	extern iNES_HEADER head;
-	if (i < 16) return *((unsigned char*)&head + i);
-	if (i < 16 + PRGsize[0]) return PRGptr[0][i - 16];
-	if (i < 16 + PRGsize[0] + CHRsize[0]) return CHRptr[0][i - 16 - PRGsize[0]];
+	if (i < 16)
+		return *((unsigned char*)&head + i);
+	if (i < 16 + PRGsize[0])
+		return PRGptr[0][i - 16];
+	if (i < 16 + PRGsize[0] + CHRsize[0])
+		return CHRptr[0][i - 16 - PRGsize[0]];
 	return 0;
 }
+
+void FCEU_WriteRomByte(uint32 i, uint8 value) {
+	if (i < 16)
+		MessageBox(hMemView,"Sorry", "You can't edit the ROM header.", MB_OK);
+	if (i < 16 + PRGsize[0])
+		PRGptr[0][i - 16] = value;
+	if (i < 16 + PRGsize[0] + CHRsize[0])
+		CHRptr[0][i - 16 - PRGsize[0]] = value;
+}
diff --git a/trunk/src/fceu.h b/trunk/src/fceu.h
index bc1af8d8..b8046a96 100644
--- a/trunk/src/fceu.h
+++ b/trunk/src/fceu.h
@@ -61,6 +61,7 @@ extern  uint8  *RAM;            //shared memory modifications
 extern int EmulationPaused;
 
 uint8 FCEU_ReadRomByte(uint32 i);
+void FCEU_WriteRomByte(uint32 i, uint8 value);
 
 extern readfunc ARead[0x10000];
 extern writefunc BWrite[0x10000];
diff --git a/trunk/src/lua-engine.cpp b/trunk/src/lua-engine.cpp
index 584baba5..1faed825 100644
--- a/trunk/src/lua-engine.cpp
+++ b/trunk/src/lua-engine.cpp
@@ -23,6 +23,7 @@
 #include "x6502.h"
 #include "utils/xstring.h"
 #include "utils/memory.h"
+#include "utils/crc32.h"
 #include "fceulua.h"
 
 #ifdef WIN32
@@ -1258,6 +1259,19 @@ static int rom_readbytesigned(lua_State *L) {
 	return 1;
 }
 
+// doesn't keep backups to allow maximum speed (for automatic rom corruptors and stuff)
+// keeping them might be an option though, just need to use memview's ApplyPatch()
+// that'd also highlight the edits in hex editor
+static int rom_writebyte(lua_State *L) 
+{
+	uint32 address = luaL_checkinteger(L,1);
+	if (address < 16)
+		luaL_error(L,"rom.writebyte() can't edit the ROM header.");
+	else
+		FCEU_WriteRomByte(address, luaL_checkinteger(L,2));
+	return 1;
+}
+
 static int rom_gethash(lua_State *L) {
 	const char *type = luaL_checkstring(L, 1);
 	if(!type) lua_pushstring(L, "");
@@ -1590,6 +1604,17 @@ static int print(lua_State *L)
 	return 0;
 }
 
+// gethash()
+//
+//  Returns the crc32 hashsum of an arbitrary buffer
+static int gethash(lua_State *L) {
+	uint8 *buffer = (uint8 *)luaL_checkstring(L, 1);
+	int size = luaL_checkinteger(L,2);
+	int hash = CalcCRC32(0, buffer, size);
+	lua_pushinteger(L, hash);
+	return 1;
+}
+
 // provides an easy way to copy a table from Lua
 // (simple assignment only makes an alias, but sometimes an independent table is desired)
 // currently this function only performs a shallow copy,
@@ -3586,8 +3611,8 @@ static int gui_gdscreenshot(lua_State *L) {
 	*ptr++ = (65534     ) & 0xFF;
 	*ptr++ = (width >> 8) & 0xFF;
 	*ptr++ = (width     ) & 0xFF;
-	*ptr++ = (height >> 8) & 0xFF;
-	*ptr++ = (height     ) & 0xFF;
+	*ptr++ = (height>> 8) & 0xFF;
+	*ptr++ = (height    ) & 0xFF;
 	*ptr++ = 1;
 	*ptr++ = 255;
 	*ptr++ = 255;
@@ -5371,7 +5396,7 @@ static const struct luaL_reg romlib [] = {
 	{"readbytesigned", rom_readbytesigned},
 	// alternate naming scheme for unsigned
 	{"readbyteunsigned", rom_readbyte},
-
+	{"writebyte", rom_writebyte},
 	{"gethash", rom_gethash},
 	{NULL,NULL}
 };
@@ -5699,6 +5724,7 @@ int FCEU_LoadLuaCode(const char *filename, const char *arg) {
 
 		// register a few utility functions outside of libraries (in the global namespace)
 		lua_register(L, "print", print);
+		lua_register(L, "gethash", gethash),
 		lua_register(L, "tostring", tostring);
 		lua_register(L, "tobitstring", tobitstring);
 		lua_register(L, "addressof", addressof);