From fd191a4920b15e168d4c8f4ad9c57ebc698a8ffc Mon Sep 17 00:00:00 2001
From: Walter van Niftrik
Date: Tue, 26 May 2009 23:34:57 +0000
Subject: SCI: Changed signatures of StrLen and StrCpy to allow NULL pointers.
 This is needed for a game bug in KQ6CD.

svn-id: r40930
---
 engines/sci/engine/kernel.cpp  | 7 +++++--
 engines/sci/engine/kstring.cpp | 8 +++++++-
 2 files changed, 12 insertions(+), 3 deletions(-)

(limited to 'engines')

diff --git a/engines/sci/engine/kernel.cpp b/engines/sci/engine/kernel.cpp
index 7b6a9a7660..31d5dc722c 100644
--- a/engines/sci/engine/kernel.cpp
+++ b/engines/sci/engine/kernel.cpp
@@ -141,8 +141,8 @@ SciKernelFunction kfunct_mappers[] = {
 	/*47*/	DEFUN("StrEnd", kStrEnd, "r"),
 	/*48*/	DEFUN("StrCat", kStrCat, "rr"),
 	/*49*/	DEFUN("StrCmp", kStrCmp, "rri*"),
-	/*4a*/	DEFUN("StrLen", kStrLen, "r"),
-	/*4b*/	DEFUN("StrCpy", kStrCpy, "rri*"),
+	/*4a*/	DEFUN("StrLen", kStrLen, "Zr"),
+	/*4b*/	DEFUN("StrCpy", kStrCpy, "rZri*"),
 	/*4c*/	DEFUN("Format", kFormat, "r.*"),
 	/*4d*/	DEFUN("GetFarText", kGetFarText, "iir"),
 	/*4e*/	DEFUN("ReadNumber", kReadNumber, "r"),
@@ -923,6 +923,9 @@ static void *_kernel_dereference_pointer(EngineState *s, reg_t pointer, int entr
 	int maxsize;
 	void *retval = s->seg_manager->dereference(pointer, &maxsize);
 
+	if (!retval)
+		return NULL;
+
 	if (pointer.offset & (align - 1)) {
 		warning("Unaligned pointer read: %04x:%04x expected with %d alignment", PRINT_REG(pointer), align);
 		return NULL;
diff --git a/engines/sci/engine/kstring.cpp b/engines/sci/engine/kstring.cpp
index 5dbacaca46..13d22cdf30 100644
--- a/engines/sci/engine/kstring.cpp
+++ b/engines/sci/engine/kstring.cpp
@@ -296,7 +296,8 @@ reg_t kStrCpy(EngineState *s, int funct_nr, int argc, reg_t *argv) {
 	if (!src) {
 		warning("Attempt to strcpy FROM invalid pointer %04x:%04x",
 		          PRINT_REG(argv[1]));
-		return NULL_REG;
+		*dest = 0;
+		return argv[1];
 	}
 
 	if (argc > 2) {
@@ -632,6 +633,11 @@ reg_t kFormat(EngineState *s, int funct_nr, int argc, reg_t *argv) {
 reg_t kStrLen(EngineState *s, int funct_nr, int argc, reg_t *argv) {
 	char *str = kernel_dereference_char_pointer(s, argv[0], 0);
 
+	if (!str) {
+		warning("StrLen: invalid pointer %04x:%04x", PRINT_REG(argv[0]));
+		return NULL_REG;
+	}
+
 	return make_reg(0, strlen(str));
 }
 
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