Fix alignment issues in message sending/reading that would crash IRIX, thanks to Canavan for supplying a shell where I could fix this (#5077)

3 files changed, 51 insertions, 18 deletions

diff --git a/src/qcommon/msg.c b/src/qcommon/msg.c
index d20803b4..580637eb 100644
--- a/src/qcommon/msg.c
+++ b/src/qcommon/msg.c
@@ -141,23 +141,28 @@ void MSG_WriteBits( msg_t *msg, int value, int bits ) {
 		bits = -bits;
 	}
 	if (msg->oob) {
-		if (bits==8) {
+		if(bits==8)
+		{
 			msg->data[msg->cursize] = value;
 			msg->cursize += 1;
 			msg->bit += 8;
-		} else if (bits==16) {
-			unsigned short *sp = (unsigned short *)&msg->data[msg->cursize];
-			*sp = LittleShort(value);
+		}
+		else if(bits==16)
+		{
+			short temp = value;
+			
+			CopyLittleShort(&msg->data[msg->cursize], &temp);
 			msg->cursize += 2;
 			msg->bit += 16;
-		} else if (bits==32) {
-			unsigned int *ip = (unsigned int *)&msg->data[msg->cursize];
-			*ip = LittleLong(value);
+		}
+		else if(bits==32)
+		{
+			CopyLittleLong(&msg->data[msg->cursize], &value);
 			msg->cursize += 4;
 			msg->bit += 32;
-		} else {
-			Com_Error(ERR_DROP, "can't read %d bits", bits);
 		}
+		else 
+			Com_Error(ERR_DROP, "can't write %d bits", bits);
 	} else {
 //		fp = fopen("c:\\netchan.bin", "a");
 		value &= (0xffffffff>>(32-bits));
@@ -199,23 +204,29 @@ int MSG_ReadBits( msg_t *msg, int bits ) {
 	}
 
 	if (msg->oob) {
-		if (bits==8) {
+		if(bits==8)
+		{
 			value = msg->data[msg->readcount];
 			msg->readcount += 1;
 			msg->bit += 8;
-		} else if (bits==16) {
-			unsigned short *sp = (unsigned short *)&msg->data[msg->readcount];
-			value = LittleShort(*sp);
+		}
+		else if(bits==16)
+		{
+			short temp;
+			
+			CopyLittleShort(&temp, &msg->data[msg->readcount]);
+			value = temp;
 			msg->readcount += 2;
 			msg->bit += 16;
-		} else if (bits==32) {
-			unsigned int *ip = (unsigned int *)&msg->data[msg->readcount];
-			value = LittleLong(*ip);
+		}
+		else if(bits==32)
+		{
+			CopyLittleLong(&value, &msg->data[msg->readcount]);
 			msg->readcount += 4;
 			msg->bit += 32;
-		} else {
-			Com_Error(ERR_DROP, "can't read %d bits", bits);
 		}
+		else
+			Com_Error(ERR_DROP, "can't read %d bits", bits);
 	} else {
 		nbits = 0;
 		if (bits&7) {
diff --git a/src/qcommon/q_platform.h b/src/qcommon/q_platform.h
index 85b176eb..f4335489 100644
--- a/src/qcommon/q_platform.h
+++ b/src/qcommon/q_platform.h
@@ -349,6 +349,8 @@ float FloatSwap (const float *f);
 #error "Endianness defined as both big and little"
 #elif defined( Q3_BIG_ENDIAN )
 
+#define CopyLittleShort(dest, src) CopyShortSwap(dest, src)
+#define CopyLittleLong(dest, src) CopyLongSwap(dest, src)
 #define LittleShort(x) ShortSwap(x)
 #define LittleLong(x) LongSwap(x)
 #define LittleFloat(x) FloatSwap(&x)
@@ -358,6 +360,8 @@ float FloatSwap (const float *f);
 
 #elif defined( Q3_LITTLE_ENDIAN )
 
+#define CopyLittleShort(dest, src) Com_Memcpy(dest, src, 2)
+#define CopyLittleLong(dest, src) Com_Memcpy(dest, src, 4)
 #define LittleShort
 #define LittleLong
 #define LittleFloat
diff --git a/src/qcommon/q_shared.c b/src/qcommon/q_shared.c
index d6aa5c90..d8bc7383 100644
--- a/src/qcommon/q_shared.c
+++ b/src/qcommon/q_shared.c
@@ -130,6 +130,24 @@ float	BigFloat (const float *l) {return _BigFloat(l);}
 float	LittleFloat (const float *l) {return _LittleFloat(l);}
 */
 
+void CopyShortSwap(void *dest, void *src)
+{
+	byte *to = dest, *from = src;
+
+	to[0] = from[1];
+	to[1] = from[0];
+}
+
+void CopyLongSwap(void *dest, void *src)
+{
+	byte *to = dest, *from = src;
+
+	to[0] = from[3];
+	to[1] = from[2];
+	to[2] = from[1];
+	to[3] = from[0];
+}
+
 short   ShortSwap (short l)
 {
 	byte    b1,b2;