Lua: load/save architecture-independent bytecode

If you run the Intel version of Crawl and then the PowerPC version,
you will get "Lua error: global_prelude: bad header in precompiled
chunk" seven times during the start of Crawl.

This patch corrects the issue by making the bytecode architecture
independent.

Signed-off-by: Steven Noonan <steven@uplinklabs.net>

2 files changed, 49 insertions, 5 deletions

diff --git a/crawl-ref/source/util/lua/src/ldump.c b/crawl-ref/source/util/lua/src/ldump.c
index f08277d3ac..2adc54ff82 100644
--- a/crawl-ref/source/util/lua/src/ldump.c
+++ b/crawl-ref/source/util/lua/src/ldump.c
@@ -62,12 +62,12 @@ static void DumpString(const TString* s, DumpState* D)
 {
  if (s==NULL || getstr(s)==NULL)
  {
-  size_t size=0;
+  unsigned int size=0;
   DumpVar(size,D);
  }
  else
  {
-  size_t size=s->tsv.len+1;		/* include trailing '\0' */
+  unsigned int size=s->tsv.len+1;		/* include trailing '\0' */
   DumpVar(size,D);
   DumpBlock(getstr(s),size,D);
  }
diff --git a/crawl-ref/source/util/lua/src/lundump.c b/crawl-ref/source/util/lua/src/lundump.c
index 7fc635eeb7..3ee5e9cab2 100644
--- a/crawl-ref/source/util/lua/src/lundump.c
+++ b/crawl-ref/source/util/lua/src/lundump.c
@@ -25,6 +25,7 @@ typedef struct {
  ZIO* Z;
  Mbuffer* b;
  const char* name;
+ int swap;
 } LoadState;
 
 #ifdef LUAC_TRUST_BINARIES
@@ -39,7 +40,6 @@ static void error(LoadState* S, const char* why)
 }
 #endif
 
-#define LoadMem(S,b,n,size)	LoadBlock(S,b,(n)*(size))
 #define	LoadByte(S)		(lu_byte)LoadChar(S)
 #define LoadVar(S,x)		LoadMem(S,&x,1,sizeof(x))
 #define LoadVector(S,b,n,size)	LoadMem(S,b,n,size)
@@ -50,6 +50,49 @@ static void LoadBlock(LoadState* S, void* b, size_t size)
  IF (r!=0, "unexpected end");
 }
 
+static void LoadMem (LoadState* S, void* b, int n, size_t size)
+{
+ LoadBlock(S,b,n*size);
+ if (S->swap)
+ {
+  char* p=(char*) b;
+  char c;
+  switch (size)
+  {
+   case 1:
+	break;
+   case 2:
+	while (n--)
+	{
+	 c=p[0]; p[0]=p[1]; p[1]=c;
+	 p+=2;
+	}
+	break;
+   case 4:
+	while (n--)
+	{
+	 c=p[0]; p[0]=p[3]; p[3]=c;
+	 c=p[1]; p[1]=p[2]; p[2]=c;
+	 p+=4;
+	}
+	break;
+   case 8:
+	while (n--)
+	{
+	 c=p[0]; p[0]=p[7]; p[7]=c;
+	 c=p[1]; p[1]=p[6]; p[6]=c;
+	 c=p[2]; p[2]=p[5]; p[5]=c;
+	 c=p[3]; p[3]=p[4]; p[4]=c;
+	 p+=8;
+	}
+	break;
+   default:
+	IF(1, "bad size");
+	break;
+  }
+ }
+}
+
 static int LoadChar(LoadState* S)
 {
  char x;
@@ -74,7 +117,7 @@ static lua_Number LoadNumber(LoadState* S)
 
 static TString* LoadString(LoadState* S)
 {
- size_t size;
+ unsigned int size;
  LoadVar(S,size);
  if (size==0)
   return NULL;
@@ -182,6 +225,7 @@ static void LoadHeader(LoadState* S)
  char s[LUAC_HEADERSIZE];
  luaU_header(h);
  LoadBlock(S,s,LUAC_HEADERSIZE);
+ S->swap=(s[6]!=h[6]); s[6]=h[6];
  IF (memcmp(h,s,LUAC_HEADERSIZE)!=0, "bad header");
 }
 
@@ -216,7 +260,7 @@ void luaU_header (char* h)
  *h++=(char)LUAC_FORMAT;
  *h++=(char)*(char*)&x;				/* endianness */
  *h++=(char)sizeof(int);
- *h++=(char)sizeof(size_t);
+ *h++=(char)sizeof(unsigned int);
  *h++=(char)sizeof(Instruction);
  *h++=(char)sizeof(lua_Number);
  *h++=(char)(((lua_Number)0.5)==0);		/* is lua_Number integral? */