From 8bce08f1026b6e30e9ada6e291a115a260dba682 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <slouken@libsdl.org>
Date: Sun, 4 Jan 2004 15:18:08 +0000
Subject: [PATCH] Added function to create RWops from const memory:
 SDL_RWFromConstMem()

---
 WhatsNew                       |  1 +
 include/SDL_rwops.h            |  1 +
 src/file/SDL_rwops.c           | 22 ++++++++++++++++++++++
 src/main/beos/exports/SDL.exp  |  1 +
 src/main/macos/exports/SDL.x   |  1 +
 src/main/macosx/exports/SDL.x  |  1 +
 src/main/win32/exports/SDL.def |  1 +
 7 files changed, 28 insertions(+)

diff --git a/WhatsNew b/WhatsNew
index 1ba280924..0421260da 100644
--- a/WhatsNew
+++ b/WhatsNew
@@ -6,6 +6,7 @@ Version 1.0:
 1.2.7:
 	Added CPU feature detection functions to SDL_cpuinfo.h:
 		SDL_HasRDTSC(), SDL_HasMMX(), SDL_Has3DNow(), SDL_HasSSE()
+	Added function to create RWops from const memory: SDL_RWFromConstMem()
 
 1.2.6:
 	Added SDL_LoadObject(), SDL_LoadFunction(), and SDL_UnloadObject()
diff --git a/include/SDL_rwops.h b/include/SDL_rwops.h
index b8ac438b8..036cd2b5d 100644
--- a/include/SDL_rwops.h
+++ b/include/SDL_rwops.h
@@ -92,6 +92,7 @@ extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFile(const char *file, const char
 extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromFP(FILE *fp, int autoclose);
 
 extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromMem(void *mem, int size);
+extern DECLSPEC SDL_RWops * SDLCALL SDL_RWFromConstMem(const void *mem, int size);
 
 extern DECLSPEC SDL_RWops * SDLCALL SDL_AllocRW(void);
 extern DECLSPEC void SDLCALL SDL_FreeRW(SDL_RWops *area);
diff --git a/src/file/SDL_rwops.c b/src/file/SDL_rwops.c
index 285557882..d39f16480 100644
--- a/src/file/SDL_rwops.c
+++ b/src/file/SDL_rwops.c
@@ -129,6 +129,11 @@ static int mem_write(SDL_RWops *context, const void *ptr, int size, int num)
 	context->hidden.mem.here += num*size;
 	return(num);
 }
+static int mem_writeconst(SDL_RWops *context, const void *ptr, int size, int num)
+{
+	SDL_SetError("Can't write to read-only memory");
+	return(-1);
+}
 static int mem_close(SDL_RWops *context)
 {
 	if ( context ) {
@@ -258,6 +263,23 @@ SDL_RWops *SDL_RWFromMem(void *mem, int size)
 	return(rwops);
 }
 
+SDL_RWops *SDL_RWFromConstMem(const void *mem, int size)
+{
+	SDL_RWops *rwops;
+
+	rwops = SDL_AllocRW();
+	if ( rwops != NULL ) {
+		rwops->seek = mem_seek;
+		rwops->read = mem_read;
+		rwops->write = mem_writeconst;
+		rwops->close = mem_close;
+		rwops->hidden.mem.base = (Uint8 *)mem;
+		rwops->hidden.mem.here = rwops->hidden.mem.base;
+		rwops->hidden.mem.stop = rwops->hidden.mem.base+size;
+	}
+	return(rwops);
+}
+
 SDL_RWops *SDL_AllocRW(void)
 {
 	SDL_RWops *area;
diff --git a/src/main/beos/exports/SDL.exp b/src/main/beos/exports/SDL.exp
index 46dc94bfc..591b9f94f 100644
--- a/src/main/beos/exports/SDL.exp
+++ b/src/main/beos/exports/SDL.exp
@@ -112,6 +112,7 @@ _SDL_CondWaitTimeout
 _SDL_RWFromFile
 _SDL_RWFromFP
 _SDL_RWFromMem
+_SDL_RWFromConstMem
 _SDL_AllocRW
 _SDL_FreeRW
 _SDL_GetWMInfo
diff --git a/src/main/macos/exports/SDL.x b/src/main/macos/exports/SDL.x
index ee4579ade..40d1a8cc4 100644
--- a/src/main/macos/exports/SDL.x
+++ b/src/main/macos/exports/SDL.x
@@ -111,6 +111,7 @@
 	SDL_RWFromFile
 	SDL_RWFromFP
 	SDL_RWFromMem
+	SDL_RWFromConstMem
 	SDL_AllocRW
 	SDL_FreeRW
 	SDL_GetWMInfo
diff --git a/src/main/macosx/exports/SDL.x b/src/main/macosx/exports/SDL.x
index 7785b90d5..37a25b989 100644
--- a/src/main/macosx/exports/SDL.x
+++ b/src/main/macosx/exports/SDL.x
@@ -112,6 +112,7 @@
 	_SDL_RWFromFile
 	_SDL_RWFromFP
 	_SDL_RWFromMem
+	_SDL_RWFromConstMem
 	_SDL_AllocRW
 	_SDL_FreeRW
 	_SDL_GetWMInfo
diff --git a/src/main/win32/exports/SDL.def b/src/main/win32/exports/SDL.def
index 61f458cbe..8cb3f9aed 100644
--- a/src/main/win32/exports/SDL.def
+++ b/src/main/win32/exports/SDL.def
@@ -112,6 +112,7 @@
 	SDL_RWFromFile
 	SDL_RWFromFP
 	SDL_RWFromMem
+	SDL_RWFromConstMem
 	SDL_AllocRW
 	SDL_FreeRW
 	SDL_GetWMInfo