From 847962910f0bff071f3bf07c9abb87764fb6cac3 Mon Sep 17 00:00:00 2001
From: claude-bot <claude@ancap.in.ua>
Date: Mon, 13 Jul 2026 12:40:03 +0000
Subject: Import aap/librw @ master

Snapshot for re3/reVC vendoring, per @lzcnt.
Source: https://github.com/aap/librw (master).
---
 tools/hopalong/vfs.cpp | 133 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 133 insertions(+)
 create mode 100644 tools/hopalong/vfs.cpp

(limited to 'tools/hopalong/vfs.cpp')

diff --git a/tools/hopalong/vfs.cpp b/tools/hopalong/vfs.cpp
new file mode 100644
index 0000000..c54d241
--- /dev/null
+++ b/tools/hopalong/vfs.cpp
@@ -0,0 +1,133 @@
+#include <rw.h>
+#include <string.h>
+
+#include "vfs.h"
+
+struct FILE_VFS
+{
+	int used;
+	rw::uint8 *data;
+	int pos;
+	int size;
+};
+FILE_VFS vfsfiles[64];
+VFS *globalVFS;
+
+void*
+vfs_fopen(const char *path, const char *mode)
+{
+	int flags = 0;
+	int i, j;
+	char *r, *w, *plus;
+
+//	printf("trying to open <%s> mode <%s>\n", path, mode);
+	const char *file = strrchr((char*)path, '/');
+	if(file)
+		file++;
+	else
+		file = path;
+	for(i = 0; i < nelem(vfsfiles); i++){
+		if(!vfsfiles[i].used)
+			goto found;
+	}
+	// no file pointer available
+	return nil;
+found:
+
+	// why can't we pass const char*? urghhh....
+	r = strchr((char*)mode, 'r');
+	w = strchr((char*)mode, 'w');
+	plus = strchr((char*)mode, '+');
+	// cannot write files
+	if(w || plus)
+		return nil;
+
+	for(j = 0; j < globalVFS->numFiles; j++){
+		if(strcmp(globalVFS->files[j].name, file) == 0)
+			goto found2;
+	}
+	// file not found
+	return nil;
+found2:
+
+	vfsfiles[i].used = 1;
+	vfsfiles[i].data = globalVFS->files[j].data;
+	vfsfiles[i].pos = 0;
+	vfsfiles[i].size = globalVFS->files[j].length;
+	return &vfsfiles[i];
+}
+
+int
+vfs_fclose(void *fp)
+{
+	FILE_VFS *f = (FILE_VFS*)fp;
+	if(!f->used)
+		return EOF;
+	f->used = 0;
+	f->data = nil;
+	return 0;
+}
+
+int
+vfs_fseek(void *fp, long offset, int whence)
+{
+	FILE_VFS *f = (FILE_VFS*)fp;
+	switch(whence){
+	case 0:
+		f->pos = offset;
+		break;
+	case 1:
+		f->pos += offset;
+		break;
+	case 2:
+		f->pos = f->size - offset;
+		break;
+	}
+	if(f->pos > f->size) f->pos = f->size;
+	return f->pos;
+}
+
+long
+vfs_ftell(void *fp)
+{
+	FILE_VFS *f = (FILE_VFS*)fp;
+	return f->pos;
+}
+
+size_t
+vfs_fread(void *ptr, size_t size, size_t nmemb, void *fp)
+{
+	FILE_VFS *f = (FILE_VFS*)fp;
+	size_t sz = size*nmemb;
+	if(sz > f->size-f->pos)
+		sz = f->size-f->pos;
+	memcpy(ptr, f->data+f->pos, sz);
+	f->pos += sz;
+	return sz/size;
+}
+
+size_t
+vfs_fwrite(const void *ptr, size_t size, size_t nmemb, void *fp)
+{
+	return 0;
+}
+
+int
+vfs_feof(void *fp)
+{
+	FILE_VFS *f = (FILE_VFS*)fp;
+	return f->pos >= f->size;
+}
+
+void
+installVFS(VFS *vfs)
+{
+	globalVFS = vfs;
+        rw::engine->filefuncs.rwfopen = vfs_fopen;
+        rw::engine->filefuncs.rwfclose = vfs_fclose;
+        rw::engine->filefuncs.rwfseek = vfs_fseek;
+        rw::engine->filefuncs.rwftell = vfs_ftell;
+        rw::engine->filefuncs.rwfread = vfs_fread;
+        rw::engine->filefuncs.rwfwrite = vfs_fwrite;
+        rw::engine->filefuncs.rwfeof = vfs_feof;
+}
-- 
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