From 68a6c95d1c3de664c360d7907d2d309beb948042 Mon Sep 17 00:00:00 2001
From: Mukund Sivaraman <muks@mukund.org>
Date: Fri, 5 Sep 2008 14:31:52 +0000
Subject: [PATCH] (win32) Add mmap implementation

---
 libtransmission/blocklist.c | 13 ++++++-
 libtransmission/platform.c  | 70 +++++++++++++++++++++++++++++++++++++
 libtransmission/platform.h  |  5 +++
 3 files changed, 87 insertions(+), 1 deletion(-)

diff --git a/libtransmission/blocklist.c b/libtransmission/blocklist.c
index 7897a5b13..4f443a60c 100644
--- a/libtransmission/blocklist.c
+++ b/libtransmission/blocklist.c
@@ -14,8 +14,14 @@
 #include <stdlib.h> /* free */
 #include <string.h>
 
+#ifdef WIN32
+#include <windows.h>
+#endif
+
 #include <libgen.h> /* basename */
+#ifndef WIN32
 #include <sys/mman.h>
+#endif
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
@@ -24,6 +30,7 @@
 #include "ggets.h"
 
 #include "transmission.h"
+#include "platform.h"
 #include "blocklist.h"
 #include "net.h" /* tr_netResolve() */
 #include "utils.h"
@@ -80,7 +87,11 @@ blocklistLoad( tr_blocklist * b )
         return;
     }
 
-    b->rules = mmap( NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0 );
+#ifndef WIN32
+     b->rules = mmap( NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0 );
+#else
+    b->rules = mmap( NULL, st.st_size, 0, 0, fd, 0 );
+#endif
     if( !b->rules ) {
         tr_err( err_fmt, b->filename, tr_strerror(errno) );
         close( fd );
diff --git a/libtransmission/platform.c b/libtransmission/platform.c
index ce6e66c37..6be839004 100644
--- a/libtransmission/platform.c
+++ b/libtransmission/platform.c
@@ -638,3 +638,73 @@ tr_lockfile( const char * filename )
 
     return ret;
 }
+
+
+#ifdef WIN32
+
+/* The following mmap functions are by Joerg Walter, and were taken from
+ * his paper at: http://www.genesys-e.de/jwalter/mix4win.htm
+ */
+
+/* Wait for spin lock */
+static int slwait (int *sl) {
+    while (InterlockedCompareExchange ((void **) sl, (void *) 1, (void *) 0) != 0) 
+	Sleep (0);
+    return 0;
+}
+
+/* Release spin lock */
+static int slrelease (int *sl) {
+    InterlockedExchange (sl, 0);
+    return 0;
+}
+
+static int g_sl;
+
+void *mmap (void *ptr, long size, long prot, long type, long handle, long arg) {
+    static long g_pagesize;
+    static long g_regionsize;
+    /* Wait for spin lock */
+    slwait (&g_sl);
+    /* First time initialization */
+    if (! g_pagesize) 
+        g_pagesize = getpagesize ();
+    if (! g_regionsize) 
+        g_regionsize = getregionsize ();
+    /* Allocate this */
+    ptr = VirtualAlloc (ptr, size,
+			MEM_RESERVE | MEM_COMMIT | MEM_TOP_DOWN, PAGE_READWRITE);
+    if (! ptr) {
+        ptr = MMAP_FAILURE;
+        goto mmap_exit;
+    }
+mmap_exit:
+    /* Release spin lock */
+    slrelease (&g_sl);
+    return ptr;
+}
+
+long munmap (void *ptr, long size) {
+    static long g_pagesize;
+    static long g_regionsize;
+    int rc = MUNMAP_FAILURE;
+    /* Wait for spin lock */
+    slwait (&g_sl);
+    /* First time initialization */
+    if (! g_pagesize) 
+        g_pagesize = getpagesize ();
+    if (! g_regionsize) 
+        g_regionsize = getregionsize ();
+    /* Free this */
+    if (! VirtualFree (ptr, 0, 
+                       MEM_RELEASE))
+        goto munmap_exit;
+    rc = 0;
+munmap_exit:
+    /* Release spin lock */
+    slrelease (&g_sl);
+    return rc;
+}
+
+#endif
+
diff --git a/libtransmission/platform.h b/libtransmission/platform.h
index 61f16af8e..1e226cf30 100644
--- a/libtransmission/platform.h
+++ b/libtransmission/platform.h
@@ -58,4 +58,9 @@ int          tr_lockHave       ( const tr_lock * );
 
 tr_lockfile_state_t tr_lockfile       ( const char * filename );
 
+#ifdef WIN32
+void *mmap (void *ptr, long size, long prot, long type, long handle, long arg);
+long munmap (void *ptr, long size);
+#endif
+
 #endif