[FFmpeg-devel] [PATCH] Windows support for av_file_map()
Daniel Verkamp
daniel
Fri Dec 31 10:35:50 CET 2010
Hi,
Here's a simple implementation of av_file_map() using
CreateFileMapping() and MapViewOfFile(), which are the rough Win32
equivalent of mmap().
This currently maps a read-only view of the file; this could be
changed to R/W to match the mmap() path if desired, but any code
expecting to actually use it for writing will fail with the non-mmap()
path anyway since the file is never written back in that case.
Thanks,
-- Daniel Verkamp
-------------- next part --------------
Index: configure
===================================================================
--- configure (revision 26178)
+++ configure (working copy)
@@ -1040,6 +1040,7 @@
machine_ioctl_bt848_h
machine_ioctl_meteor_h
malloc_h
+ MapViewOfFile
memalign
mkstemp
mmap
@@ -2685,6 +2686,7 @@
check_func_headers lzo/lzo1x.h lzo1x_999_compress
check_lib2 "windows.h psapi.h" GetProcessMemoryInfo -lpsapi
check_func_headers windows.h GetProcessTimes
+check_func_headers windows.h MapViewOfFile
check_func_headers windows.h VirtualAlloc
check_header conio.h
Index: libavutil/file.c
===================================================================
--- libavutil/file.c (revision 26178)
+++ libavutil/file.c (working copy)
@@ -22,6 +22,9 @@
#include <unistd.h>
#if HAVE_MMAP
#include <sys/mman.h>
+#elif HAVE_MAPVIEWOFFILE
+#include <io.h>
+#include <windows.h>
#endif
typedef struct {
@@ -81,6 +84,28 @@
return err;
}
*bufptr = ptr;
+#elif HAVE_MAPVIEWOFFILE
+ {
+ HANDLE mh, fh = (HANDLE)_get_osfhandle(fd);
+
+ mh = CreateFileMapping(fh, NULL, PAGE_READONLY, 0, 0, NULL);
+ if (!mh) {
+ av_log(&file_log_ctx, AV_LOG_ERROR, "Error occurred in CreateFileMapping()\n");
+ close(fd);
+ return -1;
+ }
+
+ ptr = MapViewOfFile(mh, FILE_MAP_READ, 0, 0, *size);
+ if (!ptr) {
+ av_log(&file_log_ctx, AV_LOG_ERROR, "Error occurred in MapViewOfFile()\n");
+ CloseHandle(mh);
+ close(fd);
+ return -1;
+ }
+
+ CloseHandle(mh);
+ *bufptr = ptr;
+ }
#else
*bufptr = av_malloc(*size);
if (!*bufptr) {
@@ -99,6 +124,8 @@
{
#if HAVE_MMAP
munmap(bufptr, size);
+#elif HAVE_MAPVIEWOFFILE
+ UnmapViewOfFile(bufptr);
#else
av_free(bufptr);
#endif
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