1 files changed, 141 insertions, 0 deletions
diff --git a/src/util/win32/map.c b/src/util/win32/map.c
new file mode 100644
index 000000000..52e1363ea
--- /dev/null
+++ b/src/util/win32/map.c
@@ -0,0 +1,141 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include "git2_util.h"
+
+#include "map.h"
+#include <errno.h>
+
+#ifndef NO_MMAP
+
+static DWORD get_page_size(void)
+{
+	static DWORD page_size;
+	SYSTEM_INFO sys;
+
+	if (!page_size) {
+		GetSystemInfo(&sys);
+		page_size = sys.dwPageSize;
+	}
+
+	return page_size;
+}
+
+static DWORD get_allocation_granularity(void)
+{
+	static DWORD granularity;
+	SYSTEM_INFO sys;
+
+	if (!granularity) {
+		GetSystemInfo(&sys);
+		granularity = sys.dwAllocationGranularity;
+	}
+
+	return granularity;
+}
+
+int git__page_size(size_t *page_size)
+{
+	*page_size = get_page_size();
+	return 0;
+}
+
+int git__mmap_alignment(size_t *page_size)
+{
+	*page_size = get_allocation_granularity();
+	return 0;
+}
+
+int p_mmap(git_map *out, size_t len, int prot, int flags, int fd, off64_t offset)
+{
+	HANDLE fh = (HANDLE)_get_osfhandle(fd);
+	DWORD alignment = get_allocation_granularity();
+	DWORD fmap_prot = 0;
+	DWORD view_prot = 0;
+	DWORD off_low = 0;
+	DWORD off_hi = 0;
+	off64_t page_start;
+	off64_t page_offset;
+
+	GIT_MMAP_VALIDATE(out, len, prot, flags);
+
+	out->data = NULL;
+	out->len = 0;
+	out->fmh = NULL;
+
+	if (fh == INVALID_HANDLE_VALUE) {
+		errno = EBADF;
+		git_error_set(GIT_ERROR_OS, "failed to mmap. Invalid handle value");
+		return -1;
+	}
+
+	if (prot & GIT_PROT_WRITE)
+		fmap_prot |= PAGE_READWRITE;
+	else if (prot & GIT_PROT_READ)
+		fmap_prot |= PAGE_READONLY;
+
+	if (prot & GIT_PROT_WRITE)
+		view_prot |= FILE_MAP_WRITE;
+	if (prot & GIT_PROT_READ)
+		view_prot |= FILE_MAP_READ;
+
+	page_start = (offset / alignment) * alignment;
+	page_offset = offset - page_start;
+
+	if (page_offset != 0) { /* offset must be multiple of the allocation granularity */
+		errno = EINVAL;
+		git_error_set(GIT_ERROR_OS, "failed to mmap. Offset must be multiple of allocation granularity");
+		return -1;
+	}
+
+	out->fmh = CreateFileMapping(fh, NULL, fmap_prot, 0, 0, NULL);
+	if (!out->fmh || out->fmh == INVALID_HANDLE_VALUE) {
+		git_error_set(GIT_ERROR_OS, "failed to mmap. Invalid handle value");
+		out->fmh = NULL;
+		return -1;
+	}
+
+	off_low = (DWORD)(page_start);
+	off_hi = (DWORD)(page_start >> 32);
+	out->data = MapViewOfFile(out->fmh, view_prot, off_hi, off_low, len);
+	if (!out->data) {
+		git_error_set(GIT_ERROR_OS, "failed to mmap. No data written");
+		CloseHandle(out->fmh);
+		out->fmh = NULL;
+		return -1;
+	}
+	out->len = len;
+
+	return 0;
+}
+
+int p_munmap(git_map *map)
+{
+	int error = 0;
+
+	GIT_ASSERT_ARG(map);
+
+	if (map->data) {
+		if (!UnmapViewOfFile(map->data)) {
+			git_error_set(GIT_ERROR_OS, "failed to munmap. Could not unmap view of file");
+			error = -1;
+		}
+		map->data = NULL;
+	}
+
+	if (map->fmh) {
+		if (!CloseHandle(map->fmh)) {
+			git_error_set(GIT_ERROR_OS, "failed to munmap. Could not close handle");
+			error = -1;
+		}
+		map->fmh = NULL;
+	}
+
+	return error;
+}
+
+#endif