First pass of ImageWriter
Change-Id: I4f189587a2e3cc1c265200b8fa64321b299947eb
diff --git a/src/mem_map.h b/src/mem_map.h
new file mode 100644
index 0000000..4625f91
--- /dev/null
+++ b/src/mem_map.h
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_SRC_MEM_MAP_H_
+#define ART_SRC_MEM_MAP_H_
+
+#include <sys/mman.h>
+
+#include "utils.h"
+
+namespace art {
+
+// Used to keep track of mmap segments.
+class MemMap {
+ public:
+
+ // Request an anonymous region of a specified length.
+ //
+ // On success, returns returns a MemMap instance. On failure, returns a NULL;
+ static MemMap* Map(size_t length, int prot, int flags) {
+ size_t page_aligned_size = RoundUp(length, kPageSize);
+ byte* addr = reinterpret_cast<byte*>(mmap(NULL,
+ page_aligned_size,
+ prot,
+ MAP_ANONYMOUS | flags,
+ -1,
+ 0));
+ if (addr == MAP_FAILED) {
+ return NULL;
+ }
+ return new MemMap(addr, length, addr, page_aligned_size);
+ }
+
+ // Map part of a file, taking care of non-page aligned offsets. The
+ // "start" offset is absolute, not relative.
+ //
+ // On success, returns returns a MemMap instance. On failure, returns a NULL;
+ static MemMap* Map(size_t length, int prot, int flags, int fd, off_t start) {
+ // adjust to be page-aligned
+ int page_offset = start % kPageSize;
+ off_t page_aligned_offset = start - page_offset;
+ size_t page_aligned_size = length + page_offset;
+ byte* addr = reinterpret_cast<byte*>(mmap(NULL,
+ page_aligned_size,
+ prot,
+ MAP_FILE | flags,
+ fd,
+ page_aligned_offset));
+ if (addr == MAP_FAILED) {
+ return NULL;
+ }
+ return new MemMap(addr+page_offset, length, addr, page_aligned_size);
+ }
+
+ ~MemMap() {
+ Unmap();
+ };
+
+ // Release a memory mapping, returning true on success or it was previously unmapped.
+ bool Unmap() {
+ if (base_addr_ == NULL && base_length_ == 0) {
+ return true;
+ }
+ int result = munmap(base_addr_, base_length_);
+ base_addr_ = NULL;
+ base_length_ = 0;
+ if (result == -1) {
+ return false;
+ }
+ return true;
+ }
+
+ byte* GetAddress() const {
+ return addr_;
+ }
+
+ size_t GetLength() const {
+ return length_;
+ }
+
+ private:
+ MemMap(byte* addr, size_t length, void* base_addr, size_t base_length)
+ : addr_(addr), length_(length), base_addr_(base_addr), base_length_(base_length) {
+ CHECK(addr_ != NULL);
+ CHECK(length_ != 0);
+ CHECK(base_addr_ != NULL);
+ CHECK(base_length_ != 0);
+ };
+
+ byte* addr_; // start of data
+ size_t length_; // length of data
+
+ void* base_addr_; // page-aligned base address
+ size_t base_length_; // length of mapping
+};
+
+} // namespace art
+
+#endif // ART_SRC_MEM_MAP_H_