system_cmds-643.30.1.tar.gz

[apple/system_cmds.git] / CPPUtil / UtilMappedFile.cpp

diff --git a/CPPUtil/UtilMappedFile.cpp b/CPPUtil/UtilMappedFile.cpp
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+++ b/CPPUtil/UtilMappedFile.cpp
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+//
+//  UtilMappedFile.cpp
+//  CPPUtil
+//
+//  Created by James McIlree on 4/19/13.
+//  Copyright (c) 2013 Apple. All rights reserved.
+//
+
+#include "CPPUtil.h"
+
+#include <sys/mman.h>
+
+BEGIN_UTIL_NAMESPACE
+
+static int open_fd(const char* path, size_t& file_size)
+{
+       int fd = open(path, O_RDONLY, 0);
+       if(fd >= 0) {
+               struct stat data;
+               if (fstat(fd, &data) == 0) {
+                       if (S_ISREG(data.st_mode)) {
+                               // Is it zero sized?
+                               if (data.st_size > 0) {
+                                       file_size = (size_t)data.st_size;
+                                       return fd;
+                               }
+                       }
+               }
+               close(fd);
+       }
+
+       return -1;
+}
+
+MappedFile::MappedFile(const char* path) :
+       _address(NULL),
+       _size(0)
+{
+        ASSERT(path, "Sanity");
+       int fd = open_fd(path, _size);
+       if (fd >= 0) {
+               _address = (unsigned char*)mmap(NULL, _size, PROT_READ, MAP_FILE | MAP_SHARED, fd, 0);
+               if (_address == (void*)-1) {
+                       _address = NULL;
+               }
+               close(fd);
+       }
+}
+
+MappedFile::~MappedFile()
+{
+       if (_address != NULL) {
+               munmap(_address, _size);
+       }
+}
+
+END_UTIL_NAMESPACE