解决fastboot刷机内存消耗问题

Windows实现方案及代码：

//add by hthe
void *mmap_file(const char *fn, unsigned *_sz)
{
    HANDLE    file;
    HANDLE    mapfile;
    char     *data;
    DWORD     sz;

    file = CreateFile( fn,
                       GENERIC_READ,
                       FILE_SHARE_READ,
                       NULL,
                       OPEN_EXISTING,
                       0,
                       NULL );

    if (file == INVALID_HANDLE_VALUE)
        return NULL;

    sz = GetFileSize( file, NULL );
    data      = NULL;


    mapfile = CreateFileMapping(
    file,  		   // use paging file
    NULL,                  // default security
    PAGE_READONLY,         // read/write access
    0,                     // maximum object size (high-order DWORD)
    0,                	   // maximum object size (low-order DWORD)
    fn);   

    if (mapfile == INVALID_HANDLE_VALUE)
        return NULL;    

    if (sz > 0) {
	data = (char*)MapViewOfFile(mapfile,   // handle to map object
        FILE_MAP_READ , 			// read
        0,
        0,
        sz);
		
        if (data == NULL) {
            fprintf(stderr, "load_file: could not allocate %ld bytes
", sz );
            sz = 0;
        } 
    }
	
    CloseHandle( file );
    *_sz = (unsigned) sz;
    return  data;
}

 Linux实现方案及代码：

//add by hthe
void *mmap_file(const char *fn, unsigned *_sz)
{
    char *data;
    int sz;
    int fd;
    int errno_tmp;

    data = 0;
    fd = open(fn, O_RDONLY);
    if(fd < 0) return 0;

    sz = lseek(fd, 0, SEEK_END);
    if(sz < 0) goto oops;

    if(lseek(fd, 0, SEEK_SET) != 0) goto oops;

    if((data = (char*)mmap(NULL, sz, PROT_READ, MAP_SHARED, fd, 0)) == (void*)-1) goto oops;
    
    if(_sz) *_sz = sz;
    close(fd);
    return data;

oops:
    errno_tmp = errno;
    close(fd);
    if(data != 0) free(data);
    errno = errno_tmp;
    return 0;
}