util.cc

来自「Cromfs is a compressed read-only filesys」· CC 代码 · 共 91 行

#include "util.hh"

#ifdef __GNUC__
# define likely(x)       __builtin_expect(!!(x), 1)
# define unlikely(x)     __builtin_expect(!!(x), 0)
#else
# define likely(x)   (x)
# define unlikely(x) (x)
#endif

#include <sstream>

#include <sys/stat.h>

const std::string ReportSize(uint_fast64_t size)
{
    std::stringstream st;
    st.flags(std::ios_base::fixed);
    st.precision(2);
    if(size < 90000llu) st << size << " bytes";
    else if(size < 1500000llu)    st << (size/1e3) << " kB";
    else if(size < 1500000000llu) st << (size/1e6) << " MB";
    else if(size < 1500000000000llu) st << (size/1e9) << " GB";
    else if(size < 1500000000000000llu) st << (size/1e12) << " TB";
    else st << (size/1e15) << " PB";
    return st.str();
}

static char ftypelet(unsigned mode)
{
    /* this list of modes and chars comes from glibc, lib/filemode.c, ftypelet() */
    switch(__builtin_expect(mode & S_IFMT, S_IFREG))
    {
        case S_IFREG: return '-';
#ifdef S_ISBLK
        case S_IFBLK: return 'b';
#endif
#ifdef S_ISCHR
        case S_IFCHR: return 'c';
#endif
#ifdef S_ISDIR
        case S_IFDIR: return 'd';
#endif
#ifdef S_ISFIFO
        case S_IFIFO: return 'p';
#endif
#ifdef S_ISLNK
        case S_IFLNK: return 'l';
#endif
#ifdef S_ISSOCK
        case S_IFSOCK: return 's';
#endif
    }
#ifdef S_ISMPC
    if (S_ISMPC(mode)) return 'm';
#endif
#ifdef S_ISNWK
    if (S_ISNWK(mode)) return 'n';
#endif
#ifdef S_ISDOOR
    if (S_ISDOOR(mode)) return 'D';
#endif
#ifdef S_ISCTG
    if (S_ISCTG(mode)) return 'C';
#endif
#ifdef S_ISOFD
    if (S_ISOFD(mode)) return 'M';
#endif
#ifdef S_ISOFL
    if (S_ISOFL(mode)) return 'M';
#endif
    return '?';
}

const std::string TranslateMode(unsigned mode)
{
    char result[10];
    static const char data[] = {'-','r','x','w', 'S','T', 's','t' };
    result[0] = ftypelet(mode);
    result[1] = data[!!(mode & S_IRUSR)*1]; // -,r
    result[2] = data[!!(mode & S_IWUSR)*3]; // -,w
    result[3] = data[!!(mode & S_IXUSR)*2 + 4*!!(mode & S_ISUID)]; // -,x or S,s
    result[4] = data[!!(mode & S_IRGRP)*1]; // -,r
    result[5] = data[!!(mode & S_IWGRP)*3]; // -,w
    result[6] = data[!!(mode & S_IXGRP)*2 + 4*!!(mode & S_ISGID)]; // -,x or S,s
    result[7] = data[!!(mode & S_IROTH)*1]; // -,r
    result[8] = data[!!(mode & S_IWOTH)*3]; // -,w
    result[9] = data[!!(mode & S_IXOTH)*2 + 5*!!(mode & S_ISVTX)]; // -,x or T,t
    return std::string(result,result+10);
}