sys/src/cmd/disk/exsort.c

   1 #include        <u.h>
   2 #include        <libc.h>
   3
   4 int     ulcmp(void*, void*);
   5 void    swapem(ulong*, long);
   6
   7 enum
   8 {
   9         Wormsize        = 157933,
  10 };
  11 int     wflag;
  12
  13 void
  14 main(int argc, char *argv[])
  15 {
  16         long i, l, x, lobits, hibits, tot;
  17         int f, j;
  18         char *file;
  19         ulong *b, a, lo, hi;
  20
  21         ARGBEGIN {
  22         default:
  23                 print("usage: disk/exsort [-w] [file]\n");
  24                 exits("usage");
  25         case 'w':
  26                 wflag++;
  27                 break;
  28         } ARGEND;
  29
  30         file = "/adm/cache";
  31         if(argc > 0)
  32                 file = argv[0];
  33
  34         if(wflag)
  35                 f = open(file, ORDWR);
  36         else
  37                 f = open(file, OREAD);
  38         if(f < 0) {
  39                 print("cant open %s: %r\n", file);
  40                 exits("open");
  41         }
  42         l = seek(f, 0, 2) / sizeof(long);
  43
  44         b = malloc(l*sizeof(long));
  45         if(b == 0) {
  46                 print("cant malloc %s: %r\n", file);
  47                 exits("malloc");
  48         }
  49         seek(f, 0, 0);
  50         if(read(f, b, l*sizeof(long)) != l*sizeof(long)) {
  51                 print("short read %s: %r\n", file);
  52                 exits("read");
  53         }
  54
  55         lobits = 0;
  56         hibits = 0;
  57         for(i=0; i<l; i++) {
  58                 a = b[i];
  59                 if(a & (1L<<7))
  60                         lobits++;
  61                 if(a & (1L<<31))
  62                         hibits++;
  63         }
  64
  65         print("lobits = %6ld\n", lobits);
  66         print("hibits = %6ld\n", hibits);
  67
  68         if(hibits > lobits) {
  69                 print("swapping\n");
  70                 swapem(b, l);
  71         }
  72
  73         qsort(b, l, sizeof(ulong), ulcmp);
  74
  75         tot = 0;
  76         for(j=0; j<100; j++) {
  77                 lo = j*Wormsize;
  78                 hi = lo + Wormsize;
  79
  80                 x = 0;
  81                 for(i=0; i<l; i++) {
  82                         a = b[i];
  83                         if(a >= lo && a < hi)
  84                                 x++;
  85                 }
  86                 if(x) {
  87                         print("disk %2d %6ld blocks\n", j, x);
  88                         tot += x;
  89                 }
  90         }
  91         print("total   %6ld blocks\n", tot);
  92
  93
  94         if(wflag) {
  95                 if(hibits > lobits)
  96                         swapem(b, l);
  97                 seek(f, 0, 0);
  98                 if(write(f, b, l*sizeof(long)) != l*sizeof(long)) {
  99                         print("short write %s\n", file);
 100                         exits("write");
 101                 }
 102         }
 103
 104         exits(0);
 105 }
 106
 107 int
 108 ulcmp(void *va, void *vb)
 109 {
 110         ulong *a, *b;
 111
 112         a = va;
 113         b = vb;
 114
 115         if(*a > *b)
 116                 return 1;
 117         if(*a < *b)
 118                 return -1;
 119         return 0;
 120 }
 121
 122 void
 123 swapem(ulong *b, long l)
 124 {
 125         long i;
 126         ulong x, a;
 127
 128         for(i=0; i<l; i++, b++) {
 129                 a = *b;
 130                 x = (((a>>0) & 0xff) << 24) |
 131                         (((a>>8) & 0xff) << 16) |
 132                         (((a>>16) & 0xff) << 8) |
 133                         (((a>>24) & 0xff) << 0);
 134                 *b = x;
 135         }
 136 }