tseq.c - plan9port - [fork] Plan 9 from user space
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       ---
       tseq.c (1683B)
       ---
            1 #include <u.h>
            2 #include <libc.h>
            3 
            4 double        min = 1.0;
            5 double        max = 0.0;
            6 double        incr = 1.0;
            7 int        constant = 0;
            8 int        nsteps;
            9 char        *format;
           10 
           11 void
           12 usage(void)
           13 {
           14         fprint(2, "usage: seq [-fformat] [-w] [first [incr]] last\n");
           15         exits("usage");
           16 }
           17 
           18 void
           19 buildfmt(void)
           20 {
           21         char *dp;
           22         int w, p, maxw, maxp;
           23         static char fmt[16];
           24         char buf[32];
           25         double val;
           26 
           27         format = "%g\n";
           28         if(!constant)
           29                 return;
           30         maxw = 0;
           31         maxp = 0;
           32         for(val = min; val <= max; val += incr){
           33                 sprint(buf, "%g", val);
           34                 if(strchr(buf, 'e')!=0)
           35                         return;
           36                 dp = strchr(buf,'.');
           37                 w = dp==0? strlen(buf): dp-buf;
           38                 p = dp==0? 0: strlen(strchr(buf,'.')+1);
           39                 if(w>maxw)
           40                         maxw = w;
           41                 if(p>maxp)
           42                         maxp = p;
           43         }
           44         if(maxp > 0)
           45                 maxw += maxp+1;
           46         sprint(fmt,"%%%d.%df\n", maxw, maxp);
           47         format = fmt;
           48 }
           49 
           50 void
           51 main(int argc, char *argv[]){
           52         int j, n;
           53         char buf[256], ffmt[4096];
           54         double val;
           55 
           56         ARGBEGIN{
           57         case 'w':
           58                 constant++;
           59                 break;
           60         case 'f':
           61                 format = ARGF();
           62                 if(format[strlen(format)-1] != '\n'){
           63                         sprint(ffmt, "%s\n", format);
           64                         format = ffmt;
           65                 }
           66                 break;
           67         default:
           68                 goto out;
           69         }ARGEND
           70     out:
           71         if(argc<1 || argc>3)
           72                 usage();
           73         max = atof(argv[argc-1]);
           74         if(argc > 1)
           75                 min = atof(argv[0]);
           76         if(argc > 2)
           77                 incr = atof(argv[1]);
           78         if(incr == 0){
           79                 fprint(2, "seq: zero increment\n");
           80                 exits("zero increment");
           81         }
           82         if(!format)
           83                 buildfmt();
           84         if(incr > 0){
           85                 for(val = min; val <= max; val += incr){
           86                         n = sprint(buf, format, val);
           87                         if(constant)
           88                                 for(j=0; buf[j]==' '; j++)
           89                                         buf[j] ='0';
           90                         write(1, buf, n);
           91                 }
           92         }else{
           93                 for(val = min; val >= max; val += incr){
           94                         n = sprint(buf, format, val);
           95                         if(constant)
           96                                 for(j=0; buf[j]==' '; j++)
           97                                         buf[j] ='0';
           98                         write(1, buf, n);
           99                 }
          100         }
          101         exits(0);
          102 }