docs/cut
view code/cut.c__4.3bsd-uwisc.1986-11-07 @ 25:aea7a19d400f
Schlusspointe: So muss das verstanden werden!
| author | markus schnalke <meillo@marmaro.de> |
|---|---|
| date | Mon, 29 Jun 2015 21:37:01 +0200 |
| parents | |
| children |
line source
1 static char sccsid[] = "@(#)cut.c 1.3";
2 #
3 /* cut : cut and paste columns of a table (projection of a relation) */
4 /* Release 1.5; handles single backspaces as produced by nroff */
5 # include <stdio.h> /* make: cc cut.c */
6 # define NFIELDS 512 /* max no of fields or resulting line length */
7 # define BACKSPACE 8
8 main(argc, argv)
9 int argc; char **argv;
10 {
11 int del = '\t';
12 int i, j, count, poscnt, r, s, t;
13 int endflag, supflag, cflag, fflag, backflag, filenr;
14 int sel[NFIELDS];
15 register int c;
16 register char *p1;
17 char *p2, outbuf[NFIELDS];
18 FILE *inptr;
19 endflag = supflag = cflag = fflag = 0;
22 while (argc > 1 && argv[1][0] == '-'){
23 for (i = 1; (c = argv[1][i]) != '\0'; i++) {
24 switch(c) {
25 case 'd' : del = argv[1][++i];
26 if (del == '\0') diag("no delimiter\n");
27 break;
28 case 's': supflag++ ;
29 break;
30 case 'c': cflag++ ;
31 break;
32 case 'f': fflag++ ;
33 break;
34 default : diag("Usage: cut [-s] [-d<char>] {-c<list> | -f<list>} file ...\n");
35 break;
36 }
37 if (!endflag && (cflag || fflag)) {
38 endflag = 1;
39 r = s = t = 0;
40 do { c = argv[1][++i];
41 switch(c) {
42 case '-' : if (r) diagl();
43 r = 1;
44 if (t == 0) s = 1;
45 else {s = t; t = 0;}
46 continue;
47 case '\0' :
48 case ',' : if (t >= NFIELDS) diagl();
49 if (r) { if (t == 0) t = NFIELDS - 1;
50 if (t<s) diagl();
51 for(j = s; j <= t; j++) sel[j] = 1;
52 }
53 else sel[t] = (t > 0 ? 1 : 0);
54 r = s = t = 0;
55 if (c == '\0') {i--; break;}
56 continue;
57 default :
58 if (c< '0' || c> '9') diagl();
59 t = 10*t + c - '0';
60 continue;
61 }
62 for (j = t = 0; j < NFIELDS; j++) t += sel[j];
63 if (t == 0) diag("no fields\n");
64 } while (c != '\0');
65 }
66 }
67 --argc;
68 ++argv;
69 } /* end options */
70 if (!(cflag || fflag)) diagl();
72 --argc;
73 filenr = 1;
74 do { /* for all input files */
75 if (argc > 0) inptr = fopen(argv[filenr], "r");
76 else inptr = stdin;
78 if (inptr == NULL) {
79 write(2,"Cannot open :",14);
80 diag(argv[filenr]);
81 }
82 endflag = 0;
83 do { /* for all lines of a file */
84 count = poscnt = backflag = 0;
85 p1 = &outbuf[0] - 1 ;
86 p2 = p1;
87 do { /* for all char of the line */
88 c = fgetc(inptr);
89 if (c == EOF) {
90 endflag = 1;
91 break;
92 }
93 if (count == NFIELDS - 1) diag("line too long\n");
94 if (c != '\n') *++p1 = c;
95 if (cflag && (c == BACKSPACE)) backflag++ ; else
96 { if ( !backflag ) poscnt += 1 ; else backflag-- ;}
97 if ( backflag > 1 ) diag("cannot handle multiple adjacent backspaces\n");
98 if ( ((c == '\n') && count > 0) || c == del || cflag) {
99 count += 1;
100 if (fflag) poscnt = count ;
101 if (sel[poscnt]) p2 = p1; else p1 = p2;
102 }
103 }while (c != '\n');
104 if ( !endflag && (count > 0 || !supflag)) {
105 if (*p1 == del) *p1 = '\0';
106 else *++p1 = '\0'; /*suppress trailing delimiter*/
107 puts(outbuf);
108 }
109 } while (!endflag) ;
110 fclose(inptr);
111 } while(++filenr <= argc);
112 }
114 diag(s)
115 char *s;
116 {
117 write(2, "cut : ", 6);
118 while(*s)
119 write(2,s++,1);
120 exit(2);
121 }
122 diagl()
123 {
124 diag("bad list for c/f option\n");
125 }