diff options
| -rw-r--r-- | c/gbos.h | 2 | ||||
| -rw-r--r-- | c/head.c | 13 | ||||
| -rw-r--r-- | c/libc.c | 24 | ||||
| -rw-r--r-- | c/wc.c | 23 |
4 files changed, 47 insertions, 15 deletions
@@ -17,4 +17,6 @@ unsigned char getpid(void); void putu(unsigned int n); /* print decimal */ unsigned char atou(const char *s); /* parse decimal */ unsigned char argv_parse(char **argv, unsigned char maxv); /* argc/argv */ +unsigned char hasflag(char **argv, unsigned char argc, char f); /* -x flag */ +char *optval(char **argv, unsigned char argc, char opt); /* -x VALUE */ #endif @@ -1,12 +1,13 @@ #include "gbos.h" -/* head [n]: print the first n lines of stdin (default 10). Drains the rest to - EOF so the shell sees a clean end of input. */ +/* head [-n N] [N]: print the first N lines of stdin (default 10). */ void main(void) { - char *a = getargs(); - unsigned char n = 10; - unsigned char lines = 0; + char *argv[8]; + unsigned char argc = argv_parse(argv, 8); + char *nv = optval(argv, argc, 'n'); + unsigned char n = 10, lines = 0; char c; - if (*a) n = atou(a); + if (nv) n = atou(nv); + else if (argc > 0 && argv[0][0] >= '0' && argv[0][0] <= '9') n = atou(argv[0]); for (;;) { c = readc(); if (c == EOF) break; @@ -32,3 +32,27 @@ unsigned char argv_parse(char **argv, unsigned char maxv) { } return argc; } + +/* return nonzero if single-char flag `f` appears (as -f or within -abc) */ +unsigned char hasflag(char **argv, unsigned char argc, char f) { + unsigned char i, j; + for (i = 0; i < argc; i++) { + if (argv[i][0] != '-') continue; + for (j = 1; argv[i][j]; j++) + if (argv[i][j] == f) return 1; + } + return 0; +} + +/* return the value for option -<opt> ("-n 5" or "-n5"), or 0 if absent */ +char *optval(char **argv, unsigned char argc, char opt) { + unsigned char i; + for (i = 0; i < argc; i++) { + if (argv[i][0] == '-' && argv[i][1] == opt) { + if (argv[i][2]) return &argv[i][2]; + if (i + 1 < argc) return argv[i+1]; + return 0; + } + } + return 0; +} @@ -1,20 +1,25 @@ #include "gbos.h" -/* wc: count lines, words, chars of stdin (like `wc`). */ +/* wc [-l] [-w] [-c]: count lines, words, chars of stdin (default: all). */ void main(void) { + char *argv[8]; + unsigned char argc = argv_parse(argv, 8); + unsigned char wl = hasflag(argv, argc, 'l'); + unsigned char ww = hasflag(argv, argc, 'w'); + unsigned char wch = hasflag(argv, argc, 'c'); unsigned int lines = 0, words = 0, chars = 0; - unsigned char inword = 0; + unsigned char inword = 0, first = 1; char c; + if (!wl && !ww && !wch) { wl = ww = wch = 1; } for (;;) { c = readc(); if (c == EOF) break; chars++; if (c == '\n') lines++; - if (c == ' ' || c == '\n' || c == '\r' || c == '\t') { - inword = 0; - } else if (!inword) { - inword = 1; - words++; - } + if (c == ' ' || c == '\n' || c == '\r' || c == '\t') inword = 0; + else if (!inword) { inword = 1; words++; } } - putu(lines); putc(' '); putu(words); putc(' '); putu(chars); nl(); + if (wl) { putu(lines); first = 0; } + if (ww) { if (!first) putc(' '); putu(words); first = 0; } + if (wch) { if (!first) putc(' '); putu(chars); } + nl(); } |