From 8682553498d32d3c18dea41c598ab40de18404a3 Mon Sep 17 00:00:00 2001 From: user Date: Thu, 16 Jul 2026 07:30:34 +0200 Subject: tools: wc, head, and an argc/argv demo (args) + libc.c helpers - c/libc.c: shared C helpers linked into every program - putu (print decimal), atou (parse decimal), argv_parse (tokenize getargs() into argc/argv). - wc: count lines/words/chars of stdin. head [n]: first n lines (drains rest to EOF). args: argc/argv demo. - pid now uses libc putu; build.sh links libc.c; Makefile CBLOBS + libc dep. - README: document the new tools + argv_parse. - verified: 'args one two three' -> argc=3/argv[..]; wc '2 3 16'; head 2. --- c/libc.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) create mode 100644 c/libc.c (limited to 'c/libc.c') diff --git a/c/libc.c b/c/libc.c new file mode 100644 index 0000000..3b9883b --- /dev/null +++ b/c/libc.c @@ -0,0 +1,34 @@ +/* gbos libc C helpers (compiled once, linked into every program). */ +#include "gbos.h" + +/* print an unsigned int in decimal */ +void putu(unsigned int n) { + char buf[5]; + unsigned char i = 0; + if (n == 0) { putc('0'); return; } + while (n) { buf[i++] = '0' + (n % 10); n = n / 10; } + while (i) putc(buf[--i]); +} + +/* parse a decimal number (stops at the first non-digit) */ +unsigned char atou(const char *s) { + unsigned char n = 0; + while (*s >= '0' && *s <= '9') { n = n * 10 + (*s - '0'); s++; } + return n; +} + +/* tokenize the argument string in place into argv[]; returns argc. + (replaces the spaces in the arg string with NULs) */ +unsigned char argv_parse(char **argv, unsigned char maxv) { + char *p = getargs(); + unsigned char argc = 0; + for (;;) { + while (*p == ' ') p++; + if (*p == 0) break; + if (argc < maxv) argv[argc] = p; + argc++; + while (*p != 0 && *p != ' ') p++; + if (*p == ' ') *p++ = 0; + } + return argc; +} -- cgit v1.3.1-sl0p