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#include "gbos.h"
/* grep [-v][-i][-n] PAT [file]: print the lines of a file (or stdin) that
* contain the substring PAT. Plain substring matching, no regex - '.' and '*'
* are literal characters. -v inverts the match, -i folds case, -n prefixes
* each hit with its line number.
*
* NB: no statics here. A program's _DATA area starts at $A000, which is also
* where the shell leaves the command line (usr/sh.c ARGV0), so statics would
* eat argv. Locals live on the task stack below $BFFF and are always safe. */
#define MAXLINE 80 /* two terminal rows; longer lines are clipped */
static char fold(char c, unsigned char ic) {
if (ic && c >= 'A' && c <= 'Z') return (char)(c + 32);
return c;
}
/* is pat[] present anywhere in line[0..len)? */
static unsigned char contains(char *line, unsigned char len, char *pat, unsigned char ic) {
unsigned char i, j;
if (!pat[0]) return 1; /* empty pattern matches all */
for (i = 0; i < len; i++) {
for (j = 0;; j++) {
if (!pat[j]) return 1; /* ran out of pattern: a hit */
if (i + j >= len) break; /* ran out of line: no hit here */
if (fold(line[i + j], ic) != fold(pat[j], ic)) break;
}
}
return 0;
}
void main(void) {
char *argv[8];
char line[MAXLINE];
unsigned char argc = argv_parse(argv, 8);
unsigned char inv = hasflag(argv, argc, 'v') ? 1 : 0;
unsigned char ic = hasflag(argv, argc, 'i') ? 1 : 0;
unsigned char num = hasflag(argv, argc, 'n') ? 1 : 0;
unsigned char i, len = 0, hits = 0, fd = NOFD;
unsigned int lineno = 0;
char *pat = 0, *fname = 0;
int ch;
/* first non-flag word is the pattern, second (if any) is the file */
for (i = 0; i < argc; i++) {
if (argv[i][0] == '-') continue;
if (!pat) pat = argv[i];
else {
fname = argv[i];
break;
}
}
if (!pat) {
puts("usage: grep [-vin] PAT [file]");
nl();
sexit(2);
}
if (fname) {
fd = open(fname, O_READ);
if (fd == EISDIR) {
puts("grep: is a directory");
nl();
sexit(2);
}
if (fd == NOFD) {
puts("grep: no such file");
nl();
sexit(2);
}
}
for (;;) {
if (fd == NOFD) {
char c = readc();
ch = (c == EOF) ? -1 : c;
} else ch = fgetc(fd);
if (ch == '\r') continue; /* CRLF: the LF ends the line */
if (ch >= 0 && ch != '\n') { /* ordinary character */
if (len < MAXLINE) line[len++] = (char)ch;
continue;
}
if (ch < 0 && len == 0) break; /* EOF, nothing pending */
lineno++;
if (contains(line, len, pat, ic) != inv) {
if (num) {
putu(lineno);
putc(':');
}
writes(line, len); /* one batched render */
nl();
hits = 1;
}
len = 0;
if (ch < 0) break; /* EOF after a final partial line */
}
if (fd != NOFD) close(fd);
sexit(hits ? 0 : 1); /* grep(1) exit convention */
}
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