93 lines
2.1 KiB
C
93 lines
2.1 KiB
C
/* ascii - list lines with/without ASCII characters */
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#include <sys/types.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <string.h>
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#include <stdio.h>
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#define BUFSIZE 4*1024
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static char buf[BUFSIZE + 1]; /* input buffer - +1 for sentinel */
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static char carry[BUFSIZE]; /* buffer for partial line carryover */
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int main(argc, argv)
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int argc;
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char **argv;
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{
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int nflag = 0; /* 1 if invoked with -n */
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int ascii_line; /* set to 1 if line is all ASCII */
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int ascii_file = 1; /* set to 0 if file is not all ASCII */
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int count; /* count of characters in buf */
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char *start; /* points to beginning of line */
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register char *end; /* points to end of line */
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char *sentinel; /* points past last character in buffer */
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int carry_count; /* size of carry over */
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--argc;
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++argv;
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if (argc > 0 && strcmp(*argv, "-n") == 0) {
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nflag = 1;
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--argc;
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++argv;
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}
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switch (argc) {
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case 0:
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break;
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case 1:
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close(0);
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if (open(*argv, O_RDONLY) != 0) {
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std_err("ascii: cannot open ");
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std_err(*argv);
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std_err("\n");
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exit(1);
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}
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break;
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default:
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std_err("Usage: ascii [-n] file\n");
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exit(1);
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}
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if ((count = read(0, buf, BUFSIZE)) <= 0) exit(0);
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*(sentinel = &buf[count]) = '\n';
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start = buf;
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ascii_line = 1;
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carry_count = 0;
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while (1) {
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for (end = start; *end != '\n'; ++end)
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if ((*end & 0x80) != 0) {
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ascii_line = 0;
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ascii_file = 0;
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end = (char *) memchr(end, '\n', BUFSIZE);
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break;
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}
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if (end != sentinel) {
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++end;
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if (ascii_line != nflag) {
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if (carry_count != 0)
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fwrite(carry, carry_count, 1, stdout);
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fwrite(start, (int)(end - start), 1, stdout);
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}
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carry_count = 0;
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start = end;
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ascii_line = 1;
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} else {
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if (carry_count != 0) {
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std_err("ascii: line too long\n");
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exit(1);
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}
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if (ascii_line != nflag) {
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carry_count = end - start;
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memcpy(carry, start, carry_count);
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}
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if ((count = read(0, buf, BUFSIZE)) <= 0) break;
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*(sentinel = &buf[count]) = '\n';
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start = buf;
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}
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}
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if (ascii_line != nflag && carry_count != 0)
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fwrite(carry, carry_count, 1, stdout);
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exit(ascii_file == 0);
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}
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