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82 lines
1.2 KiB
C
82 lines
1.2 KiB
C
#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <sys/mman.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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int
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main(int argc, char *argv[])
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{
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int fd;
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struct stat st;
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fd = open("map", O_RDONLY);
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if (!fd)
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exit(101);
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fstat(fd, &st);
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char *map = mmap(0, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
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if (map == MAP_FAILED)
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exit(102);
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char *s;
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char *arg;
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if (argc > 2)
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arg = argv[2];
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else
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arg = "+1";
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if (argc <= 1 || !argv[1][0]) {
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// default to first line
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arg = "1";
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}
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if (*arg == '+' || *arg == '-') {
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s = strstr(map, argv[1]);
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int a = atoi(arg);
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if (!s) {
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s = map;
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a = 0;
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}
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if (a > 0) {
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while (a-- > 0) {
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while (*s && *s != '\n')
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s++;
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s++;
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}
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} else {
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while (a++ <= 0 && map < s) {
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s--;
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while (map < s && *s != '\n')
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s--;
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}
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if (map < s && *s == '\n')
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s++;
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}
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} else {
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int a = atoi(arg);
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s = map;
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while (--a > 0) {
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char *n = strchr(s+1, '\n');
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if (!n)
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break;
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s = n;
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}
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if (s && *s)
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s++;
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}
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char *t = s;
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while (*t && *t != '\n')
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t++;
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if (!*t)
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return 1;
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t++;
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if (write(1, s, t-s) <= 0)
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return 2;
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return 0;
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}
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