105 lines
2.2 KiB
C
105 lines
2.2 KiB
C
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#include <stdio.h> // printf
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#include <fcntl.h>
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#include <string.h> // memchr
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#include <unistd.h> // read write
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#include <stdint.h> // uint32_t
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#include <stdlib.h> // exit
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#include <poll.h> // poll
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// OUTPUT: line-by-line strings
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#define line_size_exceeded "line exeeded max buffer size\n"
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#define MAXBUFFER 64000
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char buf[MAXBUFFER];
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void err(int error, const char *str) {
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fprintf (stderr, "%s\n", str);
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exit(error);
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}
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int main(int argc, const char **argv)
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{
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if (argc > 1) {
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printf ("usage: %s\n", argv[0]);
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return 0;
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}
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// fcntl(0, F_SETFL, O_SYNC);
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uint32_t tot_read = 0;
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uint32_t n_read = 0;
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struct pollfd pfd[1];
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int nready;
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pfd[0].fd = 0;
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while (1) {
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pfd[0].events = POLLIN;
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nready = poll(pfd, 1, 60 * 1000);
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if (nready == -1)
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err (1, "poll");
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if (nready == 0) {
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fprintf (stderr, "time out\n");
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}
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if ((pfd[0].revents & (POLLERR|POLLNVAL))) {
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fprintf (stderr, "bad fd %d", pfd[0].fd);
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err (1, "bad fd");
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}
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if ((pfd[0].revents & (POLLIN|POLLHUP))) {
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n_read = read(0, buf, sizeof(buf));
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if (n_read > 0) {
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// fprintf (stderr, "read %u characters\n", n_read);
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tot_read += n_read;
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// fprintf(stderr, "total read %u\n", tot_read);
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// fprintf(stderr, "could still read %u\n", MAXBUFFER - tot_read);
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if (tot_read == MAXBUFFER) {
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// print anyway
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write (1, buf, tot_read);
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write (2, line_size_exceeded, strlen(line_size_exceeded));
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printf(buf);
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n_read = 0;
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tot_read = 0;
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continue;
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}
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// print line by line (if any)
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char * p = NULL;
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while ((p = memchr(buf, '\n', tot_read)) != NULL) {
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uint32_t remaining = tot_read - (p - buf) - 1;
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write (1, buf, tot_read - remaining);
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// fprintf (stderr, "found retline, %u remaining chars\n", remaining);
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for (uint32_t i = 0; i < remaining ; i++) {
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buf[i] = buf[i + tot_read - remaining];
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}
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tot_read = remaining;
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n_read = 0;
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}
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}
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else if (n_read == 0) {
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// fprintf (stderr, "EOF\n");
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break;
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}
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else {
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err (1, "read");
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}
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}
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}
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if (tot_read > 0) {
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// fprintf(stderr, "print the %u characters remaining in the buffer\n", tot_read);
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write (1, buf, tot_read);
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}
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// fprintf (stderr, "end of the loop\n");
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return 0;
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}
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