forked from bonsai/harakit
129 lines
3.3 KiB
C
129 lines
3.3 KiB
C
/*
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* Copyright (c) 2023 Emma Tebibyte
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* SPDX-License-Identifier: AGPL-3.0-or-later
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*
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* This file is part of YAC coreutils.
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*
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* YAC coreutils is free software: you can redistribute it and/or modify it
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* under the terms of the GNU Affero General Public License as published by the
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* Free Software Foundation, either version 3 of the License, or (at your
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* option) any later version.
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*
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* YAC coreutils is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
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* details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see https://www.gnu.org/licenses/.
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*/
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#include <errno.h>
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#include <fcntl.h>
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#include <sysexits.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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void cat(FILE *file, bool u) {
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int byte = 0; /* variable for storing bytes as they are read */
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int p = 0; /* index counter for bytes in buffered reading */
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char buf[4096]; /* buffer for buffered reading */
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while (byte != EOF) {
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byte = fgetc(file);
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if (u) {
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putchar(byte);
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} else {
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if (p > sizeof(buf)) {
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fputs(buf, stdout);
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p = 0;
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}
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buf[p] = byte;
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p += 1;
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}
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}
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fwrite(buf, 1, p, stdout);
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fflush(stdout);
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if (file != stdin) { fclose(file); }
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}
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int main(int argc, char *argv[]) {
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bool u = false;
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int opt;
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int i;
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extern int optind;
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while ((opt = getopt(argc, argv, "u")) != -1) {
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switch (opt) {
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/*
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* From cat(1p):
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*
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* -u Write bytes from the input file to the standard output
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* without delay as each is read.
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*/
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case 'u':
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u = true;
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break;
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default:
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printf("Usage: %s (-u) file...\n", argv[0]);
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return EX_USAGE;
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}
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}
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/*
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* From cat(1p):
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*
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* file A pathname of an input file. If no file operands are
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* specified, the standard input shall be used. If a file is
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* '-', the cat utility shall read from the standard input at
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* that point in the sequence. The cat utility shall not close
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* and reopen standard input when it is referenced in this way,
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* but shall accept multiple occurrences of '-' as a file
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* operand.
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*/
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if (optind == argc) {
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cat(stdin, u);
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}
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FILE *file;
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for (i = optind; i < argc; i++) {
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if (argv[i][0] == '-' && argv[i][1] != '\0') {
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continue;
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} if (strcmp(argv[i], "-") == 0) {
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file = stdin;
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} else if ((file = fopen(argv[i], "r")) == NULL) {
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switch (errno) {
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case EACCES:
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printf("%s: %s: Permission denied.\n", argv[0], argv[i]);
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return EX_NOINPUT;
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case EISDIR:
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printf("%s: %s: Is a directory.\n", argv[0], argv[i]);
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return EX_NOINPUT;
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case ELOOP:
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printf("%s: %s: Is a symbolic link loop.\n", argv[0], argv[i]);
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return EX_UNAVAILABLE;
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case EMFILE:
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printf("%s: Internal error.\n", argv[0]);
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return EX_SOFTWARE;
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case ENOENT: case ENOTDIR: case ENXIO:
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printf("%s: %s: No such file or directory.\n", argv[0], argv[i]);
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return EX_NOINPUT;
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default:
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printf("%s: Unknown error.\n", argv[0]);
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return EX_UNAVAILABLE;
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}
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}
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cat(file, u);
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}
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return EX_OK;
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}
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