126 lines
2.3 KiB
C
126 lines
2.3 KiB
C
/**
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* @brief echo - Print arguments to stdout.
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*
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* Prints arguments to stdout, possibly interpreting escape
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* sequences in the arguments.
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*
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* @copyright
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* This file is part of ToaruOS and is released under the terms
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* of the NCSA / University of Illinois License - see LICENSE.md
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* Copyright (C) 2013-2018 K. Lange
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*/
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#include <ctype.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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void show_usage(char * argv[]) {
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printf(
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"echo - print arguments\n"
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"\n"
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"usage: %s [-ne] ARG...\n"
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"\n"
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" -n \033[3mdo not output a new line at the end\033[0m\n"
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" -e \033[3mprocess escape sequences\033[0m\n"
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" -? \033[3mshow this help text\033[0m\n"
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"\n", argv[0]);
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}
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int main(int argc, char ** argv) {
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int use_newline = 1;
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int process_escapes = 0;
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int opt;
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while ((opt = getopt(argc, argv, "enh?")) != -1) {
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switch (opt) {
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case '?':
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case 'h':
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show_usage(argv);
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return 1;
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case 'n':
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use_newline = 0;
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break;
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case 'e':
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process_escapes = 1;
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break;
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}
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}
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for (int i = optind; i < argc; ++i) {
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if (process_escapes) {
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char * c = argv[i];
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while (*c) {
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if (*c == '\\') {
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c++;
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switch (*c) {
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case '\\':
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putchar('\\');
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break;
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case 'a':
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putchar('\a');
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break;
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case 'b':
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putchar('\b');
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break;
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case 'c':
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return 0;
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case 'e':
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putchar('\033');
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break;
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case 'f':
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putchar('\f');
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break;
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case 'n':
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putchar('\n');
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break;
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case 't':
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putchar('\t');
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break;
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case 'v':
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putchar('\v');
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break;
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case '0':
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{
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int i = 0;
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if (!isdigit(*(c+1)) || *(c+1) > '7') {
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break;
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}
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c++;
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i = *c - '0';
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if (isdigit(*(c+1)) && *(c+1) <= '7') {
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c++;
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i = (i << 3) | (*c - '0');
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if (isdigit(*(c+1)) && *(c+1) <= '7') {
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c++;
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i = (i << 3) | (*c - '0');
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}
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}
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putchar(i);
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}
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break;
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default:
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putchar('\\');
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putchar(*c);
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break;
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}
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} else {
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putchar(*c);
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}
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c++;
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}
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} else {
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printf("%s",argv[i]);
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}
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if (i != argc - 1) {
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printf(" ");
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}
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}
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if (use_newline) {
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printf("\n");
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}
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fflush(stdout);
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return 0;
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}
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