98 lines
2.0 KiB
C
98 lines
2.0 KiB
C
#include <stdio.h>
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#include <errno.h>
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#include <string.h>
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#include <stdlib.h>
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// I want to perform some sort of hack using errno for flag passing
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static char should_stop = 0;
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char* ScreenString(const char* str) {
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size_t len = strlen(str);
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char* buf = malloc(len + 1);
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size_t i, buf_idx = 0;
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for(i = 0; i < len - 1; i++) {
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if (str[i] == '\\') {
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switch(str[i+1]) {
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case 'a':
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buf[buf_idx++] = '\a';
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break;
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case 'b':
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buf[buf_idx++] = '\b';
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break;
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case 'c':
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buf[buf_idx] = '\0';
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should_stop = 1;
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return buf;
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case 'f':
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buf[buf_idx++] = '\f';
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break;
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case 'n':
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buf[buf_idx++] = '\n';
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break;
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case 'r':
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buf[buf_idx++] = '\r';
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break;
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case 't':
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buf[buf_idx++] = '\t';
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break;
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case 'v':
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buf[buf_idx++] = '\v';
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break;
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case '\\':
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buf[buf_idx++] = '\\';
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break;
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case '0':
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unsigned int c = 0;
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int offset = 0;
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if (sscanf(str + i + 1, "%3o%n", &c, &offset)) {
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buf[buf_idx++] = c;
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i += offset;
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}
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break;
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default:
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buf[buf_idx++] = '\\';
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continue;
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}
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i++;
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} else {
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buf[buf_idx++] = str[i];
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}
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}
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if (i < len) buf[buf_idx] = str[i];
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errno = 0;
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return buf;
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}
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int main(int argc, const char **argv) {
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char newline = 1;
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if (argc > 1) {
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if (strcmp(argv[1], "-n") == 0) {
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newline = 0;
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argv++;
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argc--;
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}
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for (int i = 1; i < argc; i++) {
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char* screened = ScreenString(argv[i]);
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fputs(screened, stdout);
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free(screened);
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if (should_stop) return 0;
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if (i < argc - 1)
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putchar(' ');
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}
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}
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/* https://pubs.opengroup.org/onlinepubs/009604599/utilities/echo.html */
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/* This version does not support -n option and escape-sequences */
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/* https://gist.github.com/fogus/1094067/ */
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/* It seems like escape sequences are supported only by GNU's one */
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/* I'd implemented them anyway but you may like not to include them */
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/* Or to switch them with a flag */
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if (newline)
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putchar('\n');
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return 0;
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}
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