mirror of
https://github.com/erkin/ponysay.git
synced 2024-11-29 07:27:59 +01:00
153 lines
3.2 KiB
C
153 lines
3.2 KiB
C
/* ponysaytruncater
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* Output truncater used by ponysay to stop
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* large ponies from being printed badly.
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*
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* Licensed under WTFPL
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* See COPYING for details
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*/
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#include <stdio.h>
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#define String char*
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#define boolean char
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#define true 1
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#define false 0
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/* Stdin file descriptor ID */
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#define STDIN 0
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/* The number of columns on the current line */
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static int col = 0;
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/* Escape sequence state */
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static int esc = 0;
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/* Last bytes as written */
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static boolean ok = true;
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void write(char b, int width);
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int toInt(String string);
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/* Mane method!
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* The only argument, in addition to the executed file,
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* should be the width of the terminal which you get by
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* adding <code>`tput cols || echo 0`</code> as an argument.
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*
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* @param argc The number of startup arguments
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* @param argv The startup arguments, the first is the file itself
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*
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* @author Mattias Andrée, maandree@kth.se
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*/
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void main(int argc, String* argv)
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{
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int width = 0;
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if (argc > 1)
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width = toInt(*(argv + 1));
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char b = 0;
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if (width > 15) /* sanity */
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while (read(STDIN, &b, 1))
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write(b, width);
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else
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while (read(STDIN, &b, 1))
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printf("%c", b);
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}
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/* Writes a character to stdout, iff it fits within the terminal
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*
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* @param b The character (byte) to write
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* @param width The width of the terminal
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*/
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void write(char b, int width)
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{
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int i;
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char tabstop;
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if (esc == 0)
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{
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if (b == '\n')
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{
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if (col >= width)
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{
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/* Reset background colour */
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write('\e', width);
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write('[', width);
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write('4', width);
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write('9', width);
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write('m', width);
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}
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col = -1;
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}
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else if (b == '\t')
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{
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/* Tab to next pos ≡₈ 0 */
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tabstop = 8 - (col & 7);
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for (i = 0; i < tabstop; i++)
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write(' ', width);
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return; /* (!) */
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}
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else if (b == '\e')
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esc = 1;
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}
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else if (esc == 1)
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{
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if (b == '[') esc = 2; /* CSI: CSI ends with a letter, m is for colour */
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else if (b == ']') esc = 3; /* OSI: OSI P is for palette editing in Linux VT */
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else esc = 10; /* Nothing to see here, move along */
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}
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else if (esc == 2)
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{
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if ((('a' <= b) && (b <= 'z')) || (('A' <= b) && (b <= 'Z')))
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esc = 10;
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}
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else if ((esc == 3) && (b == 'P'))
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{
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esc = ~0;
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}
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else if (esc < 0)
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{
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esc--;
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if (esc == ~7)
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esc = 10;
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}
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else
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esc = 10;
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if (
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/* Can be printed:
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within bounds ∨
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∨ escape sequence ∨
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∨ last with printed ∧ not first byte in character */
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(col < width) ||
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(esc != 0) ||
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(ok && ((b & 0xC0) == 0x80)))
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{
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printf("%c", b);
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if ((esc == 0) && ((b & 0xC0) != 0x80))
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/* Count up columns of not in escape sequnce and */
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col++; /* the byte is not the first byte in the character */
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ok = true;
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}
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else
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ok = false;
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if (esc == 10)
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esc = 0;
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}
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/* Converts a string to an integer
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*
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* @param string The string to convert
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* @return The integer represented by the string
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*/
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int toInt(String string)
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{
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int rc = 0;
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String str = string;
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char c = 0;
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while ((c = *str++) != 0)
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rc = (rc << 1) + (rc << 3) - (c & 15);
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return -rc;
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}
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