Port of Truncater to C

1 files changed, 174 insertions, 0 deletions

diff --git a/ponysaytruncater.c b/ponysaytruncater.c
new file mode 100644
index 0000000..9c7191e
--- /dev/null
+++ b/ponysaytruncater.c
@@ -0,0 +1,174 @@
+/**
+ * ponysaytruncater — Output truncater used by ponysay to stop large ponies from being printed badly.
+ * 
+ * DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
+ * See COPYING for details
+ */
+#include <stdio.h>
+
+
+#define  String   char*
+#define  boolean  char
+
+#define  true     1
+#define  false    0
+
+
+
+/**
+ * Stdin file descriptor ID
+ */
+#define  STDIN  0
+
+
+
+/**
+ * The number of columns on the current line
+ */
+static int x =  0;
+
+/**
+ * Escape sequence state
+ */
+static int esc = 0;
+
+/**
+ * Last bytes as written
+ */
+static boolean ok = true;
+
+
+
+
+void write(char b, int width);
+int toInt(String string);
+
+
+
+/**
+ * <p>Mane method!</p>
+ * <p>
+ *   The only argument, in addition to the executed file,
+ *   should be the width of the terminal which you get by
+ *   adding <code>`tput cols || echo 0`</code> as and argument.
+ * </p>
+ * 
+ * @param  argc  The number of startup arguments
+ * @param  argv  The startup arguments, the first is the file itself
+ * 
+ * @author  Mattias Andrée, maandree@kth.se
+ */
+void main(int argc, String* argv)
+{
+    int width = 0;
+    if (argc > 1)
+        width = toInt(*(argv + 1));
+    
+    char b = 0;
+    
+    if (width > 15) //sanity
+	while (read(STDIN, &b, 1))
+	    write(b, width);
+    else
+	while (read(STDIN, &b, 1))
+	    printf("%c", b);
+}
+
+
+/**
+ * Writes a character to stdout, iff it fits within the terminal
+ * 
+ * @param  b      The character (byte) to write
+ * @param  width  The width of the terminal
+ */
+void write(char b, int width)
+{
+    int i;
+    char nx;
+    
+    if (esc == 0)
+    {
+        if (b == '\n')
+	{
+	    if (x >= width)
+	    {
+	        // Reset background colour
+	        write('\e', width);
+		write('[', width);
+		write('4', width);
+		write('9', width);
+		write('m', width);
+	    }
+	    x = -1;
+	}
+	else if (b == '\t')
+	{
+	    // Tab to next pos ≡₈ 0
+	    nx = 8 - (x & 7);
+	    for (i = 0; i < nx; i++)
+	        write(' ', width);
+	    return; //(!)
+	}
+	else if (b == '\e')
+	    esc = 1;
+    }
+    else if (esc == 1)
+    {
+        if      (b == '[')  esc = 2;  //CSI ends with a letter, m is for colour
+	else if (b == ']')  esc = 3;  //OSI, OSI P is for palett editing in Linux VT
+	else                esc = 10; //Nothing to see here, move along
+    }
+    else if (esc == 2)
+    {
+	if ((('a' <= b) && (b <= 'z')) || (('A' <= b) && (b <= 'Z')))
+	    esc = 10;
+    }
+    else if ((esc == 3) && (b == 'P'))
+    {
+	esc = ~0;
+    }
+    else if (esc < 0)
+    {
+        esc--;
+	if (esc == ~7)
+	    esc = 10;
+    }
+    else
+        esc = 10;
+              
+    if (                                // Can be printed:
+	(x < width) ||                  //       within bounds   ∨ 
+	(esc != 0) ||                   //     ∨ escape sequence ∨
+	(ok && ((b & 0xC0) == 0x80)))   //     ∨ last with printed ∧ not first byte in character
+    {
+	printf("%c", b);
+	if ((esc == 0) && ((b & 0xC0) != 0x80))  // Count up columns of not in escape sequnce and
+	    x++;                                 // the byte is not the first byte in the character
+	ok = true;
+    }
+    else
+        ok = false;
+	
+    if (esc == 10)
+        esc = 0;
+}
+
+
+/**
+ * Converts a string to an integer
+ * 
+ * @param   string  The string to convert
+ * @return          The integer represented by the string
+ */
+int toInt(String string)
+{
+    int rc = 0;
+    String str = string;
+    char c = 0;
+    
+    while ((c = *str++) != 0)
+        rc = (rc << 1) + (rc << 3) - (c & 15);
+    
+    return -rc;
+}
+