truncates the output to the width of stderr

1 files changed, 150 insertions, 0 deletions

diff --git a/Truncater.java b/Truncater.java
new file mode 100644
index 0000000..a5eb99d
--- /dev/null
+++ b/Truncater.java
@@ -0,0 +1,150 @@
+import java.io.*;
+
+public class Truncater
+{
+    public static void main(final String... args) throws IOException
+    {
+	final int width;
+	if ((width = getWidth()) > 15) //sanity
+	{
+	    final OutputStream stdout = new BufferedOutputStream(System.out);
+	    OutputStream out = new OutputStream()
+		    {
+			/**
+			 * The number of column on the current line
+			 */
+			private int x = 0;
+			
+			/**
+			 * Escape sequence state
+			 */
+			private int esc = 0;
+			
+			/**
+			 * Last bytes as written
+			 */
+			private boolean ok = true;
+			
+			
+			/**
+			 * {@inheritDoc}
+			 */
+			@Override
+			public void write(final int b) throws IOException
+			{
+			    if (this.esc == 0)
+			    {
+				if (b == '\n')
+				{
+				    if (x >= width)
+				    {
+					write('\033');
+					write('[');
+					write('4');
+					write('9');
+					write('m');
+				    }
+				    this.x = -1;
+				}
+				else if (b == '\t')
+				{
+				    int nx = 8 - (x & 7);
+				    for (int i = 0; i < nx; i++)
+					write(' ');
+				    return; //(!)
+				}
+				else if (b == '\033')
+				    this.esc = 1;
+			    }
+			    else if (this.esc == 1)
+			    {
+				if      (b == '[')  this.esc = 2;
+				else if (b == ']')  this.esc = 3;
+				else                this.esc = 10;
+			    }
+			    else if (this.esc == 2)
+			    {
+				if ((('a' <= b) && (b <= 'z')) || (('A' <= b) && (b <= 'Z')))
+				    this.esc = 10;
+			    }
+			    else if ((this.esc == 3) && (b == 'P'))
+			    {
+				this.esc = ~0;
+			    }
+			    else if (this.esc < 0)
+			    {
+				this.esc--;
+				if (this.esc == ~7)
+				    this.esc = 10;
+			    }
+			    else
+				this.esc = 10;
+			        
+			    if ((x < width) || (this.esc != 0) || (ok && ((b & 0xC0) == 0x80)))
+			    {
+				stdout.write(b);
+				if (this.esc == 0)
+				    if ((b & 0xC0) != 0x80)
+					x++;
+				ok = true;
+			    }
+			    else
+				ok = false;
+			    if (this.esc == 10)
+				this.esc = 0;
+			}
+			
+			/**
+			 * {@inheritDoc}
+			 */
+			@Override
+			public void flush() throws IOException
+			{
+			    stdout.flush();
+			}
+		};
+	    
+	    System.setOut(new PrintStream(out));
+	}
+	
+	
+	InputStream in = System.in;
+	OutputStream out = System.out;
+	
+	for (int d; (d = in.read()) != -1;)
+	    out.write(d);
+	out.flush();
+    }
+
+    /**
+     * Gets the width of the terminal
+     *
+     * @return  The width of the terminal
+     */
+    public static int getWidth()
+    {
+	try
+	{
+	    Process process = (new ProcessBuilder("/bin/sh", "-c", "tput cols 2> " + (new File("/dev/stderr")).getCanonicalPath())).start();
+	    String rcs = new String();
+	    InputStream stream = process.getInputStream();
+	    int c;
+	    while (((c = stream.read()) != '\n') && (c != -1))
+		rcs += (char)c;
+	    try
+	    {
+		stream.close();
+	    }
+	    catch (final Throwable err)
+	    {
+		//Ignore
+	    }
+	    return Integer.parseInt(rcs);
+	}
+	catch (final Throwable err)
+	{
+	    return -1;
+	}
+    }
+}
+