Groovy Hex Dump

## HexDump.groovy
package com.octodecillion.util

import static java.lang.Character.*

/**
 * Simple ASCII hex dump of file.
 * <p>
 * Example output:<br>
 * <pre>
 * OFFSET     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f  | ASCII
 * 00000000: 4c 69 6e 65 20 6f 6e 65 0d 0a 4c 69 6e 65 20 74  | L i n e   o n e . . L i n e   t
 * 00000010: 77 6f 0d 0a 4c 69 6e 65 20 74 68 72 65 65 0d 0a  | w o . . L i n e   t h r e e . .
 * 00000020: 21 2f 30 31 32 33 34 0d 0a 35 0d 0a 36 37 38 39  | ! / 0 1 2 3 4 . . 5 . . 6 7 8 9
 * 00000030: 41 7a                                            | A z
 * * </pre>
 * <p>
 * How to run on Windows cmd shell:
 * <pre>
 * hex-dump>groovy -cp src\\groovy;src\\test\\groovy;src\\test src\\groovy\\com\\octodecillion\\util\\HexDump.groovy src\\test\\resources\\test-data-1.txt
 * </pre>
 *
 * @author josef betancourt
 *
 */
class HexDump {
	/** */
	static main(args) {
		new HexDump().dump(args[0],{println it})
	}

	/** */
	public Object dump(filePath, Closure printer){
		def file = new File(filePath)

		printer printHeader()

		def (startCounter, counter) = [0,0]
		def bytes = []

		file.eachByte{
			bytes << it
			counter++
			if( !(counter % NUM_BIN_COLS)){
				printer doLine(bytes,startCounter)
				bytes = []
				startCounter=counter
			}
		}

		printer doLine(bytes, startCounter)
	}

	/** */
	private doLine(List hex, int counter){
		if(hex.size()){
			def buf = new StringBuffer()
			buf.append(printCounter(counter,OFFSET_WIDTH,PAD_CHAR,':'))
			hex.each{
				buf.append(printInCol(it,BYTE_WIDTH,PAD_CHAR,''))
			}

			def unusedCols = NUM_BIN_COLS - hex.size()
			buf.append(( (unusedCols ? ('   ' * unusedCols) : '') + ' '
				+ HEX_ASCII_SEP))

			hex.each{
				buf.append((between(it,31,127) ? toString((char)it)
					+ ' ' : '. '))
			}

			buf
		}
	}

	/** */
	private between(value,low, high){
		return value >= low && value <= high
		// (low..high).contains(value)
	}

	/** */
	private printHeader() {
		def buf = new StringBuffer()

		buf.append("OFFSET".padRight(9))

		(0..15).each{
			buf.append("${toHex(it).padLeft(3)}")
		}

		buf.append("${'| ASCII'.padLeft(9)}")
		buf
	}

	/** */
	private printCounter(num, padWidth, padChar, suffix){
		return printInCol(num,OFFSET_WIDTH,PAD_CHAR,':')
	}

	/** */
	private printInCol(num, padWidth, padChar, suffix){
		return "${toHex(num).padLeft(padWidth,padChar)}$suffix "
	}

	/** */
	private String toHex(num){
		Integer.toString(num,HEX_BASE)
	}

	private Closure printer
	private static final int NUM_BIN_COLS = 16
	private static final int BYTE_WIDTH = 2
	private static final int COLUMNS = 15 * COL_SIZE
	private static final String HEX_ASCII_SEP = '| '
	private static final String BLANK_COL = '  '
	private static final int HEX_BASE = 16
	private static final int OFFSET_WIDTH = 8
	private static final int COL_SIZE = 2
	private static final String PAD_CHAR = '0'

}

## HexDumpTest.groovy
/**
 *
 */
package com.octodecillion.util

import groovy.lang.GroovyClassLoader.InnerLoader;

import org.codehaus.groovy.reflection.ReflectionUtils

import static org.junit.Assert.*;

import org.junit.Ignore;
import org.junit.Test;

/**
  Run of HexDump.
  <p>
  Run as Windows cmd:
  <pre>
  hex-dump>groovy -cp src\\groovy;src\\test\\groovy src\\test\\groovy\\com\\octodecillion\\util\\HexDumpTest.groovy
  </pre>

  In Eclipse 4.3 must create a run configuration with:
  <pre>
	Program arguments:
	--classpath "${workspace_loc:/hex-dump}\src\groovy;${workspace_loc:/hex-dump}\bin;${workspace_loc:/hex-dump}\src\test" --main groovy.ui.GroovyMain "${resource_loc:/hex-dump/src/test/groovy/com/octodecillion/util//HexDumpTest.groovy}"

	VM arguments:
	-Dgroovy.home="${groovy_home}"

	Working directory:
	${workspace_loc:/hex-dump}

	Add JUnit 4 library to classpath.
	</pre>

  @author jbetancourt

 */
class HexDumpTest {

	private static final String DATA_FILE_1 =
	  "src/test/resources/test-data-1.txt"

	@Test
	void headerIsCorrect(){
		def expected = 'OFFSET     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f  | ASCII'
		def actual = new HexDump().printHeader()
		assert expected == actual.toString()
	}

	@Test
	void dump() {
		def file = new File(DATA_FILE_1)
		assert file.exists()

		def lines = []
		new HexDump().dump(file.getPath()){ line -> lines << line}

		def expected =
		 '00000020: 21 2f 30 31 32 33 34 0d 0a 35 0d 0a 36 37 38 39  | ! / 0 1 2 3 4 . . 5 . . 6 7 8 9 '

		def cnt = 0
		lines.each{
			if(cnt++ == 3){
				assert (it.toString()
				  == expected)
			}

			println it
		}

	}

	@Test
	void dump2() {
		def file = new File(DATA_FILE_1)
		assert file.exists()

		def lines = []
		new HexDump().dump(file.getPath()){ line -> lines << line}

		def expected =
		 '00000000: 4c 69 6e 65 20 6f 6e 65 0d 0a 4c 69 6e 65 20 74  | L i n e   o n e . . L i n e   t '

		def cnt = 0
		lines.each{
			if(cnt++ == 1){
				assert (it.toString()
				  == expected)
			}
		}

	}


}