+ file-part-hex

README.md

@@ -1,7 +1,7 @@
 | English |
 
 # Introduction
-Handy scripts collection for handling files.
+Handy scripts for handling files.
 
 Usage instructions are placed under each folder.
 
@@ -20,9 +20,11 @@ Useful to make a record before reboot, and confirm after reboot.
 
 Make life of reboot easier.
 
+# file-part-hex
+Hex view of part of a file.
+
 # Roadmap
-1. file-part-hex: Hex view of part of a file.
-2. compare-2-folders
+compare-2-folders
 
 - - - -
 
@@ -45,3 +47,6 @@ Make life of reboot easier.
 收集 Linux 运行状态，包括进程、网络、挂载点、环境变量，写入 linux.status 文件夹。
 
 可用于重启前先记录，重启后对照记录核对服务是否齐全，让重启工作轻松点。
+
+# file-part-hex
+十六进制显示文件部分内容。

file-part-hex/FilePartHex.java

@@ -0,0 +1,135 @@
+import java.io.*;
+import java.util.*;
+
+//----------------------------------------------------------------------------
+/**
+ * Hex view of part of a file.
+ *
+ * <p>
+ * Written by CHEN Qingcan, Spring 2020, Foshan China <br>
+ * Open source under WTFPL (Do What The Fuck You Want To Public License) http://www.wtfpl.net
+ *
+ * <p>
+ * Run as script via Java 11: <br>
+ * <code>
+ * java FilePartHex.java
+ * </code>
+ */
+public final class FilePartHex {
+
+	static final BufferedReader stdin = new BufferedReader (new InputStreamReader (System.in));
+	static final PrintStream stdout = System.out;
+	static final PrintStream stderr = System.err;
+	static final String HR = "--------";
+
+	static Config config = null;
+	static class  Config {
+		String    where;
+		Integer   offset = 0;
+		Integer   length = 0x10 * 0x10;
+
+		//--------------------------------------------------------------------
+		static Config getInstance (final String... args) throws IOException {
+			return args.length > 0 ? fromArgs (args) : fromStdIn ();
+		}
+
+		//--------------------------------------------------------------------
+		/** Get configuration from command line arguments. */
+		static Config fromArgs (final String... args) {
+			var config = new Config ();
+			if (args.length >= 1) {
+				config.where = args[0];
+			}
+			try {
+				if (args.length >= 2) {
+					config.offset = Integer.valueOf (args[1]);
+				}
+				if (args.length >= 3) {
+					config.length = Integer.valueOf (args[2]);
+				}
+			} catch (NumberFormatException e) {
+				stderr.println ("Argument offset and length should be a number.");
+			}
+			return config;
+		}
+
+		//--------------------------------------------------------------------
+		/** Get configuration from standard input. */
+		private static Config fromStdIn () throws IOException {
+			var config = new Config ();
+			config.where = stdinLine ("", "File path: ");
+			try { config.offset = Integer.valueOf (stdinLine ("0", "Offset (default to 0): ")); }
+			catch (NumberFormatException e) { /* ignore */ }
+			try { config.length = Integer.valueOf (stdinLine ("256", "Length (default to 256): ")); }
+			catch (NumberFormatException e) { /* ignore */ }
+			return config;
+		}
+
+		//--------------------------------------------------------------------
+		/** Prompt and then read a line from standard input. Return default value if empty input. */
+		static String stdinLine (final String defaultLine, final String format, final Object... args)
+			throws IOException {
+			stdout.printf (format, args);
+			String line = stdin.readLine ().trim ();
+			return line.length () > 0 ? line : defaultLine;
+		}
+
+	}
+
+	//------------------------------------------------------------------------
+	/** Program entry */
+	public static void main (final String... args) {
+		try {
+			config = Config.getInstance (args);
+			var r  = input ();
+			output (r);
+		} catch (IOException e) {
+			stderr.println (e.getMessage ());
+		}
+	}
+
+	//------------------------------------------------------------------------
+	/** Read bytes from file */
+	private static byte[] input () throws FileNotFoundException, IOException {
+		try (var in = new FileInputStream (config.where)) {
+			var r = new byte [config.length];
+			in.skip (config.offset);
+			int n = in.read (r, 0, config.length);
+			return Arrays.copyOf (r, n > 0 ? n : 0);
+		}
+	}
+
+	//------------------------------------------------------------------------
+	/** Bytes in hex to standard output. */
+	private static void output (final byte[] r) {
+		// table header
+		stdout.println (config.where);
+		stdout.printf ("offset %d (%X in hex) length %d (%X in hex)%n",
+			config.offset, config.offset, config.length, config.length);
+
+		// column header
+		stdout.print ("\t  ");
+		for (int i = 0 ; i < 0x10 ; i++) {
+			stdout.printf ("%02X ", i);
+		}
+		stdout.printf ("%n\t ");
+		for (int i = 0 ; i < 0x10 * 3 ; i++) {
+			stdout.print ('-');
+		}
+
+		var visible = new StringBuilder ();
+		for (int i = 0 ; i < r.length ; i++) {
+			if (i % 0x10 == 0) {
+				// line header
+				stdout.println (visible.toString ());
+				visible.setLength (0);
+				stdout.printf ("%02X\t| ", config.offset + i);
+			}
+
+			stdout.printf ("%02X ", r[i]);
+			visible.append (r[i] >= 0x20 && r[i] <= 0x7E ? (char) r[i] : '.');
+		}
+		stdout.println (visible.toString ());
+	}
+
+}

file-part-hex/README.md

@@ -0,0 +1,49 @@
+| English |
+
+# file-part-hex
+Hex view of part of a file.
+
+# System Requirements
+Java ≥ 11
+
+# Usage
+If no command line argument provided, the script will prompt to ask.
+
+Windows:
+```dos
+file-part-hex.bat [file] [offset] [length]
+```
+
+Linux:
+```bash
+./file-part-hex.sh [file] [offset] [length]
+```
+
+# Further Development
+Preview window supports MBCS (Multi-Byte Character Set), like GB2312, GBK, UTF-8, UTF-16.
+
+- - - -
+
+| Chinese | 中文 |
+
+# file-part-hex
+十六进制显示文件部分内容。
+
+# 系统需求
+Java ≥ 11
+
+# 用法
+如无命令行参数，脚本将提示输入。
+
+Windows:
+```dos
+file-part-hex.bat [file] [offset] [length]
+```
+
+Linux:
+```bash
+./file-part-hex.sh [file] [offset] [length]
+```
+
+# 展望
+支持多字节字符 (MBCS) 的预览，如 GB2312、GBK、UTF-8、UTF-16。

file-part-hex/file-part-hex.bat

@@ -0,0 +1,9 @@
+@echo off
+if defined JAVA_HOME (
+	set JAVA=%JAVA_HOME%\bin\java
+) else if defined JRE_HOME (
+	set JAVA=%JRE_HOME%\bin\java
+) else (
+	set JAVA=java
+)
+%JAVA% FilePartHex.java %*

file-part-hex/file-part-hex.sh

@@ -0,0 +1,2 @@
+#!/usr/bin/bash
+java FilePartHex.java $*

find-charset-files/FindCharsetFiles.java

@@ -45,8 +45,7 @@ public String toString () {
 
 		//--------------------------------------------------------------------
 		/** Get configuration from standard input. */
-		static Config fromStdIn ()
-			throws IOException {
+		static Config fromStdIn () throws IOException {
 			var config = new Config ();
 			String line;