Initial commit

hex.py

@@ -0,0 +1,184 @@
+#!/usr/bin/env python3
+# --------------------------------------------------------------------------
+# Hexdump command line utility. Requires Python 3.
+#
+# Author: Darren Mulholland <darren@mulholland.xyz>
+# License: Public Domain
+# --------------------------------------------------------------------------
+
+import argparse
+import os
+import signal
+import sys
+import shutil
+
+
+# Application version number.
+__version__ = '2.0.0'
+
+
+# Command line help text.
+helptext = """
+Usage: %s [FLAGS] [OPTIONS] ARGUMENTS
+
+  Hexdump utility.
+
+Arguments:
+  [file]                File to dump. Defaults to stdin.
+
+Options:
+  -l, --line <int>      Bytes per line in output (defaults to 16).
+  -n, --number <int>    Number of bytes to read.
+  -o, --offset <int>    Byte offset at which to begin reading.
+
+Flags:
+      --help            Display this help text and exit.
+      --version         Display version number and exit.
+
+""" % os.path.basename(sys.argv[0])
+
+
+# Custom argparse 'action' to print our own help text instead of the default.
+class HelpAction(argparse.Action):
+    def __call__(self, parser, namespace, values, option_string=None):
+        print(helptext.strip())
+        sys.exit()
+
+
+# Suppress 'broken pipe' warnings when piping output through pagers.
+# This resolves the issue when running under Cygwin on Windows.
+if hasattr(signal, 'SIGPIPE'):
+    signal.signal(signal.SIGPIPE, signal.SIG_DFL)
+
+
+# Wrapper for the sys.stdout.write() function.
+def write(s):
+    # Suppress 'broken pipe' warnings when piping output through pagers.
+    # This resolves the issue when running natively on Windows.
+    try:
+        sys.stdout.write(s)
+    except (IOError, OSError):
+        sys.exit()
+
+
+# Print a single line of output to stdout.
+def writeln(offset, buffer, bytes_per_line):
+
+    # Write the line number.
+    write('% 6X │' % offset)
+
+    for i in range(bytes_per_line):
+
+        # Write an extra space in front of every fourth byte except the first.
+        if i > 0 and i % 4 == 0:
+            write(' ')
+
+        # Write the byte in hex form, or a spacer if we're out of bytes.
+        write(' %02X' % buffer[i] if i < len(buffer) else '   ')
+
+    write(' │ ')
+
+    # Write a character for each byte in the printable ascii range.
+    for i in range(len(buffer)):
+        write('%c' % buffer[i] if 32 <= buffer[i] <= 126 else '·')
+
+    write('\n')
+
+
+# Dump the specified file to stdout.
+def dump(file, offset, bytes_to_read, bytes_per_line):
+
+    # If an offset has been specified, attempt to seek to it.
+    if offset:
+        if file.seekable():
+            file.seek(offset)
+        else:
+            sys.exit('Error: %s is not seekable.' % file.name)
+
+    # Print a line.
+    cols, _ = shutil.get_terminal_size()
+    print("─" * cols)
+
+    # Read and dump one line per iteration.
+    while True:
+
+        # If bytes_to_read < 0 (read all), try to read one full line.
+        if bytes_to_read < 0:
+            max_bytes = bytes_per_line
+
+        # Else if line length < bytes_to_read, try to read one full line.
+        elif bytes_per_line < bytes_to_read:
+            max_bytes = bytes_per_line
+
+        # Otherwise, try to read all the remaining bytes in one go.
+        else:
+            max_bytes = bytes_to_read
+
+        # Attempt to read up to max_bytes from the file.
+        buffer = file.read(max_bytes)
+
+        # A buffer length of zero means we're done.
+        if len(buffer):
+            writeln(offset, buffer, bytes_per_line)
+            offset += len(buffer)
+            bytes_to_read -= len(buffer)
+        else:
+            break
+
+    print("─" * cols)
+
+
+def main():
+
+    # Setting add_help to false prevents the parser from automatically
+    # generating a -h flag.
+    parser = argparse.ArgumentParser(add_help=False)
+
+    # The filename argument is optional. We default to reading from
+    # stdin if it's omitted.
+    parser.add_argument('file',
+        nargs='?',
+        help='file to dump (default: stdin)',
+        type=argparse.FileType('rb'),
+        default=sys.stdin.buffer,
+    )
+
+    # Flags.
+    parser.add_argument('--help',
+        action = HelpAction,
+        nargs=0,
+        help = 'print this help message and exit',
+    )
+    parser.add_argument('--version',
+        action='version',
+        version=__version__,
+    )
+
+    # Options.
+    parser.add_argument('-l', '--line',
+        help='bytes per line in output (default: 16)',
+        default=16,
+        type=int,
+        dest='bpl',
+    )
+    parser.add_argument('-n', '--number',
+        nargs='?',
+        help='number of bytes to read (default: 256)',
+        type=int,
+        default=-1,
+        const=256,
+        dest='btr',
+    )
+    parser.add_argument('-o', '--offset',
+        help='offset at which to begin reading (default: 0)',
+        type=int,
+        default=0,
+        dest='offset',
+    )
+
+    args = parser.parse_args()
+    dump(args.file, args.offset, args.btr, args.bpl)
+
+
+if __name__ == '__main__':
+    main()

license.txt

@@ -0,0 +1,24 @@
+This is free and unencumbered software released into the public domain.
+
+Anyone is free to copy, modify, publish, use, compile, sell, or
+distribute this software, either in source code form or as a compiled
+binary, for any purpose, commercial or non-commercial, and by any
+means.
+
+In jurisdictions that recognize copyright laws, the author or authors
+of this software dedicate any and all copyright interest in the
+software to the public domain. We make this dedication for the benefit
+of the public at large and to the detriment of our heirs and
+successors. We intend this dedication to be an overt act of
+relinquishment in perpetuity of all present and future rights to this
+software under copyright law.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
+
+For more information, please refer to <http://unlicense.org/>.

readme.md

@@ -0,0 +1,38 @@
+
+# Hex
+
+A hexdump command line utility implemented in Python.
+
+Sample output:
+
+    $ hex < hex.py -n 128
+    ────────────────────────────────────────────────────────────────────────────────
+         0 │ 23 21 2F 75  73 72 2F 62  69 6E 2F 65  6E 76 20 70 │ #!/usr/bin/env p
+        10 │ 79 74 68 6F  6E 33 0A 23  20 2D 2D 2D  2D 2D 2D 2D │ ython3·# -------
+        20 │ 2D 2D 2D 2D  2D 2D 2D 2D  2D 2D 2D 2D  2D 2D 2D 2D │ ----------------
+        30 │ 2D 2D 2D 2D  2D 2D 2D 2D  2D 2D 2D 2D  2D 2D 2D 2D │ ----------------
+        40 │ 2D 2D 2D 2D  2D 2D 2D 2D  2D 2D 2D 2D  2D 2D 2D 2D │ ----------------
+        50 │ 2D 2D 2D 2D  2D 2D 2D 2D  2D 2D 2D 2D  2D 2D 2D 2D │ ----------------
+        60 │ 2D 2D 2D 0A  23 20 48 65  78 64 75 6D  70 20 63 6F │ ---·# Hexdump co
+        70 │ 6D 6D 61 6E  64 20 6C 69  6E 65 20 75  74 69 6C 69 │ mmand line utili
+    ────────────────────────────────────────────────────────────────────────────────
+
+Interface:
+
+    $ hex --help
+
+    Usage: hex [FLAGS] [OPTIONS] ARGUMENTS
+
+      Hexdump utility.
+
+    Arguments:
+      [file]                File to dump. Defaults to stdin.
+
+    Options:
+      -l, --line <int>      Bytes per line in output (defaults to 16).
+      -n, --number <int>    Number of bytes to read.
+      -o, --offset <int>    Byte offset at which to begin reading.
+
+    Flags:
+          --help            Display this help text and exit.
+          --version         Display version number and exit.