"""Routine to "compile" a .py file to a .pyc (or .pyo) file.

This module has intimate knowledge of the format of .pyc files.
"""

import imp
MAGIC = imp.get_magic()

def wr_long(f, x):
	"Internal; write a 32-bit int to a file in little-endian order."
	f.write(chr( x        & 0xff))
	f.write(chr((x >> 8)  & 0xff))
	f.write(chr((x >> 16) & 0xff))
	f.write(chr((x >> 24) & 0xff))

def compile(file, cfile=None, dfile=None):
	"""Byte-compile one Python source file to Python bytecode.
	Arguments:
	file:  source filename
	cfile: target filename; defaults to source with 'c' or 'o' appended
			('c' normally, 'o' in optimizing mode, giving .pyc or .pyo)
	dfile: purported filename; defaults to source (this is the filename
			that will show up in error messages)
 
	Note that it isn't necessary to byte-compile Python modules for
	execution efficiency -- Python itself byte-compiles a module when
	it is loaded, and if it can, writes out the bytecode to the
	corresponding .pyc (or .pyo) file.
 
	However, if a Python installation is shared between users, it is a
	good idea to byte-compile all modules upon installation, since
	other users may not be able to write in the source directories,
	and thus they won't be able to write the .pyc/.pyo file, and then
	they would be byte-compiling every module each time it is loaded.
	This can slow down program start-up considerably.
 
	See compileall.py for a script/module that uses this module to
	byte-compile all installed files (or all files in selected
	directories).
 
	"""
	import os, marshal, __builtin__
	f = open(file)
	try:
		timestamp = os.fstat(file.fileno())
	except AttributeError:
		timestamp = long(os.stat(file)[8])
	codestring = f.read()
	f.close()
	if codestring and codestring[-1] != '\n':
		codestring = codestring + '\n'
	codeobject = __builtin__.compile(codestring, dfile or file, 'exec')
	if not cfile:
		cfile = file + (__debug__ and 'c' or 'o')
	fc = open(cfile, 'wb')
	fc.write('\0\0\0\0')
	wr_long(fc, timestamp)
	marshal.dump(codeobject, fc)
	fc.flush()
	fc.seek(0, 0)
	fc.write(MAGIC)
	fc.close()
	if os.name == 'mac':
		import macfs
		macfs.FSSpec(cfile).SetCreatorType('Pyth', 'PYC ')
		macfs.FSSpec(file).SetCreatorType('Pyth', 'TEXT')
