Add a base85 codec

mercurial/base85.c

@@ -0,0 +1,132 b''
+/*
+ base85 codec
+
+ Copyright 2006 Brendan Cully <[e-mail]>
+
+ This software may be used and distributed according to the terms of
+ the GNU General Public License, incorporated herein by reference.
+
+ Largely based on git's implementation
+*/
+
+#include <Python.h>
+
+static const char b85chars[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	"abcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~";
+static char b85dec[256];
+
+static void
+b85prep(void)
+{
+	int i;
+
+	memset(b85dec, 0, sizeof(b85dec));
+	for (i = 0; i < sizeof(b85chars); i++)
+		b85dec[(int)(b85chars[i])] = i + 1;
+}
+
+static PyObject *
+b85encode(PyObject *self, PyObject *args)
+{
+	const unsigned char *text;
+	PyObject *out;
+	char *dst;
+	int len, olen, i;
+	unsigned int acc, val, ch;
+
+	if (!PyArg_ParseTuple(args, "s#", &text, &len))
+		return NULL;
+
+	olen = (len + 3) / 4 * 5;
+	if (!(out = PyString_FromStringAndSize(NULL, olen)))
+		return NULL;
+
+	dst = PyString_AS_STRING(out);
+
+	while (len)
+	{
+		acc = 0;
+		for (i = 24; i >= 0; i -= 8) {
+			ch = *text++;
+			acc |= ch << i;
+			if (--len == 0)
+				break;
+		}
+		for (i = 4; i >= 0; i--) {
+			val = acc % 85;
+			acc /= 85;
+			dst[i] = b85chars[val];
+		}
+		dst += 5;
+	}
+
+	return out;
+}
+
+static PyObject *
+b85decode(PyObject *self, PyObject *args)
+{
+	PyObject *out;
+	const char *text;
+	char *dst;
+	int len, i, j, olen, c;
+	unsigned int acc;
+
+	if (!PyArg_ParseTuple(args, "s#", &text, &len))
+		return NULL;
+
+	olen = (len + 4) / 5 * 4;
+	if (!(out = PyString_FromStringAndSize(NULL, olen)))
+		return NULL;
+
+	dst = PyString_AS_STRING(out);
+
+	for (i = 1; len; i++)
+	{
+		acc = 0;
+		for (j = 0; j < 4 && --len; j++)
+		{
+			c = b85dec[(int)*text++] - 1;
+			if (c < 0)
+				return PyErr_Format(PyExc_ValueError, "Bad base85 character at position %d", i);
+			acc = acc * 85 + c;
+		}
+		if (len--)
+		{
+			c = b85dec[(int)*text++] - 1;
+			if (c < 0)
+				return PyErr_Format(PyExc_ValueError, "Bad base85 character at position %d", i);
+		}
+		else
+			c = 0;
+		/* overflow detection: 0xffffffff == "|NsC0",
+		 * "|NsC" == 0x03030303 */
+		if (acc > 0x03030303 || (acc *= 85) > 0xffffffff - c)
+			return PyErr_Format(PyExc_ValueError, "Bad base85 sequence at position %d", i);
+		
+		acc += c;
+
+		for (j = 0; j < 4; j++)
+		{
+			acc = (acc << 8) | (acc >> 24);
+			*dst++ = (char)acc;
+		}
+	}
+
+	return out;
+}
+
+static char base85_doc[] = "Base85 Data Encoding";
+
+static PyMethodDef methods[] = {
+	{"b85encode", b85encode, METH_VARARGS, "encode text in base85\n"},
+	{"b85decode", b85decode, METH_VARARGS, "decode base85 text\n"},
+	{NULL, NULL}
+};
+
+PyMODINIT_FUNC initbase85(void)
+{
+	Py_InitModule3("base85", methods, base85_doc);
+
+	b85prep();
+}

setup.py

@@ -1,102 +1,103 b''
 #!/usr/bin/env python
 #
 # This is the mercurial setup script.
 #
 # './setup.py install', or
 # './setup.py --help' for more options
 
 import sys
 if not hasattr(sys, 'version_info') or sys.version_info < (2, 3):
     raise SystemExit, "Mercurial requires python 2.3 or later."
 
 import os
 from distutils.core import setup, Extension
 from distutils.command.install_data import install_data
 
 # mercurial.packagescan must be the first mercurial module imported
 import mercurial.packagescan
 import mercurial.version
 
 # py2exe needs to be installed to work
 try:
     import py2exe
 
     # Help py2exe to find win32com.shell
     try:
         import modulefinder
         import win32com
         for p in win32com.__path__[1:]: # Take the path to win32comext
             modulefinder.AddPackagePath("win32com", p)
         pn = "win32com.shell"
         __import__(pn)
         m = sys.modules[pn]
         for p in m.__path__[1:]:
             modulefinder.AddPackagePath(pn, p)
     except ImportError:
         pass
 
     # Due to the use of demandload py2exe is not finding the modules.
     # packagescan.getmodules creates a list of modules included in
     # the mercurial package plus depdent modules.
     from py2exe.build_exe import py2exe as build_exe
 
     class py2exe_for_demandload(build_exe):
         """ overwrites the py2exe command class for getting the build
         directory and for setting the 'includes' option."""
         def initialize_options(self):
             self.build_lib = None
             build_exe.initialize_options(self)
         def finalize_options(self):
             # Get the build directory, ie. where to search for modules.
             self.set_undefined_options('build',
                                        ('build_lib', 'build_lib'))
             # Sets the 'includes' option with the list of needed modules
             if not self.includes:
                 self.includes = []
             else:
                 self.includes = self.includes.split(',')
             mercurial.packagescan.scan(self.build_lib, 'mercurial')
             mercurial.packagescan.scan(self.build_lib, 'mercurial.hgweb')
             mercurial.packagescan.scan(self.build_lib, 'hgext')
             self.includes += mercurial.packagescan.getmodules()
             build_exe.finalize_options(self)
 except ImportError:
     py2exe_for_demandload = None
 
 
 # specify version string, otherwise 'hg identify' will be used:
 version = ''
 
 class install_package_data(install_data):
     def finalize_options(self):
         self.set_undefined_options('install',
                                    ('install_lib', 'install_dir'))
         install_data.finalize_options(self)
 
 mercurial.version.remember_version(version)
 cmdclass = {'install_data': install_package_data}
 py2exe_opts = {}
 if py2exe_for_demandload is not None:
     cmdclass['py2exe'] = py2exe_for_demandload
     py2exe_opts['console'] = ['hg']
 
 setup(name='mercurial',
       version=mercurial.version.get_version(),
       author='Matt Mackall',
       author_email='[e-mail]',
       url='http://selenic.com/mercurial',
       description='Scalable distributed SCM',
       license='GNU GPL',
       packages=['mercurial', 'mercurial.hgweb', 'hgext'],
       ext_modules=[Extension('mercurial.mpatch', ['mercurial/mpatch.c']),
-                   Extension('mercurial.bdiff', ['mercurial/bdiff.c'])],
+                   Extension('mercurial.bdiff', ['mercurial/bdiff.c']),
+                   Extension('mercurial.base85', ['mercurial/base85.c'])],
       data_files=[(os.path.join('mercurial', root),
                    [os.path.join(root, file_) for file_ in files])
                   for root, dirs, files in os.walk('templates')],
       cmdclass=cmdclass,
       scripts=['hg', 'hgmerge'],
       options=dict(bdist_mpkg=dict(zipdist=True,
                                    license='COPYING',
                                    readme='contrib/macosx/Readme.html',
                                    welcome='contrib/macosx/Welcome.html')),
       **py2exe_opts)