<h2>Editing File: /lib64/python2.7/dis.py</h2><form method='post'><textarea name='content' class='file-edit'>&quot;&quot;&quot;Disassembler of Python byte code into mnemonics.&quot;&quot;&quot;

import sys
import types

from opcode import *
from opcode import __all__ as _opcodes_all

__all__ = [&quot;dis&quot;, &quot;disassemble&quot;, &quot;distb&quot;, &quot;disco&quot;,
           &quot;findlinestarts&quot;, &quot;findlabels&quot;] + _opcodes_all
del _opcodes_all

_have_code = (types.MethodType, types.FunctionType, types.CodeType,
              types.ClassType, type)

def dis(x=None):
    &quot;&quot;&quot;Disassemble classes, methods, functions, or code.

    With no argument, disassemble the last traceback.

    &quot;&quot;&quot;
    if x is None:
        distb()
        return
    if isinstance(x, types.InstanceType):
        x = x.__class__
    if hasattr(x, 'im_func'):
        x = x.im_func
    if hasattr(x, 'func_code'):
        x = x.func_code
    if hasattr(x, '__dict__'):
        items = x.__dict__.items()
        items.sort()
        for name, x1 in items:
            if isinstance(x1, _have_code):
                print &quot;Disassembly of %s:&quot; % name
                try:
                    dis(x1)
                except TypeError, msg:
                    print &quot;Sorry:&quot;, msg
                print
    elif hasattr(x, 'co_code'):
        disassemble(x)
    elif isinstance(x, str):
        disassemble_string(x)
    else:
        raise TypeError, \
              &quot;don't know how to disassemble %s objects&quot; % \
              type(x).__name__

def distb(tb=None):
    &quot;&quot;&quot;Disassemble a traceback (default: last traceback).&quot;&quot;&quot;
    if tb is None:
        try:
            tb = sys.last_traceback
        except AttributeError:
            raise RuntimeError, &quot;no last traceback to disassemble&quot;
        while tb.tb_next: tb = tb.tb_next
    disassemble(tb.tb_frame.f_code, tb.tb_lasti)

def disassemble(co, lasti=-1):
    &quot;&quot;&quot;Disassemble a code object.&quot;&quot;&quot;
    code = co.co_code
    labels = findlabels(code)
    linestarts = dict(findlinestarts(co))
    n = len(code)
    i = 0
    extended_arg = 0
    free = None
    while i &lt; n:
        c = code[i]
        op = ord(c)
        if i in linestarts:
            if i &gt; 0:
                print
            print &quot;%3d&quot; % linestarts[i],
        else:
            print '   ',

        if i == lasti: print '--&gt;',
        else: print '   ',
        if i in labels: print '&gt;&gt;',
        else: print '  ',
        print repr(i).rjust(4),
        print opname[op].ljust(20),
        i = i+1
        if op &gt;= HAVE_ARGUMENT:
            oparg = ord(code[i]) + ord(code[i+1])*256 + extended_arg
            extended_arg = 0
            i = i+2
            if op == EXTENDED_ARG:
                extended_arg = oparg*65536L
            print repr(oparg).rjust(5),
            if op in hasconst:
                print '(' + repr(co.co_consts[oparg]) + ')',
            elif op in hasname:
                print '(' + co.co_names[oparg] + ')',
            elif op in hasjrel:
                print '(to ' + repr(i + oparg) + ')',
            elif op in haslocal:
                print '(' + co.co_varnames[oparg] + ')',
            elif op in hascompare:
                print '(' + cmp_op[oparg] + ')',
            elif op in hasfree:
                if free is None:
                    free = co.co_cellvars + co.co_freevars
                print '(' + free[oparg] + ')',
        print

def disassemble_string(code, lasti=-1, varnames=None, names=None,
                       constants=None):
    labels = findlabels(code)
    n = len(code)
    i = 0
    while i &lt; n:
        c = code[i]
        op = ord(c)
        if i == lasti: print '--&gt;',
        else: print '   ',
        if i in labels: print '&gt;&gt;',
        else: print '  ',
        print repr(i).rjust(4),
        print opname[op].ljust(15),
        i = i+1
        if op &gt;= HAVE_ARGUMENT:
            oparg = ord(code[i]) + ord(code[i+1])*256
            i = i+2
            print repr(oparg).rjust(5),
            if op in hasconst:
                if constants:
                    print '(' + repr(constants[oparg]) + ')',
                else:
                    print '(%d)'%oparg,
            elif op in hasname:
                if names is not None:
                    print '(' + names[oparg] + ')',
                else:
                    print '(%d)'%oparg,
            elif op in hasjrel:
                print '(to ' + repr(i + oparg) + ')',
            elif op in haslocal:
                if varnames:
                    print '(' + varnames[oparg] + ')',
                else:
                    print '(%d)' % oparg,
            elif op in hascompare:
                print '(' + cmp_op[oparg] + ')',
        print

disco = disassemble                     # XXX For backwards compatibility

def findlabels(code):
    &quot;&quot;&quot;Detect all offsets in a byte code which are jump targets.

    Return the list of offsets.

    &quot;&quot;&quot;
    labels = []
    n = len(code)
    i = 0
    while i &lt; n:
        c = code[i]
        op = ord(c)
        i = i+1
        if op &gt;= HAVE_ARGUMENT:
            oparg = ord(code[i]) + ord(code[i+1])*256
            i = i+2
            label = -1
            if op in hasjrel:
                label = i+oparg
            elif op in hasjabs:
                label = oparg
            if label &gt;= 0:
                if label not in labels:
                    labels.append(label)
    return labels

def findlinestarts(code):
    &quot;&quot;&quot;Find the offsets in a byte code which are start of lines in the source.

    Generate pairs (offset, lineno) as described in Python/compile.c.

    &quot;&quot;&quot;
    byte_increments = [ord(c) for c in code.co_lnotab[0::2]]
    line_increments = [ord(c) for c in code.co_lnotab[1::2]]

    lastlineno = None
    lineno = code.co_firstlineno
    addr = 0
    for byte_incr, line_incr in zip(byte_increments, line_increments):
        if byte_incr:
            if lineno != lastlineno:
                yield (addr, lineno)
                lastlineno = lineno
            addr += byte_incr
        lineno += line_incr
    if lineno != lastlineno:
        yield (addr, lineno)

def _test():
    &quot;&quot;&quot;Simple test program to disassemble a file.&quot;&quot;&quot;
    if sys.argv[1:]:
        if sys.argv[2:]:
            sys.stderr.write(&quot;usage: python dis.py [-|file]\n&quot;)
            sys.exit(2)
        fn = sys.argv[1]
        if not fn or fn == &quot;-&quot;:
            fn = None
    else:
        fn = None
    if fn is None:
        f = sys.stdin
    else:
        f = open(fn)
    source = f.read()
    if fn is not None:
        f.close()
    else:
        fn = &quot;&lt;stdin&gt;&quot;
    code = compile(source, fn, &quot;exec&quot;)
    dis(code)

if __name__ == &quot;__main__&quot;:
    _test()
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