Adding cython v0.20.2 in third-party.

third_party/cython/src/Cython/Compiler/Buffer.py

Index: third_party/cython/src/Cython/Compiler/Buffer.py
diff --git a/third_party/cython/src/Cython/Compiler/Buffer.py b/third_party/cython/src/Cython/Compiler/Buffer.py
new file mode 100644
index 0000000000000000000000000000000000000000..229ab8b3853494f78f9547359c4df19253e80b30
--- /dev/null
+++ b/third_party/cython/src/Cython/Compiler/Buffer.py
@@ -0,0 +1,744 @@
+from Cython.Compiler.Visitor import CythonTransform
+from Cython.Compiler.ModuleNode import ModuleNode
+from Cython.Compiler.Errors import CompileError
+from Cython.Compiler.UtilityCode import CythonUtilityCode
+from Cython.Compiler.Code import UtilityCode, TempitaUtilityCode
+
+from Cython.Compiler import Options
+from Cython.Compiler import Interpreter
+from Cython.Compiler import PyrexTypes
+from Cython.Compiler import Naming
+from Cython.Compiler import Symtab
+
+
+def dedent(text, reindent=0):
+    from textwrap import dedent
+    text = dedent(text)
+    if reindent > 0:
+        indent = " " * reindent
+        text = '\n'.join([indent + x for x in text.split('\n')])
+    return text
+
+class IntroduceBufferAuxiliaryVars(CythonTransform):
+
+    #
+    # Entry point
+    #
+
+    buffers_exists = False
+    using_memoryview = False
+
+    def __call__(self, node):
+        assert isinstance(node, ModuleNode)
+        self.max_ndim = 0
+        result = super(IntroduceBufferAuxiliaryVars, self).__call__(node)
+        if self.buffers_exists:
+            use_bufstruct_declare_code(node.scope)
+            use_py2_buffer_functions(node.scope)
+            node.scope.use_utility_code(empty_bufstruct_utility)
+
+        return result
+
+
+    #
+    # Basic operations for transforms
+    #
+    def handle_scope(self, node, scope):
+        # For all buffers, insert extra variables in the scope.
+        # The variables are also accessible from the buffer_info
+        # on the buffer entry
+        bufvars = [entry for name, entry
+                   in scope.entries.iteritems()
+                   if entry.type.is_buffer]
+        if len(bufvars) > 0:
+            bufvars.sort(key=lambda entry: entry.name)
+            self.buffers_exists = True
+
+        memviewslicevars = [entry for name, entry
+                in scope.entries.iteritems()
+                if entry.type.is_memoryviewslice]
+        if len(memviewslicevars) > 0:
+            self.buffers_exists = True
+
+
+        for (name, entry) in scope.entries.iteritems():
+            if name == 'memoryview' and isinstance(entry.utility_code_definition, CythonUtilityCode):
+                self.using_memoryview = True
+                break
+
+
+        if isinstance(node, ModuleNode) and len(bufvars) > 0:
+            # for now...note that pos is wrong
+            raise CompileError(node.pos, "Buffer vars not allowed in module scope")
+        for entry in bufvars:
+            if entry.type.dtype.is_ptr:
+                raise CompileError(node.pos, "Buffers with pointer types not yet supported.")
+
+            name = entry.name
+            buftype = entry.type
+            if buftype.ndim > Options.buffer_max_dims:
+                raise CompileError(node.pos,
+                        "Buffer ndims exceeds Options.buffer_max_dims = %d" % Options.buffer_max_dims)
+            if buftype.ndim > self.max_ndim:
+                self.max_ndim = buftype.ndim
+
+            # Declare auxiliary vars
+            def decvar(type, prefix):
+                cname = scope.mangle(prefix, name)
+                aux_var = scope.declare_var(name=None, cname=cname,
+                                            type=type, pos=node.pos)
+                if entry.is_arg:
+                    aux_var.used = True # otherwise, NameNode will mark whether it is used
+
+                return aux_var
+
+            auxvars = ((PyrexTypes.c_pyx_buffer_nd_type, Naming.pybuffernd_prefix),
+                       (PyrexTypes.c_pyx_buffer_type, Naming.pybufferstruct_prefix))
+            pybuffernd, rcbuffer = [decvar(type, prefix) for (type, prefix) in auxvars]
+
+            entry.buffer_aux = Symtab.BufferAux(pybuffernd, rcbuffer)
+
+        scope.buffer_entries = bufvars
+        self.scope = scope
+
+    def visit_ModuleNode(self, node):
+        self.handle_scope(node, node.scope)
+        self.visitchildren(node)
+        return node
+
+    def visit_FuncDefNode(self, node):
+        self.handle_scope(node, node.local_scope)
+        self.visitchildren(node)
+        return node
+
+#
+# Analysis
+#
+buffer_options = ("dtype", "ndim", "mode", "negative_indices", "cast") # ordered!
+buffer_defaults = {"ndim": 1, "mode": "full", "negative_indices": True, "cast": False}
+buffer_positional_options_count = 1 # anything beyond this needs keyword argument
+
+ERR_BUF_OPTION_UNKNOWN = '"%s" is not a buffer option'
+ERR_BUF_TOO_MANY = 'Too many buffer options'
+ERR_BUF_DUP = '"%s" buffer option already supplied'
+ERR_BUF_MISSING = '"%s" missing'
+ERR_BUF_MODE = 'Only allowed buffer modes are: "c", "fortran", "full", "strided" (as a compile-time string)'
+ERR_BUF_NDIM = 'ndim must be a non-negative integer'
+ERR_BUF_DTYPE = 'dtype must be "object", numeric type or a struct'
+ERR_BUF_BOOL = '"%s" must be a boolean'
+
+def analyse_buffer_options(globalpos, env, posargs, dictargs, defaults=None, need_complete=True):
+    """
+    Must be called during type analysis, as analyse is called
+    on the dtype argument.
+
+    posargs and dictargs should consist of a list and a dict
+    of tuples (value, pos). Defaults should be a dict of values.
+
+    Returns a dict containing all the options a buffer can have and
+    its value (with the positions stripped).
+    """
+    if defaults is None:
+        defaults = buffer_defaults
+
+    posargs, dictargs = Interpreter.interpret_compiletime_options(posargs, dictargs, type_env=env, type_args = (0,'dtype'))
+
+    if len(posargs) > buffer_positional_options_count:
+        raise CompileError(posargs[-1][1], ERR_BUF_TOO_MANY)
+
+    options = {}
+    for name, (value, pos) in dictargs.iteritems():
+        if not name in buffer_options:
+            raise CompileError(pos, ERR_BUF_OPTION_UNKNOWN % name)
+        options[name] = value
+
+    for name, (value, pos) in zip(buffer_options, posargs):
+        if not name in buffer_options:
+            raise CompileError(pos, ERR_BUF_OPTION_UNKNOWN % name)
+        if name in options:
+            raise CompileError(pos, ERR_BUF_DUP % name)
+        options[name] = value
+
+    # Check that they are all there and copy defaults
+    for name in buffer_options:
+        if not name in options:
+            try:
+                options[name] = defaults[name]
+            except KeyError:
+                if need_complete:
+                    raise CompileError(globalpos, ERR_BUF_MISSING % name)
+
+    dtype = options.get("dtype")
+    if dtype and dtype.is_extension_type:
+        raise CompileError(globalpos, ERR_BUF_DTYPE)
+
+    ndim = options.get("ndim")
+    if ndim and (not isinstance(ndim, int) or ndim < 0):
+        raise CompileError(globalpos, ERR_BUF_NDIM)
+
+    mode = options.get("mode")
+    if mode and not (mode in ('full', 'strided', 'c', 'fortran')):
+        raise CompileError(globalpos, ERR_BUF_MODE)
+
+    def assert_bool(name):
+        x = options.get(name)
+        if not isinstance(x, bool):
+            raise CompileError(globalpos, ERR_BUF_BOOL % name)
+
+    assert_bool('negative_indices')
+    assert_bool('cast')
+
+    return options
+
+
+#
+# Code generation
+#
+
+class BufferEntry(object):
+    def __init__(self, entry):
+        self.entry = entry
+        self.type = entry.type
+        self.cname = entry.buffer_aux.buflocal_nd_var.cname
+        self.buf_ptr = "%s.rcbuffer->pybuffer.buf" % self.cname
+        self.buf_ptr_type = self.entry.type.buffer_ptr_type
+
+    def get_buf_suboffsetvars(self):
+        return self._for_all_ndim("%s.diminfo[%d].suboffsets")
+
+    def get_buf_stridevars(self):
+        return self._for_all_ndim("%s.diminfo[%d].strides")
+
+    def get_buf_shapevars(self):
+        return self._for_all_ndim("%s.diminfo[%d].shape")
+
+    def _for_all_ndim(self, s):
+        return [s % (self.cname, i) for i in range(self.type.ndim)]
+
+    def generate_buffer_lookup_code(self, code, index_cnames):
+        # Create buffer lookup and return it
+        # This is done via utility macros/inline functions, which vary
+        # according to the access mode used.
+        params = []
+        nd = self.type.ndim
+        mode = self.type.mode
+        if mode == 'full':
+            for i, s, o in zip(index_cnames,
+                               self.get_buf_stridevars(),
+                               self.get_buf_suboffsetvars()):
+                params.append(i)
+                params.append(s)
+                params.append(o)
+            funcname = "__Pyx_BufPtrFull%dd" % nd
+            funcgen = buf_lookup_full_code
+        else:
+            if mode == 'strided':
+                funcname = "__Pyx_BufPtrStrided%dd" % nd
+                funcgen = buf_lookup_strided_code
+            elif mode == 'c':
+                funcname = "__Pyx_BufPtrCContig%dd" % nd
+                funcgen = buf_lookup_c_code
+            elif mode == 'fortran':
+                funcname = "__Pyx_BufPtrFortranContig%dd" % nd
+                funcgen = buf_lookup_fortran_code
+            else:
+                assert False
+            for i, s in zip(index_cnames, self.get_buf_stridevars()):
+                params.append(i)
+                params.append(s)
+
+        # Make sure the utility code is available
+        if funcname not in code.globalstate.utility_codes:
+            code.globalstate.utility_codes.add(funcname)
+            protocode = code.globalstate['utility_code_proto']
+            defcode = code.globalstate['utility_code_def']
+            funcgen(protocode, defcode, name=funcname, nd=nd)
+
+        buf_ptr_type_code = self.buf_ptr_type.declaration_code("")
+        ptrcode = "%s(%s, %s, %s)" % (funcname, buf_ptr_type_code, self.buf_ptr,
+                                      ", ".join(params))
+        return ptrcode
+
+
+def get_flags(buffer_aux, buffer_type):
+    flags = 'PyBUF_FORMAT'
+    mode = buffer_type.mode
+    if mode == 'full':
+        flags += '| PyBUF_INDIRECT'
+    elif mode == 'strided':
+        flags += '| PyBUF_STRIDES'
+    elif mode == 'c':
+        flags += '| PyBUF_C_CONTIGUOUS'
+    elif mode == 'fortran':
+        flags += '| PyBUF_F_CONTIGUOUS'
+    else:
+        assert False
+    if buffer_aux.writable_needed: flags += "| PyBUF_WRITABLE"
+    return flags
+
+def used_buffer_aux_vars(entry):
+    buffer_aux = entry.buffer_aux
+    buffer_aux.buflocal_nd_var.used = True
+    buffer_aux.rcbuf_var.used = True
+
+def put_unpack_buffer_aux_into_scope(buf_entry, code):
+    # Generate code to copy the needed struct info into local
+    # variables.
+    buffer_aux, mode = buf_entry.buffer_aux, buf_entry.type.mode
+    pybuffernd_struct = buffer_aux.buflocal_nd_var.cname
+
+    fldnames = ['strides', 'shape']
+    if mode == 'full':
+        fldnames.append('suboffsets')
+
+    ln = []
+    for i in range(buf_entry.type.ndim):
+        for fldname in fldnames:
+            ln.append("%s.diminfo[%d].%s = %s.rcbuffer->pybuffer.%s[%d];" % \
+                    (pybuffernd_struct, i, fldname,
+                     pybuffernd_struct, fldname, i))
+    code.putln(' '.join(ln))
+
+def put_init_vars(entry, code):
+    bufaux = entry.buffer_aux
+    pybuffernd_struct = bufaux.buflocal_nd_var.cname
+    pybuffer_struct = bufaux.rcbuf_var.cname
+    # init pybuffer_struct
+    code.putln("%s.pybuffer.buf = NULL;" % pybuffer_struct)
+    code.putln("%s.refcount = 0;" % pybuffer_struct)
+    # init the buffer object
+    # code.put_init_var_to_py_none(entry)
+    # init the pybuffernd_struct
+    code.putln("%s.data = NULL;" % pybuffernd_struct)
+    code.putln("%s.rcbuffer = &%s;" % (pybuffernd_struct, pybuffer_struct))
+
+def put_acquire_arg_buffer(entry, code, pos):
+    code.globalstate.use_utility_code(acquire_utility_code)
+    buffer_aux = entry.buffer_aux
+    getbuffer = get_getbuffer_call(code, entry.cname, buffer_aux, entry.type)
+
+    # Acquire any new buffer
+    code.putln("{")
+    code.putln("__Pyx_BufFmt_StackElem __pyx_stack[%d];" % entry.type.dtype.struct_nesting_depth())
+    code.putln(code.error_goto_if("%s == -1" % getbuffer, pos))
+    code.putln("}")
+    # An exception raised in arg parsing cannot be catched, so no
+    # need to care about the buffer then.
+    put_unpack_buffer_aux_into_scope(entry, code)
+
+def put_release_buffer_code(code, entry):
+    code.globalstate.use_utility_code(acquire_utility_code)
+    code.putln("__Pyx_SafeReleaseBuffer(&%s.rcbuffer->pybuffer);" % entry.buffer_aux.buflocal_nd_var.cname)
+
+def get_getbuffer_call(code, obj_cname, buffer_aux, buffer_type):
+    ndim = buffer_type.ndim
+    cast = int(buffer_type.cast)
+    flags = get_flags(buffer_aux, buffer_type)
+    pybuffernd_struct = buffer_aux.buflocal_nd_var.cname
+
+    dtype_typeinfo = get_type_information_cname(code, buffer_type.dtype)
+
+    return ("__Pyx_GetBufferAndValidate(&%(pybuffernd_struct)s.rcbuffer->pybuffer, "
+            "(PyObject*)%(obj_cname)s, &%(dtype_typeinfo)s, %(flags)s, %(ndim)d, "
+            "%(cast)d, __pyx_stack)" % locals())
+
+def put_assign_to_buffer(lhs_cname, rhs_cname, buf_entry,
+                         is_initialized, pos, code):
+    """
+    Generate code for reassigning a buffer variables. This only deals with getting
+    the buffer auxiliary structure and variables set up correctly, the assignment
+    itself and refcounting is the responsibility of the caller.
+
+    However, the assignment operation may throw an exception so that the reassignment
+    never happens.
+
+    Depending on the circumstances there are two possible outcomes:
+    - Old buffer released, new acquired, rhs assigned to lhs
+    - Old buffer released, new acquired which fails, reaqcuire old lhs buffer
+      (which may or may not succeed).
+    """
+
+    buffer_aux, buffer_type = buf_entry.buffer_aux, buf_entry.type
+    code.globalstate.use_utility_code(acquire_utility_code)
+    pybuffernd_struct = buffer_aux.buflocal_nd_var.cname
+    flags = get_flags(buffer_aux, buffer_type)
+
+    code.putln("{")  # Set up necesarry stack for getbuffer
+    code.putln("__Pyx_BufFmt_StackElem __pyx_stack[%d];" % buffer_type.dtype.struct_nesting_depth())
+
+    getbuffer = get_getbuffer_call(code, "%s", buffer_aux, buffer_type) # fill in object below
+
+    if is_initialized:
+        # Release any existing buffer
+        code.putln('__Pyx_SafeReleaseBuffer(&%s.rcbuffer->pybuffer);' % pybuffernd_struct)
+        # Acquire
+        retcode_cname = code.funcstate.allocate_temp(PyrexTypes.c_int_type, manage_ref=False)
+        code.putln("%s = %s;" % (retcode_cname, getbuffer % rhs_cname))
+        code.putln('if (%s) {' % (code.unlikely("%s < 0" % retcode_cname)))
+        # If acquisition failed, attempt to reacquire the old buffer
+        # before raising the exception. A failure of reacquisition
+        # will cause the reacquisition exception to be reported, one
+        # can consider working around this later.
+        type, value, tb = [code.funcstate.allocate_temp(PyrexTypes.py_object_type, manage_ref=False)
+                           for i in range(3)]
+        code.putln('PyErr_Fetch(&%s, &%s, &%s);' % (type, value, tb))
+        code.putln('if (%s) {' % code.unlikely("%s == -1" % (getbuffer % lhs_cname)))
+        code.putln('Py_XDECREF(%s); Py_XDECREF(%s); Py_XDECREF(%s);' % (type, value, tb)) # Do not refnanny these!
+        code.globalstate.use_utility_code(raise_buffer_fallback_code)
+        code.putln('__Pyx_RaiseBufferFallbackError();')
+        code.putln('} else {')
+        code.putln('PyErr_Restore(%s, %s, %s);' % (type, value, tb))
+        for t in (type, value, tb):
+            code.funcstate.release_temp(t)
+        code.putln('}')
+        code.putln('}')
+        # Unpack indices
+        put_unpack_buffer_aux_into_scope(buf_entry, code)
+        code.putln(code.error_goto_if_neg(retcode_cname, pos))
+        code.funcstate.release_temp(retcode_cname)
+    else:
+        # Our entry had no previous value, so set to None when acquisition fails.
+        # In this case, auxiliary vars should be set up right in initialization to a zero-buffer,
+        # so it suffices to set the buf field to NULL.
+        code.putln('if (%s) {' % code.unlikely("%s == -1" % (getbuffer % rhs_cname)))
+        code.putln('%s = %s; __Pyx_INCREF(Py_None); %s.rcbuffer->pybuffer.buf = NULL;' %
+                   (lhs_cname,
+                    PyrexTypes.typecast(buffer_type, PyrexTypes.py_object_type, "Py_None"),
+                    pybuffernd_struct))
+        code.putln(code.error_goto(pos))
+        code.put('} else {')
+        # Unpack indices
+        put_unpack_buffer_aux_into_scope(buf_entry, code)
+        code.putln('}')
+
+    code.putln("}") # Release stack
+
+def put_buffer_lookup_code(entry, index_signeds, index_cnames, directives,
+                           pos, code, negative_indices, in_nogil_context):
+    """
+    Generates code to process indices and calculate an offset into
+    a buffer. Returns a C string which gives a pointer which can be
+    read from or written to at will (it is an expression so caller should
+    store it in a temporary if it is used more than once).
+
+    As the bounds checking can have any number of combinations of unsigned
+    arguments, smart optimizations etc. we insert it directly in the function
+    body. The lookup however is delegated to a inline function that is instantiated
+    once per ndim (lookup with suboffsets tend to get quite complicated).
+
+    entry is a BufferEntry
+    """
+    negative_indices = directives['wraparound'] and negative_indices
+
+    if directives['boundscheck']:
+        # Check bounds and fix negative indices.
+        # We allocate a temporary which is initialized to -1, meaning OK (!).
+        # If an error occurs, the temp is set to the dimension index the
+        # error is occuring at.
+        tmp_cname = code.funcstate.allocate_temp(PyrexTypes.c_int_type, manage_ref=False)
+        code.putln("%s = -1;" % tmp_cname)
+        for dim, (signed, cname, shape) in enumerate(zip(index_signeds, index_cnames,
+                                                         entry.get_buf_shapevars())):
+            if signed != 0:
+                # not unsigned, deal with negative index
+                code.putln("if (%s < 0) {" % cname)
+                if negative_indices:
+                    code.putln("%s += %s;" % (cname, shape))
+                    code.putln("if (%s) %s = %d;" % (
+                        code.unlikely("%s < 0" % cname), tmp_cname, dim))
+                else:
+                    code.putln("%s = %d;" % (tmp_cname, dim))
+                code.put("} else ")
+            # check bounds in positive direction
+            if signed != 0:
+                cast = ""
+            else:
+                cast = "(size_t)"
+            code.putln("if (%s) %s = %d;" % (
+                code.unlikely("%s >= %s%s" % (cname, cast, shape)),
+                              tmp_cname, dim))
+
+        if in_nogil_context:
+            code.globalstate.use_utility_code(raise_indexerror_nogil)
+            func = '__Pyx_RaiseBufferIndexErrorNogil'
+        else:
+            code.globalstate.use_utility_code(raise_indexerror_code)
+            func = '__Pyx_RaiseBufferIndexError'
+
+        code.putln("if (%s) {" % code.unlikely("%s != -1" % tmp_cname))
+        code.putln('%s(%s);' % (func, tmp_cname))
+        code.putln(code.error_goto(pos))
+        code.putln('}')
+        code.funcstate.release_temp(tmp_cname)
+    elif negative_indices:
+        # Only fix negative indices.
+        for signed, cname, shape in zip(index_signeds, index_cnames,
+                                        entry.get_buf_shapevars()):
+            if signed != 0:
+                code.putln("if (%s < 0) %s += %s;" % (cname, cname, shape))
+
+    return entry.generate_buffer_lookup_code(code, index_cnames)
+
+
+def use_bufstruct_declare_code(env):
+    env.use_utility_code(buffer_struct_declare_code)
+
+
+def get_empty_bufstruct_code(max_ndim):
+    code = dedent("""
+        static Py_ssize_t __Pyx_zeros[] = {%s};
+        static Py_ssize_t __Pyx_minusones[] = {%s};
+    """) % (", ".join(["0"] * max_ndim), ", ".join(["-1"] * max_ndim))
+    return UtilityCode(proto=code)
+
+empty_bufstruct_utility = get_empty_bufstruct_code(Options.buffer_max_dims)
+
+def buf_lookup_full_code(proto, defin, name, nd):
+    """
+    Generates a buffer lookup function for the right number
+    of dimensions. The function gives back a void* at the right location.
+    """
+    # _i_ndex, _s_tride, sub_o_ffset
+    macroargs = ", ".join(["i%d, s%d, o%d" % (i, i, i) for i in range(nd)])
+    proto.putln("#define %s(type, buf, %s) (type)(%s_imp(buf, %s))" % (name, macroargs, name, macroargs))
+
+    funcargs = ", ".join(["Py_ssize_t i%d, Py_ssize_t s%d, Py_ssize_t o%d" % (i, i, i) for i in range(nd)])
+    proto.putln("static CYTHON_INLINE void* %s_imp(void* buf, %s);" % (name, funcargs))
+    defin.putln(dedent("""
+        static CYTHON_INLINE void* %s_imp(void* buf, %s) {
+          char* ptr = (char*)buf;
+        """) % (name, funcargs) + "".join([dedent("""\
+          ptr += s%d * i%d;
+          if (o%d >= 0) ptr = *((char**)ptr) + o%d;
+        """) % (i, i, i, i) for i in range(nd)]
+        ) + "\nreturn ptr;\n}")
+
+def buf_lookup_strided_code(proto, defin, name, nd):
+    """
+    Generates a buffer lookup function for the right number
+    of dimensions. The function gives back a void* at the right location.
+    """
+    # _i_ndex, _s_tride
+    args = ", ".join(["i%d, s%d" % (i, i) for i in range(nd)])
+    offset = " + ".join(["i%d * s%d" % (i, i) for i in range(nd)])
+    proto.putln("#define %s(type, buf, %s) (type)((char*)buf + %s)" % (name, args, offset))
+
+def buf_lookup_c_code(proto, defin, name, nd):
+    """
+    Similar to strided lookup, but can assume that the last dimension
+    doesn't need a multiplication as long as.
+    Still we keep the same signature for now.
+    """
+    if nd == 1:
+        proto.putln("#define %s(type, buf, i0, s0) ((type)buf + i0)" % name)
+    else:
+        args = ", ".join(["i%d, s%d" % (i, i) for i in range(nd)])
+        offset = " + ".join(["i%d * s%d" % (i, i) for i in range(nd - 1)])
+        proto.putln("#define %s(type, buf, %s) ((type)((char*)buf + %s) + i%d)" % (name, args, offset, nd - 1))
+
+def buf_lookup_fortran_code(proto, defin, name, nd):
+    """
+    Like C lookup, but the first index is optimized instead.
+    """
+    if nd == 1:
+        proto.putln("#define %s(type, buf, i0, s0) ((type)buf + i0)" % name)
+    else:
+        args = ", ".join(["i%d, s%d" % (i, i) for i in range(nd)])
+        offset = " + ".join(["i%d * s%d" % (i, i) for i in range(1, nd)])
+        proto.putln("#define %s(type, buf, %s) ((type)((char*)buf + %s) + i%d)" % (name, args, offset, 0))
+
+
+def use_py2_buffer_functions(env):
+    env.use_utility_code(GetAndReleaseBufferUtilityCode())
+
+class GetAndReleaseBufferUtilityCode(object):
+    # Emulation of PyObject_GetBuffer and PyBuffer_Release for Python 2.
+    # For >= 2.6 we do double mode -- use the new buffer interface on objects
+    # which has the right tp_flags set, but emulation otherwise.
+
+    requires = None
+    is_cython_utility = False
+
+    def __init__(self):
+        pass
+
+    def __eq__(self, other):
+        return isinstance(other, GetAndReleaseBufferUtilityCode)
+
+    def __hash__(self):
+        return 24342342
+
+    def get_tree(self): pass
+
+    def put_code(self, output):
+        code = output['utility_code_def']
+        proto_code = output['utility_code_proto']
+        env = output.module_node.scope
+        cython_scope = env.context.cython_scope
+        
+        # Search all types for __getbuffer__ overloads
+        types = []
+        visited_scopes = set()
+        def find_buffer_types(scope):
+            if scope in visited_scopes:
+                return
+            visited_scopes.add(scope)
+            for m in scope.cimported_modules:
+                find_buffer_types(m)
+            for e in scope.type_entries:
+                if isinstance(e.utility_code_definition, CythonUtilityCode):
+                    continue
+                t = e.type
+                if t.is_extension_type:
+                    if scope is cython_scope and not e.used:
+                        continue
+                    release = get = None
+                    for x in t.scope.pyfunc_entries:
+                        if x.name == u"__getbuffer__": get = x.func_cname
+                        elif x.name == u"__releasebuffer__": release = x.func_cname
+                    if get:
+                        types.append((t.typeptr_cname, get, release))
+
+        find_buffer_types(env)
+
+        util_code = TempitaUtilityCode.load(
+            "GetAndReleaseBuffer", from_file="Buffer.c",
+            context=dict(types=types))
+
+        proto = util_code.format_code(util_code.proto)
+        impl = util_code.format_code(
+            util_code.inject_string_constants(util_code.impl, output)[1])
+
+        proto_code.putln(proto)
+        code.putln(impl)
+
+
+def mangle_dtype_name(dtype):
+    # Use prefixes to seperate user defined types from builtins
+    # (consider "typedef float unsigned_int")
+    if dtype.is_pyobject:
+        return "object"
+    elif dtype.is_ptr:
+        return "ptr"
+    else:
+        if dtype.is_typedef or dtype.is_struct_or_union:
+            prefix = "nn_"
+        else:
+            prefix = ""
+        type_decl = dtype.declaration_code("")
+        type_decl = type_decl.replace(" ", "_")
+        return prefix + type_decl.replace("[", "_").replace("]", "_")
+
+def get_type_information_cname(code, dtype, maxdepth=None):
+    """
+    Output the run-time type information (__Pyx_TypeInfo) for given dtype,
+    and return the name of the type info struct.
+
+    Structs with two floats of the same size are encoded as complex numbers.
+    One can seperate between complex numbers declared as struct or with native
+    encoding by inspecting to see if the fields field of the type is
+    filled in.
+    """
+    namesuffix = mangle_dtype_name(dtype)
+    name = "__Pyx_TypeInfo_%s" % namesuffix
+    structinfo_name = "__Pyx_StructFields_%s" % namesuffix
+
+    if dtype.is_error: return "<error>"
+
+    # It's critical that walking the type info doesn't use more stack
+    # depth than dtype.struct_nesting_depth() returns, so use an assertion for this
+    if maxdepth is None: maxdepth = dtype.struct_nesting_depth()
+    if maxdepth <= 0:
+        assert False
+
+    if name not in code.globalstate.utility_codes:
+        code.globalstate.utility_codes.add(name)
+        typecode = code.globalstate['typeinfo']
+
+        arraysizes = []
+        if dtype.is_array:
+            while dtype.is_array:
+                arraysizes.append(dtype.size)
+                dtype = dtype.base_type
+
+        complex_possible = dtype.is_struct_or_union and dtype.can_be_complex()
+
+        declcode = dtype.declaration_code("")
+        if dtype.is_simple_buffer_dtype():
+            structinfo_name = "NULL"
+        elif dtype.is_struct:
+            fields = dtype.scope.var_entries
+            # Must pre-call all used types in order not to recurse utility code
+            # writing.
+            assert len(fields) > 0
+            types = [get_type_information_cname(code, f.type, maxdepth - 1)
+                     for f in fields]
+            typecode.putln("static __Pyx_StructField %s[] = {" % structinfo_name, safe=True)
+            for f, typeinfo in zip(fields, types):
+                typecode.putln('  {&%s, "%s", offsetof(%s, %s)},' %
+                           (typeinfo, f.name, dtype.declaration_code(""), f.cname), safe=True)
+            typecode.putln('  {NULL, NULL, 0}', safe=True)
+            typecode.putln("};", safe=True)
+        else:
+            assert False
+
+        rep = str(dtype)
+
+        flags = "0"
+        is_unsigned = "0"
+        if dtype is PyrexTypes.c_char_type:
+            is_unsigned = "IS_UNSIGNED(%s)" % declcode
+            typegroup = "'H'"
+        elif dtype.is_int:
+            is_unsigned = "IS_UNSIGNED(%s)" % declcode
+            typegroup = "%s ? 'U' : 'I'" % is_unsigned
+        elif complex_possible or dtype.is_complex:
+            typegroup = "'C'"
+        elif dtype.is_float:
+            typegroup = "'R'"
+        elif dtype.is_struct:
+            typegroup = "'S'"
+            if dtype.packed:
+                flags = "__PYX_BUF_FLAGS_PACKED_STRUCT"
+        elif dtype.is_pyobject:
+            typegroup = "'O'"
+        else:
+            assert False, dtype
+
+        typeinfo = ('static __Pyx_TypeInfo %s = '
+                        '{ "%s", %s, sizeof(%s), { %s }, %s, %s, %s, %s };')
+        tup = (name, rep, structinfo_name, declcode,
+               ', '.join([str(x) for x in arraysizes]) or '0', len(arraysizes),
+               typegroup, is_unsigned, flags)
+        typecode.putln(typeinfo % tup, safe=True)
+
+    return name
+
+def load_buffer_utility(util_code_name, context=None, **kwargs):
+    if context is None:
+        return UtilityCode.load(util_code_name, "Buffer.c", **kwargs)
+    else:
+        return TempitaUtilityCode.load(util_code_name, "Buffer.c", context=context, **kwargs)
+
+context = dict(max_dims=str(Options.buffer_max_dims))
+buffer_struct_declare_code = load_buffer_utility("BufferStructDeclare",
+                                                 context=context)
+
+
+# Utility function to set the right exception
+# The caller should immediately goto_error
+raise_indexerror_code = load_buffer_utility("BufferIndexError")
+raise_indexerror_nogil = load_buffer_utility("BufferIndexErrorNogil")
+
+raise_buffer_fallback_code = load_buffer_utility("BufferFallbackError")
+buffer_structs_code = load_buffer_utility(
+        "BufferFormatStructs", proto_block='utility_code_proto_before_types')
+acquire_utility_code = load_buffer_utility("BufferFormatCheck",
+                                           context=context,
+                                           requires=[buffer_structs_code])
+
+# See utility code BufferFormatFromTypeInfo
+_typeinfo_to_format_code = load_buffer_utility("TypeInfoToFormat", context={},
+                                               requires=[buffer_structs_code])
+typeinfo_compare_code = load_buffer_utility("TypeInfoCompare", context={},
+                                            requires=[buffer_structs_code])