init

squashfs-root/usr/lib/python2.7/site-packages/xcbgen/align.py

@@ -0,0 +1,177 @@
+'''
+This module contains helper classes for alignment arithmetic and checks
+'''
+
+from fractions import gcd
+
+class Alignment(object):
+
+    def __init__(self, align=4, offset=0):
+        self.align = align
+        # normalize the offset (just in case)
+        self.offset = offset % align
+
+
+    def __eq__(self, other):
+        return self.align == other.align and self.offset == other.offset
+
+    def __str__(self):
+        return "(align=%d, offset=%d)" % (self.align, self.offset)
+
+    @staticmethod
+    def for_primitive_type(size):
+        # compute the required start_alignment based on the size of the type
+        if size % 8 == 0:
+            # do 8-byte primitives require 8-byte alignment in X11?
+            return Alignment(8,0)
+        elif size % 4 == 0:
+            return Alignment(4,0)
+        elif size % 2 == 0:
+            return Alignment(2,0)
+        else:
+            return Alignment(1,0)
+
+
+    def align_after_fixed_size(self, size):
+        new_offset = (self.offset + size) % self.align
+        return Alignment(self.align, new_offset)
+
+
+    def is_guaranteed_at(self, external_align):
+        '''
+        Assuming the given external_align, checks whether
+        self is fulfilled for all cases.
+        Returns True if yes, False otherwise.
+        '''
+        if self.align == 1 and self.offset == 0:
+            # alignment 1 with offset 0 is always fulfilled
+            return True
+
+        if external_align is None:
+            # there is no external align -> fail
+            return False
+
+        if external_align.align < self.align:
+            # the external align guarantees less alignment -> not guaranteed
+            return False
+
+        if external_align.align % self.align != 0:
+            # the external align cannot be divided by our align
+            # -> not guaranteed
+            # (this can only happen if there are alignments that are not
+            # a power of 2, which is highly discouraged. But better be
+            # safe and check for it)
+            return False
+
+        if external_align.offset % self.align != self.offset:
+            # offsets do not match
+            return False
+
+        return True
+
+
+    def combine_with(self, other):
+        # returns the alignment that is guaranteed when
+        # both, self or other, can happen
+        new_align = gcd(self.align, other.align)
+        new_offset_candidate1 = self.offset % new_align
+        new_offset_candidate2 = other.offset % new_align
+        if new_offset_candidate1 == new_offset_candidate2:
+            new_offset = new_offset_candidate1
+        else:
+            offset_diff = abs(new_offset_candidate2 - new_offset_candidate1)
+            new_align = gcd(new_align, offset_diff)
+            new_offset_candidate1 = self.offset % new_align
+            new_offset_candidate2 = other.offset % new_align
+            assert new_offset_candidate1 == new_offset_candidate2
+            new_offset = new_offset_candidate1
+        # return the result
+        return Alignment(new_align, new_offset)
+
+
+class AlignmentLog(object):
+
+    def __init__(self):
+        self.ok_list = []
+        self.fail_list = []
+        self.verbosity = 1
+
+    def __str__(self):
+        result = ""
+
+        # output the OK-list
+        for (align_before, field_name, type_obj, callstack, align_after) in self.ok_list:
+            stacksize = len(callstack)
+            indent = '  ' * stacksize
+            if self.ok_callstack_is_relevant(callstack):
+                if field_name is None or field_name == "":
+                    result += ("    %sok: %s:\n\t%sbefore: %s, after: %s\n"
+                        % (indent, str(type_obj), indent, str(align_before), str(align_after)))
+                else:
+                    result += ("    %sok: field \"%s\" in %s:\n\t%sbefore: %s, after: %s\n"
+                        % (indent, str(field_name), str(type_obj),
+                           indent, str(align_before), str(align_after)))
+                if self.verbosity >= 1:
+                    result += self.callstack_to_str(indent, callstack)
+
+        # output the fail-list
+        for (align_before, field_name, type_obj, callstack, reason) in self.fail_list:
+            stacksize = len(callstack)
+            indent = '  ' * stacksize
+            if field_name is None or field_name == "":
+                result += ("    %sfail: align %s is incompatible with\n\t%s%s\n\t%sReason: %s\n"
+                    % (indent, str(align_before), indent, str(type_obj), indent, reason))
+            else:
+                result += ("    %sfail: align %s is incompatible with\n\t%sfield \"%s\" in %s\n\t%sReason: %s\n"
+                    % (indent, str(align_before), indent, str(field_name), str(type_obj), indent, reason))
+
+            if self.verbosity >= 1:
+                result += self.callstack_to_str(indent, callstack)
+
+
+        return result
+
+
+    def callstack_to_str(self, indent, callstack):
+        result = "\t%scallstack: [\n" % indent
+        for stack_elem in callstack:
+            result += "\t  %s%s\n" % (indent, str(stack_elem))
+        result += "\t%s]\n" % indent
+        return result
+
+
+    def ok_callstack_is_relevant(self, ok_callstack):
+        # determine whether an ok callstack is relevant for logging
+        if self.verbosity >= 2:
+            return True
+
+        # empty callstacks are always relevant
+        if len(ok_callstack) == 0:
+            return True
+
+        # check whether the ok_callstack is a subset or equal to a fail_callstack
+        for (align_before, field_name, type_obj, fail_callstack, reason) in self.fail_list:
+            if len(ok_callstack) <= len(fail_callstack):
+                zipped = zip(ok_callstack, fail_callstack[:len(ok_callstack)])
+                is_subset = all([i == j for i, j in zipped])
+                if is_subset:
+                    return True
+
+        return False
+
+
+    def ok(self, align_before, field_name, type_obj, callstack, align_after):
+        self.ok_list.append((align_before, field_name, type_obj, callstack, align_after))
+
+    def fail(self, align_before, field_name, type_obj, callstack, reason):
+        self.fail_list.append((align_before, field_name, type_obj, callstack, reason))
+
+    def append(self, other):
+        self.ok_list.extend(other.ok_list)
+        self.fail_list.extend(other.fail_list)
+
+    def ok_count(self):
+        return len(self.ok_list)
+
+
+