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Unified Diff: core/scripts/make_token_matcher.py

Issue 22498002: Roll IDL to multivm@1329 (Closed) Base URL: https://dart.googlecode.com/svn/third_party/WebCore
Patch Set: Created 7 years, 4 months ago
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Index: core/scripts/make_token_matcher.py
diff --git a/core/scripts/make_token_matcher.py b/core/scripts/make_token_matcher.py
new file mode 100755
index 0000000000000000000000000000000000000000..3631ed95f6d5fdd2eac7c4c542442b0a975c3fe0
--- /dev/null
+++ b/core/scripts/make_token_matcher.py
@@ -0,0 +1,231 @@
+#!/usr/bin/env python
+# Copyright (C) 2013 Google Inc. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+# * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+# * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+# * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import io
+import itertools
+import re
+import sys
+
+
+class BadInput(Exception):
+ """Unsupported input has been found."""
+
+
+class SwitchCase(object):
+ """Represents a CASE block."""
+ def __init__(self, identifier, block):
+ self.identifier = identifier
+ self.block = block
+
+
+class Optimizer(object):
+ """Generates optimized identifier matching code."""
+ def __init__(self, output_file, array_variable, length_variable):
+ self.output_file = output_file
+ self.array_variable = array_variable
+ self.length_variable = length_variable
+
+ def inspect(self, cases):
+ lengths = list(set([len(c.identifier) for c in cases]))
+ lengths.sort()
+
+ def response(length):
+ self.inspect_array([c for c in cases if len(c.identifier) == length], range(length))
+ self.write_selection(self.length_variable, lengths, str, response)
+
+ def score(self, alternatives):
+ return -sum([len(list(count)) ** 2 for _, count in itertools.groupby(sorted(alternatives))])
+
+ def choose_selection_pos(self, cases, pending):
+ candidates = [pos for pos in pending if all(alternative.isalpha() for alternative in [c.identifier[pos] for c in cases])]
+ if not candidates:
+ raise BadInput('Case-insensitive switching on non-alphabetic characters not yet implemented')
+ return sorted(candidates, key=lambda pos: self.score([c.identifier[pos] for c in cases]))[0]
+
+ def inspect_array(self, cases, pending):
+ assert len(cases) >= 1
+ if pending:
+ common = [pos for pos in pending
+ if len(set([c.identifier[pos] for c in cases])) == 1]
+ if common:
+ identifier = cases[0].identifier
+ for index in xrange(len(common)):
+ if index == 0:
+ self.output_file.write(u'if (LIKELY(')
+ else:
+ self.output_file.write(u' && ')
+ pos = common[index]
+ if identifier[pos].isalpha():
+ self.output_file.write("(%s[%d] | 0x20) == '%s'" %
+ (self.array_variable, pos, identifier[pos]))
+ else:
+ self.output_file.write("%s[%d] == '%s'" %
+ (self.array_variable, pos, identifier[pos]))
+ self.output_file.write(u')) {\n')
+ next_pending = list(set(pending) - set(common))
+ next_pending.sort()
+ self.inspect_array(cases, next_pending)
+ self.output_file.write(u'}\n')
+ else:
+ pos = self.choose_selection_pos(cases, pending)
+ next_pending = filter(lambda p: p != pos, pending)
+
+ alternatives = list(set([c.identifier[pos] for c in cases]))
+ alternatives.sort()
+
+ def literal(alternative):
+ if isinstance(alternative, int):
+ return str(alternative)
+ else:
+ return "'%s'" % alternative
+
+ def response(alternative):
+ self.inspect_array([c for c in cases if c.identifier[pos] == alternative],
+ next_pending)
+
+ expression = '(%s[%d] | 0x20)' % (self.array_variable, pos)
+ self.write_selection(expression, alternatives, literal, response)
+ else:
+ assert len(cases) == 1
+ for block_line in cases[0].block:
+ self.output_file.write(block_line)
+
+ def write_selection(self, expression, alternatives, literal, response):
+ if len(alternatives) == 1:
+ self.output_file.write(u'if (LIKELY(%s == %s)) {\n' % (expression, literal(alternatives[0])))
+ response(alternatives[0])
+ self.output_file.write(u'}\n')
+ elif len(alternatives) == 2:
+ self.output_file.write(u'if (%s == %s) {\n' % (expression, literal(alternatives[0])))
+ response(alternatives[0])
+ self.output_file.write(u'} else if (LIKELY(%s == %s)) {\n' % (expression, literal(alternatives[1])))
+ response(alternatives[1])
+ self.output_file.write(u'}\n')
+ else:
+ self.output_file.write('switch (%s) {\n' % expression)
+ for alternative in alternatives:
+ self.output_file.write(u'case %s: {\n' % literal(alternative))
+ response(alternative)
+ self.output_file.write(u'} break;\n')
+ self.output_file.write(u'}\n')
+
+
+class LineProcessor(object):
+ def process_line(self, line):
+ pass
+
+
+class MainLineProcessor(LineProcessor):
+ """Processes the contents of an input file."""
+ SWITCH_PATTERN = re.compile(r'\s*SWITCH\s*\((\w*),\s*(\w*)\) \{$')
+
+ def __init__(self, output_file):
+ self.output_file = output_file
+
+ def process_line(self, line):
+ match_switch = MainLineProcessor.SWITCH_PATTERN.match(line)
+ if match_switch:
+ array_variable = match_switch.group(1)
+ length_variable = match_switch.group(2)
+ return SwitchLineProcessor(self, self.output_file, array_variable, length_variable)
+ else:
+ self.output_file.write(line)
+ return self
+
+
+class SwitchLineProcessor(LineProcessor):
+ """Processes the contents of a SWITCH block."""
+ CASE_PATTERN = re.compile(r'\s*CASE\s*\(\"([a-z0-9_\-\(]*)\"\) \{$')
+ CLOSE_BRACE_PATTERN = re.compile(r'\s*\}$')
+ EMPTY_PATTERN = re.compile(r'\s*$')
+
+ def __init__(self, parent, output_file, array_variable, length_variable):
+ self.parent = parent
+ self.output_file = output_file
+ self.array_variable = array_variable
+ self.length_variable = length_variable
+ self.cases = []
+
+ def process_line(self, line):
+ match_case = SwitchLineProcessor.CASE_PATTERN.match(line)
+ match_close_brace = SwitchLineProcessor.CLOSE_BRACE_PATTERN.match(line)
+ match_empty = SwitchLineProcessor.EMPTY_PATTERN.match(line)
+ if match_case:
+ identifier = match_case.group(1)
+ return CaseLineProcessor(self, self.output_file, identifier)
+ elif match_close_brace:
+ Optimizer(self.output_file, self.array_variable, self.length_variable).inspect(self.cases)
+ return self.parent
+ elif match_empty:
+ return self
+ else:
+ raise BadInput('Invalid line within SWITCH: %s' % line)
+
+ def add_case(self, latest_case):
+ if latest_case.identifier in [c.identifier for c in self.cases]:
+ raise BadInput('Repeated case: %s' % latest_case.identifier)
+ self.cases.append(latest_case)
+
+
+class CaseLineProcessor(LineProcessor):
+ """Processes the contents of a CASE block."""
+ CLOSE_BRACE_PATTERN = re.compile(r'\s*\}$')
+ BREAK_PATTERN = re.compile(r'break;')
+
+ def __init__(self, parent, output_file, identifier):
+ self.parent = parent
+ self.output_file = output_file
+ self.identifier = identifier
+ self.block = []
+
+ def process_line(self, line):
+ match_close_brace = CaseLineProcessor.CLOSE_BRACE_PATTERN.match(line)
+ match_break = CaseLineProcessor.BREAK_PATTERN.search(line)
+ if match_close_brace:
+ self.parent.add_case(SwitchCase(self.identifier, self.block))
+ return self.parent
+ elif match_break:
+ raise BadInput('break within CASE not supported: %s' % line)
+ else:
+ self.block.append(line)
+ return self
+
+
+def process_file(input_name, output_name):
+ """Transforms input file into legal C++ source code."""
+ with io.open(input_name) as input_file:
+ with io.open(output_name, 'w') as output_file:
+ processor = MainLineProcessor(output_file)
+ input_lines = input_file.readlines()
+ for line in input_lines:
+ processor = processor.process_line(line)
+
+
+if __name__ == '__main__':
+ process_file(sys.argv[1], sys.argv[2])
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