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]) |