locale: Rewrite locale/gen-translit.pl in Python

This commit does not change the generated output file.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

locale/gen-translit.py

@@ -0,0 +1,177 @@
+#!/usr/bin/python3
+# Generate the locale/C-translit.h file.
+# Copyright (C) 2018 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+#
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <http://www.gnu.org/licenses/>.
+
+import re
+import sys
+
+
+class StringLiteral:
+    "Source of a string literal and its decomposition into code points."
+    def __init__(self, s):
+        # States:
+        #  0 regular character sequence
+        #  1 backslash seen
+        #  2 in hexadecimal escape sequence
+        state = 0
+        result = []
+        for ch in s:
+            if state == 0:
+                if ch == '\\':
+                    state = 1
+                else:
+                    result.append(ord(ch))
+            elif state == 1:
+                if ch in "\\\"":
+                    result.append(ord(ch))
+                    state = 0
+                elif ch == 'x':
+                    state = 2
+                    result.append(0)
+                else:
+                    raise ValueError("invalid character {!r} in {!r}".format(
+                        ch, s))
+            elif state == 2:
+                if ch in "0123456789abcdefABCDEF":
+                    result[-1] = result[-1] * 16 + int(ch, 16)
+                else:
+                    if ch == '\\':
+                        state = 1
+                    else:
+                        state = 0
+        if state == 1:
+            raise ValueError("trailing backslash in {!r}".format(s))
+
+        self.source = s
+        self.decoded = tuple(result)
+
+
+class Translit:
+    "Pair of transliteration and source."
+
+    __RE_TRANSLIT = re.compile(
+        r'^"((?:[^"\\]|\\x[0-9a-fA-F])+)"\s+'
+        r'"((?:[^"\\]|\\["\\])*)"\s*(?:#.*)?$')
+
+    def __init__(self, line):
+        match = self.__RE_TRANSLIT.match(line)
+        if not match:
+            raise IOError("invalid line {}: {!r}".format(
+                lineno + 1, line))
+        codepoints, replacement = match.groups()
+        self.codepoints = StringLiteral(codepoints)
+        self.replacement = StringLiteral(replacement)
+
+
+# List of Translit objects.
+translits = []
+
+# Read transliterations from standard input.
+for lineno, line in enumerate(sys.stdin):
+    line = line.strip()
+    # Skip empty lines and comments.
+    if (not line) or line[0] == '#':
+        continue
+    translit = Translit(line)
+    # Check ordering of codepoints.
+    if translits \
+       and translit.codepoints.decoded <= translits[-1].codepoints.decoded:
+        raise IOError("unexpected codepoint {!r} on line {}: {!r}".format(
+            translit.codeponts.decoded, lineno + 1, line))
+    translits.append(translit)
+
+# Generate the C sources.
+write = sys.stdout.write
+write("#include <stdint.h>\n")
+write("#define NTRANSLIT {}\n".format(len(translits)))
+
+write("static const uint32_t translit_from_idx[] =\n{\n  ")
+col = 2
+total = 0
+for translit in translits:
+    if total > 0:
+        if col + 7 >= 79:
+            write(",\n  ")
+            col = 2
+        else:
+            write(", ")
+            col += 2
+    write("{:4}".format(total))
+    total += len(translit.codepoints.decoded) + 1
+    col += 4
+write("\n};\n")
+
+write("static const wchar_t translit_from_tbl[] =\n ")
+col = 1
+first = True
+for translit in translits:
+    if first:
+        first = False
+    else:
+        if col + 6 >= 79:
+            write("\n ")
+            col = 1
+        write(" L\"\\0\"")
+        col += 6
+    if col > 2 and col + len(translit.codepoints.source) + 4 >= 79:
+        write("\n  ")
+        col = 2
+    else:
+        write(" ")
+        col += 1
+    write("L\"{}\"".format(translit.codepoints.source))
+    col += len(translit.codepoints.source) + 3
+write(";\n")
+
+write("static const uint32_t translit_to_idx[] =\n{\n  ")
+col = 2
+total = 0
+for translit in translits:
+    if total > 0:
+        if col + 7 >= 79:
+            write(",\n  ")
+            col = 2
+        else:
+            write(", ")
+            col += 2
+    write("{:4}".format(total))
+    total += len(translit.replacement.decoded) + 2
+    col += 4
+write("\n};\n")
+
+write("static const wchar_t translit_to_tbl[] =\n ")
+col = 1
+first = True
+for translit in translits:
+    if first:
+        first = False
+    else:
+        if col + 6 >= 79:
+            write("\n ")
+            col = 1
+        write(" L\"\\0\"")
+        col += 6
+    if col > 2 and col + len(translit.replacement.source) + 6 >= 79:
+        write("\n  ")
+        col = 2
+    else:
+        write(" ")
+        col += 1
+    write("L\"{}\\0\"".format(translit.replacement.source))
+    col += len(translit.replacement.source) + 5
+write(";\n")