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-rwxr-xr-xgfx/harfbuzz/src/gen-vowel-constraints.py229
1 files changed, 229 insertions, 0 deletions
diff --git a/gfx/harfbuzz/src/gen-vowel-constraints.py b/gfx/harfbuzz/src/gen-vowel-constraints.py
new file mode 100755
index 0000000000..3c1f6211eb
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+++ b/gfx/harfbuzz/src/gen-vowel-constraints.py
@@ -0,0 +1,229 @@
+#!/usr/bin/env python3
+
+"""Generator of the function to prohibit certain vowel sequences.
+
+It creates ``_hb_preprocess_text_vowel_constraints``, which inserts dotted
+circles into sequences prohibited by the USE script development spec.
+This function should be used as the ``preprocess_text`` of an
+``hb_ot_shaper_t``.
+
+usage: ./gen-vowel-constraints.py ms-use/IndicShapingInvalidCluster.txt Scripts.txt
+
+Input file:
+* https://unicode.org/Public/UCD/latest/ucd/Scripts.txt
+"""
+
+import collections
+def write (s):
+ sys.stdout.flush ()
+ sys.stdout.buffer.write (s.encode ('utf-8'))
+import sys
+
+if len (sys.argv) != 3:
+ sys.exit (__doc__)
+
+with open (sys.argv[2], encoding='utf-8') as f:
+ scripts_header = [f.readline () for i in range (2)]
+ scripts = {}
+ script_order = {}
+ for line in f:
+ j = line.find ('#')
+ if j >= 0:
+ line = line[:j]
+ fields = [x.strip () for x in line.split (';')]
+ if len (fields) == 1:
+ continue
+ uu = fields[0].split ('..')
+ start = int (uu[0], 16)
+ if len (uu) == 1:
+ end = start
+ else:
+ end = int (uu[1], 16)
+ script = fields[1]
+ for u in range (start, end + 1):
+ scripts[u] = script
+ if script not in script_order:
+ script_order[script] = start
+
+class ConstraintSet (object):
+ """A set of prohibited code point sequences.
+
+ Args:
+ constraint (List[int]): A prohibited code point sequence.
+
+ """
+ def __init__ (self, constraint):
+ # Either a list or a dictionary. As a list of code points, it
+ # represents a prohibited code point sequence. As a dictionary,
+ # it represents a set of prohibited sequences, where each item
+ # represents the set of prohibited sequences starting with the
+ # key (a code point) concatenated with any of the values
+ # (ConstraintSets).
+ self._c = constraint
+
+ def add (self, constraint):
+ """Add a constraint to this set."""
+ if not constraint:
+ return
+ first = constraint[0]
+ rest = constraint[1:]
+ if isinstance (self._c, list):
+ if constraint == self._c[:len (constraint)]:
+ self._c = constraint
+ elif self._c != constraint[:len (self._c)]:
+ self._c = {self._c[0]: ConstraintSet (self._c[1:])}
+ if isinstance (self._c, dict):
+ if first in self._c:
+ self._c[first].add (rest)
+ else:
+ self._c[first] = ConstraintSet (rest)
+
+ @staticmethod
+ def _indent (depth):
+ return (' ' * depth).replace (' ', '\t')
+
+ def __str__ (self, index=0, depth=4):
+ s = []
+ indent = self._indent (depth)
+ if isinstance (self._c, list):
+ if len (self._c) == 0:
+ assert index == 2, 'Cannot use `matched` for this constraint; the general case has not been implemented'
+ s.append ('{}matched = true;\n'.format (indent))
+ elif len (self._c) == 1:
+ assert index == 1, 'Cannot use `matched` for this constraint; the general case has not been implemented'
+ s.append ('{}matched = 0x{:04X}u == buffer->cur ({}).codepoint;\n'.format (indent, next (iter (self._c)), index or ''))
+ else:
+ s.append ('{}if (0x{:04X}u == buffer->cur ({}).codepoint &&\n'.format (indent, self._c[0], index or ''))
+ if index:
+ s.append ('{}buffer->idx + {} < count &&\n'.format (self._indent (depth + 2), index + 1))
+ for i, cp in enumerate (self._c[1:], start=1):
+ s.append ('{}0x{:04X}u == buffer->cur ({}).codepoint{}\n'.format (
+ self._indent (depth + 2), cp, index + i, ')' if i == len (self._c) - 1 else ' &&'))
+ s.append ('{}{{\n'.format (indent))
+ for i in range (index):
+ s.append ('{}(void) buffer->next_glyph ();\n'.format (self._indent (depth + 1)))
+ s.append ('{}matched = true;\n'.format (self._indent (depth + 1)))
+ s.append ('{}}}\n'.format (indent))
+ else:
+ s.append ('{}switch (buffer->cur ({}).codepoint)\n'.format(indent, index or ''))
+ s.append ('{}{{\n'.format (indent))
+ cases = collections.defaultdict (set)
+ for first, rest in sorted (self._c.items ()):
+ cases[rest.__str__ (index + 1, depth + 2)].add (first)
+ for body, labels in sorted (cases.items (), key=lambda b_ls: sorted (b_ls[1])[0]):
+ for i, cp in enumerate (sorted (labels)):
+ if i % 4 == 0:
+ s.append (self._indent (depth + 1))
+ else:
+ s.append (' ')
+ s.append ('case 0x{:04X}u:{}'.format (cp, '\n' if i % 4 == 3 else ''))
+ if len (labels) % 4 != 0:
+ s.append ('\n')
+ s.append (body)
+ s.append ('{}break;\n'.format (self._indent (depth + 2)))
+ s.append ('{}}}\n'.format (indent))
+ return ''.join (s)
+
+constraints = {}
+with open (sys.argv[1], encoding='utf-8') as f:
+ constraints_header = []
+ while True:
+ line = f.readline ().strip ()
+ if line == '#':
+ break
+ constraints_header.append(line)
+ for line in f:
+ j = line.find ('#')
+ if j >= 0:
+ line = line[:j]
+ constraint = [int (cp, 16) for cp in line.split (';')[0].split ()]
+ if not constraint: continue
+ assert 2 <= len (constraint), 'Prohibited sequence is too short: {}'.format (constraint)
+ script = scripts[constraint[0]]
+ if script in constraints:
+ constraints[script].add (constraint)
+ else:
+ constraints[script] = ConstraintSet (constraint)
+ assert constraints, 'No constraints found'
+
+print ('/* == Start of generated functions == */')
+print ('/*')
+print (' * The following functions are generated by running:')
+print (' *')
+print (' * %s ms-use/IndicShapingInvalidCluster.txt Scripts.txt' % sys.argv[0])
+print (' *')
+print (' * on files with these headers:')
+print (' *')
+for line in constraints_header:
+ print (' * %s' % line.strip ())
+print (' *')
+for line in scripts_header:
+ print (' * %s' % line.strip ())
+print (' */')
+
+print ()
+print ('#include "hb.hh"')
+print ()
+print ('#ifndef HB_NO_OT_SHAPE')
+print ()
+print ('#include "hb-ot-shaper-vowel-constraints.hh"')
+print ()
+print ('static void')
+print ('_output_dotted_circle (hb_buffer_t *buffer)')
+print ('{')
+print (' (void) buffer->output_glyph (0x25CCu);')
+print (' _hb_glyph_info_reset_continuation (&buffer->prev());')
+print ('}')
+print ()
+print ('static void')
+print ('_output_with_dotted_circle (hb_buffer_t *buffer)')
+print ('{')
+print (' _output_dotted_circle (buffer);')
+print (' (void) buffer->next_glyph ();')
+print ('}')
+print ()
+
+print ('void')
+print ('_hb_preprocess_text_vowel_constraints (const hb_ot_shape_plan_t *plan HB_UNUSED,')
+print ('\t\t\t\t hb_buffer_t *buffer,')
+print ('\t\t\t\t hb_font_t *font HB_UNUSED)')
+print ('{')
+print ('#ifdef HB_NO_OT_SHAPER_VOWEL_CONSTRAINTS')
+print (' return;')
+print ('#endif')
+print (' if (buffer->flags & HB_BUFFER_FLAG_DO_NOT_INSERT_DOTTED_CIRCLE)')
+print (' return;')
+print ()
+print (' /* UGLY UGLY UGLY business of adding dotted-circle in the middle of')
+print (' * vowel-sequences that look like another vowel. Data for each script')
+print (' * collected from the USE script development spec.')
+print (' *')
+print (' * https://github.com/harfbuzz/harfbuzz/issues/1019')
+print (' */')
+print (' buffer->clear_output ();')
+print (' unsigned int count = buffer->len;')
+print (' switch ((unsigned) buffer->props.script)')
+print (' {')
+
+for script, constraints in sorted (constraints.items (), key=lambda s_c: script_order[s_c[0]]):
+ print (' case HB_SCRIPT_{}:'.format (script.upper ()))
+ print (' for (buffer->idx = 0; buffer->idx + 1 < count && buffer->successful;)')
+ print (' {')
+ print ('\tbool matched = false;')
+ write (str (constraints))
+ print ('\t(void) buffer->next_glyph ();')
+ print ('\tif (matched) _output_with_dotted_circle (buffer);')
+ print (' }')
+ print (' break;')
+ print ()
+
+print (' default:')
+print (' break;')
+print (' }')
+print (' buffer->sync ();')
+print ('}')
+
+print ()
+print ()
+print ('#endif')
+print ('/* == End of generated functions == */')