#!/usr/bin/env python3 # SPDX-License-Identifier: GPL-2.0 # # Leverage Python's unidecode module to generate ucs_fallback_table.h # # The generated table maps complex characters to their simpler fallback forms # for a terminal display when corresponding glyphs are unavailable. # # Usage: # python3 gen_ucs_fallback_table.py # Generate fallback tables # python3 gen_ucs_fallback_table.py -o FILE # Specify output file import unicodedata from unidecode import unidecode import sys import argparse from collections import defaultdict # Try to get unidecode version try: from importlib.metadata import version unidecode_version = version('unidecode') except: unidecode_version = 'unknown' # This script's file name from pathlib import Path this_file = Path(__file__).name # Default output file name DEFAULT_OUT_FILE = "ucs_fallback_table.h" # Define the range marker value RANGE_MARKER = 0x00 def generate_fallback_map(): """Generate a fallback map using unidecode for all relevant Unicode points.""" fallback_map = {} # Process BMP characters (0x0000 - 0xFFFF) to keep table size manageable for cp in range(0x0080, 0x10000): # Skip ASCII range (0x00-0x7F) char = chr(cp) # Skip unassigned/control characters try: if not unicodedata.name(char, ''): continue except ValueError: continue # Get the unidecode transliteration ascii_version = unidecode(char) # Only store if it results in a single character mapping if len(ascii_version) == 1: fallback_map[cp] = ord(ascii_version) # Apply manual overrides for special cases fallback_map.update(get_special_overrides()) return fallback_map def get_special_overrides(): """Get special case overrides that need different handling than unidecode provides... or doesn't provide at all.""" overrides = {} # Multi-character unidecode output # These map to single chars instead of unidecode's multiple-char mappings # In a terminal fallback context, we need a single character rather than multiple overrides[0x00C6] = ord('E') # Æ LATIN CAPITAL LETTER AE -> E (unidecode: "AE") overrides[0x00E6] = ord('e') # æ LATIN SMALL LETTER AE -> e (unidecode: "ae") overrides[0x0152] = ord('E') # Œ LATIN CAPITAL LIGATURE OE -> E (unidecode: "OE") overrides[0x0153] = ord('e') # œ LATIN SMALL LETTER LIGATURE OE -> e (unidecode: "oe") overrides[0x00DF] = ord('s') # ß LATIN SMALL LETTER SHARP S -> s (unidecode: "ss") # Comparison operators that unidecode renders as multiple characters overrides[0x2264] = ord('<') # ≤ LESS-THAN OR EQUAL TO -> < (unidecode: "<=") overrides[0x2265] = ord('>') # ≥ GREATER-THAN OR EQUAL TO -> > (unidecode: ">=") # Unidecode returns an empty string for these overrides[0x2260] = ord('#') # ≠ NOT EQUAL TO -> # (unidecode: empty string) # Quadrant block characters that unidecode doesn't map for cp in range(0x2596, 0x259F+1): overrides[cp] = ord('#') # ▖ ▗ ▘ ▙ etc. - map to # (unidecode: empty string) # Directional arrows # These provide better semantic meaning than unidecode's mappings overrides[0x2192] = ord('>') # → RIGHTWARDS ARROW -> > (unidecode: "-") overrides[0x2190] = ord('<') # ← LEFTWARDS ARROW -> < (unidecode: "-") overrides[0x2191] = ord('^') # ↑ UPWARDS ARROW -> ^ (unidecode: "|") overrides[0x2193] = ord('v') # ↓ DOWNWARDS ARROW -> v (unidecode: "|") # Double arrows with their directional semantic mappings overrides[0x21D0] = ord('<') # ⇐ LEFTWARDS DOUBLE ARROW -> < overrides[0x21D1] = ord('^') # ⇑ UPWARDS DOUBLE ARROW -> ^ overrides[0x21D2] = ord('>') # ⇒ RIGHTWARDS DOUBLE ARROW -> > overrides[0x21D3] = ord('v') # ⇓ DOWNWARDS DOUBLE ARROW -> v # Halfwidth arrows # These need the same treatment as their normal-width counterparts overrides[0xFFE9] = ord('<') # ￩ HALFWIDTH LEFTWARDS ARROW -> < (unidecode: "-") overrides[0xFFEA] = ord('^') # ￪ HALFWIDTH UPWARDS ARROW -> ^ (unidecode: "|") overrides[0xFFEB] = ord('>') # ￫ HALFWIDTH RIGHTWARDS ARROW -> > (unidecode: "-") overrides[0xFFEC] = ord('v') # ￬ HALFWIDTH DOWNWARDS ARROW -> v (unidecode: "|") # Currency symbols - each mapped to a representative letter overrides[0x00A2] = ord('c') # ¢ CENT SIGN -> c overrides[0x00A3] = ord('L') # £ POUND SIGN -> L overrides[0x00A5] = ord('Y') # ¥ YEN SIGN -> Y overrides[0x20AC] = ord('E') # € EURO SIGN -> E # Symbols mapped to letters overrides[0x00A7] = ord('S') # § SECTION SIGN -> S overrides[0x00A9] = ord('C') # © COPYRIGHT SIGN -> C overrides[0x00AE] = ord('R') # ® REGISTERED SIGN -> R overrides[0x2122] = ord('T') # ™ TRADE MARK SIGN -> T # Degree-related symbols overrides[0x00B0] = ord('o') # ° DEGREE SIGN -> o overrides[0x2103] = ord('C') # ℃ DEGREE CELSIUS -> C overrides[0x2109] = ord('F') # ℉ DEGREE FAHRENHEIT -> F # Angle quotation marks overrides[0x00AB] = ord('<') # « LEFT-POINTING DOUBLE ANGLE QUOTATION MARK -> < overrides[0x00BB] = ord('>') # » RIGHT-POINTING DOUBLE ANGLE QUOTATION MARK -> > # Operators with circular shape overrides[0x2218] = ord('o') # ∘ RING OPERATOR -> o overrides[0x2219] = ord('.') # ∙ BULLET OPERATOR -> . # Negated mathematical symbols (preserving the negation semantics) # Negated symbols mapped to exclamation mark (semantically "not") for cp in (0x2204, 0x2209, 0x220C, 0x2224, 0x2226, 0x226E, 0x226F, 0x2280, 0x2281, 0x2284, 0x2285): overrides[cp] = ord('!') # Negated math symbols -> ! (not) # Negated symbols mapped to hash sign (semantically "not equal") for cp in (0x2241, 0x2244, 0x2249, 0x2262, 0x2268, 0x2269, 0x226D, 0x228A, 0x228B): overrides[cp] = ord('#') # Negated equality symbols -> # (not equal) # Negated arrows - all mapped to exclamation mark for cp in (0x219A, 0x219B, 0x21AE, 0x21CD, 0x21CE, 0x21CF): overrides[cp] = ord('!') # Negated arrows -> ! (not) # Dashes and hyphens for cp in (0x2010, 0x2011, 0x2012, 0x2013, 0x2014, 0x2015, 0x2043, 0x2052): overrides[cp] = ord('-') # Dashes and hyphens -> - # Question mark punctuation for cp in (0x203D, 0x2047, 0x2048): overrides[cp] = ord('?') # Question marks -> ? # Exclamation mark punctuation for cp in (0x203C, 0x2049): overrides[cp] = ord('!') # Exclamation marks -> ! # Asterisk-like symbols for cp in (0x2042, 0x2051, 0x2055): overrides[cp] = ord('*') # Other specific punctuation with unique mappings overrides[0x201E] = ord('"') # „ DOUBLE LOW-9 QUOTATION MARK overrides[0x2023] = ord('>') # ‣ TRIANGULAR BULLET overrides[0x2026] = ord('.') # … HORIZONTAL ELLIPSIS overrides[0x2033] = ord('"') # ″ DOUBLE PRIME overrides[0x204B] = ord('P') # ⁋ REVERSED PILCROW SIGN overrides[0x204C] = ord('<') # ⁌ BLACK LEFTWARDS BULLET overrides[0x204D] = ord('>') # ⁍ BLACK RIGHTWARDS BULLET overrides[0x204F] = ord(';') # ⁏ REVERSED SEMICOLON overrides[0x205B] = ord(':') # ⁛ FOUR DOT MARK # Check marks overrides[0x2713] = ord('v') # ✓ CHECK MARK overrides[0x2714] = ord('V') # ✔ HEAVY CHECK MARK # X marks - lowercase for regular, uppercase for heavy for cp in (0x2715, 0x2717): overrides[cp] = ord('x') # Regular X marks -> x for cp in (0x2716, 0x2718): overrides[cp] = ord('X') # Heavy X marks -> X # Stars and asterisk-like symbols mapped to '*' for cp in (0x2605, 0x2606, 0x262A, 0x269D, 0x2698): overrides[cp] = ord('*') # All star and asterisk symbols -> * for cp in range(0x2721, 0x2746+1): overrides[cp] = ord('*') # All star and asterisk symbols -> * for cp in range(0x2749, 0x274B+1): overrides[cp] = ord('*') # Last set of asterisk symbols -> * for cp in (0x229B, 0x22C6, 0x235F, 0x2363): overrides[cp] = ord('*') # Star operators -> * # Special exclusions with fallback value of 0 # These will be filtered out in organize_by_pages() # Exclude U+2028 (LINE SEPARATOR) overrides[0x2028] = 0 # LINE SEPARATOR (unidecode: '\n') # Full-width to ASCII mapping (covering all printable ASCII 33-126) # 0xFF01 (！) to 0xFF5E (～) -> ASCII 33 (!) to 126 (~) # Those are excluded here to reduce the table size. # It is more efficient to process them programmatically in # ucs.c:ucs_get_fallback(). for cp in range(0xFF01, 0xFF5E + 1): overrides[cp] = 0 # Double-width ASCII characters return overrides def organize_by_pages(fallback_map): """Organize the fallback mappings by their high byte (page).""" # Group by high byte (page) page_groups = defaultdict(list) for code, fallback in fallback_map.items(): # Skip characters with fallback value of 0 (excluded characters) if fallback == 0: continue page = code >> 8 # Get the high byte (page) offset = code & 0xFF # Get the low byte (offset within page) page_groups[page].append((offset, fallback)) # Sort each page's entries by offset for page in page_groups: page_groups[page].sort() return page_groups def compress_ranges(page_groups): """Compress consecutive entries with the same fallback character into ranges. A range is only compressed if it contains 3 or more consecutive entries.""" compressed_pages = {} for page, entries in page_groups.items(): compressed_entries = [] i = 0 while i < len(entries): start_offset, fallback = entries[i] # Look ahead to find consecutive entries with the same fallback j = i + 1 while (j < len(entries) and entries[j][0] == entries[j-1][0] + 1 and # consecutive offsets entries[j][1] == fallback): # same fallback j += 1 # Calculate the range end end_offset = entries[j-1][0] # If we found a range with 3 or more entries (worth compressing) if j - i >= 3: # Add a range entry compressed_entries.append((start_offset, RANGE_MARKER)) compressed_entries.append((end_offset, fallback)) else: # Add the individual entries as is for k in range(i, j): compressed_entries.append(entries[k]) i = j compressed_pages[page] = compressed_entries return compressed_pages def cp_name(cp): """Get the Unicode character name for a code point.""" try: return unicodedata.name(chr(cp)) except: return f"U+{cp:04X}" def generate_fallback_tables(out_file=DEFAULT_OUT_FILE): """Generate the fallback character tables.""" # Generate fallback map using unidecode fallback_map = generate_fallback_map() print(f"Generated {len(fallback_map)} total fallback mappings") # Organize by pages page_groups = organize_by_pages(fallback_map) print(f"Organized into {len(page_groups)} pages") # Compress ranges compressed_pages = compress_ranges(page_groups) total_compressed_entries = sum(len(entries) for entries in compressed_pages.values()) print(f"Total compressed entries: {total_compressed_entries}") # Create output file with open(out_file, 'w') as f: f.write(f"""\ /* SPDX-License-Identifier: GPL-2.0 */ /* * {out_file} - Unicode character fallback table * * Auto-generated by {this_file} * * Unicode Version: {unicodedata.unidata_version} * Unidecode Version: {unidecode_version} * * This file contains optimized tables that map complex Unicode characters * to simpler fallback characters for terminal display when corresponding * glyphs are unavailable. */ static const struct ucs_page_desc ucs_fallback_pages[] = {{ """) # Convert compressed_pages to a sorted list of (page, entries) tuples sorted_pages = sorted(compressed_pages.items()) # Track the start index for each page start_index = 0 # Write page descriptors for page, entries in sorted_pages: count = len(entries) f.write(f"\t{{ 0x{page:02X}, {count}, {start_index} }},\n") start_index += count # Write entries array f.write("""\ }; /* Page entries array (referenced by page descriptors) */ static const struct ucs_page_entry ucs_fallback_entries[] = { """) # Write all entries for page, entries in sorted_pages: page_hex = f"0x{page:02X}" f.write(f"\t/* Entries for page {page_hex} */\n") for i, (offset, fallback) in enumerate(entries): # Convert to hex for better readability offset_hex = f"0x{offset:02X}" fallback_hex = f"0x{fallback:02X}" # Handle comments codepoint = (page << 8) | offset if fallback == RANGE_MARKER: comment = f"{cp_name(codepoint)} -> ..." else: comment = f"{cp_name(codepoint)} -> '{chr(fallback)}'" f.write(f"\t{{ 0x{offset:02X}, 0x{fallback:02X} }}, /* {comment} */\n") f.write(f"""\ }}; #define UCS_PAGE_ENTRY_RANGE_MARKER {RANGE_MARKER} """) if __name__ == "__main__": parser = argparse.ArgumentParser(description="Generate Unicode fallback character tables") parser.add_argument("-o", "--output", dest="output_file", default=DEFAULT_OUT_FILE, help=f"Output file name (default: {DEFAULT_OUT_FILE})") args = parser.parse_args() generate_fallback_tables(out_file=args.output_file)