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#!/usr/bin/env python3
# Huffman lookup table generator script for psxpress
# (C) 2022 spicyjpeg - MPL licensed
import sys, json
from array import array
from itertools import repeat
from argparse import ArgumentParser, FileType
HUFFMAN_TREE = {
"10": 0xfe00, # End of block
"11": ( 0, 1 ),
"01": {
"1": ( 1, 1 ),
"00": ( 0, 2 ),
"01": ( 2, 1 )
},
"001": {
"01": ( 0, 3 ),
"10": ( 4, 1 ),
"11": ( 3, 1 ),
"00000": ( 13, 1 ),
"00001": ( 0, 6 ),
"00010": ( 12, 1 ),
"00011": ( 11, 1 ),
"00100": ( 3, 2 ),
"00101": ( 1, 3 ),
"00110": ( 0, 5 ),
"00111": ( 10, 1 )
},
"0001": {
"00": ( 7, 1 ),
"01": ( 6, 1 ),
"10": ( 1, 2 ),
"11": ( 5, 1 )
},
"00001": {
"00": ( 2, 2 ),
"01": ( 9, 1 ),
"10": ( 0, 4 ),
"11": ( 8, 1 )
},
"0000001": {
"000": ( 16, 1 ),
"001": ( 5, 2 ),
"010": ( 0, 7 ),
"011": ( 2, 3 ),
"100": ( 1, 4 ),
"101": ( 15, 1 ),
"110": ( 14, 1 ),
"111": ( 4, 2 )
},
"00000001": {
"0000": ( 0, 11 ),
"0001": ( 8, 2 ),
"0010": ( 4, 3 ),
"0011": ( 0, 10 ),
"0100": ( 2, 4 ),
"0101": ( 7, 2 ),
"0110": ( 21, 2 ),
"0111": ( 20, 1 ),
"1000": ( 0, 9 ),
"1001": ( 19, 1 ),
"1010": ( 18, 1 ),
"1011": ( 1, 5 ),
"1100": ( 3, 3 ),
"1101": ( 0, 8 ),
"1110": ( 6, 2 ),
"1111": ( 17, 1 )
},
"000000001": {
"0000": ( 10, 2 ),
"0001": ( 9, 2 ),
"0010": ( 5, 3 ),
"0011": ( 3, 4 ),
"0100": ( 2, 5 ),
"0101": ( 1, 7 ),
"0110": ( 1, 6 ),
"0111": ( 0, 15 ),
"1000": ( 0, 14 ),
"1001": ( 0, 13 ),
"1010": ( 0, 12 ),
"1011": ( 26, 1 ),
"1100": ( 25, 1 ),
"1101": ( 24, 1 ),
"1110": ( 23, 1 ),
"1111": ( 22, 1 )
},
"0000000001": {
"0000": ( 0, 31 ),
"0001": ( 0, 30 ),
"0010": ( 0, 29 ),
"0011": ( 0, 28 ),
"0100": ( 0, 27 ),
"0101": ( 0, 26 ),
"0110": ( 0, 25 ),
"0111": ( 0, 24 ),
"1000": ( 0, 23 ),
"1001": ( 0, 22 ),
"1010": ( 0, 21 ),
"1011": ( 0, 20 ),
"1100": ( 0, 19 ),
"1101": ( 0, 18 ),
"1110": ( 0, 17 ),
"1111": ( 0, 16 )
},
"00000000001": {
"0000": ( 0, 40 ),
"0001": ( 0, 39 ),
"0010": ( 0, 38 ),
"0011": ( 0, 37 ),
"0100": ( 0, 36 ),
"0101": ( 0, 35 ),
"0110": ( 0, 34 ),
"0111": ( 0, 33 ),
"1000": ( 0, 32 ),
"1001": ( 1, 14 ),
"1010": ( 1, 13 ),
"1011": ( 1, 12 ),
"1100": ( 1, 11 ),
"1101": ( 1, 10 ),
"1110": ( 1, 9 ),
"1111": ( 1, 8 )
},
"000000000001": {
"0000": ( 1, 18 ),
"0001": ( 1, 17 ),
"0010": ( 1, 16 ),
"0011": ( 1, 15 ),
"0100": ( 6, 3 ),
"0101": ( 16, 2 ),
"0110": ( 15, 2 ),
"0111": ( 14, 2 ),
"1000": ( 13, 2 ),
"1001": ( 12, 2 ),
"1010": ( 11, 2 ),
"1011": ( 31, 1 ),
"1100": ( 30, 1 ),
"1101": ( 29, 1 ),
"1110": ( 28, 1 ),
"1111": ( 27, 1 )
}
}
## Utilities
def to_int10(value):
clamped = min(max(int(value), -0x200), 0x1ff)
return clamped + (0 if clamped >= 0 else 0x400)
def uint32_to_lines(data, indent = "\t", columns = 6):
for offset in range(0, len(data), columns):
line = f"{indent}0x{data[offset]:08x}"
for item in data[(offset + 1):(offset + columns)]:
line += f", 0x{item:08x}"
yield line
## Table generation
def iterate_tree(tree):
for code, value in tree.items():
if type(value) is dict:
# Iterate through any subtree recursively.
for suffix, _value in iterate_tree(value):
yield f"{code}{suffix}", _value
elif type(value) is tuple:
run_length, ac = value
yield f"{code}0", (run_length << 10) | to_int10(ac)
yield f"{code}1", (run_length << 10) | to_int10(-ac)
else:
yield code, value
def generate_table(codes, table_bits, prefix_bits = 0):
table = array("I", repeat(0, 2 ** table_bits))
for code, value in codes:
used_bits = len(code)
free_bits = table_bits - (used_bits - prefix_bits)
index = int(code[prefix_bits:], 2) << free_bits
# Fill out every entry in the table whose index starts with the same
# string of bits.
for combo in range(2 ** free_bits):
table[index | combo] = (used_bits << 16) | value
return table
def compress_table(table):
values = []
last_value = table[0]
run_length = 0
for value in table[1:]:
if value == last_value and run_length < 0x7ff:
run_length += 1
continue
# The run length is stored in the top 11 bits of each value, which are
# otherwise unused.
values.append((run_length << 21) | last_value)
last_value = value
run_length = 0
values.append((run_length << 21) | last_value)
return array("I", values)
## Main
UNCOMPRESSED_TEMPLATE = """static const DECDCTTAB {name} = {{
.lut = {{
{short}
}},
.lut00 = {{
{long}
}}
}};
"""
COMPRESSED_TEMPLATE = """static const uint32_t {name}[{length}] = {{
{table}
}};
"""
def get_args():
parser = ArgumentParser(
description = "Generates a Huffman lookup table structure, to be used by DecDCTvlc2()."
)
parser.add_argument(
"-c", "--compress",
action = "store_true",
help = "generate run-length compressed data instead of a DECDCTTAB struct"
)
parser.add_argument(
"-n", "--name",
type = str,
default = "_default_huffman_table",
help = "set the symbol name in the generated C source",
metavar = "file"
)
parser.add_argument(
"-t", "--tree",
type = FileType("rt"),
help = "use a custom Huffman tree from the specified JSON file",
metavar = "json_file"
)
parser.add_argument(
"-o", "--output",
type = FileType("wt"),
default = sys.stdout,
help = "where to output generated table (stdout by default)",
metavar = "file"
)
return parser.parse_args()
def main():
args = get_args()
tree = json.load(args.tree) if args.tree else HUFFMAN_TREE
short_codes, short_bits = [], 0
long_codes, long_bits = [], 0
for pair in iterate_tree(tree):
if (code := pair[0]).startswith("00000000"):
long_codes.append(pair)
long_bits = max(long_bits, len(code) - 8)
else:
short_codes.append(pair)
short_bits = max(short_bits, len(code))
short_table = generate_table(short_codes, short_bits, 0)
long_table = generate_table(long_codes, long_bits, 8)
if args.compress:
short_table.extend(long_table)
table = compress_table(short_table)
source = COMPRESSED_TEMPLATE.format(
name = args.name,
length = len(table),
table = ",\n".join(uint32_to_lines(table, "\t"))
)
else:
source = UNCOMPRESSED_TEMPLATE.format(
name = args.name,
short = ",\n".join(uint32_to_lines(short_table, "\t\t")),
long = ",\n".join(uint32_to_lines(long_table, "\t\t"))
)
with args.output as _file:
_file.write(source)
if __name__ == "__main__":
main()
|
