cembed.py

#!/usr/bin/env python3

# SPDX-License-Identifier: 0BSD
# SPDX-FileCopyrightText: (C) 2025 Zephyr Lykos

import argparse
import io
import json
import sys
from itertools import islice
from typing import cast

parser = argparse.ArgumentParser(
    prog="cembed",
    description="Create C header with file data embedded in a char array",
)

parser.add_argument(
    "infile",
    nargs="?",
    type=argparse.FileType("rb"),
    default=sys.stdin.buffer,
)
parser.add_argument(
    "outfile",
    nargs="?",
    type=argparse.FileType("w", encoding="utf-8"),
    default=sys.stdout,
)
parser.add_argument(
    "--shader",
    action="store_true",
)
parser.add_argument(
    "--msvc",
    action="store_true",
)

args = parser.parse_args()

infile = cast(io.BufferedReader, args.infile)
outfile = cast(io.TextIOWrapper, args.outfile)

lines: list[str] = []

if args.shader and not args.msvc:
    for line in infile:
        if line == b"\n":
            lines.append("\n")
        elif line.strip().startswith(b"#line"):
            lines.append(line.decode().rstrip())
        else:
            if line.endswith(b";\n") or line.endswith(b"{\n") or line.endswith(b"}\n"):
                line = line[:-1]

            stripped = line.lstrip()
            lines.append(
                " " * (len(line) - len(stripped)) + json.dumps(stripped.decode())
            )

    TEMPLATE = rf"""
#ifndef SHADER_MINIFIER_IMPL
#ifndef SHADER_MINIFIER_HEADER
# define SHADER_MINIFIER_HEADER
# define VAR_resolution "resolution"
# define VAR_time "time"
#endif
#else
{"\n".join(lines)},
#endif
"""
else:
    size = 0

    while buffer := infile.read(0x1000):
        it = iter(buffer)
        size += len(buffer)
        while batch := tuple(islice(it, 0x10)):
            lines.append("".join(format(i, "#04x") + "," for i in batch))

    if args.shader:
        TEMPLATE = rf"""
#ifndef SHADER_MINIFIER_IMPL
#ifndef SHADER_MINIFIER_HEADER
# define SHADER_MINIFIER_HEADER
# define VAR_resolution "resolution"
# define VAR_time "time"
#endif
#else
(const char[{size:#x}]) {{
{"\n".join(lines)}
}},
#endif
"""

    else:
        TEMPLATE = rf"""
#define i_embed (const char[{size:#x}]) {{ \
{"\\\n".join(lines)} \
}}
"""

outfile.write(f"""// clang-format off
{TEMPLATE.strip()}
// clang-format on""")