symuid/symuid/library/cmus.py

# -*- coding: utf-8 -*-

import re
import sys


def _int_from_bytes_sys(data_bytes):
    return int.from_bytes(data_bytes, byteorder=sys.byteorder)


class Track:

    RESERVED_PAD_REGEX = rb'\xff{16,}'
    STRING_TERMINATOR = b'\x00'

    def __init__(self, cache_size, cache_bytes):
        """
        struct cache_entry {
            // size of this struct including size itself
            uint32_t size;
            int32_t play_count;
            int64_t mtime;
            int32_t duration;
            int32_t bitrate;
            int32_t bpm;
            uint8_t _reserved[CACHE_ENTRY_RESERVED_SIZE];
            // filename, codec, codec_profile and N * (key, val)
            char strings[];
        };
        """
        assert len(cache_bytes) + 4 == cache_size
        self._play_count = _int_from_bytes_sys(cache_bytes[0:4])
        # self._mtime = _int_from_bytes_sys(cache_bytes[4:12])
        # self._duration_seconds = _int_from_bytes_sys(cache_bytes[12:16])
        # self._bitrate = _int_from_bytes_sys(cache_bytes[16:20])
        # self._bpm = _int_from_bytes_sys(cache_bytes[20:24])
        strings = re.split(self.RESERVED_PAD_REGEX, cache_bytes)[1] \
            .split(self.STRING_TERMINATOR)
        self._path = strings[0]

    @property
    def path(self):
        return self._path

    @property
    def play_count(self):
        return self._play_count