initial commit: adx loop parser

adx/adx_parser.py

@@ -0,0 +1,119 @@
+from math import modf #fuck me rounding is hard
+
+# header map
+# https://wiki.multimedia.cx/index.php/CRI_ADX_file
+
+MAGIC_OFF = 0x00
+MAGIC_LEN = 2
+MAGIC = 0x8000
+
+DATA_OFF_OFF = 0x02
+DATA_OFF_LEN = 2
+DATA_OFF_MIN = 0x38
+
+FORMAT_OFF = 0x04
+FORMAT_LEN = 1
+FORMAT = 3 # always 3 for adx apparently
+
+LOOP_TYPE_OFF = 0x12
+LOOP_TYPE_LEN = 1
+LOOP_TYPE_SUP = [4] # supported loop styles
+
+SRATE_OFF = 0x08
+SRATE_LEN = 4
+
+SCOUNT_OFF = 0x0c
+SCOUNT_LEN = 4
+
+CRYPT_OFF = 0x13
+CRYPT_LEN = 1
+
+LOOP4_FLAG_OFF = 0x24
+LOOP4_FLAG_LEN = 4
+
+LOOP4_START_OFF = 0x28
+LOOP4_START_LEN = 4
+
+LOOP4_END_OFF = 0x30
+LOOP4_END_LEN = 4
+
+
+#class independent functions
+
+def dumb_round(number):
+	dec = modf(number)[0]
+	if (dec <= 0.5):
+		return int(number)
+	else:
+		return int(number+1)
+
+class adx_file(object):
+	magic = 0
+	form = 0
+	l_style = 0
+	encrypted = 0
+	sam_rate = 0
+	sam_count = 0
+	l_flag = 0
+	l_start = 0
+	l_end = 0
+	l_exists = 0
+	d_offset = 0
+	is_valid = 0
+
+	data = None
+
+	def __init__(self, data):
+		# first, validate
+		self.data = data
+		self.magic = self.get_val(MAGIC_OFF, MAGIC_LEN)
+		self.form = self.get_val(FORMAT_OFF, FORMAT_LEN)
+		self.l_style = self.get_val(LOOP_TYPE_OFF, LOOP_TYPE_LEN)
+		self.encrypted = self.get_val(CRYPT_OFF, CRYPT_LEN)
+		self.d_offset = self.get_val(DATA_OFF_OFF, DATA_OFF_LEN)
+		if self.d_offset < DATA_OFF_MIN:
+			return None
+		self.l_exists = 1
+		# now load things for math
+		self.sam_rate = self.get_val(SRATE_OFF, SRATE_LEN)
+		self.sam_count = self.get_val(SCOUNT_OFF, SCOUNT_LEN)
+		self.validate()
+
+	def get_val(self, offset, length):
+		return int.from_bytes(self.data[offset:offset+length], byteorder='big', signed=False)
+
+	def validate(self):
+		if self.magic != MAGIC:
+			raise ValueError("Invalid ADX File")
+		if self.form != FORMAT:
+			raise ValueError("Invalid ADX File")
+		if self.encrypted:
+			raise NotImplementedError("Encryption Not Supported")
+		self.is_valid = 1
+
+	def parse_loop_data(self):
+		if adxf.l_style == 4:
+			adxf.l_flag = adxf.get_val(LOOP4_FLAG_OFF, LOOP4_FLAG_LEN)
+			adxf.l_start = adxf.get_val(LOOP4_START_OFF, LOOP4_START_LEN)
+			adxf.l_end = adxf.get_val(LOOP4_END_OFF, LOOP4_END_LEN)
+		if not adxf.l_flag:
+			return None
+		if adxf.l_start == 0 and adxf.l_end == adxf.sam_count:
+			return None
+		if adxf.l_start > adxf.sam_count or adxf.l_end > adxf.sam_count:
+			raise ValueError("Invalid Loop Data")
+			return None
+		if not adxf.l_style in LOOP_TYPE_SUP:
+			raise NotImplementedError("Loop Style {} Not Implemented".format(str(adxf.l_style)))
+			return None
+		ret = {}
+		ret['duration'] = adxf.sam_count / adxf.sam_rate
+		ret['loop_start'] = {}
+		ret['loop_start']['seconds'] = adxf.l_start / adxf.sam_rate
+		ret['loop_start']['samples_native'] = adxf.l_start
+		ret['loop_start']['samples_48k'] = dumb_round(adxf.l_start / adxf.sam_rate * 48000)
+		ret['loop_end'] = {}
+		ret['loop_end']['seconds'] = adxf.l_end / adxf.sam_rate
+		ret['loop_end']['samples_native'] = adxf.l_end
+		ret['loop_end']['samples_48k'] = dumb_round(adxf.l_end / adxf.sam_rate * 48000)
+		return ret