Module refinery.units.encoding.b65536

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Reference: https://github.com/Parkayun/base65536
from refinery.units import Unit
from refinery.lib.structures import MemoryFile

_BLOCK_START = {
    0: 13312, 1: 13568, 2: 13824, 3: 14080, 4: 14336, 5: 14592, 6: 14848, 7:
    15104, 8: 15360, 9: 15616, 10: 15872, 11: 16128, 12: 16384, 13: 16640, 14:
    16896, 15: 17152, 16: 17408, 17: 17664, 18: 17920, 19: 18176, 20: 18432,
    21: 18688, 22: 18944, 23: 19200, 24: 19456, 25: 19968, 26: 20224, 27:
    20480, 28: 20736, 29: 20992, 30: 21248, 31: 21504, 32: 21760, 33: 22016,
    34: 22272, 35: 22528, 36: 22784, 37: 23040, 38: 23296, 39: 23552, 40:
    23808, 41: 24064, 42: 24320, 43: 24576, 44: 24832, 45: 25088, 46: 25344,
    47: 25600, 48: 25856, 49: 26112, 50: 26368, 51: 26624, 52: 26880, 53:
    27136, 54: 27392, 55: 27648, 56: 27904, 57: 28160, 58: 28416, 59: 28672,
    60: 28928, 61: 29184, 62: 29440, 63: 29696, 64: 29952, 65: 30208, 66:
    30464, 67: 30720, 68: 30976, 69: 31232, 70: 31488, 71: 31744, 72: 32000,
    73: 32256, 74: 32512, 75: 32768, 76: 33024, 77: 33280, 78: 33536, 79:
    33792, 80: 34048, 81: 34304, 82: 34560, 83: 34816, 84: 35072, 85: 35328,
    86: 35584, 87: 35840, 88: 36096, 89: 36352, 90: 36608, 91: 36864, 92:
    37120, 93: 37376, 94: 37632, 95: 37888, 96: 38144, 97: 38400, 98: 38656,
    99: 38912, 100: 39168, 101: 39424, 102: 39680, 103: 39936, 104: 40192, 105:
    40448, 106: 41216, 107: 41472, 108: 41728, 109: 42240, 110: 67072, 111:
    73728, 112: 73984, 113: 74240, 114: 77824, 115: 78080, 116: 78336, 117:
    78592, 118: 82944, 119: 83200, 120: 92160, 121: 92416, 122: 131072, 123:
    131328, 124: 131584, 125: 131840, 126: 132096, 127: 132352, 128: 132608,
    129: 132864, 130: 133120, 131: 133376, 132: 133632, 133: 133888, 134:
    134144, 135: 134400, 136: 134656, 137: 134912, 138: 135168, 139: 135424,
    140: 135680, 141: 135936, 142: 136192, 143: 136448, 144: 136704, 145:
    136960, 146: 137216, 147: 137472, 148: 137728, 149: 137984, 150: 138240,
    151: 138496, 152: 138752, 153: 139008, 154: 139264, 155: 139520, 156:
    139776, 157: 140032, 158: 140288, 159: 140544, 160: 140800, 161: 141056,
    162: 141312, 163: 141568, 164: 141824, 165: 142080, 166: 142336, 167:
    142592, 168: 142848, 169: 143104, 170: 143360, 171: 143616, 172: 143872,
    173: 144128, 174: 144384, 175: 144640, 176: 144896, 177: 145152, 178:
    145408, 179: 145664, 180: 145920, 181: 146176, 182: 146432, 183: 146688,
    184: 146944, 185: 147200, 186: 147456, 187: 147712, 188: 147968, 189:
    148224, 190: 148480, 191: 148736, 192: 148992, 193: 149248, 194: 149504,
    195: 149760, 196: 150016, 197: 150272, 198: 150528, 199: 150784, 200:
    151040, 201: 151296, 202: 151552, 203: 151808, 204: 152064, 205: 152320,
    206: 152576, 207: 152832, 208: 153088, 209: 153344, 210: 153600, 211:
    153856, 212: 154112, 213: 154368, 214: 154624, 215: 154880, 216: 155136,
    217: 155392, 218: 155648, 219: 155904, 220: 156160, 221: 156416, 222:
    156672, 223: 156928, 224: 157184, 225: 157440, 226: 157696, 227: 157952,
    228: 158208, 229: 158464, 230: 158720, 231: 158976, 232: 159232, 233:
    159488, 234: 159744, 235: 160000, 236: 160256, 237: 160512, 238: 160768,
    239: 161024, 240: 161280, 241: 161536, 242: 161792, 243: 162048, 244:
    162304, 245: 162560, 246: 162816, 247: 163072, 248: 163328, 249: 163584,
    250: 163840, 251: 164096, 252: 164352, 253: 164608, 254: 164864, 255:
    165120, -1: 5376}
_B2 = {
    5376: -1, 13312: 0, 13568: 1, 13824: 2, 14080: 3, 14336: 4, 14592: 5,
    14848: 6, 15104: 7, 15360: 8, 15616: 9, 15872: 10, 16128: 11, 16384: 12,
    16640: 13, 16896: 14, 17152: 15, 17408: 16, 17664: 17, 17920: 18, 18176:
    19, 18432: 20, 18688: 21, 18944: 22, 19200: 23, 19456: 24, 19968: 25,
    20224: 26, 20480: 27, 20736: 28, 20992: 29, 21248: 30, 21504: 31, 21760:
    32, 22016: 33, 22272: 34, 22528: 35, 22784: 36, 23040: 37, 23296: 38,
    23552: 39, 23808: 40, 24064: 41, 24320: 42, 24576: 43, 24832: 44, 25088:
    45, 25344: 46, 25600: 47, 25856: 48, 26112: 49, 26368: 50, 26624: 51,
    26880: 52, 27136: 53, 27392: 54, 27648: 55, 27904: 56, 28160: 57, 28416:
    58, 28672: 59, 28928: 60, 29184: 61, 29440: 62, 29696: 63, 29952: 64,
    30208: 65, 30464: 66, 30720: 67, 30976: 68, 31232: 69, 31488: 70, 31744:
    71, 32000: 72, 32256: 73, 32512: 74, 32768: 75, 33024: 76, 33280: 77,
    33536: 78, 33792: 79, 34048: 80, 34304: 81, 34560: 82, 34816: 83, 35072:
    84, 35328: 85, 35584: 86, 35840: 87, 36096: 88, 36352: 89, 36608: 90,
    36864: 91, 37120: 92, 37376: 93, 37632: 94, 37888: 95, 38144: 96, 38400:
    97, 38656: 98, 38912: 99, 39168: 100, 39424: 101, 39680: 102, 39936: 103,
    40192: 104, 40448: 105, 41216: 106, 41472: 107, 41728: 108, 42240: 109,
    67072: 110, 73728: 111, 73984: 112, 74240: 113, 77824: 114, 78080: 115,
    78336: 116, 78592: 117, 82944: 118, 83200: 119, 92160: 120, 92416: 121,
    131072: 122, 131328: 123, 131584: 124, 131840: 125, 132096: 126, 132352:
    127, 132608: 128, 132864: 129, 133120: 130, 133376: 131, 133632: 132,
    133888: 133, 134144: 134, 134400: 135, 134656: 136, 134912: 137, 135168:
    138, 135424: 139, 135680: 140, 135936: 141, 136192: 142, 136448: 143,
    136704: 144, 136960: 145, 137216: 146, 137472: 147, 137728: 148, 137984:
    149, 138240: 150, 138496: 151, 138752: 152, 139008: 153, 139264: 154,
    139520: 155, 139776: 156, 140032: 157, 140288: 158, 140544: 159, 140800:
    160, 141056: 161, 141312: 162, 141568: 163, 141824: 164, 142080: 165,
    142336: 166, 142592: 167, 142848: 168, 143104: 169, 143360: 170, 143616:
    171, 143872: 172, 144128: 173, 144384: 174, 144640: 175, 144896: 176,
    145152: 177, 145408: 178, 145664: 179, 145920: 180, 146176: 181, 146432:
    182, 146688: 183, 146944: 184, 147200: 185, 147456: 186, 147712: 187,
    147968: 188, 148224: 189, 148480: 190, 148736: 191, 148992: 192, 149248:
    193, 149504: 194, 149760: 195, 150016: 196, 150272: 197, 150528: 198,
    150784: 199, 151040: 200, 151296: 201, 151552: 202, 151808: 203, 152064:
    204, 152320: 205, 152576: 206, 152832: 207, 153088: 208, 153344: 209,
    153600: 210, 153856: 211, 154112: 212, 154368: 213, 154624: 214, 154880:
    215, 155136: 216, 155392: 217, 155648: 218, 155904: 219, 156160: 220,
    156416: 221, 156672: 222, 156928: 223, 157184: 224, 157440: 225, 157696:
    226, 157952: 227, 158208: 228, 158464: 229, 158720: 230, 158976: 231,
    159232: 232, 159488: 233, 159744: 234, 160000: 235, 160256: 236, 160512:
    237, 160768: 238, 161024: 239, 161280: 240, 161536: 241, 161792: 242,
    162048: 243, 162304: 244, 162560: 245, 162816: 246, 163072: 247, 163328:
    248, 163584: 249, 163840: 250, 164096: 251, 164352: 252, 164608: 253,
    164864: 254, 165120: 255}


class b65536(Unit):
    """
    Base65536 encoding and decoding.
    A relatively esoteric encoding scheme utilizing the UTF-16 / UTF-32 character set.
    """
    def reverse(self, data):
        if not data:
            return B''

        output = MemoryFile()
        length = len(data)
        for x in range(0, length, 2):
            b1 = data[x]
            b2 = data[x + 1] if x + 1 < length else -1
            code_point = _BLOCK_START[b2] + b1
            output.write(chr(code_point).encode())
        return output.getvalue()

    def process(self, data):
        if not data:
            return B''

        done = False
        output = MemoryFile()
        for ch in data.decode():
            code_point = ord(ch)
            b1 = code_point & ((1 << 8) - 1)
            try:
                b2 = _B2[code_point - b1]
            except KeyError:
                self.log_info('Invalid base65536 code point: %d, skipping' % code_point)
                continue
            b = b1.to_bytes(1, "little") if b2 == -1 else b1.to_bytes(1, "little") + b2.to_bytes(1, "little")
            if len(b) == 1:
                if done:
                    raise ValueError('base65536 sequence continued after final byte')
                done = True
            output.write(b)
        return output.getvalue()