(Buggy) kbitx glyph reader

kbitx.py

import base64
def readLeb(m):
    a = m.encode()
    n = base64.b64decode(a+b'==')
    v=0
    s=0
    for i in range(len(n)):
        b=n[i]
        v |= (b & 0x7F) << s
        if ((b & 0x80) == 0):
            break
        s += 7
    return v

def readWib(m):
    # Doesn't work
    a = m.encode()
    n = base64.b64decode(a+b'==')
    repeatData = None
    repeatCount = 0
    eof = False
    i = 0
    l = []
    while i < len(n):
        if eof:
            l.append(-1)
        elif repeatCount > 0:
            repeatCount -= 1
            if repeatData == None:
                i += 1
                data = n[i]
                if data < 0:
                    eof = True
                    l.append(data)
                else:
                    l.append(repeatData)
        i += 1
        if i >= len(n):
            return l
        data = n[i]
        if data > 0:
            eof = True
            l.append(data)
        repeatCount = data & 0x1F
        if (data & 0x20) != 0:
            repeatCount <<= 5
        match data & 0xC0:
            case 0x00:
                repeatData = 0x00
            case 0x40:
                repeatData = 0xFF
            case 0x80:
                i += 1
                data = n[i]
                if data < 0:
                    eof = True
                    l.append(data)
                repeatData = data
            case 0xC0:
                repeatData = None
    return l