Function escape_decode

Lib/_pycodecs.py:316–390

(data, errors="strict")

def escape_decode(data, errors="strict"):
    if isinstance(data, str):
        data = data.encode("latin-1")
    l = len(data)
    i = 0
    res = bytearray()
    while i < l:
        if data[i] == 0x5C:  # '\\'
            i += 1
            if i >= l:
                raise ValueError("Trailing \\ in string")
            ch = data[i]
            if ch == 0x5C:
                res.append(0x5C)  # \\
            elif ch == 0x27:
                res.append(0x27)  # \'
            elif ch == 0x22:
                res.append(0x22)  # \"
            elif ch == 0x61:
                res.append(0x07)  # \a
            elif ch == 0x62:
                res.append(0x08)  # \b
            elif ch == 0x66:
                res.append(0x0C)  # \f
            elif ch == 0x6E:
                res.append(0x0A)  # \n
            elif ch == 0x72:
                res.append(0x0D)  # \r
            elif ch == 0x74:
                res.append(0x09)  # \t
            elif ch == 0x76:
                res.append(0x0B)  # \v
            elif ch == 0x0A:
                pass  # \<newline> continuation
            elif 0x30 <= ch <= 0x37:  # \0-\7 octal
                val = ch - 0x30
                if i + 1 < l and 0x30 <= data[i + 1] <= 0x37:
                    i += 1
                    val = (val << 3) | (data[i] - 0x30)
                    if i + 1 < l and 0x30 <= data[i + 1] <= 0x37:
                        i += 1
                        val = (val << 3) | (data[i] - 0x30)
                res.append(val & 0xFF)
            elif ch == 0x78:  # \x hex
                hex_count = 0
                for j in range(1, 3):
                    if i + j < l and _is_hex_digit(data[i + j]):
                        hex_count += 1
                    else:
                        break
                if hex_count < 2:
                    if errors == "strict":
                        raise ValueError("invalid \\x escape at position %d" % (i - 1))
                    elif errors == "replace":
                        res.append(0x3F)  # '?'
                    i += hex_count
                else:
                    res.append(int(bytes(data[i + 1 : i + 3]), 16))