stringscanner.py

#Modified by Joao Paulo Barraca <jpbarraca@ua.pt>


class StringScanner(object):
    def str(self):
        return self.__data

    def __init__(self, string_chunks):
        # TODO(mihaip) switch to reading from the chunks array directly to avoid
        # extra string copies
        def flatten(chunks):
            if type(chunks) == str:
                return chunks
            else:
                chunk_strings = []
                for chunk in chunks:
                    chunk_strings.append(flatten(chunk))
                return "".join(chunk_strings)

        self.__data = flatten(string_chunks)
        self.__index = 0
        self.__length = len(self.__data)

    def Peek(self):
        if self.__index >= self.__length:
            return None
        return self.__data[self.__index]

    def ReadChar(self):
        if self.__index >= self.__length:
            return None
        c = self.__data[self.__index]
        self.__index += 1
        return c

    def ReadUntil(self, c):
        start = self.__index
        end = start
        dlen = len(self.__data)
        while dlen > end:
            if self.__data[end] != c:
                end = end + 1
            else:
                break
        self.__index = end
        return self.__data[start:end]

    def ConsumeAll(self, c):
        while self.__index < self.__length and self.__data[self.__index] == c:
            self.__index += 1

    def ConsumeChar(self, c):
        assert c == self.__data[self.__index]
        self.__index += 1

    def ReadUntilLength(self, length):
        ret = self.__data[self.__index:self.__index + length]
        self.__index += length
        return ret

    def ConsumeValue(self):
        value = None
        # Literal string
        if self.Peek() == "{":
            self.ConsumeChar("{")
            literal_length = int(self.ReadUntil("}"))
            self.ConsumeChar("}")

            value = self.ReadUntilLength(literal_length)

        # Quoted string
        elif self.Peek() == "\"":
            # TODO(mihaip): can quotes be escaped inside?
            self.ConsumeChar("\"")
            value = self.ReadUntil("\"")
            self.ConsumeChar("\"")
        # Parenthesized list
        elif self.Peek() == "(":
            self.ConsumeChar("(")
            value = []
            parenthesis_depth = 1

            while parenthesis_depth > 0:
                c = self.ReadChar()
                if c == "(":
                    parenthesis_depth += 1
                if c == ")":
                    parenthesis_depth -= 1

                if parenthesis_depth > 0:
                    value.append(c)

            value = "".join(value).split()
        # Numbers
        else:
            value = self.ReadUntil(" ")

        return value