#include "sass.hpp"

#include "base64vlq.hpp"

namespace Sass {

  std::string Base64VLQ::encode(const int number) const

  {

    std::string encoded = "";

    int vlq = to_vlq_signed(number);

    do {

      int digit = vlq & VLQ_BASE_MASK;

      vlq >>= VLQ_BASE_SHIFT;

      if (vlq > 0) {

        digit |= VLQ_CONTINUATION_BIT;

      }

      encoded += base64_encode(digit);

    } while (vlq > 0);

    return encoded;

  }

  char Base64VLQ::base64_encode(const int number) const

  {

    int index = number;

    if (index < 0) index = 0;

    if (index > 63) index = 63;

    return CHARACTERS[index];

  }

  int Base64VLQ::to_vlq_signed(const int number) const

  {

    return (number < 0) ? ((-number) << 1) + 1 : (number << 1) + 0;

  }

  const char* Base64VLQ::CHARACTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

  const int Base64VLQ::VLQ_BASE_SHIFT = 5;

  const int Base64VLQ::VLQ_BASE = 1 << VLQ_BASE_SHIFT;

  const int Base64VLQ::VLQ_BASE_MASK = VLQ_BASE - 1;

  const int Base64VLQ::VLQ_CONTINUATION_BIT = VLQ_BASE;

}