// Copyright 2019, OpenCensus Authors

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//     http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

#include <cstdint>

#include <string>

#include "absl/strings/string_view.h"

#include "opencensus/common/internal/varint.h"

namespace opencensus {

namespace common {

void AppendVarint32(uint32_t i, std::string* out) {

  do {

    // Encode 7 bits.

    uint8_t c = i & 0x7F;

    i = i >> 7;

    if (i != 0) {

      c |= 0x80;

    }

    out->push_back(c);

  } while (i != 0);

}

bool ParseVarint32(absl::string_view* input, uint32_t* out) {

  absl::string_view s = *input;

  uint32_t i = 0;

  uint8_t c;

  int shift = 0;

  do {

    if (s.empty()) {

      return false;  // Too short.

    }

    c = s[0];

    s = s.substr(1);

    if (shift == 28 && c > 0x0f) {

      return false;  // Out of range for uint32_t.

    }

    i |= (c & 0x7F) << shift;

    shift += 7;

  } while (c & 0x80);

  *input = s;

  *out = i;

  return true;

}

}  // namespace common

}  // namespace opencensus