/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * 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.
 */

#ifndef THRIFT_UTIL_VARINTUTILS_H_
#define THRIFT_UTIL_VARINTUTILS_H_ 1

#include <stdint.h>
#include <stdlib.h>

namespace apache {
namespace thrift {

namespace util {

/**
 * Read an i16 from the wire as a varint. The MSB of each byte is set
 * if there is another byte to follow. This can read up to 3 bytes.
 */
uint32_t readVarint16(
    const uint8_t* ptr, int16_t* i16, const uint8_t* boundary);

/**
 * Read an i32 from the wire as a varint. The MSB of each byte is set
 * if there is another byte to follow. This can read up to 5 bytes.
 */
uint32_t readVarint32(
    const uint8_t* ptr, int32_t* i32, const uint8_t* boundary);

/**
 * Read an i64 from the wire as a proper varint. The MSB of each byte is set
 * if there is another byte to follow. This can read up to 10 bytes.
 * Caller is responsible for advancing ptr after call.
 */
uint32_t readVarint64(
    const uint8_t* ptr, int64_t* i64, const uint8_t* boundary);

/**
 * Write an i32 as a varint. Results in 1-5 bytes on the wire.
 */
uint32_t writeVarint32(uint32_t n, uint8_t* pkt);

/**
 * Convert n into a zigzag int. This allows negative numbers to be
 * represented compactly as a varint.
 */
constexpr uint32_t i32ToZigzag(const int32_t n);

constexpr uint64_t i64ToZigzag(const int64_t l);

/**
 * Convert from zigzag long to long.
 */
int64_t zigzagToI64(uint64_t n);

int32_t zigzagToI32(uint32_t n);

uint32_t toI32ZigZagOrdinal(size_t pos);

size_t fromI32ZigZagOrdinal(uint32_t pos);

} // namespace util
} // namespace thrift
} // namespace apache

#include <thrift/lib/cpp/util/VarintUtils-inl.h>

#endif // THRIFT_UTIL_VARINTUTILS_H_
