| // Copyright (c) 2019 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // Utility methods to convert between absolute indexing (used in the dynamic |
| // table), relative indexing used on the encoder stream, and relative indexing |
| // and post-base indexing used on request streams (in header blocks). See: |
| // https://quicwg.org/base-drafts/draft-ietf-quic-qpack.html#indexing |
| // https://quicwg.org/base-drafts/draft-ietf-quic-qpack.html#relative-indexing |
| // https://quicwg.org/base-drafts/draft-ietf-quic-qpack.html#post-base |
| |
| #ifndef QUICHE_QUIC_CORE_QPACK_QPACK_INDEX_CONVERSIONS_H_ |
| #define QUICHE_QUIC_CORE_QPACK_QPACK_INDEX_CONVERSIONS_H_ |
| |
| #include <cstdint> |
| |
| namespace quic { |
| |
| // Conversion functions used in the encoder do not check for overflow/underflow. |
| // Since the maximum index is limited by maximum dynamic table capacity |
| // (represented on uint64_t) divided by minimum header field size (defined to be |
| // 32 bytes), overflow is not possible. The caller is responsible for providing |
| // input that does not underflow. |
| |
| uint64_t QpackAbsoluteIndexToEncoderStreamRelativeIndex( |
| uint64_t absolute_index, |
| uint64_t inserted_entry_count); |
| |
| uint64_t QpackAbsoluteIndexToRequestStreamRelativeIndex(uint64_t absolute_index, |
| uint64_t base); |
| |
| // Conversion functions used in the decoder operate on input received from the |
| // network. These functions return false on overflow or underflow. |
| |
| // TODO The encoder stream uses relative index (but different from the kind of |
| // relative index used on a request stream). This method converts relative |
| // index to absolute index (zero based). It returns true on success, or false |
| // if conversion fails due to overflow/underflow. |
| |
| bool QpackEncoderStreamRelativeIndexToAbsoluteIndex( |
| uint64_t relative_index, |
| uint64_t inserted_entry_count, |
| uint64_t* absolute_index); |
| |
| // TODO The request stream can use relative index (but different from the kind |
| // of relative index used on the encoder stream), and post-base index. These |
| // methods convert relative index and post-base index to absolute index (one |
| // based). They return true on success, or false if conversion fails due to |
| // overflow/underflow. |
| |
| // On success, |*absolute_index| is guaranteed to be strictly less than |
| // std::numeric_limits<uint64_t>::max(). |
| bool QpackRequestStreamRelativeIndexToAbsoluteIndex(uint64_t relative_index, |
| uint64_t base, |
| uint64_t* absolute_index); |
| |
| // On success, |*absolute_index| is guaranteed to be strictly less than |
| // std::numeric_limits<uint64_t>::max(). |
| bool QpackPostBaseIndexToAbsoluteIndex(uint64_t post_base_index, |
| uint64_t base, |
| uint64_t* absolute_index); |
| |
| } // namespace quic |
| |
| #endif // QUICHE_QUIC_CORE_QPACK_QPACK_INDEX_CONVERSIONS_H_ |