// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef ZIRCON_SYSTEM_ULIB_FIDL_ENVELOPE_FRAMES_H_
#define ZIRCON_SYSTEM_ULIB_FIDL_ENVELOPE_FRAMES_H_

#include <stdalign.h>
#include <cstdint>
#include <cstdlib>

#include <lib/fidl/coding.h>
#include <zircon/assert.h>
#include <zircon/compiler.h>

namespace fidl {

class EnvelopeFrames {
public:
    struct EnvelopeState {
        uint32_t bytes_so_far;
        uint32_t handles_so_far;

        EnvelopeState(uint32_t bytes_so_far, uint32_t handles_so_far)
            : bytes_so_far(bytes_so_far), handles_so_far(handles_so_far) {}

    private:
        // Default constructor used by |EnvelopeFrames| to avoid unnecessarily zeroing
        // the |envelope_states_| array.
        EnvelopeState() = default;
        friend class EnvelopeFrames;
    };

    const EnvelopeState& Pop() {
        ZX_ASSERT(envelope_depth_ != 0);
        envelope_depth_--;
        return envelope_states_[envelope_depth_];
    }

    bool Push(const EnvelopeState& state) {
        if (envelope_depth_ == FIDL_RECURSION_DEPTH) {
            return false;
        }
        envelope_states_[envelope_depth_] = state;
        envelope_depth_++;
        return true;
    }

private:
    uint32_t envelope_depth_ = 0;
    EnvelopeState envelope_states_[FIDL_RECURSION_DEPTH];
};

} // namespace fidl


#endif  // ZIRCON_SYSTEM_ULIB_FIDL_ENVELOPE_FRAMES_H_