keybuffer.h

// Copyright 2024 Guillaume Stordeur <guillaume.stordeur@gmail.com>
// Copyright 2024 Matt Skalecki <ikcelaks@gmail.com>
// Copyright 2024 QKekos <q.kekos.q@gmail.com>
// SPDX-License-Identifier: Apache-2.0
#pragma once

//////////////////////////////////////////////////////////////////
// Public API

#define ST_DEFAULT_KEY_ACTION 0xffff

#define ST_KEY_FLAG_IS_ANCHOR_MATCH 0x01
#define ST_KEY_FLAG_IS_ONE_SHOT_SHIFT 0x02
#define ST_KEY_FLAG_IS_FULL_SHIFT 0x04

typedef struct
{
    uint8_t triecode;
    uint8_t key_flags;
    uint16_t action_taken;
} st_key_action_t;

typedef struct
{
    st_key_action_t * const data;       // array of keycodes
    const int               capacity;   // max buffer size
    int                     size;       // number of current keys in buffer
    int                     head;       // current head for circular access
    uint8_t         * const seq_ref_cache;
    const int               seq_ref_capacity;
    int                     seq_ref_size;
    int                     seq_ref_head;
} st_key_buffer_t;

st_key_action_t *st_key_buffer_get(const st_key_buffer_t *buf, int index);
uint8_t         st_key_buffer_get_triecode(const st_key_buffer_t *buf, int index);
void            st_key_buffer_reset(st_key_buffer_t *buf);
void            st_key_buffer_push(st_key_buffer_t *buf, uint8_t triecode, uint8_t key_flags);
void            st_key_buffer_pop(st_key_buffer_t *buf);
void            st_key_buffer_print(const st_key_buffer_t *buf);
void            st_key_buffer_push_seq_ref(st_key_buffer_t *buf, uint8_t triecode);
uint8_t         st_key_buffer_get_seq_ref(const st_key_buffer_t * const buf, int index);
bool            st_key_buffer_advance_seq_ref_index(const st_key_buffer_t * const buf, int *index);

#ifdef ST_TESTER
bool            st_key_buffer_has_unexpanded_seq(st_key_buffer_t *buf);
void            st_key_buffer_to_ascii_str(const st_key_buffer_t *buf, char *str);
#endif