/**
 * Marlin 3D Printer Firmware
 * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
 * Based on Sprinter and grbl.
 * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */

/**
 * libs/heatshrink/heatshrink_decoder.h
 */
#pragma once

#include "heatshrink_common.h"
#include "heatshrink_config.h"

#include <stdint.h>
#include <stddef.h>

typedef enum {
  HSDR_SINK_OK,               /* data sunk, ready to poll */
  HSDR_SINK_FULL,             /* out of space in internal buffer */
  HSDR_SINK_ERROR_NULL=-1,    /* NULL argument */
} HSD_sink_res;

typedef enum {
  HSDR_POLL_EMPTY,            /* input exhausted */
  HSDR_POLL_MORE,             /* more data remaining, call again w/ fresh output buffer */
  HSDR_POLL_ERROR_NULL=-1,    /* NULL arguments */
  HSDR_POLL_ERROR_UNKNOWN=-2,
} HSD_poll_res;

typedef enum {
  HSDR_FINISH_DONE,           /* output is done */
  HSDR_FINISH_MORE,           /* more output remains */
  HSDR_FINISH_ERROR_NULL=-1,  /* NULL arguments */
} HSD_finish_res;

#if HEATSHRINK_DYNAMIC_ALLOC
#define HEATSHRINK_DECODER_INPUT_BUFFER_SIZE(BUF) \
  ((BUF)->input_buffer_size)
#define HEATSHRINK_DECODER_WINDOW_BITS(BUF) \
  ((BUF)->window_sz2)
#define HEATSHRINK_DECODER_LOOKAHEAD_BITS(BUF) \
  ((BUF)->lookahead_sz2)
#else
#define HEATSHRINK_DECODER_INPUT_BUFFER_SIZE(_) \
  HEATSHRINK_STATIC_INPUT_BUFFER_SIZE
#define HEATSHRINK_DECODER_WINDOW_BITS(_) \
  (HEATSHRINK_STATIC_WINDOW_BITS)
#define HEATSHRINK_DECODER_LOOKAHEAD_BITS(BUF) \
  (HEATSHRINK_STATIC_LOOKAHEAD_BITS)
#endif

typedef struct {
  uint16_t input_size;        /* bytes in input buffer */
  uint16_t input_index;       /* offset to next unprocessed input byte */
  uint16_t output_count;      /* how many bytes to output */
  uint16_t output_index;      /* index for bytes to output */
  uint16_t head_index;        /* head of window buffer */
  uint8_t state;              /* current state machine node */
  uint8_t current_byte;       /* current byte of input */
  uint8_t bit_index;          /* current bit index */

#if HEATSHRINK_DYNAMIC_ALLOC
  /* Fields that are only used if dynamically allocated. */
  uint8_t window_sz2;         /* window buffer bits */
  uint8_t lookahead_sz2;      /* lookahead bits */
  uint16_t input_buffer_size; /* input buffer size */

  /* Input buffer, then expansion window buffer */
  uint8_t buffers[];
#else
  /* Input buffer, then expansion window buffer */
  uint8_t buffers[(1 << HEATSHRINK_DECODER_WINDOW_BITS(_)) + HEATSHRINK_DECODER_INPUT_BUFFER_SIZE(_)];
#endif
} heatshrink_decoder;

#if HEATSHRINK_DYNAMIC_ALLOC
/* Allocate a decoder with an input buffer of INPUT_BUFFER_SIZE bytes,
 * an expansion buffer size of 2^WINDOW_SZ2, and a lookahead
 * size of 2^lookahead_sz2. (The window buffer and lookahead sizes
 * must match the settings used when the data was compressed.)
 * Returns NULL on error. */
heatshrink_decoder *heatshrink_decoder_alloc(uint16_t input_buffer_size, uint8_t expansion_buffer_sz2, uint8_t lookahead_sz2);

/* Free a decoder. */
void heatshrink_decoder_free(heatshrink_decoder *hsd);
#endif

/* Reset a decoder. */
void heatshrink_decoder_reset(heatshrink_decoder *hsd);

/* Sink at most SIZE bytes from IN_BUF into the decoder. *INPUT_SIZE is set to
 * indicate how many bytes were actually sunk (in case a buffer was filled). */
HSD_sink_res heatshrink_decoder_sink(heatshrink_decoder *hsd, uint8_t *in_buf, size_t size, size_t *input_size);

/* Poll for output from the decoder, copying at most OUT_BUF_SIZE bytes into
 * OUT_BUF (setting *OUTPUT_SIZE to the actual amount copied). */
HSD_poll_res heatshrink_decoder_poll(heatshrink_decoder *hsd, uint8_t *out_buf, size_t out_buf_size, size_t *output_size);

/* Notify the dencoder that the input stream is finished.
 * If the return value is HSDR_FINISH_MORE, there is still more output, so
 * call heatshrink_decoder_poll and repeat. */
HSD_finish_res heatshrink_decoder_finish(heatshrink_decoder *hsd);