#ifndef COM_LZW_H
#define COM_LZW_H

#include <stdbool.h>
#include <stdint.h>

/* Alphabet table for use in LZW algorithms */
struct com_lzw_table {
  /* table_size   indexed entry is reserved for clear code */
  /* table_size+1 indexed entry is reserved for terminator */
  struct com_lzw_table_entry *table;
  uint32_t init_size; /* Alphabet size, table clear is done over it */
  uint32_t size;
  uint32_t cap;
  bool continuous; /* If true, first order search is simple indexing, where
                     codepoint = index, up to table_init_size */
};

struct com_lzw_table_entry {
  uint16_t child_chain; /* Start of linked list inside table, or 0 if none */
  uint16_t next_child;  /* Index of next child, or 0 if none */
  char code;            /* Single byte, children bytes are appended to it */
};

/* Returns table that is optimized for continuous range of codepoints */
/* Useful for binary compression, such as .GIF and .SAM formats */
struct com_lzw_table com_lzw_continous_table(uint8_t codepoints);

/* Returns table with alphabet inferred from the incoming data */
/* Useful for alphanumeric compression, where not all codepoints are in use */
/* TODO: Sort table by frequency? */
struct com_lzw_table com_lzw_infer_table(const char *datain, uint32_t sizein);

/* Each bit corresponds to a byte value, position-wise */
struct com_lzw_encoded_alphabet {
  uint64_t b0;
  uint64_t b1;
  uint64_t b2;
  uint64_t b3;
};
struct com_lzw_encoded_alphabet
com_lzw_encode_alphabet(const struct com_lzw_table *table);

struct com_lzw_table
com_lzw_decode_table(struct com_lzw_encoded_alphabet alphabet);

/* Return table to its original form */
void com_lzw_clear_table(struct com_lzw_table *table);

void com_lzw_free_table(struct com_lzw_table *table);

bool com_lzw_compress(const struct com_lzw_table *table, const char *datain,
                      uint32_t sizein, char **dataout, uint32_t *sizeout);

#endif