/* Lzlib - Compression library for the lzip format
   Copyright (C) 2009-2024 Antonio Diaz Diaz.

   This library is free software. Redistribution and use in source and
   binary forms, with or without modification, are permitted provided
   that the following conditions are met:

   1. Redistributions of source code must retain the above copyright
   notice, this list of conditions, and the following disclaimer.

   2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions, and the following disclaimer in the
   documentation and/or other materials provided with the distribution.

   This library 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.
*/

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

#include "lzlib.h"
#include "lzip.h"
#include "cbuffer.c"
#include "decoder.h"
#include "decoder.c"
#include "encoder_base.h"
#include "encoder_base.c"
#include "encoder.h"
#include "encoder.c"
#include "fast_encoder.h"
#include "fast_encoder.c"


struct LZ_Encoder
  {
  unsigned long long partial_in_size;
  unsigned long long partial_out_size;
  struct LZ_encoder_base * lz_encoder_base;	/* these 3 pointers make a */
  struct LZ_encoder * lz_encoder;		/* polymorphic encoder */
  struct FLZ_encoder * flz_encoder;
  enum LZ_Errno lz_errno;
  bool fatal;
  };

static void LZ_Encoder_init( struct LZ_Encoder * const e )
  {
  e->partial_in_size = 0;
  e->partial_out_size = 0;
  e->lz_encoder_base = 0;
  e->lz_encoder = 0;
  e->flz_encoder = 0;
  e->lz_errno = LZ_ok;
  e->fatal = false;
  }


struct LZ_Decoder
  {
  unsigned long long partial_in_size;
  unsigned long long partial_out_size;
  struct Range_decoder * rdec;
  struct LZ_decoder * lz_decoder;
  enum LZ_Errno lz_errno;
  Lzip_header member_header;		/* header of current member */
  bool fatal;
  bool first_header;			/* true until first header is read */
  bool seeking;
  };

static void LZ_Decoder_init( struct LZ_Decoder * const d )
  {
  int i;
  d->partial_in_size = 0;
  d->partial_out_size = 0;
  d->rdec = 0;
  d->lz_decoder = 0;
  d->lz_errno = LZ_ok;
  for( i = 0; i < Lh_size; ++i ) d->member_header[i] = 0;
  d->fatal = false;
  d->first_header = true;
  d->seeking = false;
  }


static bool check_encoder( struct LZ_Encoder * const e )
  {
  if( !e ) return false;
  if( !e->lz_encoder_base || ( !e->lz_encoder && !e->flz_encoder ) ||
      ( e->lz_encoder && e->flz_encoder ) )
    { e->lz_errno = LZ_bad_argument; return false; }
  return true;
  }


static bool check_decoder( struct LZ_Decoder * const d )
  {
  if( !d ) return false;
  if( !d->rdec )
    { d->lz_errno = LZ_bad_argument; return false; }
  return true;
  }


/* ------------------------- Misc Functions ------------------------- */

int LZ_api_version( void ) { return LZ_API_VERSION; }

const char * LZ_version( void ) { return LZ_version_string; }

const char * LZ_strerror( const enum LZ_Errno lz_errno )
  {
  switch( lz_errno )
    {
    case LZ_ok            : return "ok";
    case LZ_bad_argument  : return "Bad argument";
    case LZ_mem_error     : return "Not enough memory";
    case LZ_sequence_error: return "Sequence error";
    case LZ_header_error  : return "Header error";
    case LZ_unexpected_eof: return "Unexpected EOF";
    case LZ_data_error    : return "Data error";
    case LZ_library_error : return "Library error";
    }
  return "Invalid error code";
  }


int LZ_min_dictionary_bits( void ) { return min_dictionary_bits; }
int LZ_min_dictionary_size( void ) { return min_dictionary_size; }
int LZ_max_dictionary_bits( void ) { return max_dictionary_bits; }
int LZ_max_dictionary_size( void ) { return max_dictionary_size; }
int LZ_min_match_len_limit( void ) { return min_match_len_limit; }
int LZ_max_match_len_limit( void ) { return max_match_len; }


/* --------------------- Compression Functions --------------------- */

struct LZ_Encoder * LZ_compress_open( const int dictionary_size,
                                      const int match_len_limit,
                                      const unsigned long long member_size )
  {
  Lzip_header header;
  struct LZ_Encoder * const e =
    (struct LZ_Encoder *)malloc( sizeof (struct LZ_Encoder) );
  if( !e ) return 0;
  LZ_Encoder_init( e );
  if( !Lh_set_dictionary_size( header, dictionary_size ) ||
      match_len_limit < min_match_len_limit ||
      match_len_limit > max_match_len ||
      member_size < min_dictionary_size )
    e->lz_errno = LZ_bad_argument;
  else
    {
    if( dictionary_size == 65535 && match_len_limit == 16 )
      {
      e->flz_encoder = (struct FLZ_encoder *)malloc( sizeof (struct FLZ_encoder) );
      if( e->flz_encoder && FLZe_init( e->flz_encoder, member_size ) )
        { e->lz_encoder_base = &e->flz_encoder->eb; return e; }
      free( e->flz_encoder ); e->flz_encoder = 0;
      }
    else
      {
      e->lz_encoder = (struct LZ_encoder *)malloc( sizeof (struct LZ_encoder) );
      if( e->lz_encoder && LZe_init( e->lz_encoder, Lh_get_dictionary_size( header ),
                                     match_len_limit, member_size ) )
        { e->lz_encoder_base = &e->lz_encoder->eb; return e; }
      free( e->lz_encoder ); e->lz_encoder = 0;
      }
    e->lz_errno = LZ_mem_error;
    }
  e->fatal = true;
  return e;
  }


int LZ_compress_close( struct LZ_Encoder * const e )
  {
  if( !e ) return -1;
  if( e->lz_encoder_base )
    { LZeb_free( e->lz_encoder_base );
      free( e->lz_encoder ); free( e->flz_encoder ); }
  free( e );
  return 0;
  }


int LZ_compress_finish( struct LZ_Encoder * const e )
  {
  if( !check_encoder( e ) || e->fatal ) return -1;
  Mb_finish( &e->lz_encoder_base->mb );
  /* if (open --> write --> finish) use same dictionary size as lzip. */
  /* this does not save any memory. */
  if( Mb_data_position( &e->lz_encoder_base->mb ) == 0 &&
      Re_member_position( &e->lz_encoder_base->renc ) == Lh_size )
    {
    Mb_adjust_dictionary_size( &e->lz_encoder_base->mb );
    Lh_set_dictionary_size( e->lz_encoder_base->renc.header,
                            e->lz_encoder_base->mb.dictionary_size );
    e->lz_encoder_base->renc.cb.buffer[5] = e->lz_encoder_base->renc.header[5];
    }
  return 0;
  }


int LZ_compress_restart_member( struct LZ_Encoder * const e,
                                const unsigned long long member_size )
  {
  if( !check_encoder( e ) || e->fatal ) return -1;
  if( !LZeb_member_finished( e->lz_encoder_base ) )
    { e->lz_errno = LZ_sequence_error; return -1; }
  if( member_size < min_dictionary_size )
    { e->lz_errno = LZ_bad_argument; return -1; }

  e->partial_in_size += Mb_data_position( &e->lz_encoder_base->mb );
  e->partial_out_size += Re_member_position( &e->lz_encoder_base->renc );

  if( e->lz_encoder ) LZe_reset( e->lz_encoder, member_size );
  else FLZe_reset( e->flz_encoder, member_size );
  e->lz_errno = LZ_ok;
  return 0;
  }


int LZ_compress_sync_flush( struct LZ_Encoder * const e )
  {
  if( !check_encoder( e ) || e->fatal ) return -1;
  if( !e->lz_encoder_base->mb.at_stream_end )
    e->lz_encoder_base->mb.sync_flush_pending = true;
  return 0;
  }


int LZ_compress_read( struct LZ_Encoder * const e,
                      uint8_t * const buffer, const int size )
  {
  if( !check_encoder( e ) || e->fatal ) return -1;
  if( size < 0 ) return 0;

  { struct LZ_encoder_base * const eb = e->lz_encoder_base;
  int out_size = Re_read_data( &eb->renc, buffer, size );
  /* minimize number of calls to encode_member */
  if( out_size < size || size == 0 )
    {
    if( ( e->flz_encoder && !FLZe_encode_member( e->flz_encoder ) ) ||
        ( e->lz_encoder && !LZe_encode_member( e->lz_encoder ) ) )
      { e->lz_errno = LZ_library_error; e->fatal = true; return -1; }
    if( eb->mb.sync_flush_pending && Mb_available_bytes( &eb->mb ) <= 0 )
      LZeb_try_sync_flush( eb );
    out_size += Re_read_data( &eb->renc, buffer + out_size, size - out_size );
    }
  return out_size; }
  }


int LZ_compress_write( struct LZ_Encoder * const e,
                       const uint8_t * const buffer, const int size )
  {
  if( !check_encoder( e ) || e->fatal ) return -1;
  return Mb_write_data( &e->lz_encoder_base->mb, buffer, size );
  }


int LZ_compress_write_size( struct LZ_Encoder * const e )
  {
  if( !check_encoder( e ) || e->fatal ) return -1;
  return Mb_free_bytes( &e->lz_encoder_base->mb );
  }


enum LZ_Errno LZ_compress_errno( struct LZ_Encoder * const e )
  {
  if( !e ) return LZ_bad_argument;
  return e->lz_errno;
  }


int LZ_compress_finished( struct LZ_Encoder * const e )
  {
  if( !check_encoder( e ) ) return -1;
  return Mb_data_finished( &e->lz_encoder_base->mb ) &&
         LZeb_member_finished( e->lz_encoder_base );
  }


int LZ_compress_member_finished( struct LZ_Encoder * const e )
  {
  if( !check_encoder( e ) ) return -1;
  return LZeb_member_finished( e->lz_encoder_base );
  }


unsigned long long LZ_compress_data_position( struct LZ_Encoder * const e )
  {
  if( !check_encoder( e ) ) return 0;
  return Mb_data_position( &e->lz_encoder_base->mb );
  }


unsigned long long LZ_compress_member_position( struct LZ_Encoder * const e )
  {
  if( !check_encoder( e ) ) return 0;
  return Re_member_position( &e->lz_encoder_base->renc );
  }


unsigned long long LZ_compress_total_in_size( struct LZ_Encoder * const e )
  {
  if( !check_encoder( e ) ) return 0;
  return e->partial_in_size + Mb_data_position( &e->lz_encoder_base->mb );
  }


unsigned long long LZ_compress_total_out_size( struct LZ_Encoder * const e )
  {
  if( !check_encoder( e ) ) return 0;
  return e->partial_out_size + Re_member_position( &e->lz_encoder_base->renc );
  }


/* -------------------- Decompression Functions -------------------- */

struct LZ_Decoder * LZ_decompress_open( void )
  {
  struct LZ_Decoder * const d =
    (struct LZ_Decoder *)malloc( sizeof (struct LZ_Decoder) );
  if( !d ) return 0;
  LZ_Decoder_init( d );

  d->rdec = (struct Range_decoder *)malloc( sizeof (struct Range_decoder) );
  if( !d->rdec || !Rd_init( d->rdec ) )
    {
    if( d->rdec ) { Rd_free( d->rdec ); free( d->rdec ); d->rdec = 0; }
    d->lz_errno = LZ_mem_error; d->fatal = true;
    }
  return d;
  }


int LZ_decompress_close( struct LZ_Decoder * const d )
  {
  if( !d ) return -1;
  if( d->lz_decoder )
    { LZd_free( d->lz_decoder ); free( d->lz_decoder ); }
  if( d->rdec ) { Rd_free( d->rdec ); free( d->rdec ); }
  free( d );
  return 0;
  }


int LZ_decompress_finish( struct LZ_Decoder * const d )
  {
  if( !check_decoder( d ) || d->fatal ) return -1;
  if( d->seeking )
    { d->seeking = false; d->partial_in_size += Rd_purge( d->rdec ); }
  else Rd_finish( d->rdec );
  return 0;
  }


int LZ_decompress_reset( struct LZ_Decoder * const d )
  {
  if( !check_decoder( d ) ) return -1;
  if( d->lz_decoder )
    { LZd_free( d->lz_decoder ); free( d->lz_decoder ); d->lz_decoder = 0; }
  d->partial_in_size = 0;
  d->partial_out_size = 0;
  Rd_reset( d->rdec );
  d->lz_errno = LZ_ok;
  d->fatal = false;
  d->first_header = true;
  d->seeking = false;
  return 0;
  }


int LZ_decompress_sync_to_member( struct LZ_Decoder * const d )
  {
  unsigned skipped = 0;
  if( !check_decoder( d ) ) return -1;
  if( d->lz_decoder )
    { LZd_free( d->lz_decoder ); free( d->lz_decoder ); d->lz_decoder = 0; }
  if( Rd_find_header( d->rdec, &skipped ) ) d->seeking = false;
  else
    {
    if( !d->rdec->at_stream_end ) d->seeking = true;
    else { d->seeking = false; d->partial_in_size += Rd_purge( d->rdec ); }
    }
  d->partial_in_size += skipped;
  d->lz_errno = LZ_ok;
  d->fatal = false;
  return 0;
  }


int LZ_decompress_read( struct LZ_Decoder * const d,
                        uint8_t * const buffer, const int size )
  {
  int result;
  if( !check_decoder( d ) ) return -1;
  if( size < 0 ) return 0;
  if( d->fatal )	/* don't return error until pending bytes are read */
    { if( d->lz_decoder && !Cb_empty( &d->lz_decoder->cb ) ) goto get_data;
      return -1; }
  if( d->seeking ) return 0;

  if( d->lz_decoder && LZd_member_finished( d->lz_decoder ) )
    {
    d->partial_out_size += LZd_data_position( d->lz_decoder );
    LZd_free( d->lz_decoder ); free( d->lz_decoder ); d->lz_decoder = 0;
    }
  if( !d->lz_decoder )
    {
    int rd;
    d->partial_in_size += d->rdec->member_position;
    d->rdec->member_position = 0;
    if( Rd_available_bytes( d->rdec ) < Lh_size + 5 &&
        !d->rdec->at_stream_end ) return 0;
    if( Rd_finished( d->rdec ) && !d->first_header ) return 0;
    rd = Rd_read_data( d->rdec, d->member_header, Lh_size );
    if( rd < Lh_size || Rd_finished( d->rdec ) )	/* End Of File */
      {
      if( rd <= 0 || Lh_check_prefix( d->member_header, rd ) )
        d->lz_errno = LZ_unexpected_eof;
      else
        d->lz_errno = LZ_header_error;
      d->fatal = true;
      return -1;
      }
    if( !Lh_check_magic( d->member_header ) )
      {
      /* unreading the header prevents sync_to_member from skipping a member
         if leading garbage is shorter than a full header; "lgLZIP\x01\x0C" */
      if( Rd_unread_data( d->rdec, rd ) )
        {
        if( d->first_header || !Lh_check_corrupt( d->member_header ) )
          d->lz_errno = LZ_header_error;
        else
          d->lz_errno = LZ_data_error;		/* corrupt header */
        }
      else
        d->lz_errno = LZ_library_error;
      d->fatal = true;
      return -1;
      }
    if( !Lh_check_version( d->member_header ) ||
        !isvalid_ds( Lh_get_dictionary_size( d->member_header ) ) )
      {
      /* Skip a possible "LZIP" leading garbage; "LZIPLZIP\x01\x0C".
         Leave member_pos pointing to the first error. */
      if( Rd_unread_data( d->rdec, 1 + !Lh_check_version( d->member_header ) ) )
        d->lz_errno = LZ_data_error;	/* bad version or bad dict size */
      else
        d->lz_errno = LZ_library_error;
      d->fatal = true;
      return -1;
      }
    d->first_header = false;
    if( Rd_available_bytes( d->rdec ) < 5 )
      {
      /* set position at EOF */
      d->rdec->member_position += Cb_used_bytes( &d->rdec->cb );
      Cb_reset( &d->rdec->cb );
      d->lz_errno = LZ_unexpected_eof;
      d->fatal = true;
      return -1;
      }
    d->lz_decoder = (struct LZ_decoder *)malloc( sizeof (struct LZ_decoder) );
    if( !d->lz_decoder || !LZd_init( d->lz_decoder, d->rdec,
                             Lh_get_dictionary_size( d->member_header ) ) )
      {					/* not enough free memory */
      if( d->lz_decoder )
        { LZd_free( d->lz_decoder ); free( d->lz_decoder ); d->lz_decoder = 0; }
      d->lz_errno = LZ_mem_error;
      d->fatal = true;
      return -1;
      }
    d->rdec->reload_pending = true;
    }
  result = LZd_decode_member( d->lz_decoder );
  if( result != 0 )
    {
    if( result == 2 )			/* set input position at EOF */
      { d->rdec->member_position += Cb_used_bytes( &d->rdec->cb );
        Cb_reset( &d->rdec->cb );
        d->lz_errno = LZ_unexpected_eof; }
    else if( result == 5 ) d->lz_errno = LZ_library_error;
    else d->lz_errno = LZ_data_error;
    d->fatal = true;
    if( Cb_empty( &d->lz_decoder->cb ) ) return -1;
    }
get_data:
  return Cb_read_data( &d->lz_decoder->cb, buffer, size );
  }


int LZ_decompress_write( struct LZ_Decoder * const d,
                         const uint8_t * const buffer, const int size )
  {
  int result;
  if( !check_decoder( d ) || d->fatal ) return -1;
  if( size < 0 ) return 0;

  result = Rd_write_data( d->rdec, buffer, size );
  while( d->seeking )
    {
    int size2;
    unsigned skipped = 0;
    if( Rd_find_header( d->rdec, &skipped ) ) d->seeking = false;
    d->partial_in_size += skipped;
    if( result >= size ) break;
    size2 = Rd_write_data( d->rdec, buffer + result, size - result );
    if( size2 > 0 ) result += size2;
    else break;
    }
  return result;
  }


int LZ_decompress_write_size( struct LZ_Decoder * const d )
  {
  if( !check_decoder( d ) || d->fatal ) return -1;
  return Rd_free_bytes( d->rdec );
  }


enum LZ_Errno LZ_decompress_errno( struct LZ_Decoder * const d )
  {
  if( !d ) return LZ_bad_argument;
  return d->lz_errno;
  }


int LZ_decompress_finished( struct LZ_Decoder * const d )
  {
  if( !check_decoder( d ) || d->fatal ) return -1;
  return Rd_finished( d->rdec ) &&
         ( !d->lz_decoder || LZd_member_finished( d->lz_decoder ) );
  }


int LZ_decompress_member_finished( struct LZ_Decoder * const d )
  {
  if( !check_decoder( d ) || d->fatal ) return -1;
  return d->lz_decoder && LZd_member_finished( d->lz_decoder );
  }


int LZ_decompress_member_version( struct LZ_Decoder * const d )
  {
  if( !check_decoder( d ) ) return -1;
  return Lh_version( d->member_header );
  }


int LZ_decompress_dictionary_size( struct LZ_Decoder * const d )
  {
  if( !check_decoder( d ) ) return -1;
  return Lh_get_dictionary_size( d->member_header );
  }


unsigned LZ_decompress_data_crc( struct LZ_Decoder * const d )
  {
  if( check_decoder( d ) && d->lz_decoder )
    return LZd_crc( d->lz_decoder );
  return 0;
  }


unsigned long long LZ_decompress_data_position( struct LZ_Decoder * const d )
  {
  if( check_decoder( d ) && d->lz_decoder )
    return LZd_data_position( d->lz_decoder );
  return 0;
  }


unsigned long long LZ_decompress_member_position( struct LZ_Decoder * const d )
  {
  if( !check_decoder( d ) ) return 0;
  return d->rdec->member_position;
  }


unsigned long long LZ_decompress_total_in_size( struct LZ_Decoder * const d )
  {
  if( !check_decoder( d ) ) return 0;
  return d->partial_in_size + d->rdec->member_position;
  }


unsigned long long LZ_decompress_total_out_size( struct LZ_Decoder * const d )
  {
  if( !check_decoder( d ) ) return 0;
  if( d->lz_decoder )
    return d->partial_out_size + LZd_data_position( d->lz_decoder );
  return d->partial_out_size;
  }