/***************************************************************************/

/*                                                                         */

/*  ftbzip2.c                                                              */

/*                                                                         */

/*    FreeType support for .bz2 compressed files.                          */

/*                                                                         */

/*  This optional component relies on libbz2.  It should mainly be used to */

/*  parse compressed PCF fonts, as found with many X11 server              */

/*  distributions.                                                         */

/*                                                                         */

/*  Copyright 2010 by                                                      */

/*  Joel Klinghed.                                                         */

/*                                                                         */

/*  Based on src/gzip/ftgzip.c, Copyright 2002 - 2010 by                   */

/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */

/*                                                                         */

/*  This file is part of the FreeType project, and may only be used,       */

/*  modified, and distributed under the terms of the FreeType project      */

/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */

/*  this file you indicate that you have read the license and              */

/*  understand and accept it fully.                                        */

/*                                                                         */

/***************************************************************************/

#include <ft2build.h>

#include FT_INTERNAL_MEMORY_H

#include FT_INTERNAL_STREAM_H

#include FT_INTERNAL_DEBUG_H

#include FT_BZIP2_H

#include FT_CONFIG_STANDARD_LIBRARY_H

#include FT_MODULE_ERRORS_H

#undef __FTERRORS_H__

#define FT_ERR_PREFIX  Bzip2_Err_

#define FT_ERR_BASE    FT_Mod_Err_Bzip2

#include FT_ERRORS_H

#ifdef FT_CONFIG_OPTION_USE_BZIP2

#ifdef FT_CONFIG_OPTION_PIC

#error "bzip2 code does not support PIC yet"

#endif

#define BZ_NO_STDIO /* Do not need FILE */

#include <bzlib.h>

/***************************************************************************/

/***************************************************************************/

/*****                                                                 *****/

/*****           B Z I P 2   M E M O R Y   M A N A G E M E N T         *****/

/*****                                                                 *****/

/***************************************************************************/

/***************************************************************************/

  /* it is better to use FreeType memory routines instead of raw

     'malloc/free' */

  typedef void *(* alloc_func)(void*, int, int);

  typedef void (* free_func)(void*, void*);

  static void*

  ft_bzip2_alloc( FT_Memory  memory,

                  int        items,

                  int        size )

  {

    FT_ULong    sz = (FT_ULong)size * items;

    FT_Error    error;

    FT_Pointer  p  = NULL;

    (void)FT_ALLOC( p, sz );

    return p;

  }

  static void

  ft_bzip2_free( FT_Memory  memory,

                 void*      address )

  {

    FT_MEM_FREE( address );

  }

/***************************************************************************/

/***************************************************************************/

/*****                                                                 *****/

/*****              B Z I P 2   F I L E   D E S C R I P T O R          *****/

/*****                                                                 *****/

/***************************************************************************/

/***************************************************************************/

#define FT_BZIP2_BUFFER_SIZE  4096

  typedef struct  FT_BZip2FileRec_

  {

    FT_Stream  source;         /* parent/source stream        */

    FT_Stream  stream;         /* embedding stream            */

    FT_Memory  memory;         /* memory allocator            */

    bz_stream  bzstream;       /* bzlib input stream          */

    FT_Byte    input[FT_BZIP2_BUFFER_SIZE];  /* input read buffer  */

    FT_Byte    buffer[FT_BZIP2_BUFFER_SIZE]; /* output buffer      */

    FT_ULong   pos;                          /* position in output */

    FT_Byte*   cursor;

    FT_Byte*   limit;

  } FT_BZip2FileRec, *FT_BZip2File;

  /* check and skip .bz2 header - we don't support `transparent' compression */

  static FT_Error

  ft_bzip2_check_header( FT_Stream  stream )

  {

    FT_Error  error = Bzip2_Err_Ok;

    FT_Byte   head[4];

    if ( FT_STREAM_SEEK( 0 )       ||

         FT_STREAM_READ( head, 4 ) )

      goto Exit;

    /* head[0] && head[1] are the magic numbers;    */

    /* head[2] is the version, and head[3] the blocksize */

    if ( head[0] != 0x42  ||

         head[1] != 0x5a  ||

         head[2] != 0x68  )  /* only support bzip2 (huffman) */

    {

      error = Bzip2_Err_Invalid_File_Format;

      goto Exit;

    }

  Exit:

    return error;

  }

  static FT_Error

  ft_bzip2_file_init( FT_BZip2File  zip,

                      FT_Stream     stream,

                      FT_Stream     source )

  {

    bz_stream*  bzstream = &zip->bzstream;

    FT_Error    error    = Bzip2_Err_Ok;

    zip->stream = stream;

    zip->source = source;

    zip->memory = stream->memory;

    zip->limit  = zip->buffer + FT_BZIP2_BUFFER_SIZE;

    zip->cursor = zip->limit;

    zip->pos    = 0;

    /* check .bz2 header */

    {

      stream = source;

      error = ft_bzip2_check_header( stream );

      if ( error )

        goto Exit;

      if ( FT_STREAM_SEEK( 0 ) )

        goto Exit;

    }

    /* initialize bzlib */

    bzstream->bzalloc = (alloc_func)ft_bzip2_alloc;

    bzstream->bzfree  = (free_func) ft_bzip2_free;

    bzstream->opaque  = zip->memory;

    bzstream->avail_in = 0;

    bzstream->next_in  = (char*)zip->buffer;

    if ( BZ2_bzDecompressInit( bzstream, 0, 0 ) != BZ_OK ||

         bzstream->next_in == NULL                       )

      error = Bzip2_Err_Invalid_File_Format;

  Exit:

    return error;

  }

  static void

  ft_bzip2_file_done( FT_BZip2File  zip )

  {

    bz_stream*  bzstream = &zip->bzstream;

    BZ2_bzDecompressEnd( bzstream );

    /* clear the rest */

    bzstream->bzalloc   = NULL;

    bzstream->bzfree    = NULL;

    bzstream->opaque    = NULL;

    bzstream->next_in   = NULL;

    bzstream->next_out  = NULL;

    bzstream->avail_in  = 0;

    bzstream->avail_out = 0;

    zip->memory = NULL;

    zip->source = NULL;

    zip->stream = NULL;

  }

  static FT_Error

  ft_bzip2_file_reset( FT_BZip2File  zip )

  {

    FT_Stream  stream = zip->source;

    FT_Error   error;

    if ( !FT_STREAM_SEEK( 0 ) )

    {

      bz_stream*  bzstream = &zip->bzstream;

      BZ2_bzDecompressEnd( bzstream );

      bzstream->avail_in  = 0;

      bzstream->next_in   = (char*)zip->input;

      bzstream->avail_out = 0;

      bzstream->next_out  = (char*)zip->buffer;

      zip->limit  = zip->buffer + FT_BZIP2_BUFFER_SIZE;

      zip->cursor = zip->limit;

      zip->pos    = 0;

      BZ2_bzDecompressInit( bzstream, 0, 0 );

    }

    return error;

  }

  static FT_Error

  ft_bzip2_file_fill_input( FT_BZip2File  zip )

  {

    bz_stream*  bzstream = &zip->bzstream;

    FT_Stream   stream    = zip->source;

    FT_ULong    size;

    if ( stream->read )

    {

      size = stream->read( stream, stream->pos, zip->input,

                           FT_BZIP2_BUFFER_SIZE );

      if ( size == 0 )

        return Bzip2_Err_Invalid_Stream_Operation;

    }

    else

    {

      size = stream->size - stream->pos;

      if ( size > FT_BZIP2_BUFFER_SIZE )

        size = FT_BZIP2_BUFFER_SIZE;

      if ( size == 0 )

        return Bzip2_Err_Invalid_Stream_Operation;

      FT_MEM_COPY( zip->input, stream->base + stream->pos, size );

    }

    stream->pos += size;

    bzstream->next_in  = (char*)zip->input;

    bzstream->avail_in = size;

    return Bzip2_Err_Ok;

  }

  static FT_Error

  ft_bzip2_file_fill_output( FT_BZip2File  zip )

  {

    bz_stream*  bzstream = &zip->bzstream;

    FT_Error    error    = Bzip2_Err_Ok;

    zip->cursor         = zip->buffer;

    bzstream->next_out  = (char*)zip->cursor;

    bzstream->avail_out = FT_BZIP2_BUFFER_SIZE;

    while ( bzstream->avail_out > 0 )

    {

      int  err;

      if ( bzstream->avail_in == 0 )

      {

        error = ft_bzip2_file_fill_input( zip );

        if ( error )

          break;

      }

      err = BZ2_bzDecompress( bzstream );

      if ( err == BZ_STREAM_END )

      {

        zip->limit = (FT_Byte*)bzstream->next_out;

        if ( zip->limit == zip->cursor )

          error = Bzip2_Err_Invalid_Stream_Operation;

        break;

      }

      else if ( err != BZ_OK )

      {

        error = Bzip2_Err_Invalid_Stream_Operation;

        break;

      }

    }

    return error;

  }

  /* fill output buffer; `count' must be <= FT_BZIP2_BUFFER_SIZE */

  static FT_Error

  ft_bzip2_file_skip_output( FT_BZip2File  zip,

                             FT_ULong      count )

  {

    FT_Error  error = Bzip2_Err_Ok;

    FT_ULong  delta;

    for (;;)

    {

      delta = (FT_ULong)( zip->limit - zip->cursor );

      if ( delta >= count )

        delta = count;

      zip->cursor += delta;

      zip->pos    += delta;

      count -= delta;

      if ( count == 0 )

        break;

      error = ft_bzip2_file_fill_output( zip );

      if ( error )

        break;

    }

    return error;

  }

  static FT_ULong

  ft_bzip2_file_io( FT_BZip2File  zip,

                    FT_ULong      pos,

                    FT_Byte*      buffer,

                    FT_ULong      count )

  {

    FT_ULong  result = 0;

    FT_Error  error;

    /* Reset inflate stream if we're seeking backwards.        */

    /* Yes, that is not too efficient, but it saves memory :-) */

    if ( pos < zip->pos )

    {

      error = ft_bzip2_file_reset( zip );

      if ( error )

        goto Exit;

    }

    /* skip unwanted bytes */

    if ( pos > zip->pos )

    {

      error = ft_bzip2_file_skip_output( zip, (FT_ULong)( pos - zip->pos ) );

      if ( error )

        goto Exit;

    }

    if ( count == 0 )

      goto Exit;

    /* now read the data */

    for (;;)

    {

      FT_ULong  delta;

      delta = (FT_ULong)( zip->limit - zip->cursor );

      if ( delta >= count )

        delta = count;

      FT_MEM_COPY( buffer, zip->cursor, delta );

      buffer      += delta;

      result      += delta;

      zip->cursor += delta;

      zip->pos    += delta;

      count -= delta;

      if ( count == 0 )

        break;

      error = ft_bzip2_file_fill_output( zip );

      if ( error )

        break;

    }

  Exit:

    return result;

  }

/***************************************************************************/

/***************************************************************************/

/*****                                                                 *****/

/*****               B Z   E M B E D D I N G   S T R E A M             *****/

/*****                                                                 *****/

/***************************************************************************/

/***************************************************************************/

  static void

  ft_bzip2_stream_close( FT_Stream  stream )

  {

    FT_BZip2File  zip    = (FT_BZip2File)stream->descriptor.pointer;

    FT_Memory     memory = stream->memory;

    if ( zip )

    {

      /* finalize bzip file descriptor */

      ft_bzip2_file_done( zip );

      FT_FREE( zip );

      stream->descriptor.pointer = NULL;

    }

  }

  static FT_ULong

  ft_bzip2_stream_io( FT_Stream  stream,

                      FT_ULong   pos,

                      FT_Byte*   buffer,

                      FT_ULong   count )

  {

    FT_BZip2File  zip = (FT_BZip2File)stream->descriptor.pointer;

    return ft_bzip2_file_io( zip, pos, buffer, count );

  }

  FT_EXPORT_DEF( FT_Error )

  FT_Stream_OpenBzip2( FT_Stream  stream,

                       FT_Stream  source )

  {

    FT_Error      error;

    FT_Memory     memory = source->memory;

    FT_BZip2File  zip;

    /*

     *  check the header right now; this prevents allocating unnecessary

     *  objects when we don't need them

     */

    error = ft_bzip2_check_header( source );

    if ( error )

      goto Exit;

    FT_ZERO( stream );

    stream->memory = memory;

    if ( !FT_QNEW( zip ) )

    {

      error = ft_bzip2_file_init( zip, stream, source );

      if ( error )

      {

        FT_FREE( zip );

        goto Exit;

      }

      stream->descriptor.pointer = zip;

    }

    stream->size  = 0x7FFFFFFFL;  /* don't know the real size! */

    stream->pos   = 0;

    stream->base  = 0;

    stream->read  = ft_bzip2_stream_io;

    stream->close = ft_bzip2_stream_close;

  Exit:

    return error;

  }

#else  /* !FT_CONFIG_OPTION_USE_BZIP2 */

  FT_EXPORT_DEF( FT_Error )

  FT_Stream_OpenBzip2( FT_Stream  stream,

                       FT_Stream  source )

  {

    FT_UNUSED( stream );

    FT_UNUSED( source );

    return Bzip2_Err_Unimplemented_Feature;

  }

#endif /* !FT_CONFIG_OPTION_USE_BZIP2 */

/* END */