misc/libfreetype/src/lzw/ftzopen.c
author koda
Sun, 29 Jan 2012 18:52:01 +0100
changeset 6613 c7bf3b7c49dd
parent 5172 88f2e05288ba
permissions -rw-r--r--
disabling the discovery of SDL13+ on desktop. SDL13 has become SDL2 with a completely different ABI and will require a new FindSDL2 module for Cmake to be found; for current sdl development installations, hedgewars will either use the compatibility layer (present in sdl1.3 but not in sdl2) or just fail to build (in case sdl2 is installed but sdl1.2.* is not). whew

/***************************************************************************/
/*                                                                         */
/*  ftzopen.c                                                              */
/*                                                                         */
/*    FreeType support for .Z compressed files.                            */
/*                                                                         */
/*  This optional component relies on NetBSD's zopen().  It should mainly  */
/*  be used to parse compressed PCF fonts, as found with many X11 server   */
/*  distributions.                                                         */
/*                                                                         */
/*  Copyright 2005, 2006, 2007, 2009 by David Turner.                      */
/*                                                                         */
/*  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 "ftzopen.h"
#include FT_INTERNAL_MEMORY_H
#include FT_INTERNAL_STREAM_H
#include FT_INTERNAL_DEBUG_H


  static int
  ft_lzwstate_refill( FT_LzwState  state )
  {
    FT_ULong  count;


    if ( state->in_eof )
      return -1;

    count = FT_Stream_TryRead( state->source,
                               state->buf_tab,
                               state->num_bits );  /* WHY? */

    state->buf_size   = (FT_UInt)count;
    state->buf_total += count;
    state->in_eof     = FT_BOOL( count < state->num_bits );
    state->buf_offset = 0;
    state->buf_size   = ( state->buf_size << 3 ) - ( state->num_bits - 1 );

    if ( count == 0 )  /* end of file */
      return -1;

    return 0;
  }


  static FT_Int32
  ft_lzwstate_get_code( FT_LzwState  state )
  {
    FT_UInt   num_bits = state->num_bits;
    FT_Int    offset   = state->buf_offset;
    FT_Byte*  p;
    FT_Int    result;


    if ( state->buf_clear                    ||
         offset >= state->buf_size           ||
         state->free_ent >= state->free_bits )
    {
      if ( state->free_ent >= state->free_bits )
      {
        state->num_bits  = ++num_bits;
        state->free_bits = state->num_bits < state->max_bits
                           ? (FT_UInt)( ( 1UL << num_bits ) - 256 )
                           : state->max_free + 1;
      }

      if ( state->buf_clear )
      {
        state->num_bits  = num_bits = LZW_INIT_BITS;
        state->free_bits = (FT_UInt)( ( 1UL << num_bits ) - 256 );
        state->buf_clear = 0;
      }

      if ( ft_lzwstate_refill( state ) < 0 )
        return -1;

      offset = 0;
    }

    state->buf_offset = offset + num_bits;

    p         = &state->buf_tab[offset >> 3];
    offset   &= 7;
    result    = *p++ >> offset;
    offset    = 8 - offset;
    num_bits -= offset;

    if ( num_bits >= 8 )
    {
      result   |= *p++ << offset;
      offset   += 8;
      num_bits -= 8;
    }
    if ( num_bits > 0 )
      result |= ( *p & LZW_MASK( num_bits ) ) << offset;

    return result;
  }


  /* grow the character stack */
  static int
  ft_lzwstate_stack_grow( FT_LzwState  state )
  {
    if ( state->stack_top >= state->stack_size )
    {
      FT_Memory  memory = state->memory;
      FT_Error   error;
      FT_Offset  old_size = state->stack_size;
      FT_Offset  new_size = old_size;

      new_size = new_size + ( new_size >> 1 ) + 4;

      if ( state->stack == state->stack_0 )
      {
        state->stack = NULL;
        old_size     = 0;
      }

      if ( FT_RENEW_ARRAY( state->stack, old_size, new_size ) )
        return -1;

      state->stack_size = new_size;
    }
    return 0;
  }


  /* grow the prefix/suffix arrays */
  static int
  ft_lzwstate_prefix_grow( FT_LzwState  state )
  {
    FT_UInt    old_size = state->prefix_size;
    FT_UInt    new_size = old_size;
    FT_Memory  memory   = state->memory;
    FT_Error   error;


    if ( new_size == 0 )  /* first allocation -> 9 bits */
      new_size = 512;
    else
      new_size += new_size >> 2;  /* don't grow too fast */

    /*
     *  Note that the `suffix' array is located in the same memory block
     *  pointed to by `prefix'.
     *
     *  I know that sizeof(FT_Byte) == 1 by definition, but it is clearer
     *  to write it literally.
     *
     */
    if ( FT_REALLOC_MULT( state->prefix, old_size, new_size,
                          sizeof ( FT_UShort ) + sizeof ( FT_Byte ) ) )
      return -1;

    /* now adjust `suffix' and move the data accordingly */
    state->suffix = (FT_Byte*)( state->prefix + new_size );

    FT_MEM_MOVE( state->suffix,
                 state->prefix + old_size,
                 old_size * sizeof ( FT_Byte ) );

    state->prefix_size = new_size;
    return 0;
  }


  FT_LOCAL_DEF( void )
  ft_lzwstate_reset( FT_LzwState  state )
  {
    state->in_eof     = 0;
    state->buf_offset = 0;
    state->buf_size   = 0;
    state->buf_clear  = 0;
    state->buf_total  = 0;
    state->stack_top  = 0;
    state->num_bits   = LZW_INIT_BITS;
    state->phase      = FT_LZW_PHASE_START;
  }


  FT_LOCAL_DEF( void )
  ft_lzwstate_init( FT_LzwState  state,
                    FT_Stream    source )
  {
    FT_ZERO( state );

    state->source = source;
    state->memory = source->memory;

    state->prefix      = NULL;
    state->suffix      = NULL;
    state->prefix_size = 0;

    state->stack      = state->stack_0;
    state->stack_size = sizeof ( state->stack_0 );

    ft_lzwstate_reset( state );
  }


  FT_LOCAL_DEF( void )
  ft_lzwstate_done( FT_LzwState  state )
  {
    FT_Memory  memory = state->memory;


    ft_lzwstate_reset( state );

    if ( state->stack != state->stack_0 )
      FT_FREE( state->stack );

    FT_FREE( state->prefix );
    state->suffix = NULL;

    FT_ZERO( state );
  }


#define FTLZW_STACK_PUSH( c )                        \
  FT_BEGIN_STMNT                                     \
    if ( state->stack_top >= state->stack_size &&    \
         ft_lzwstate_stack_grow( state ) < 0   )     \
      goto Eof;                                      \
                                                     \
    state->stack[state->stack_top++] = (FT_Byte)(c); \
  FT_END_STMNT


  FT_LOCAL_DEF( FT_ULong )
  ft_lzwstate_io( FT_LzwState  state,
                  FT_Byte*     buffer,
                  FT_ULong     out_size )
  {
    FT_ULong  result = 0;

    FT_UInt  old_char = state->old_char;
    FT_UInt  old_code = state->old_code;
    FT_UInt  in_code  = state->in_code;


    if ( out_size == 0 )
      goto Exit;

    switch ( state->phase )
    {
    case FT_LZW_PHASE_START:
      {
        FT_Byte   max_bits;
        FT_Int32  c;


        /* skip magic bytes, and read max_bits + block_flag */
        if ( FT_Stream_Seek( state->source, 2 ) != 0               ||
             FT_Stream_TryRead( state->source, &max_bits, 1 ) != 1 )
          goto Eof;

        state->max_bits   = max_bits & LZW_BIT_MASK;
        state->block_mode = max_bits & LZW_BLOCK_MASK;
        state->max_free   = (FT_UInt)( ( 1UL << state->max_bits ) - 256 );

        if ( state->max_bits > LZW_MAX_BITS )
          goto Eof;

        state->num_bits = LZW_INIT_BITS;
        state->free_ent = ( state->block_mode ? LZW_FIRST
                                              : LZW_CLEAR ) - 256;
        in_code  = 0;

        state->free_bits = state->num_bits < state->max_bits
                           ? (FT_UInt)( ( 1UL << state->num_bits ) - 256 )
                           : state->max_free + 1;

        c = ft_lzwstate_get_code( state );
        if ( c < 0 )
          goto Eof;

        old_code = old_char = (FT_UInt)c;

        if ( buffer )
          buffer[result] = (FT_Byte)old_char;

        if ( ++result >= out_size )
          goto Exit;

        state->phase = FT_LZW_PHASE_CODE;
      }
      /* fall-through */

    case FT_LZW_PHASE_CODE:
      {
        FT_Int32  c;
        FT_UInt   code;


      NextCode:
        c = ft_lzwstate_get_code( state );
        if ( c < 0 )
          goto Eof;

        code = (FT_UInt)c;

        if ( code == LZW_CLEAR && state->block_mode )
        {
          /* why not LZW_FIRST-256 ? */
          state->free_ent  = ( LZW_FIRST - 1 ) - 256;
          state->buf_clear = 1;
          c = ft_lzwstate_get_code( state );
          if ( c < 0 )
            goto Eof;

          code = (FT_UInt)c;
        }

        in_code = code; /* save code for later */

        if ( code >= 256U )
        {
          /* special case for KwKwKwK */
          if ( code - 256U >= state->free_ent )
          {
            FTLZW_STACK_PUSH( old_char );
            code = old_code;
          }

          while ( code >= 256U )
          {
            if ( !state->prefix )
              goto Eof;

            FTLZW_STACK_PUSH( state->suffix[code - 256] );
            code = state->prefix[code - 256];
          }
        }

        old_char = code;
        FTLZW_STACK_PUSH( old_char );

        state->phase = FT_LZW_PHASE_STACK;
      }
      /* fall-through */

    case FT_LZW_PHASE_STACK:
      {
        while ( state->stack_top > 0 )
        {
          --state->stack_top;

          if ( buffer )
            buffer[result] = state->stack[state->stack_top];

          if ( ++result == out_size )
            goto Exit;
        }

        /* now create new entry */
        if ( state->free_ent < state->max_free )
        {
          if ( state->free_ent >= state->prefix_size &&
               ft_lzwstate_prefix_grow( state ) < 0  )
            goto Eof;

          FT_ASSERT( state->free_ent < state->prefix_size );

          state->prefix[state->free_ent] = (FT_UShort)old_code;
          state->suffix[state->free_ent] = (FT_Byte)  old_char;

          state->free_ent += 1;
        }

        old_code = in_code;

        state->phase = FT_LZW_PHASE_CODE;
        goto NextCode;
      }

    default:  /* state == EOF */
      ;
    }

  Exit:
    state->old_code = old_code;
    state->old_char = old_char;
    state->in_code  = in_code;

    return result;

  Eof:
    state->phase = FT_LZW_PHASE_EOF;
    goto Exit;
  }


/* END */