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      1 /****************************************************************************
      2  *
      3  * ftstream.h
      4  *
      5  *   Stream handling (specification).
      6  *
      7  * Copyright (C) 1996-2020 by
      8  * David Turner, Robert Wilhelm, and Werner Lemberg.
      9  *
     10  * This file is part of the FreeType project, and may only be used,
     11  * modified, and distributed under the terms of the FreeType project
     12  * license, LICENSE.TXT.  By continuing to use, modify, or distribute
     13  * this file you indicate that you have read the license and
     14  * understand and accept it fully.
     15  *
     16  */
     17 
     18 
     19 #ifndef FTSTREAM_H_
     20 #define FTSTREAM_H_
     21 
     22 
     23 #include <ft2build.h>
     24 #include <freetype/ftsystem.h>
     25 #include <freetype/internal/ftobjs.h>
     26 
     27 
     28 FT_BEGIN_HEADER
     29 
     30 
     31   /* format of an 8-bit frame_op value:           */
     32   /*                                              */
     33   /* bit  76543210                                */
     34   /*      xxxxxxes                                */
     35   /*                                              */
     36   /* s is set to 1 if the value is signed.        */
     37   /* e is set to 1 if the value is little-endian. */
     38   /* xxx is a command.                            */
     39 
     40 #define FT_FRAME_OP_SHIFT         2
     41 #define FT_FRAME_OP_SIGNED        1
     42 #define FT_FRAME_OP_LITTLE        2
     43 #define FT_FRAME_OP_COMMAND( x )  ( x >> FT_FRAME_OP_SHIFT )
     44 
     45 #define FT_MAKE_FRAME_OP( command, little, sign ) \
     46           ( ( command << FT_FRAME_OP_SHIFT ) | ( little << 1 ) | sign )
     47 
     48 #define FT_FRAME_OP_END    0
     49 #define FT_FRAME_OP_START  1  /* start a new frame     */
     50 #define FT_FRAME_OP_BYTE   2  /* read 1-byte value     */
     51 #define FT_FRAME_OP_SHORT  3  /* read 2-byte value     */
     52 #define FT_FRAME_OP_LONG   4  /* read 4-byte value     */
     53 #define FT_FRAME_OP_OFF3   5  /* read 3-byte value     */
     54 #define FT_FRAME_OP_BYTES  6  /* read a bytes sequence */
     55 
     56 
     57   typedef enum  FT_Frame_Op_
     58   {
     59     ft_frame_end       = 0,
     60     ft_frame_start     = FT_MAKE_FRAME_OP( FT_FRAME_OP_START, 0, 0 ),
     61 
     62     ft_frame_byte      = FT_MAKE_FRAME_OP( FT_FRAME_OP_BYTE,  0, 0 ),
     63     ft_frame_schar     = FT_MAKE_FRAME_OP( FT_FRAME_OP_BYTE,  0, 1 ),
     64 
     65     ft_frame_ushort_be = FT_MAKE_FRAME_OP( FT_FRAME_OP_SHORT, 0, 0 ),
     66     ft_frame_short_be  = FT_MAKE_FRAME_OP( FT_FRAME_OP_SHORT, 0, 1 ),
     67     ft_frame_ushort_le = FT_MAKE_FRAME_OP( FT_FRAME_OP_SHORT, 1, 0 ),
     68     ft_frame_short_le  = FT_MAKE_FRAME_OP( FT_FRAME_OP_SHORT, 1, 1 ),
     69 
     70     ft_frame_ulong_be  = FT_MAKE_FRAME_OP( FT_FRAME_OP_LONG, 0, 0 ),
     71     ft_frame_long_be   = FT_MAKE_FRAME_OP( FT_FRAME_OP_LONG, 0, 1 ),
     72     ft_frame_ulong_le  = FT_MAKE_FRAME_OP( FT_FRAME_OP_LONG, 1, 0 ),
     73     ft_frame_long_le   = FT_MAKE_FRAME_OP( FT_FRAME_OP_LONG, 1, 1 ),
     74 
     75     ft_frame_uoff3_be  = FT_MAKE_FRAME_OP( FT_FRAME_OP_OFF3, 0, 0 ),
     76     ft_frame_off3_be   = FT_MAKE_FRAME_OP( FT_FRAME_OP_OFF3, 0, 1 ),
     77     ft_frame_uoff3_le  = FT_MAKE_FRAME_OP( FT_FRAME_OP_OFF3, 1, 0 ),
     78     ft_frame_off3_le   = FT_MAKE_FRAME_OP( FT_FRAME_OP_OFF3, 1, 1 ),
     79 
     80     ft_frame_bytes     = FT_MAKE_FRAME_OP( FT_FRAME_OP_BYTES, 0, 0 ),
     81     ft_frame_skip      = FT_MAKE_FRAME_OP( FT_FRAME_OP_BYTES, 0, 1 )
     82 
     83   } FT_Frame_Op;
     84 
     85 
     86   typedef struct  FT_Frame_Field_
     87   {
     88     FT_Byte    value;
     89     FT_Byte    size;
     90     FT_UShort  offset;
     91 
     92   } FT_Frame_Field;
     93 
     94 
     95   /* Construct an FT_Frame_Field out of a structure type and a field name. */
     96   /* The structure type must be set in the FT_STRUCTURE macro before       */
     97   /* calling the FT_FRAME_START() macro.                                   */
     98   /*                                                                       */
     99 #define FT_FIELD_SIZE( f )                          \
    100           (FT_Byte)sizeof ( ((FT_STRUCTURE*)0)->f )
    101 
    102 #define FT_FIELD_SIZE_DELTA( f )                       \
    103           (FT_Byte)sizeof ( ((FT_STRUCTURE*)0)->f[0] )
    104 
    105 #define FT_FIELD_OFFSET( f )                         \
    106           (FT_UShort)( offsetof( FT_STRUCTURE, f ) )
    107 
    108 #define FT_FRAME_FIELD( frame_op, field ) \
    109           {                               \
    110             frame_op,                     \
    111             FT_FIELD_SIZE( field ),       \
    112             FT_FIELD_OFFSET( field )      \
    113           }
    114 
    115 #define FT_MAKE_EMPTY_FIELD( frame_op )  { frame_op, 0, 0 }
    116 
    117 #define FT_FRAME_START( size )   { ft_frame_start, 0, size }
    118 #define FT_FRAME_END             { ft_frame_end, 0, 0 }
    119 
    120 #define FT_FRAME_LONG( f )       FT_FRAME_FIELD( ft_frame_long_be, f )
    121 #define FT_FRAME_ULONG( f )      FT_FRAME_FIELD( ft_frame_ulong_be, f )
    122 #define FT_FRAME_SHORT( f )      FT_FRAME_FIELD( ft_frame_short_be, f )
    123 #define FT_FRAME_USHORT( f )     FT_FRAME_FIELD( ft_frame_ushort_be, f )
    124 #define FT_FRAME_OFF3( f )       FT_FRAME_FIELD( ft_frame_off3_be, f )
    125 #define FT_FRAME_UOFF3( f )      FT_FRAME_FIELD( ft_frame_uoff3_be, f )
    126 #define FT_FRAME_BYTE( f )       FT_FRAME_FIELD( ft_frame_byte, f )
    127 #define FT_FRAME_CHAR( f )       FT_FRAME_FIELD( ft_frame_schar, f )
    128 
    129 #define FT_FRAME_LONG_LE( f )    FT_FRAME_FIELD( ft_frame_long_le, f )
    130 #define FT_FRAME_ULONG_LE( f )   FT_FRAME_FIELD( ft_frame_ulong_le, f )
    131 #define FT_FRAME_SHORT_LE( f )   FT_FRAME_FIELD( ft_frame_short_le, f )
    132 #define FT_FRAME_USHORT_LE( f )  FT_FRAME_FIELD( ft_frame_ushort_le, f )
    133 #define FT_FRAME_OFF3_LE( f )    FT_FRAME_FIELD( ft_frame_off3_le, f )
    134 #define FT_FRAME_UOFF3_LE( f )   FT_FRAME_FIELD( ft_frame_uoff3_le, f )
    135 
    136 #define FT_FRAME_SKIP_LONG       { ft_frame_long_be, 0, 0 }
    137 #define FT_FRAME_SKIP_SHORT      { ft_frame_short_be, 0, 0 }
    138 #define FT_FRAME_SKIP_BYTE       { ft_frame_byte, 0, 0 }
    139 
    140 #define FT_FRAME_BYTES( field, count ) \
    141           {                            \
    142             ft_frame_bytes,            \
    143             count,                     \
    144             FT_FIELD_OFFSET( field )   \
    145           }
    146 
    147 #define FT_FRAME_SKIP_BYTES( count )  { ft_frame_skip, count, 0 }
    148 
    149 
    150   /**************************************************************************
    151    *
    152    * Integer extraction macros -- the 'buffer' parameter must ALWAYS be of
    153    * type 'char*' or equivalent (1-byte elements).
    154    */
    155 
    156 #define FT_BYTE_( p, i )  ( ((const FT_Byte*)(p))[(i)] )
    157 
    158 #define FT_INT16( x )   ( (FT_Int16)(x)  )
    159 #define FT_UINT16( x )  ( (FT_UInt16)(x) )
    160 #define FT_INT32( x )   ( (FT_Int32)(x)  )
    161 #define FT_UINT32( x )  ( (FT_UInt32)(x) )
    162 
    163 
    164 #define FT_BYTE_U16( p, i, s )  ( FT_UINT16( FT_BYTE_( p, i ) ) << (s) )
    165 #define FT_BYTE_U32( p, i, s )  ( FT_UINT32( FT_BYTE_( p, i ) ) << (s) )
    166 
    167 
    168   /*
    169    *    function      acts on      increases  does range   for    emits
    170    *                                pointer    checking   frames  error
    171    *  -------------------------------------------------------------------
    172    *   FT_PEEK_XXX  buffer pointer      no         no        no     no
    173    *   FT_NEXT_XXX  buffer pointer     yes         no        no     no
    174    *   FT_GET_XXX   stream->cursor     yes        yes       yes     no
    175    *   FT_READ_XXX  stream->pos        yes        yes        no    yes
    176    */
    177 
    178 
    179   /*
    180    * `FT_PEEK_XXX' are generic macros to get data from a buffer position.  No
    181    * safety checks are performed.
    182    */
    183 #define FT_PEEK_SHORT( p )  FT_INT16( FT_BYTE_U16( p, 0, 8 ) | \
    184                                       FT_BYTE_U16( p, 1, 0 ) )
    185 
    186 #define FT_PEEK_USHORT( p )  FT_UINT16( FT_BYTE_U16( p, 0, 8 ) | \
    187                                         FT_BYTE_U16( p, 1, 0 ) )
    188 
    189 #define FT_PEEK_LONG( p )  FT_INT32( FT_BYTE_U32( p, 0, 24 ) | \
    190                                      FT_BYTE_U32( p, 1, 16 ) | \
    191                                      FT_BYTE_U32( p, 2,  8 ) | \
    192                                      FT_BYTE_U32( p, 3,  0 ) )
    193 
    194 #define FT_PEEK_ULONG( p )  FT_UINT32( FT_BYTE_U32( p, 0, 24 ) | \
    195                                        FT_BYTE_U32( p, 1, 16 ) | \
    196                                        FT_BYTE_U32( p, 2,  8 ) | \
    197                                        FT_BYTE_U32( p, 3,  0 ) )
    198 
    199 #define FT_PEEK_OFF3( p )  FT_INT32( FT_BYTE_U32( p, 0, 16 ) | \
    200                                      FT_BYTE_U32( p, 1,  8 ) | \
    201                                      FT_BYTE_U32( p, 2,  0 ) )
    202 
    203 #define FT_PEEK_UOFF3( p )  FT_UINT32( FT_BYTE_U32( p, 0, 16 ) | \
    204                                        FT_BYTE_U32( p, 1,  8 ) | \
    205                                        FT_BYTE_U32( p, 2,  0 ) )
    206 
    207 #define FT_PEEK_SHORT_LE( p )  FT_INT16( FT_BYTE_U16( p, 1, 8 ) | \
    208                                          FT_BYTE_U16( p, 0, 0 ) )
    209 
    210 #define FT_PEEK_USHORT_LE( p )  FT_UINT16( FT_BYTE_U16( p, 1, 8 ) |  \
    211                                            FT_BYTE_U16( p, 0, 0 ) )
    212 
    213 #define FT_PEEK_LONG_LE( p )  FT_INT32( FT_BYTE_U32( p, 3, 24 ) | \
    214                                         FT_BYTE_U32( p, 2, 16 ) | \
    215                                         FT_BYTE_U32( p, 1,  8 ) | \
    216                                         FT_BYTE_U32( p, 0,  0 ) )
    217 
    218 #define FT_PEEK_ULONG_LE( p )  FT_UINT32( FT_BYTE_U32( p, 3, 24 ) | \
    219                                           FT_BYTE_U32( p, 2, 16 ) | \
    220                                           FT_BYTE_U32( p, 1,  8 ) | \
    221                                           FT_BYTE_U32( p, 0,  0 ) )
    222 
    223 #define FT_PEEK_OFF3_LE( p )  FT_INT32( FT_BYTE_U32( p, 2, 16 ) | \
    224                                         FT_BYTE_U32( p, 1,  8 ) | \
    225                                         FT_BYTE_U32( p, 0,  0 ) )
    226 
    227 #define FT_PEEK_UOFF3_LE( p )  FT_UINT32( FT_BYTE_U32( p, 2, 16 ) | \
    228                                           FT_BYTE_U32( p, 1,  8 ) | \
    229                                           FT_BYTE_U32( p, 0,  0 ) )
    230 
    231   /*
    232    * `FT_NEXT_XXX' are generic macros to get data from a buffer position
    233    * which is then increased appropriately.  No safety checks are performed.
    234    */
    235 #define FT_NEXT_CHAR( buffer )       \
    236           ( (signed char)*buffer++ )
    237 
    238 #define FT_NEXT_BYTE( buffer )         \
    239           ( (unsigned char)*buffer++ )
    240 
    241 #define FT_NEXT_SHORT( buffer )                                   \
    242           ( (short)( buffer += 2, FT_PEEK_SHORT( buffer - 2 ) ) )
    243 
    244 #define FT_NEXT_USHORT( buffer )                                            \
    245           ( (unsigned short)( buffer += 2, FT_PEEK_USHORT( buffer - 2 ) ) )
    246 
    247 #define FT_NEXT_OFF3( buffer )                                  \
    248           ( (long)( buffer += 3, FT_PEEK_OFF3( buffer - 3 ) ) )
    249 
    250 #define FT_NEXT_UOFF3( buffer )                                           \
    251           ( (unsigned long)( buffer += 3, FT_PEEK_UOFF3( buffer - 3 ) ) )
    252 
    253 #define FT_NEXT_LONG( buffer )                                  \
    254           ( (long)( buffer += 4, FT_PEEK_LONG( buffer - 4 ) ) )
    255 
    256 #define FT_NEXT_ULONG( buffer )                                           \
    257           ( (unsigned long)( buffer += 4, FT_PEEK_ULONG( buffer - 4 ) ) )
    258 
    259 
    260 #define FT_NEXT_SHORT_LE( buffer )                                   \
    261           ( (short)( buffer += 2, FT_PEEK_SHORT_LE( buffer - 2 ) ) )
    262 
    263 #define FT_NEXT_USHORT_LE( buffer )                                            \
    264           ( (unsigned short)( buffer += 2, FT_PEEK_USHORT_LE( buffer - 2 ) ) )
    265 
    266 #define FT_NEXT_OFF3_LE( buffer )                                  \
    267           ( (long)( buffer += 3, FT_PEEK_OFF3_LE( buffer - 3 ) ) )
    268 
    269 #define FT_NEXT_UOFF3_LE( buffer )                                           \
    270           ( (unsigned long)( buffer += 3, FT_PEEK_UOFF3_LE( buffer - 3 ) ) )
    271 
    272 #define FT_NEXT_LONG_LE( buffer )                                  \
    273           ( (long)( buffer += 4, FT_PEEK_LONG_LE( buffer - 4 ) ) )
    274 
    275 #define FT_NEXT_ULONG_LE( buffer )                                           \
    276           ( (unsigned long)( buffer += 4, FT_PEEK_ULONG_LE( buffer - 4 ) ) )
    277 
    278 
    279   /**************************************************************************
    280    *
    281    * The `FT_GET_XXX` macros use an implicit 'stream' variable.
    282    *
    283    * Note that a call to `FT_STREAM_SEEK` or `FT_STREAM_POS` has **no**
    284    * effect on `FT_GET_XXX`!  They operate on `stream->pos`, while
    285    * `FT_GET_XXX` use `stream->cursor`.
    286    */
    287 #if 0
    288 #define FT_GET_MACRO( type )    FT_NEXT_ ## type ( stream->cursor )
    289 
    290 #define FT_GET_CHAR()       FT_GET_MACRO( CHAR )
    291 #define FT_GET_BYTE()       FT_GET_MACRO( BYTE )
    292 #define FT_GET_SHORT()      FT_GET_MACRO( SHORT )
    293 #define FT_GET_USHORT()     FT_GET_MACRO( USHORT )
    294 #define FT_GET_OFF3()       FT_GET_MACRO( OFF3 )
    295 #define FT_GET_UOFF3()      FT_GET_MACRO( UOFF3 )
    296 #define FT_GET_LONG()       FT_GET_MACRO( LONG )
    297 #define FT_GET_ULONG()      FT_GET_MACRO( ULONG )
    298 #define FT_GET_TAG4()       FT_GET_MACRO( ULONG )
    299 
    300 #define FT_GET_SHORT_LE()   FT_GET_MACRO( SHORT_LE )
    301 #define FT_GET_USHORT_LE()  FT_GET_MACRO( USHORT_LE )
    302 #define FT_GET_LONG_LE()    FT_GET_MACRO( LONG_LE )
    303 #define FT_GET_ULONG_LE()   FT_GET_MACRO( ULONG_LE )
    304 
    305 #else
    306 #define FT_GET_MACRO( func, type )        ( (type)func( stream ) )
    307 
    308 #define FT_GET_CHAR()       FT_GET_MACRO( FT_Stream_GetChar, FT_Char )
    309 #define FT_GET_BYTE()       FT_GET_MACRO( FT_Stream_GetChar, FT_Byte )
    310 #define FT_GET_SHORT()      FT_GET_MACRO( FT_Stream_GetUShort, FT_Short )
    311 #define FT_GET_USHORT()     FT_GET_MACRO( FT_Stream_GetUShort, FT_UShort )
    312 #define FT_GET_OFF3()       FT_GET_MACRO( FT_Stream_GetUOffset, FT_Long )
    313 #define FT_GET_UOFF3()      FT_GET_MACRO( FT_Stream_GetUOffset, FT_ULong )
    314 #define FT_GET_LONG()       FT_GET_MACRO( FT_Stream_GetULong, FT_Long )
    315 #define FT_GET_ULONG()      FT_GET_MACRO( FT_Stream_GetULong, FT_ULong )
    316 #define FT_GET_TAG4()       FT_GET_MACRO( FT_Stream_GetULong, FT_ULong )
    317 
    318 #define FT_GET_SHORT_LE()   FT_GET_MACRO( FT_Stream_GetUShortLE, FT_Short )
    319 #define FT_GET_USHORT_LE()  FT_GET_MACRO( FT_Stream_GetUShortLE, FT_UShort )
    320 #define FT_GET_LONG_LE()    FT_GET_MACRO( FT_Stream_GetULongLE, FT_Long )
    321 #define FT_GET_ULONG_LE()   FT_GET_MACRO( FT_Stream_GetULongLE, FT_ULong )
    322 #endif
    323 
    324 
    325 #define FT_READ_MACRO( func, type, var )        \
    326           ( var = (type)func( stream, &error ), \
    327             error != FT_Err_Ok )
    328 
    329   /*
    330    * The `FT_READ_XXX' macros use implicit `stream' and `error' variables.
    331    *
    332    * `FT_READ_XXX' can be controlled with `FT_STREAM_SEEK' and
    333    * `FT_STREAM_POS'.  They use the full machinery to check whether a read is
    334    * valid.
    335    */
    336 #define FT_READ_BYTE( var )       FT_READ_MACRO( FT_Stream_ReadChar, FT_Byte, var )
    337 #define FT_READ_CHAR( var )       FT_READ_MACRO( FT_Stream_ReadChar, FT_Char, var )
    338 #define FT_READ_SHORT( var )      FT_READ_MACRO( FT_Stream_ReadUShort, FT_Short, var )
    339 #define FT_READ_USHORT( var )     FT_READ_MACRO( FT_Stream_ReadUShort, FT_UShort, var )
    340 #define FT_READ_OFF3( var )       FT_READ_MACRO( FT_Stream_ReadUOffset, FT_Long, var )
    341 #define FT_READ_UOFF3( var )      FT_READ_MACRO( FT_Stream_ReadUOffset, FT_ULong, var )
    342 #define FT_READ_LONG( var )       FT_READ_MACRO( FT_Stream_ReadULong, FT_Long, var )
    343 #define FT_READ_ULONG( var )      FT_READ_MACRO( FT_Stream_ReadULong, FT_ULong, var )
    344 
    345 #define FT_READ_SHORT_LE( var )   FT_READ_MACRO( FT_Stream_ReadUShortLE, FT_Short, var )
    346 #define FT_READ_USHORT_LE( var )  FT_READ_MACRO( FT_Stream_ReadUShortLE, FT_UShort, var )
    347 #define FT_READ_LONG_LE( var )    FT_READ_MACRO( FT_Stream_ReadULongLE, FT_Long, var )
    348 #define FT_READ_ULONG_LE( var )   FT_READ_MACRO( FT_Stream_ReadULongLE, FT_ULong, var )
    349 
    350 
    351 #ifndef FT_CONFIG_OPTION_NO_DEFAULT_SYSTEM
    352 
    353   /* initialize a stream for reading a regular system stream */
    354   FT_BASE( FT_Error )
    355   FT_Stream_Open( FT_Stream    stream,
    356                   const char*  filepathname );
    357 
    358 #endif /* FT_CONFIG_OPTION_NO_DEFAULT_SYSTEM */
    359 
    360 
    361   /* create a new (input) stream from an FT_Open_Args structure */
    362   FT_BASE( FT_Error )
    363   FT_Stream_New( FT_Library           library,
    364                  const FT_Open_Args*  args,
    365                  FT_Stream           *astream );
    366 
    367   /* free a stream */
    368   FT_BASE( void )
    369   FT_Stream_Free( FT_Stream  stream,
    370                   FT_Int     external );
    371 
    372   /* initialize a stream for reading in-memory data */
    373   FT_BASE( void )
    374   FT_Stream_OpenMemory( FT_Stream       stream,
    375                         const FT_Byte*  base,
    376                         FT_ULong        size );
    377 
    378   /* close a stream (does not destroy the stream structure) */
    379   FT_BASE( void )
    380   FT_Stream_Close( FT_Stream  stream );
    381 
    382 
    383   /* seek within a stream. position is relative to start of stream */
    384   FT_BASE( FT_Error )
    385   FT_Stream_Seek( FT_Stream  stream,
    386                   FT_ULong   pos );
    387 
    388   /* skip bytes in a stream */
    389   FT_BASE( FT_Error )
    390   FT_Stream_Skip( FT_Stream  stream,
    391                   FT_Long    distance );
    392 
    393   /* return current stream position */
    394   FT_BASE( FT_ULong )
    395   FT_Stream_Pos( FT_Stream  stream );
    396 
    397   /* read bytes from a stream into a user-allocated buffer, returns an */
    398   /* error if not all bytes could be read.                             */
    399   FT_BASE( FT_Error )
    400   FT_Stream_Read( FT_Stream  stream,
    401                   FT_Byte*   buffer,
    402                   FT_ULong   count );
    403 
    404   /* read bytes from a stream at a given position */
    405   FT_BASE( FT_Error )
    406   FT_Stream_ReadAt( FT_Stream  stream,
    407                     FT_ULong   pos,
    408                     FT_Byte*   buffer,
    409                     FT_ULong   count );
    410 
    411   /* try to read bytes at the end of a stream; return number of bytes */
    412   /* really available                                                 */
    413   FT_BASE( FT_ULong )
    414   FT_Stream_TryRead( FT_Stream  stream,
    415                      FT_Byte*   buffer,
    416                      FT_ULong   count );
    417 
    418   /* Enter a frame of `count' consecutive bytes in a stream.  Returns an */
    419   /* error if the frame could not be read/accessed.  The caller can use  */
    420   /* the `FT_Stream_GetXXX' functions to retrieve frame data without     */
    421   /* error checks.                                                       */
    422   /*                                                                     */
    423   /* You must _always_ call `FT_Stream_ExitFrame' once you have entered  */
    424   /* a stream frame!                                                     */
    425   /*                                                                     */
    426   /* Nested frames are not permitted.                                    */
    427   /*                                                                     */
    428   FT_BASE( FT_Error )
    429   FT_Stream_EnterFrame( FT_Stream  stream,
    430                         FT_ULong   count );
    431 
    432   /* exit a stream frame */
    433   FT_BASE( void )
    434   FT_Stream_ExitFrame( FT_Stream  stream );
    435 
    436 
    437   /* Extract a stream frame.  If the stream is disk-based, a heap block */
    438   /* is allocated and the frame bytes are read into it.  If the stream  */
    439   /* is memory-based, this function simply sets a pointer to the data.  */
    440   /*                                                                    */
    441   /* Useful to optimize access to memory-based streams transparently.   */
    442   /*                                                                    */
    443   /* `FT_Stream_GetXXX' functions can't be used.                        */
    444   /*                                                                    */
    445   /* An extracted frame must be `freed' with a call to the function     */
    446   /* `FT_Stream_ReleaseFrame'.                                          */
    447   /*                                                                    */
    448   FT_BASE( FT_Error )
    449   FT_Stream_ExtractFrame( FT_Stream  stream,
    450                           FT_ULong   count,
    451                           FT_Byte**  pbytes );
    452 
    453   /* release an extract frame (see `FT_Stream_ExtractFrame') */
    454   FT_BASE( void )
    455   FT_Stream_ReleaseFrame( FT_Stream  stream,
    456                           FT_Byte**  pbytes );
    457 
    458 
    459   /* read a byte from an entered frame */
    460   FT_BASE( FT_Char )
    461   FT_Stream_GetChar( FT_Stream  stream );
    462 
    463   /* read a 16-bit big-endian unsigned integer from an entered frame */
    464   FT_BASE( FT_UShort )
    465   FT_Stream_GetUShort( FT_Stream  stream );
    466 
    467   /* read a 24-bit big-endian unsigned integer from an entered frame */
    468   FT_BASE( FT_ULong )
    469   FT_Stream_GetUOffset( FT_Stream  stream );
    470 
    471   /* read a 32-bit big-endian unsigned integer from an entered frame */
    472   FT_BASE( FT_ULong )
    473   FT_Stream_GetULong( FT_Stream  stream );
    474 
    475   /* read a 16-bit little-endian unsigned integer from an entered frame */
    476   FT_BASE( FT_UShort )
    477   FT_Stream_GetUShortLE( FT_Stream  stream );
    478 
    479   /* read a 32-bit little-endian unsigned integer from an entered frame */
    480   FT_BASE( FT_ULong )
    481   FT_Stream_GetULongLE( FT_Stream  stream );
    482 
    483 
    484   /* read a byte from a stream */
    485   FT_BASE( FT_Char )
    486   FT_Stream_ReadChar( FT_Stream  stream,
    487                       FT_Error*  error );
    488 
    489   /* read a 16-bit big-endian unsigned integer from a stream */
    490   FT_BASE( FT_UShort )
    491   FT_Stream_ReadUShort( FT_Stream  stream,
    492                         FT_Error*  error );
    493 
    494   /* read a 24-bit big-endian unsigned integer from a stream */
    495   FT_BASE( FT_ULong )
    496   FT_Stream_ReadUOffset( FT_Stream  stream,
    497                          FT_Error*  error );
    498 
    499   /* read a 32-bit big-endian integer from a stream */
    500   FT_BASE( FT_ULong )
    501   FT_Stream_ReadULong( FT_Stream  stream,
    502                        FT_Error*  error );
    503 
    504   /* read a 16-bit little-endian unsigned integer from a stream */
    505   FT_BASE( FT_UShort )
    506   FT_Stream_ReadUShortLE( FT_Stream  stream,
    507                           FT_Error*  error );
    508 
    509   /* read a 32-bit little-endian unsigned integer from a stream */
    510   FT_BASE( FT_ULong )
    511   FT_Stream_ReadULongLE( FT_Stream  stream,
    512                          FT_Error*  error );
    513 
    514   /* Read a structure from a stream.  The structure must be described */
    515   /* by an array of FT_Frame_Field records.                           */
    516   FT_BASE( FT_Error )
    517   FT_Stream_ReadFields( FT_Stream              stream,
    518                         const FT_Frame_Field*  fields,
    519                         void*                  structure );
    520 
    521 
    522 #define FT_STREAM_POS()           \
    523           FT_Stream_Pos( stream )
    524 
    525 #define FT_STREAM_SEEK( position )                               \
    526           FT_SET_ERROR( FT_Stream_Seek( stream,                  \
    527                                         (FT_ULong)(position) ) )
    528 
    529 #define FT_STREAM_SKIP( distance )                              \
    530           FT_SET_ERROR( FT_Stream_Skip( stream,                 \
    531                                         (FT_Long)(distance) ) )
    532 
    533 #define FT_STREAM_READ( buffer, count )                       \
    534           FT_SET_ERROR( FT_Stream_Read( stream,               \
    535                                         (FT_Byte*)(buffer),   \
    536                                         (FT_ULong)(count) ) )
    537 
    538 #define FT_STREAM_READ_AT( position, buffer, count )            \
    539           FT_SET_ERROR( FT_Stream_ReadAt( stream,               \
    540                                           (FT_ULong)(position), \
    541                                           (FT_Byte*)(buffer),   \
    542                                           (FT_ULong)(count) ) )
    543 
    544 #define FT_STREAM_READ_FIELDS( fields, object )                          \
    545           FT_SET_ERROR( FT_Stream_ReadFields( stream, fields, object ) )
    546 
    547 
    548 #define FT_FRAME_ENTER( size )                                           \
    549           FT_SET_ERROR(                                                  \
    550             FT_DEBUG_INNER( FT_Stream_EnterFrame( stream,                \
    551                                                   (FT_ULong)(size) ) ) )
    552 
    553 #define FT_FRAME_EXIT()                                   \
    554           FT_DEBUG_INNER( FT_Stream_ExitFrame( stream ) )
    555 
    556 #define FT_FRAME_EXTRACT( size, bytes )                                       \
    557           FT_SET_ERROR(                                                       \
    558             FT_DEBUG_INNER( FT_Stream_ExtractFrame( stream,                   \
    559                                                     (FT_ULong)(size),         \
    560                                                     (FT_Byte**)&(bytes) ) ) )
    561 
    562 #define FT_FRAME_RELEASE( bytes )                                         \
    563           FT_DEBUG_INNER( FT_Stream_ReleaseFrame( stream,                 \
    564                                                   (FT_Byte**)&(bytes) ) )
    565 
    566 
    567 FT_END_HEADER
    568 
    569 #endif /* FTSTREAM_H_ */
    570 
    571 
    572 /* END */
    573