Improve stream extraction macro documentation.

This commit is contained in:
Werner Lemberg 2018-07-21 07:38:13 +02:00
parent 154832d466
commit a2370f21b5
2 changed files with 25 additions and 5 deletions

View File

@ -165,6 +165,10 @@ FT_BEGIN_HEADER
#define FT_BYTE_U32( p, i, s ) ( FT_UINT32( FT_BYTE_( p, i ) ) << (s) )
/*
* `FT_PEEK_XXX' are generic macros to get data from a buffer position.
* No safety checks are performed.
*/
#define FT_PEEK_SHORT( p ) FT_INT16( FT_BYTE_U16( p, 0, 8 ) | \
FT_BYTE_U16( p, 1, 0 ) )
@ -213,7 +217,10 @@ FT_BEGIN_HEADER
FT_BYTE_U32( p, 1, 8 ) | \
FT_BYTE_U32( p, 0, 0 ) )
/*
* `FT_NEXT_XXX' are generic macros to get data from a buffer position
* which is then increased appropriately. No safety checks are performed.
*/
#define FT_NEXT_CHAR( buffer ) \
( (signed char)*buffer++ )
@ -260,7 +267,11 @@ FT_BEGIN_HEADER
/**************************************************************************
*
* Each GET_xxxx() macro uses an implicit `stream' variable.
* The `FT_GET_XXX' macros use an implicit `stream' variable.
*
* Note that a call to `FT_STREAM_SEEK' or `FT_STREAM_POS' has *no* effect
* on `FT_GET_XXX'! They operate on `stream->pos', while `FT_GET_XXX' use
* `stream->cursor'.
*/
#if 0
#define FT_GET_MACRO( type ) FT_NEXT_ ## type ( stream->cursor )
@ -299,10 +310,18 @@ FT_BEGIN_HEADER
#define FT_GET_ULONG_LE() FT_GET_MACRO( FT_Stream_GetULongLE, FT_ULong )
#endif
#define FT_READ_MACRO( func, type, var ) \
( var = (type)func( stream, &error ), \
error != FT_Err_Ok )
/*
* The `FT_READ_XXX' macros use implicit `stream' and `error' variables.
*
* `FT_READ_XXX' can be controlled with `FT_STREAM_SEEK' and
* `FT_STREAM_POS'. They use the full machinery to check whether a read
* is valid.
*/
#define FT_READ_BYTE( var ) FT_READ_MACRO( FT_Stream_ReadChar, FT_Byte, var )
#define FT_READ_CHAR( var ) FT_READ_MACRO( FT_Stream_ReadChar, FT_Char, var )
#define FT_READ_SHORT( var ) FT_READ_MACRO( FT_Stream_ReadUShort, FT_Short, var )
@ -387,10 +406,10 @@ FT_BEGIN_HEADER
/* Enter a frame of `count' consecutive bytes in a stream. Returns an */
/* error if the frame could not be read/accessed. The caller can use */
/* the FT_Stream_Get_XXX functions to retrieve frame data without */
/* the `FT_Stream_Get_XXX' functions to retrieve frame data without */
/* error checks. */
/* */
/* You must _always_ call FT_Stream_ExitFrame() once you have entered */
/* You must _always_ call `FT_Stream_ExitFrame' once you have entered */
/* a stream frame! */
/* */
FT_BASE( FT_Error )
@ -415,7 +434,7 @@ FT_BEGIN_HEADER
FT_ULong count,
FT_Byte** pbytes );
/* release an extract frame (see FT_Stream_ExtractFrame) */
/* release an extract frame (see `FT_Stream_ExtractFrame') */
FT_BASE( void )
FT_Stream_ReleaseFrame( FT_Stream stream,
FT_Byte** pbytes );

View File

@ -219,6 +219,7 @@
{
FT_Memory memory = stream->memory;
#ifdef FT_DEBUG_MEMORY
ft_mem_free( memory, *pbytes );
*pbytes = NULL;