freetype2/include/freetype/ftotval.h

/****************************************************************************
 *
 * ftotval.h
 *
 *   FreeType API for validating OpenType tables (specification).
 *
 * Copyright 2004-2018 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.
 *
 */


/****************************************************************************
 *
 *
 * Warning: This module might be moved to a different library in the
 *         future to avoid a tight dependency between FreeType and the
 *         OpenType specification.
 *
 *
 */


#ifndef FTOTVAL_H_
#define FTOTVAL_H_

#include <ft2build.h>
#include FT_FREETYPE_H

#ifdef FREETYPE_H
#error "freetype.h of FreeType 1 has been loaded!"
#error "Please fix the directory search order for header files"
#error "so that freetype.h of FreeType 2 is found first."
#endif


FT_BEGIN_HEADER


  /**************************************************************************
   *
   * @Section:
   *   ot_validation
   *
   * @Title:
   *   OpenType Validation
   *
   * @Abstract:
   *   An API to validate OpenType tables.
   *
   * @Description:
   *   This section contains the declaration of functions to validate
   *   some OpenType tables (BASE, GDEF, GPOS, GSUB, JSTF, MATH).
   *
   * @Order:
   *   FT_OpenType_Validate
   *   FT_OpenType_Free
   *
   *   FT_VALIDATE_OTXXX
   *
   */


 /**********************************************************************
  *
  * @enum:
  *    FT_VALIDATE_OTXXX
  *
  * @description:
  *    A list of bit-field constants used with @FT_OpenType_Validate to
  *    indicate which OpenType tables should be validated.
  *
  * @values:
  *    FT_VALIDATE_BASE ::
  *      Validate BASE table.
  *
  *    FT_VALIDATE_GDEF ::
  *      Validate GDEF table.
  *
  *    FT_VALIDATE_GPOS ::
  *      Validate GPOS table.
  *
  *    FT_VALIDATE_GSUB ::
  *      Validate GSUB table.
  *
  *    FT_VALIDATE_JSTF ::
  *      Validate JSTF table.
  *
  *    FT_VALIDATE_MATH ::
  *      Validate MATH table.
  *
  *    FT_VALIDATE_OT ::
  *      Validate all OpenType tables (BASE, GDEF, GPOS, GSUB, JSTF, MATH).
  *
  */
#define FT_VALIDATE_BASE  0x0100
#define FT_VALIDATE_GDEF  0x0200
#define FT_VALIDATE_GPOS  0x0400
#define FT_VALIDATE_GSUB  0x0800
#define FT_VALIDATE_JSTF  0x1000
#define FT_VALIDATE_MATH  0x2000

#define FT_VALIDATE_OT  ( FT_VALIDATE_BASE | \
                          FT_VALIDATE_GDEF | \
                          FT_VALIDATE_GPOS | \
                          FT_VALIDATE_GSUB | \
                          FT_VALIDATE_JSTF | \
                          FT_VALIDATE_MATH )

 /**********************************************************************
  *
  * @function:
  *    FT_OpenType_Validate
  *
  * @description:
  *    Validate various OpenType tables to assure that all offsets and
  *    indices are valid.  The idea is that a higher-level library that
  *    actually does the text layout can access those tables without
  *    error checking (which can be quite time consuming).
  *
  * @input:
  *    face ::
  *      A handle to the input face.
  *
  *    validation_flags ::
  *      A bit field that specifies the tables to be validated.  See
  *      @FT_VALIDATE_OTXXX for possible values.
  *
  * @output:
  *    BASE_table ::
  *      A pointer to the BASE table.
  *
  *    GDEF_table ::
  *      A pointer to the GDEF table.
  *
  *    GPOS_table ::
  *      A pointer to the GPOS table.
  *
  *    GSUB_table ::
  *      A pointer to the GSUB table.
  *
  *    JSTF_table ::
  *      A pointer to the JSTF table.
  *
  * @return:
  *   FreeType error code.  0~means success.
  *
  * @note:
  *   This function only works with OpenType fonts, returning an error
  *   otherwise.
  *
  *   After use, the application should deallocate the five tables with
  *   @FT_OpenType_Free.  A NULL value indicates that the table either
  *   doesn't exist in the font, or the application hasn't asked for
  *   validation.
  */
  FT_EXPORT( FT_Error )
  FT_OpenType_Validate( FT_Face    face,
                        FT_UInt    validation_flags,
                        FT_Bytes  *BASE_table,
                        FT_Bytes  *GDEF_table,
                        FT_Bytes  *GPOS_table,
                        FT_Bytes  *GSUB_table,
                        FT_Bytes  *JSTF_table );

 /**********************************************************************
  *
  * @function:
  *    FT_OpenType_Free
  *
  * @description:
  *    Free the buffer allocated by OpenType validator.
  *
  * @input:
  *    face ::
  *      A handle to the input face.
  *
  *    table ::
  *      The pointer to the buffer that is allocated by
  *      @FT_OpenType_Validate.
  *
  * @note:
  *   This function must be used to free the buffer allocated by
  *   @FT_OpenType_Validate only.
  */
  FT_EXPORT( void )
  FT_OpenType_Free( FT_Face   face,
                    FT_Bytes  table );

  /* */


FT_END_HEADER

#endif /* FTOTVAL_H_ */


/* END */