harfbuzz/src/hb-shape.cc

/*
 * Copyright © 2009  Red Hat, Inc.
 *
 *  This is part of HarfBuzz, a text shaping library.
 *
 * Permission is hereby granted, without written agreement and without
 * license or royalty fees, to use, copy, modify, and distribute this
 * software and its documentation for any purpose, provided that the
 * above copyright notice and the following two paragraphs appear in
 * all copies of this software.
 *
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 *
 * Red Hat Author(s): Behdad Esfahbod
 */

#include "hb-private.hh"

#include "hb-shape.h"

#include "hb-buffer-private.hh"

#ifdef HAVE_UNISCRIBE
# include "hb-uniscribe.h"
#endif
#ifdef HAVE_OT
# include "hb-ot-shape.h"
#endif
#include "hb-fallback-shape-private.hh"

typedef hb_bool_t (*hb_shape_func_t) (hb_font_t          *font,
				      hb_buffer_t        *buffer,
				      const hb_feature_t *features,
				      unsigned int        num_features,
				      const char         *shaper_options);

#define HB_SHAPER_IMPLEMENT(name) {#name, hb_##name##_shape}
static const struct hb_shaper_pair_t {
  const char name[16];
  hb_shape_func_t func;
} shapers[] = {
  /* v--- Add new shapers in the right place here */
#ifdef HAVE_UNISCRIBE
  HB_SHAPER_IMPLEMENT (uniscribe),
#endif
#ifdef HAVE_OT
  HB_SHAPER_IMPLEMENT (ot),
#endif
  HB_SHAPER_IMPLEMENT (fallback) /* should be last */
};
#undef HB_SHAPER_IMPLEMENT

static class static_shaper_list_t {
  public:
  static_shaper_list_t (void) {
    char *env = getenv ("HB_SHAPER_LIST");
    shaper_list = NULL;
    if (!env || !*env)
      return;
    unsigned int count = 3; /* initial, fallback, null */
    for (const char *p = env; (p == strchr (p, ':')) && p++; )
      count++;
    if (count <= ARRAY_LENGTH (static_shaper_list))
      shaper_list = static_shaper_list;
    else
      shaper_list = (const char **) malloc (count * sizeof (shaper_list[0]));

    count = 0;
    shaper_list[count++] = env;
    for (char *p = env; (p == strchr (p, ':')) && (*p = '\0', TRUE) && p++; )
      shaper_list[count++] = p;
    shaper_list[count++] = "fallback";
    shaper_list[count] = NULL;
  }
  const char **shaper_list;
  const char *static_shaper_list[10];
} env_shaper_list;

hb_bool_t
hb_shape (hb_font_t           *font,
	  hb_buffer_t         *buffer,
	  const hb_feature_t  *features,
	  unsigned int         num_features,
	  const char          *shaper_options,
	  const char         **shaper_list)
{
  if (likely (!shaper_list))
    shaper_list = env_shaper_list.shaper_list;

  if (likely (!shaper_list)) {
    for (unsigned int i = 0; i < ARRAY_LENGTH (shapers); i++)
      if (likely (shapers[i].func (font, buffer,
				   features, num_features,
				   shaper_options)))
        return TRUE;
  } else {
    while (*shaper_list) {
      for (unsigned int i = 0; i < ARRAY_LENGTH (shapers); i++)
	if (0 == strcmp (*shaper_list, shapers[i].name) &&
	    likely (shapers[i].func (font, buffer,
				     features, num_features,
				     shaper_options)))
	  return TRUE;
      shaper_list++;
    }
  }
  return FALSE;
}