/*

 * Copyright © 1998-2004  David Turner and Werner Lemberg

 * Copyright © 2004,2007,2009,2010  Red Hat, Inc.

 * Copyright © 2011,2012  Google, 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): Owen Taylor, Behdad Esfahbod

 * Google Author(s): Behdad Esfahbod

 */

#ifndef HB_BUFFER_PRIVATE_HH

#define HB_BUFFER_PRIVATE_HH

#include "hb-private.hh"

#include "hb-object-private.hh"

#include "hb-unicode-private.hh"

#ifndef HB_BUFFER_MAX_EXPANSION_FACTOR

#define HB_BUFFER_MAX_EXPANSION_FACTOR 32

#endif

#ifndef HB_BUFFER_MAX_LEN_MIN

#define HB_BUFFER_MAX_LEN_MIN 8192

#endif

#ifndef HB_BUFFER_MAX_LEN_DEFAULT

#define HB_BUFFER_MAX_LEN_DEFAULT 0x3FFFFFFF /* Shaping more than a billion chars? Let us know! */

#endif

ASSERT_STATIC (sizeof (hb_glyph_info_t) == 20);

ASSERT_STATIC (sizeof (hb_glyph_info_t) == sizeof (hb_glyph_position_t));

HB_MARK_AS_FLAG_T (hb_buffer_flags_t);

HB_MARK_AS_FLAG_T (hb_buffer_serialize_flags_t);

enum hb_buffer_scratch_flags_t {

  HB_BUFFER_SCRATCH_FLAG_DEFAULT                        = 0x00000000u,

  HB_BUFFER_SCRATCH_FLAG_HAS_NON_ASCII                  = 0x00000001u,

  HB_BUFFER_SCRATCH_FLAG_HAS_DEFAULT_IGNORABLES         = 0x00000002u,

  HB_BUFFER_SCRATCH_FLAG_HAS_SPACE_FALLBACK             = 0x00000004u,

  HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT            = 0x00000008u,

  /* Reserved for complex shapers' internal use. */

  HB_BUFFER_SCRATCH_FLAG_COMPLEX0                       = 0x01000000u,

  HB_BUFFER_SCRATCH_FLAG_COMPLEX1                       = 0x02000000u,

  HB_BUFFER_SCRATCH_FLAG_COMPLEX2                       = 0x04000000u,

  HB_BUFFER_SCRATCH_FLAG_COMPLEX3                       = 0x08000000u,

};

HB_MARK_AS_FLAG_T (hb_buffer_scratch_flags_t);

/*

 * hb_buffer_t

 */

struct hb_buffer_t {

  hb_object_header_t header;

  ASSERT_POD ();

  /* Information about how the text in the buffer should be treated */

  hb_unicode_funcs_t *unicode; /* Unicode functions */

  hb_buffer_flags_t flags; /* BOT / EOT / etc. */

  hb_buffer_cluster_level_t cluster_level;

  hb_codepoint_t replacement; /* U+FFFD or something else. */

  hb_buffer_scratch_flags_t scratch_flags; /* Have space-flallback, etc. */

  unsigned int max_len; /* Maximum allowed len. */

  /* Buffer contents */

  hb_buffer_content_type_t content_type;

  hb_segment_properties_t props; /* Script, language, direction */

  bool in_error; /* Allocation failed */

  bool have_output; /* Whether we have an output buffer going on */

  bool have_positions; /* Whether we have positions */

  unsigned int idx; /* Cursor into ->info and ->pos arrays */

  unsigned int len; /* Length of ->info and ->pos arrays */

  unsigned int out_len; /* Length of ->out array if have_output */

  unsigned int allocated; /* Length of allocated arrays */

  hb_glyph_info_t     *info;

  hb_glyph_info_t     *out_info;

  hb_glyph_position_t *pos;

  inline hb_glyph_info_t &cur (unsigned int i = 0) { return info[idx + i]; }

  inline hb_glyph_info_t cur (unsigned int i = 0) const { return info[idx + i]; }

  inline hb_glyph_position_t &cur_pos (unsigned int i = 0) { return pos[idx + i]; }

  inline hb_glyph_position_t cur_pos (unsigned int i = 0) const { return pos[idx + i]; }

  inline hb_glyph_info_t &prev (void) { return out_info[out_len ? out_len - 1 : 0]; }

  inline hb_glyph_info_t prev (void) const { return out_info[out_len ? out_len - 1 : 0]; }

  inline bool has_separate_output (void) const { return info != out_info; }

  unsigned int serial;

  /* Text before / after the main buffer contents.

   * Always in Unicode, and ordered outward.

   * Index 0 is for "pre-context", 1 for "post-context". */

  static const unsigned int CONTEXT_LENGTH = 5;

  hb_codepoint_t context[2][CONTEXT_LENGTH];

  unsigned int context_len[2];

  /* Debugging API */

  hb_buffer_message_func_t message_func;

  void *message_data;

  hb_destroy_func_t message_destroy;

  /* Internal debugging. */

  /* The bits here reflect current allocations of the bytes in glyph_info_t's var1 and var2. */

#ifndef HB_NDEBUG

  uint8_t allocated_var_bits;

#endif

  inline void allocate_var (unsigned int start, unsigned int count)

  {

#ifndef HB_NDEBUG

    unsigned int end = start + count;

    assert (end <= 8);

    unsigned int bits = (1u<<end) - (1u<<start);

    assert (0 == (allocated_var_bits & bits));

    allocated_var_bits |= bits;

#endif

  }

  inline void deallocate_var (unsigned int start, unsigned int count)

  {

#ifndef HB_NDEBUG

    unsigned int end = start + count;

    assert (end <= 8);

    unsigned int bits = (1u<<end) - (1u<<start);

    assert (bits == (allocated_var_bits & bits));

    allocated_var_bits &= ~bits;

#endif

  }

  inline void assert_var (unsigned int start, unsigned int count)

  {

#ifndef HB_NDEBUG

    unsigned int end = start + count;

    assert (end <= 8);

    unsigned int bits = (1u<<end) - (1u<<start);

    assert (bits == (allocated_var_bits & bits));

#endif

  }

  inline void deallocate_var_all (void)

  {

#ifndef HB_NDEBUG

    allocated_var_bits = 0;

#endif

  }

  /* Methods */

  HB_INTERNAL void reset (void);

  HB_INTERNAL void clear (void);

  inline unsigned int backtrack_len (void) const

  { return have_output? out_len : idx; }

  inline unsigned int lookahead_len (void) const

  { return len - idx; }

  inline unsigned int next_serial (void) { return serial++; }

  HB_INTERNAL void add (hb_codepoint_t  codepoint,

                        unsigned int    cluster);

  HB_INTERNAL void add_info (const hb_glyph_info_t &glyph_info);

  HB_INTERNAL void reverse_range (unsigned int start, unsigned int end);

  HB_INTERNAL void reverse (void);

  HB_INTERNAL void reverse_clusters (void);

  HB_INTERNAL void guess_segment_properties (void);

  HB_INTERNAL void swap_buffers (void);

  HB_INTERNAL void remove_output (void);

  HB_INTERNAL void clear_output (void);

  HB_INTERNAL void clear_positions (void);

  HB_INTERNAL void replace_glyphs (unsigned int num_in,

                                   unsigned int num_out,

                                   const hb_codepoint_t *glyph_data);

  HB_INTERNAL void replace_glyph (hb_codepoint_t glyph_index);

  /* Makes a copy of the glyph at idx to output and replace glyph_index */

  HB_INTERNAL void output_glyph (hb_codepoint_t glyph_index);

  HB_INTERNAL void output_info (const hb_glyph_info_t &glyph_info);

  /* Copies glyph at idx to output but doesn't advance idx */

  HB_INTERNAL void copy_glyph (void);

  HB_INTERNAL bool move_to (unsigned int i); /* i is output-buffer index. */

  /* Copies glyph at idx to output and advance idx.

   * If there's no output, just advance idx. */

  inline void

  next_glyph (void)

  {

    if (have_output)

    {

      if (unlikely (out_info != info || out_len != idx)) {

        if (unlikely (!make_room_for (1, 1))) return;

        out_info[out_len] = info[idx];

      }

      out_len++;

    }

    idx++;

  }

  /* Advance idx without copying to output. */

  inline void skip_glyph (void) { idx++; }

  inline void reset_masks (hb_mask_t mask)

  {

    for (unsigned int j = 0; j < len; j++)

      info[j].mask = mask;

  }

  inline void add_masks (hb_mask_t mask)

  {

    for (unsigned int j = 0; j < len; j++)

      info[j].mask |= mask;

  }

  HB_INTERNAL void set_masks (hb_mask_t value,

                              hb_mask_t mask,

                              unsigned int cluster_start,

                              unsigned int cluster_end);

  HB_INTERNAL void merge_clusters (unsigned int start,

                                   unsigned int end)

  {

    if (end - start < 2)

      return;

    merge_clusters_impl (start, end);

  }

  HB_INTERNAL void merge_clusters_impl (unsigned int start,

                                        unsigned int end);

  HB_INTERNAL void merge_out_clusters (unsigned int start,

                                       unsigned int end);

  /* Merge clusters for deleting current glyph, and skip it. */

  HB_INTERNAL void delete_glyph (void);

  /* Internal methods */

  HB_INTERNAL bool enlarge (unsigned int size);

  inline bool ensure (unsigned int size)

  { return likely (!size || size < allocated) ? true : enlarge (size); }

  inline bool ensure_inplace (unsigned int size)

  { return likely (!size || size < allocated); }

  HB_INTERNAL bool make_room_for (unsigned int num_in, unsigned int num_out);

  HB_INTERNAL bool shift_forward (unsigned int count);

  typedef long scratch_buffer_t;

  HB_INTERNAL scratch_buffer_t *get_scratch_buffer (unsigned int *size);

  inline void clear_context (unsigned int side) { context_len[side] = 0; }

  HB_INTERNAL void sort (unsigned int start, unsigned int end, int(*compar)(const hb_glyph_info_t *, const hb_glyph_info_t *));

  inline bool messaging (void) { return unlikely (message_func); }

  inline bool message (hb_font_t *font, const char *fmt, ...) HB_PRINTF_FUNC(3, 4)

  {

    if (!messaging ())

      return true;

    va_list ap;

    va_start (ap, fmt);

    bool ret = message_impl (font, fmt, ap);

    va_end (ap);

    return ret;

  }

  HB_INTERNAL bool message_impl (hb_font_t *font, const char *fmt, va_list ap) HB_PRINTF_FUNC(3, 0);

};

#define HB_BUFFER_XALLOCATE_VAR(b, func, var) \

  b->func (offsetof (hb_glyph_info_t, var) - offsetof(hb_glyph_info_t, var1), \

           sizeof (b->info[0].var))

#define HB_BUFFER_ALLOCATE_VAR(b, var)          HB_BUFFER_XALLOCATE_VAR (b, allocate_var,   var ())

#define HB_BUFFER_DEALLOCATE_VAR(b, var)        HB_BUFFER_XALLOCATE_VAR (b, deallocate_var, var ())

#define HB_BUFFER_ASSERT_VAR(b, var)            HB_BUFFER_XALLOCATE_VAR (b, assert_var,     var ())

#endif /* HB_BUFFER_PRIVATE_HH */