Roll HarfBuzz to 0.9.32

third_party/harfbuzz-ng/src/hb-ot-cmap-table.hh

+/*
+ * Copyright © 2014  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.
+ *
+ * Google Author(s): Behdad Esfahbod
+ */
+
+#ifndef HB_OT_CMAP_TABLE_HH
+#define HB_OT_CMAP_TABLE_HH
+
+#include "hb-open-type-private.hh"
+
+
+namespace OT {
+
+
+/*
+ * cmap -- Character To Glyph Index Mapping Table
+ */
+
+#define HB_OT_TAG_cmap HB_TAG('c','m','a','p')
+
+
+struct CmapSubtableFormat0
+{
+  inline bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const
+  {
+    hb_codepoint_t gid = codepoint < 256 ? glyphIdArray[codepoint] : 0;
+    if (!gid)
+      return false;
+    *glyph = gid;
+    return true;
+  }
+
+  inline bool sanitize (hb_sanitize_context_t *c) {
+    TRACE_SANITIZE (this);
+    return TRACE_RETURN (c->check_struct (this));
+  }
+
+  protected:
+  USHORT        format;         /* Format number is set to 0. */
+  USHORT        lengthZ;        /* Byte length of this subtable. */
+  USHORT        languageZ;      /* Ignore. */
+  BYTE          glyphIdArray[256];/* An array that maps character
+                                 * code to glyph index values. */
+  public:
+  DEFINE_SIZE_STATIC (6 + 256);
+};
+
+struct CmapSubtableFormat4
+{
+  inline bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const
+  {
+    unsigned int segCount;
+    const USHORT *endCount;
+    const USHORT *startCount;
+    const USHORT *idDelta;
+    const USHORT *idRangeOffset;
+    const USHORT *glyphIdArray;
+    unsigned int glyphIdArrayLength;
+
+    segCount = this->segCountX2 / 2;
+    endCount = this->values;
+    startCount = endCount + segCount + 1;
+    idDelta = startCount + segCount;
+    idRangeOffset = idDelta + segCount;
+    glyphIdArray = idRangeOffset + segCount;
+    glyphIdArrayLength = (this->length - 16 - 8 * segCount) / 2;
+
+    /* Custom two-array bsearch. */
+    int min = 0, max = (int) segCount - 1;
+    unsigned int i;
+    while (min <= max)
+    {
+      int mid = (min + max) / 2;
+      if (codepoint < startCount[mid])
+        max = mid - 1;
+      else if (codepoint > endCount[mid])
+        min = mid + 1;
+      else
+      {
+        i = mid;
+        goto found;
+      }
+    }
+    return false;
+
+  found:
+    hb_codepoint_t gid;
+    unsigned int rangeOffset = idRangeOffset[i];
+    if (rangeOffset == 0)
+      gid = codepoint + idDelta[i];
+    else
+    {
+      /* Somebody has been smoking... */
+      unsigned int index = rangeOffset / 2 + (codepoint - startCount[i]) + i - segCount;
+      if (unlikely (index >= glyphIdArrayLength))
+        return false;
+      gid = glyphIdArray[index];
+      if (unlikely (!gid))
+        return false;
+      gid += idDelta[i];
+    }
+
+    *glyph = gid & 0xFFFFu;
+    return true;
+  }
+
+  inline bool sanitize (hb_sanitize_context_t *c)
+  {
+    TRACE_SANITIZE (this);
+    if (unlikely (!c->check_struct (this)))
+      return TRACE_RETURN (false);
+
+    if (unlikely (!c->check_range (this, length)))
+    {
+      /* Some broken fonts have too long of a "length" value.
+       * If that is the case, just change the value to truncate
+       * the subtable at the end of the blob. */
+      uint16_t new_length = (uint16_t) MIN ((uintptr_t) 65535,
+                                            (uintptr_t) (c->end -
+                                                         (char *) this));
+      if (!c->try_set (&length, new_length))
+        return TRACE_RETURN (false);
+    }
+
+    return TRACE_RETURN (16 + 4 * (unsigned int) segCountX2 <= length);
+  }
+
+  protected:
+  USHORT        format;         /* Format number is set to 4. */
+  USHORT        length;         /* This is the length in bytes of the
+                                 * subtable. */
+  USHORT        languageZ;      /* Ignore. */
+  USHORT        segCountX2;     /* 2 x segCount. */
+  USHORT        searchRangeZ;   /* 2 * (2**floor(log2(segCount))) */
+  USHORT        entrySelectorZ; /* log2(searchRange/2) */
+  USHORT        rangeShiftZ;    /* 2 x segCount - searchRange */
+
+  USHORT        values[VAR];
+#if 0
+  USHORT        endCount[segCount];     /* End characterCode for each segment,
+                                         * last=0xFFFFu. */
+  USHORT        reservedPad;            /* Set to 0. */
+  USHORT        startCount[segCount];   /* Start character code for each segment. */
+  SHORT         idDelta[segCount];      /* Delta for all character codes in segment. */
+  USHORT        idRangeOffset[segCount];/* Offsets into glyphIdArray or 0 */
+  USHORT        glyphIdArray[VAR];      /* Glyph index array (arbitrary length) */
+#endif
+
+  public:
+  DEFINE_SIZE_ARRAY (14, values);
+};
+
+struct CmapSubtableLongGroup
+{
+  friend struct CmapSubtableFormat12;
+  friend struct CmapSubtableFormat13;
+
+  int cmp (hb_codepoint_t codepoint) const
+  {
+    if (codepoint < startCharCode) return -1;
+    if (codepoint > endCharCode)   return +1;
+    return 0;
+  }
+
+  inline bool sanitize (hb_sanitize_context_t *c) {
+    TRACE_SANITIZE (this);
+    return TRACE_RETURN (c->check_struct (this));
+  }
+
+  private:
+  ULONG         startCharCode;  /* First character code in this group. */
+  ULONG         endCharCode;    /* Last character code in this group. */
+  ULONG         glyphID;        /* Glyph index; interpretation depends on
+                                 * subtable format. */
+  public:
+  DEFINE_SIZE_STATIC (12);
+};
+
+template <typename UINT>
+struct CmapSubtableTrimmed
+{
+  inline bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const
+  {
+    /* Rely on our implicit array bound-checking. */
+    hb_codepoint_t gid = glyphIdArray[codepoint - startCharCode];
+    if (!gid)
+      return false;
+    *glyph = gid;
+    return true;
+  }
+
+  inline bool sanitize (hb_sanitize_context_t *c) {
+    TRACE_SANITIZE (this);
+    return TRACE_RETURN (c->check_struct (this) && glyphIdArray.sanitize (c));
+  }
+
+  protected:
+  UINT          formatReserved; /* Subtable format and (maybe) padding. */
+  UINT          lengthZ;        /* Byte length of this subtable. */
+  UINT          languageZ;      /* Ignore. */
+  UINT          startCharCode;  /* First character code covered. */
+  ArrayOf<GlyphID, UINT>
+                glyphIdArray;   /* Array of glyph index values for character
+                                 * codes in the range. */
+  public:
+  DEFINE_SIZE_ARRAY (5 * sizeof (UINT), glyphIdArray);
+};
+
+struct CmapSubtableFormat6  : CmapSubtableTrimmed<USHORT> {};
+struct CmapSubtableFormat10 : CmapSubtableTrimmed<ULONG > {};
+
+template <typename T>
+struct CmapSubtableLongSegmented
+{
+  inline bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const
+  {
+    int i = groups.bsearch (codepoint);
+    if (i == -1)
+      return false;
+    *glyph = T::group_get_glyph (groups[i], codepoint);
+    return true;
+  }
+
+  inline bool sanitize (hb_sanitize_context_t *c) {
+    TRACE_SANITIZE (this);
+    return TRACE_RETURN (c->check_struct (this) && groups.sanitize (c));
+  }
+
+  protected:
+  USHORT        format;         /* Subtable format; set to 12. */
+  USHORT        reservedZ;      /* Reserved; set to 0. */
+  ULONG         lengthZ;        /* Byte length of this subtable. */
+  ULONG         languageZ;      /* Ignore. */
+  SortedArrayOf<CmapSubtableLongGroup, ULONG>
+                groups;         /* Groupings. */
+  public:
+  DEFINE_SIZE_ARRAY (16, groups);
+};
+
+struct CmapSubtableFormat12 : CmapSubtableLongSegmented<CmapSubtableFormat12>
+{
+  static inline hb_codepoint_t group_get_glyph (const CmapSubtableLongGroup &group,
+                                                hb_codepoint_t u)
+  { return group.glyphID + (u - group.startCharCode); }
+};
+
+struct CmapSubtableFormat13 : CmapSubtableLongSegmented<CmapSubtableFormat13>
+{
+  static inline hb_codepoint_t group_get_glyph (const CmapSubtableLongGroup &group,
+                                                hb_codepoint_t u HB_UNUSED)
+  { return group.glyphID; }
+};
+
+typedef enum
+{
+  GLYPH_VARIANT_NOT_FOUND = 0,
+  GLYPH_VARIANT_FOUND = 1,
+  GLYPH_VARIANT_USE_DEFAULT = 2
+} glyph_variant_t;
+
+struct UnicodeValueRange
+{
+  inline int cmp (const hb_codepoint_t &codepoint) const
+  {
+    if (codepoint < startUnicodeValue) return -1;
+    if (codepoint > startUnicodeValue + additionalCount) return +1;
+    return 0;
+  }
+
+  inline bool sanitize (hb_sanitize_context_t *c) {
+    TRACE_SANITIZE (this);
+    return TRACE_RETURN (c->check_struct (this));
+  }
+
+  UINT24        startUnicodeValue;      /* First value in this range. */
+  BYTE          additionalCount;        /* Number of additional values in this
+                                         * range. */
+  public:
+  DEFINE_SIZE_STATIC (4);
+};
+
+typedef SortedArrayOf<UnicodeValueRange, ULONG> DefaultUVS;
+
+struct UVSMapping
+{
+  inline int cmp (const hb_codepoint_t &codepoint) const
+  {
+    return unicodeValue.cmp (codepoint);
+  }
+
+  inline bool sanitize (hb_sanitize_context_t *c) {
+    TRACE_SANITIZE (this);
+    return TRACE_RETURN (c->check_struct (this));
+  }
+
+  UINT24        unicodeValue;   /* Base Unicode value of the UVS */
+  GlyphID       glyphID;        /* Glyph ID of the UVS */
+  public:
+  DEFINE_SIZE_STATIC (5);
+};
+
+typedef SortedArrayOf<UVSMapping, ULONG> NonDefaultUVS;
+
+struct VariationSelectorRecord
+{
+  inline glyph_variant_t get_glyph (hb_codepoint_t codepoint,
+                                    hb_codepoint_t *glyph,
+                                    const void *base) const
+  {
+    int i;
+    const DefaultUVS &defaults = base+defaultUVS;
+    i = defaults.bsearch (codepoint);
+    if (i != -1)
+      return GLYPH_VARIANT_USE_DEFAULT;
+    const NonDefaultUVS &nonDefaults = base+nonDefaultUVS;
+    i = nonDefaults.bsearch (codepoint);
+    if (i != -1)
+    {
+      *glyph = nonDefaults[i].glyphID;
+       return GLYPH_VARIANT_FOUND;
+    }
+    return GLYPH_VARIANT_NOT_FOUND;
+  }
+
+  inline int cmp (const hb_codepoint_t &variation_selector) const
+  {
+    return varSelector.cmp (variation_selector);
+  }
+
+  inline bool sanitize (hb_sanitize_context_t *c, void *base) {
+    TRACE_SANITIZE (this);
+    return TRACE_RETURN (c->check_struct (this) &&
+                         defaultUVS.sanitize (c, base) &&
+                         nonDefaultUVS.sanitize (c, base));
+  }
+
+  UINT24        varSelector;    /* Variation selector. */
+  OffsetTo<DefaultUVS, ULONG>
+                defaultUVS;     /* Offset to Default UVS Table. May be 0. */
+  OffsetTo<NonDefaultUVS, ULONG>
+                nonDefaultUVS;  /* Offset to Non-Default UVS Table. May be 0. */
+  public:
+  DEFINE_SIZE_STATIC (11);
+};
+
+struct CmapSubtableFormat14
+{
+  inline glyph_variant_t get_glyph_variant (hb_codepoint_t codepoint,
+                                            hb_codepoint_t variation_selector,
+                                            hb_codepoint_t *glyph) const
+  {
+    return record[record.bsearch(variation_selector)].get_glyph (codepoint, glyph, this);
+  }
+
+  inline bool sanitize (hb_sanitize_context_t *c) {
+    TRACE_SANITIZE (this);
+    return TRACE_RETURN (c->check_struct (this) &&
+                         record.sanitize (c, this));
+  }
+
+  protected:
+  USHORT        format;         /* Format number is set to 0. */
+  ULONG         lengthZ;        /* Byte length of this subtable. */
+  SortedArrayOf<VariationSelectorRecord, ULONG>
+                record;         /* Variation selector records; sorted
+                                 * in increasing order of `varSelector'. */
+  public:
+  DEFINE_SIZE_ARRAY (10, record);
+};
+
+struct CmapSubtable
+{
+  /* Note: We intentionally do NOT implement subtable formats 2 and 8. */
+
+  inline bool get_glyph (hb_codepoint_t codepoint,
+                         hb_codepoint_t *glyph) const
+  {
+    switch (u.format) {
+    case  0: return u.format0 .get_glyph(codepoint, glyph);
+    case  4: return u.format4 .get_glyph(codepoint, glyph);
+    case  6: return u.format6 .get_glyph(codepoint, glyph);
+    case 10: return u.format10.get_glyph(codepoint, glyph);
+    case 12: return u.format12.get_glyph(codepoint, glyph);
+    case 13: return u.format13.get_glyph(codepoint, glyph);
+    case 14:
+    default: return false;
+    }
+  }
+
+  inline glyph_variant_t get_glyph_variant (hb_codepoint_t codepoint,
+                                            hb_codepoint_t variation_selector,
+                                            hb_codepoint_t *glyph) const
+  {
+    switch (u.format) {
+    case 14: return u.format14.get_glyph_variant(codepoint, variation_selector, glyph);
+    default: return GLYPH_VARIANT_NOT_FOUND;
+    }
+  }
+
+  inline bool sanitize (hb_sanitize_context_t *c) {
+    TRACE_SANITIZE (this);
+    if (!u.format.sanitize (c)) return TRACE_RETURN (false);
+    switch (u.format) {
+    case  0: return TRACE_RETURN (u.format0 .sanitize (c));
+    case  4: return TRACE_RETURN (u.format4 .sanitize (c));
+    case  6: return TRACE_RETURN (u.format6 .sanitize (c));
+    case 10: return TRACE_RETURN (u.format10.sanitize (c));
+    case 12: return TRACE_RETURN (u.format12.sanitize (c));
+    case 13: return TRACE_RETURN (u.format13.sanitize (c));
+    case 14: return TRACE_RETURN (u.format14.sanitize (c));
+    default:return TRACE_RETURN (true);
+    }
+  }
+
+  protected:
+  union {
+  USHORT                format;         /* Format identifier */
+  CmapSubtableFormat0   format0;
+  CmapSubtableFormat4   format4;
+  CmapSubtableFormat6   format6;
+  CmapSubtableFormat10  format10;
+  CmapSubtableFormat12  format12;
+  CmapSubtableFormat13  format13;
+  CmapSubtableFormat14  format14;
+  } u;
+  public:
+  DEFINE_SIZE_UNION (2, format);
+};
+
+
+struct EncodingRecord
+{
+  inline int cmp (const EncodingRecord &other) const
+  {
+    int ret;
+    ret = platformID.cmp (other.platformID);
+    if (ret) return ret;
+    ret = encodingID.cmp (other.encodingID);
+    if (ret) return ret;
+    return 0;
+  }
+
+  inline bool sanitize (hb_sanitize_context_t *c, void *base) {
+    TRACE_SANITIZE (this);
+    return TRACE_RETURN (c->check_struct (this) &&
+                         subtable.sanitize (c, base));
+  }
+
+  USHORT        platformID;     /* Platform ID. */
+  USHORT        encodingID;     /* Platform-specific encoding ID. */
+  OffsetTo<CmapSubtable, ULONG>
+                subtable;       /* Byte offset from beginning of table to the subtable for this encoding. */
+  public:
+  DEFINE_SIZE_STATIC (8);
+};
+
+struct cmap
+{
+  static const hb_tag_t tableTag        = HB_OT_TAG_cmap;
+
+  inline const CmapSubtable *find_subtable (unsigned int platform_id,
+                                            unsigned int encoding_id) const
+  {
+    EncodingRecord key;
+    key.platformID.set (platform_id);
+    key.encodingID.set (encoding_id);
+
+    /* Note: We can use bsearch, but since it has no performance
+     * implications, we use lsearch and as such accept fonts with
+     * unsorted subtable list. */
+    int result = encodingRecord./*bsearch*/lsearch (key);
+    if (result == -1 || !encodingRecord[result].subtable)
+      return NULL;
+
+    return &(this+encodingRecord[result].subtable);
+  }
+
+  inline bool sanitize (hb_sanitize_context_t *c) {
+    TRACE_SANITIZE (this);
+    return TRACE_RETURN (c->check_struct (this) &&
+                         likely (version == 0) &&
+                         encodingRecord.sanitize (c, this));
+  }
+
+  USHORT                version;        /* Table version number (0). */
+  SortedArrayOf<EncodingRecord>
+                        encodingRecord; /* Encoding tables. */
+  public:
+  DEFINE_SIZE_ARRAY (4, encodingRecord);
+};
+
+
+} /* namespace OT */
+
+
+#endif /* HB_OT_CMAP_TABLE_HH */