Imported Upstream version 2.4.0
[platform/upstream/harfbuzz.git] / src / hb-subset-glyf.cc
index cca364d..ee004ee 100644 (file)
 #include "hb-set.h"
 #include "hb-subset-glyf.hh"
 
+struct loca_data_t
+{
+  bool          is_short;
+  void         *data;
+  unsigned int  size;
+
+  inline bool
+  _write_loca_entry (unsigned int  id,
+                     unsigned int  offset)
+  {
+    unsigned int entry_size = is_short ? sizeof (OT::HBUINT16) : sizeof (OT::HBUINT32);
+    if ((id + 1) * entry_size <= size)
+    {
+      if (is_short) {
+        ((OT::HBUINT16*) data) [id].set (offset / 2);
+      } else {
+        ((OT::HBUINT32*) data) [id].set (offset);
+      }
+      return true;
+    }
+
+    // Offset was not written because the write is out of bounds.
+    DEBUG_MSG(SUBSET,
+              nullptr,
+              "WARNING: Attempted to write an out of bounds loca entry at index %d. Loca size is %d.",
+              id,
+              size);
+    return false;
+  }
+};
+
+/**
+ * If hints are being dropped find the range which in glyf at which
+ * the hinting instructions are located. Add them to the instruction_ranges
+ * vector.
+ */
 static bool
-_calculate_glyf_and_loca_prime_size (const OT::glyf::accelerator_t &glyf,
-                                    hb_vector_t<hb_codepoint_t> &glyph_ids,
-                                    hb_bool_t drop_hints,
-                                    bool *use_short_loca /* OUT */,
-                                    unsigned int *glyf_size /* OUT */,
-                                    unsigned int *loca_size /* OUT */,
-                                    hb_vector_t<unsigned int> *instruction_ranges /* OUT */)
+_add_instructions_range (const OT::glyf::accelerator_t &glyf,
+                         hb_codepoint_t                 glyph_id,
+                         unsigned int                   glyph_start_offset,
+                         unsigned int                   glyph_end_offset,
+                         bool                           drop_hints,
+                         hb_vector_t<unsigned int>     *instruction_ranges /* OUT */)
 {
-  unsigned int total = 0;
-  for (unsigned int i = 0; i < glyph_ids.length; i++)
+  if (!instruction_ranges->resize (instruction_ranges->length + 2))
   {
-    hb_codepoint_t next_glyph = glyph_ids[i];
-    if (!instruction_ranges->resize (instruction_ranges->length + 2))
+    DEBUG_MSG(SUBSET, nullptr, "Failed to resize instruction_ranges.");
+    return false;
+  }
+  unsigned int *instruction_start = &(*instruction_ranges)[instruction_ranges->length - 2];
+  *instruction_start = 0;
+  unsigned int *instruction_end = &(*instruction_ranges)[instruction_ranges->length - 1];
+  *instruction_end = 0;
+
+  if (drop_hints)
+  {
+    if (unlikely (!glyf.get_instruction_offsets (glyph_start_offset, glyph_end_offset,
+                                                 instruction_start, instruction_end)))
     {
-      DEBUG_MSG(SUBSET, nullptr, "Failed to resize instruction_ranges.");
+      DEBUG_MSG(SUBSET, nullptr, "Unable to get instruction offsets for %d", glyph_id);
       return false;
     }
-    unsigned int *instruction_start = &(*instruction_ranges)[instruction_ranges->length - 2];
-    *instruction_start = 0;
-    unsigned int *instruction_end = &(*instruction_ranges)[instruction_ranges->length - 1];
-    *instruction_end = 0;
+  }
+
+  return true;
+}
 
+static bool
+_calculate_glyf_and_loca_prime_size (const OT::glyf::accelerator_t &glyf,
+                                     const hb_subset_plan_t        *plan,
+                                     loca_data_t                   *loca_data, /* OUT */
+                                    unsigned int                  *glyf_size /* OUT */,
+                                    hb_vector_t<unsigned int>     *instruction_ranges /* OUT */)
+{
+  unsigned int total = 0;
+
+  hb_codepoint_t next_glyph = HB_SET_VALUE_INVALID;
+  while (plan->glyphset ()->next (&next_glyph))
+  {
     unsigned int start_offset, end_offset;
     if (unlikely (!(glyf.get_offsets (next_glyph, &start_offset, &end_offset) &&
                    glyf.remove_padding (start_offset, &end_offset))))
     {
       DEBUG_MSG(SUBSET, nullptr, "Invalid gid %d", next_glyph);
-      continue;
+      start_offset = end_offset = 0;
     }
-    if (end_offset - start_offset < OT::glyf::GlyphHeader::static_size)
-      continue; /* 0-length glyph */
 
-    if (drop_hints)
-    {
-      if (unlikely (!glyf.get_instruction_offsets (start_offset, end_offset,
-                                                  instruction_start, instruction_end)))
-      {
-       DEBUG_MSG(SUBSET, nullptr, "Unable to get instruction offsets for %d", next_glyph);
-       return false;
-      }
-    }
+    bool is_zero_length = end_offset - start_offset < OT::glyf::GlyphHeader::static_size;
+    if (!_add_instructions_range (glyf,
+                                  next_glyph,
+                                  start_offset,
+                                  end_offset,
+                                  plan->drop_hints && !is_zero_length,
+                                  instruction_ranges))
+      return false;
 
-    total += end_offset - start_offset - (*instruction_end - *instruction_start);
+    if (is_zero_length)
+      continue; /* 0-length glyph */
+
+    total += end_offset - start_offset
+             - ((*instruction_ranges)[instruction_ranges->length - 1]
+                - (*instruction_ranges)[instruction_ranges->length - 2]);
     /* round2 so short loca will work */
     total += total % 2;
   }
 
   *glyf_size = total;
-  *use_short_loca = (total <= 131070);
-  *loca_size = (glyph_ids.length + 1)
-      * (*use_short_loca ? sizeof (OT::HBUINT16) : sizeof (OT::HBUINT32));
+  loca_data->is_short = (total <= 131070);
+  loca_data->size = (plan->num_output_glyphs () + 1)
+      * (loca_data->is_short ? sizeof (OT::HBUINT16) : sizeof (OT::HBUINT32));
 
   DEBUG_MSG(SUBSET, nullptr, "preparing to subset glyf: final size %d, loca size %d, using %s loca",
            total,
-           *loca_size,
-           *use_short_loca ? "short" : "long");
+           loca_data->size,
+           loca_data->is_short ? "short" : "long");
   return true;
 }
 
-static bool
-_write_loca_entry (unsigned int  id,
-                  unsigned int  offset,
-                  bool          is_short,
-                  void         *loca_prime,
-                  unsigned int  loca_size)
-{
-  unsigned int entry_size = is_short ? sizeof (OT::HBUINT16) : sizeof (OT::HBUINT32);
-  if ((id + 1) * entry_size <= loca_size)
-  {
-    if (is_short) {
-      ((OT::HBUINT16*) loca_prime) [id].set (offset / 2);
-    } else {
-      ((OT::HBUINT32*) loca_prime) [id].set (offset);
-    }
-    return true;
-  }
-
-  // Offset was not written because the write is out of bounds.
-  DEBUG_MSG(SUBSET,
-           nullptr,
-           "WARNING: Attempted to write an out of bounds loca entry at index %d. Loca size is %d.",
-           id,
-           loca_size);
-  return false;
-}
-
 static void
-_update_components (hb_subset_plan_t * plan,
-                   char glyph_start,
-                   unsigned int length)
+_update_components (const hb_subset_plan_t *plan,
+                   char                   *glyph_start,
+                   unsigned int            length)
 {
   OT::glyf::CompositeGlyphHeader::Iterator iterator;
   if (OT::glyf::CompositeGlyphHeader::get_iterator (glyph_start,
@@ -153,24 +184,35 @@ static bool _remove_composite_instruction_flag (char *glyf_prime, unsigned int l
 }
 
 static bool
-_write_glyf_and_loca_prime (hb_subset_plan_t              *plan,
+_write_glyf_and_loca_prime (const hb_subset_plan_t        *plan,
                            const OT::glyf::accelerator_t &glyf,
                            const char                    *glyf_data,
-                           bool                           use_short_loca,
-                           hb_vector_t<unsigned int> &instruction_ranges,
+                           hb_vector_t<unsigned int>     &instruction_ranges,
                            unsigned int                   glyf_prime_size,
                            char                          *glyf_prime_data /* OUT */,
-                           unsigned int                   loca_prime_size,
-                           char                          *loca_prime_data /* OUT */)
+                           loca_data_t                   *loca_prime /* OUT */)
 {
-  hb_vector_t<hb_codepoint_t> &glyph_ids = plan->glyphs;
   char *glyf_prime_data_next = glyf_prime_data;
 
   bool success = true;
-  for (unsigned int i = 0; i < glyph_ids.length; i++)
+
+
+  unsigned int i = 0;
+  hb_codepoint_t new_gid;
+  for (new_gid = 0; new_gid < plan->num_output_glyphs (); new_gid++)
   {
+    hb_codepoint_t old_gid;
+    if (!plan->old_gid_for_new_gid (new_gid, &old_gid))
+    {
+      // Empty glyph, add a loca entry and carry on.
+      loca_prime->_write_loca_entry (new_gid,
+                                     glyf_prime_data_next - glyf_prime_data);
+      continue;
+    }
+
+
     unsigned int start_offset, end_offset;
-    if (unlikely (!(glyf.get_offsets (glyph_ids[i], &start_offset, &end_offset) &&
+    if (unlikely (!(glyf.get_offsets (old_gid, &start_offset, &end_offset) &&
                    glyf.remove_padding (start_offset, &end_offset))))
       end_offset = start_offset = 0;
 
@@ -182,9 +224,9 @@ _write_glyf_and_loca_prime (hb_subset_plan_t              *plan,
     if (glyf_prime_data_next + length > glyf_prime_data + glyf_prime_size)
     {
       DEBUG_MSG(SUBSET,
-                nullptr,
-                "WARNING: Attempted to write an out of bounds glyph entry for gid %d (length %d)",
-                i, length);
+                nullptr,
+                "WARNING: Attempted to write an out of bounds glyph entry for gid %d (length %d)",
+                i, length);
       return false;
     }
 
@@ -204,22 +246,20 @@ _write_glyf_and_loca_prime (hb_subset_plan_t              *plan,
        memset (glyf_prime_data_next + instruction_start - start_offset - 2, 0, 2);
     }
 
-    success = success && _write_loca_entry (i,
-                                           glyf_prime_data_next - glyf_prime_data,
-                                           use_short_loca,
-                                           loca_prime_data,
-                                           loca_prime_size);
+    success = success && loca_prime->_write_loca_entry (new_gid,
+                                                        glyf_prime_data_next - glyf_prime_data);
     _update_components (plan, glyf_prime_data_next, length);
 
     // TODO: don't align to two bytes if using long loca.
     glyf_prime_data_next += length + (length % 2); // Align to 2 bytes for short loca.
+
+    i++;
   }
 
-  success = success && _write_loca_entry (glyph_ids.length,
-                                         glyf_prime_data_next - glyf_prime_data,
-                                         use_short_loca,
-                                         loca_prime_data,
-                                         loca_prime_size);
+  // loca table has n+1 entries where the last entry signifies the end location of the last
+  // glyph.
+  success = success && loca_prime->_write_loca_entry (new_gid,
+                                                      glyf_prime_data_next - glyf_prime_data);
   return success;
 }
 
@@ -228,52 +268,48 @@ _hb_subset_glyf_and_loca (const OT::glyf::accelerator_t  &glyf,
                          const char                     *glyf_data,
                          hb_subset_plan_t               *plan,
                          bool                           *use_short_loca,
-                         hb_blob_t                     **glyf_prime /* OUT */,
-                         hb_blob_t                     **loca_prime /* OUT */)
+                         hb_blob_t                     **glyf_prime_blob /* OUT */,
+                         hb_blob_t                     **loca_prime_blob /* OUT */)
 {
   // TODO(grieger): Sanity check allocation size for the new table.
-  hb_vector_t<hb_codepoint_t> &glyphs_to_retain = plan->glyphs;
-
+  loca_data_t loca_prime;
   unsigned int glyf_prime_size;
-  unsigned int loca_prime_size;
   hb_vector_t<unsigned int> instruction_ranges;
   instruction_ranges.init ();
 
   if (unlikely (!_calculate_glyf_and_loca_prime_size (glyf,
-                                                     glyphs_to_retain,
-                                                     plan->drop_hints,
-                                                     use_short_loca,
+                                                      plan,
+                                                      &loca_prime,
                                                      &glyf_prime_size,
-                                                     &loca_prime_size,
                                                      &instruction_ranges))) {
     instruction_ranges.fini ();
     return false;
   }
+  *use_short_loca = loca_prime.is_short;
 
   char *glyf_prime_data = (char *) calloc (1, glyf_prime_size);
-  char *loca_prime_data = (char *) calloc (1, loca_prime_size);
+  loca_prime.data = (void *) calloc (1, loca_prime.size);
   if (unlikely (!_write_glyf_and_loca_prime (plan, glyf, glyf_data,
-                                            *use_short_loca,
                                             instruction_ranges,
                                             glyf_prime_size, glyf_prime_data,
-                                            loca_prime_size, loca_prime_data))) {
+                                            &loca_prime))) {
     free (glyf_prime_data);
-    free (loca_prime_data);
+    free (loca_prime.data);
     instruction_ranges.fini ();
     return false;
   }
   instruction_ranges.fini ();
 
-  *glyf_prime = hb_blob_create (glyf_prime_data,
-                               glyf_prime_size,
-                               HB_MEMORY_MODE_READONLY,
-                               glyf_prime_data,
-                               free);
-  *loca_prime = hb_blob_create (loca_prime_data,
-                               loca_prime_size,
-                               HB_MEMORY_MODE_READONLY,
-                               loca_prime_data,
-                               free);
+  *glyf_prime_blob = hb_blob_create (glyf_prime_data,
+                                     glyf_prime_size,
+                                     HB_MEMORY_MODE_READONLY,
+                                     glyf_prime_data,
+                                     free);
+  *loca_prime_blob = hb_blob_create ((char *) loca_prime.data,
+                                     loca_prime.size,
+                                     HB_MEMORY_MODE_READONLY,
+                                     loca_prime.data,
+                                     free);
   return true;
 }