[subset] Do some refactoring in hb-subset-glyf.cc.

- Extract code out into helper methods in several places.
- Bundle loca address, size and is short into a struct.
This commit is contained in:
Garret Rieger 2019-01-18 15:11:26 -08:00
parent b7f971884e
commit 4b1ac3a2fa
1 changed files with 148 additions and 116 deletions

View File

@ -29,32 +29,103 @@
#include "hb-set.h" #include "hb-set.h"
#include "hb-subset-glyf.hh" #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;
}
inline bool
_add_empty_glyphs_to_loca (hb_codepoint_t from_gid,
hb_codepoint_t to_gid,
unsigned int offset)
{
bool success = true;
while (from_gid < to_gid)
{
success = success && _write_loca_entry (from_gid,
offset);
from_gid++;
}
return success;
}
};
/**
* 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
_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 */)
{
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, "Unable to get instruction offsets for %d", glyph_id);
return false;
}
}
return true;
}
static bool static bool
_calculate_glyf_and_loca_prime_size (const OT::glyf::accelerator_t &glyf, _calculate_glyf_and_loca_prime_size (const OT::glyf::accelerator_t &glyf,
hb_vector_t<hb_codepoint_t> &glyph_ids, const hb_subset_plan_t *plan,
const hb_map_t *glyph_map, loca_data_t *loca_data, /* OUT */
hb_bool_t drop_hints, unsigned int *glyf_size /* OUT */,
bool *use_short_loca /* OUT */, hb_vector_t<unsigned int> *instruction_ranges /* OUT */)
unsigned int *glyf_size /* OUT */,
unsigned int *loca_size /* OUT */,
hb_vector_t<unsigned int> *instruction_ranges /* OUT */)
{ {
unsigned int total = 0; unsigned int total = 0;
hb_codepoint_t max_new_gid = 0; hb_codepoint_t max_new_gid = 0;
for (unsigned int i = 0; i < glyph_ids.length; i++) for (unsigned int i = 0; i < plan->glyphs.length; i++)
{ {
hb_codepoint_t next_glyph = glyph_ids[i]; hb_codepoint_t next_glyph = plan->glyphs[i];
hb_codepoint_t next_glyph_new_gid = glyph_map->get (next_glyph); hb_codepoint_t new_gid_for_next_glyph;
max_new_gid = MAX (max_new_gid, next_glyph_new_gid); if (plan->new_gid_for_old_gid (next_glyph, &new_gid_for_next_glyph))
if (!instruction_ranges->resize (instruction_ranges->length + 2)) max_new_gid = MAX (max_new_gid, new_gid_for_next_glyph);
{
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;
unsigned int start_offset, end_offset; unsigned int start_offset, end_offset;
if (unlikely (!(glyf.get_offsets (next_glyph, &start_offset, &end_offset) && if (unlikely (!(glyf.get_offsets (next_glyph, &start_offset, &end_offset) &&
@ -63,63 +134,38 @@ _calculate_glyf_and_loca_prime_size (const OT::glyf::accelerator_t &glyf,
DEBUG_MSG(SUBSET, nullptr, "Invalid gid %d", next_glyph); DEBUG_MSG(SUBSET, nullptr, "Invalid gid %d", next_glyph);
continue; continue;
} }
if (end_offset - start_offset < OT::glyf::GlyphHeader::static_size)
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;
if (is_zero_length)
continue; /* 0-length glyph */ continue; /* 0-length glyph */
if (drop_hints) total += end_offset - start_offset
{ - ((*instruction_ranges)[instruction_ranges->length - 1]
if (unlikely (!glyf.get_instruction_offsets (start_offset, end_offset, - (*instruction_ranges)[instruction_ranges->length - 2]);
instruction_start, instruction_end)))
{
DEBUG_MSG(SUBSET, nullptr, "Unable to get instruction offsets for %d", next_glyph);
return false;
}
}
total += end_offset - start_offset - (*instruction_end - *instruction_start);
/* round2 so short loca will work */ /* round2 so short loca will work */
total += total % 2; total += total % 2;
} }
*glyf_size = total; *glyf_size = total;
*use_short_loca = (total <= 131070); loca_data->is_short = (total <= 131070);
*loca_size = (max_new_gid + 2) loca_data->size = (max_new_gid + 2)
* (*use_short_loca ? sizeof (OT::HBUINT16) : sizeof (OT::HBUINT32)); * (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", DEBUG_MSG(SUBSET, nullptr, "preparing to subset glyf: final size %d, loca size %d, using %s loca",
total, total,
*loca_size, loca_data->size,
*use_short_loca ? "short" : "long"); loca_data->is_short ? "short" : "long");
return true; 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 static void
_update_components (const hb_subset_plan_t *plan, _update_components (const hb_subset_plan_t *plan,
char *glyph_start, char *glyph_start,
@ -160,33 +206,28 @@ static bool
_write_glyf_and_loca_prime (const hb_subset_plan_t *plan, _write_glyf_and_loca_prime (const hb_subset_plan_t *plan,
const OT::glyf::accelerator_t &glyf, const OT::glyf::accelerator_t &glyf,
const char *glyf_data, 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, unsigned int glyf_prime_size,
char *glyf_prime_data /* OUT */, char *glyf_prime_data /* OUT */,
unsigned int loca_prime_size, loca_data_t *loca_prime /* OUT */)
char *loca_prime_data /* OUT */)
{ {
const hb_vector_t<hb_codepoint_t> &glyph_ids = plan->glyphs; const hb_vector_t<hb_codepoint_t> &glyph_ids = plan->glyphs;
const hb_map_t *glyph_map = plan->glyph_map;
char *glyf_prime_data_next = glyf_prime_data; char *glyf_prime_data_next = glyf_prime_data;
bool success = true; bool success = true;
hb_codepoint_t gid = 0; unsigned int current_gid = 0;
for (unsigned int i = 0; i < glyph_ids.length; i++) for (unsigned int i = 0; i < glyph_ids.length; i++)
{ {
while (gid < glyph_map->get (glyph_ids[i])) hb_codepoint_t next_gid = current_gid;
{ success = success && plan->new_gid_for_old_gid (glyph_ids[i], &next_gid);
// If we are retaining existing gids then there will potentially be gaps
// in the loca table between glyphs. Fill in this gap with glyphs that have // If we are retaining existing gids then there will potentially be gaps
// no outlines. // in the loca table between glyphs. Fill in this gap with glyphs that have
success = success && _write_loca_entry (gid, // no outlines.
glyf_prime_data_next - glyf_prime_data, success = success && loca_prime->_add_empty_glyphs_to_loca (current_gid,
use_short_loca, next_gid,
loca_prime_data, glyf_prime_data_next - glyf_prime_data);
loca_prime_size); current_gid = next_gid;
gid++;
}
unsigned int start_offset, end_offset; unsigned int start_offset, end_offset;
if (unlikely (!(glyf.get_offsets (glyph_ids[i], &start_offset, &end_offset) && if (unlikely (!(glyf.get_offsets (glyph_ids[i], &start_offset, &end_offset) &&
@ -223,23 +264,19 @@ _write_glyf_and_loca_prime (const hb_subset_plan_t *plan,
memset (glyf_prime_data_next + instruction_start - start_offset - 2, 0, 2); memset (glyf_prime_data_next + instruction_start - start_offset - 2, 0, 2);
} }
success = success && _write_loca_entry (gid, success = success && loca_prime->_write_loca_entry (current_gid,
glyf_prime_data_next - glyf_prime_data, glyf_prime_data_next - glyf_prime_data);
use_short_loca,
loca_prime_data,
loca_prime_size);
_update_components (plan, glyf_prime_data_next, length); _update_components (plan, glyf_prime_data_next, length);
// TODO: don't align to two bytes if using long loca. // 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. glyf_prime_data_next += length + (length % 2); // Align to 2 bytes for short loca.
gid++; current_gid++;
} }
success = success && _write_loca_entry (gid, // loca table has n+1 entries where the last entry signifies the end location of the last
glyf_prime_data_next - glyf_prime_data, // glyph.
use_short_loca, success = success && loca_prime->_write_loca_entry (current_gid,
loca_prime_data, glyf_prime_data_next - glyf_prime_data);
loca_prime_size);
return success; return success;
} }
@ -248,53 +285,48 @@ _hb_subset_glyf_and_loca (const OT::glyf::accelerator_t &glyf,
const char *glyf_data, const char *glyf_data,
hb_subset_plan_t *plan, hb_subset_plan_t *plan,
bool *use_short_loca, bool *use_short_loca,
hb_blob_t **glyf_prime /* OUT */, hb_blob_t **glyf_prime_blob /* OUT */,
hb_blob_t **loca_prime /* OUT */) hb_blob_t **loca_prime_blob /* OUT */)
{ {
// TODO(grieger): Sanity check allocation size for the new table. // 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 glyf_prime_size;
unsigned int loca_prime_size;
hb_vector_t<unsigned int> instruction_ranges; hb_vector_t<unsigned int> instruction_ranges;
instruction_ranges.init (); instruction_ranges.init ();
if (unlikely (!_calculate_glyf_and_loca_prime_size (glyf, if (unlikely (!_calculate_glyf_and_loca_prime_size (glyf,
glyphs_to_retain, plan,
plan->glyph_map, &loca_prime,
plan->drop_hints,
use_short_loca,
&glyf_prime_size, &glyf_prime_size,
&loca_prime_size,
&instruction_ranges))) { &instruction_ranges))) {
instruction_ranges.fini (); instruction_ranges.fini ();
return false; return false;
} }
*use_short_loca = loca_prime.is_short;
char *glyf_prime_data = (char *) calloc (1, glyf_prime_size); 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, if (unlikely (!_write_glyf_and_loca_prime (plan, glyf, glyf_data,
*use_short_loca,
instruction_ranges, instruction_ranges,
glyf_prime_size, glyf_prime_data, glyf_prime_size, glyf_prime_data,
loca_prime_size, loca_prime_data))) { &loca_prime))) {
free (glyf_prime_data); free (glyf_prime_data);
free (loca_prime_data); free (loca_prime.data);
instruction_ranges.fini (); instruction_ranges.fini ();
return false; return false;
} }
instruction_ranges.fini (); instruction_ranges.fini ();
*glyf_prime = hb_blob_create (glyf_prime_data, *glyf_prime_blob = hb_blob_create (glyf_prime_data,
glyf_prime_size, glyf_prime_size,
HB_MEMORY_MODE_READONLY, HB_MEMORY_MODE_READONLY,
glyf_prime_data, glyf_prime_data,
free); free);
*loca_prime = hb_blob_create (loca_prime_data, *loca_prime_blob = hb_blob_create ((char *) loca_prime.data,
loca_prime_size, loca_prime.size,
HB_MEMORY_MODE_READONLY, HB_MEMORY_MODE_READONLY,
loca_prime_data, loca_prime.data,
free); free);
return true; return true;
} }