Path: blob/master/thirdparty/harfbuzz/src/OT/glyf/SimpleGlyph.hh
9913 views
#ifndef OT_GLYF_SIMPLEGLYPH_HH
#define OT_GLYF_SIMPLEGLYPH_HH
#include "../../hb-open-type.hh"
namespace OT {
namespace glyf_impl {
struct SimpleGlyph
{
enum simple_glyph_flag_t
{
FLAG_ON_CURVE = 0x01,
FLAG_X_SHORT = 0x02,
FLAG_Y_SHORT = 0x04,
FLAG_REPEAT = 0x08,
FLAG_X_SAME = 0x10,
FLAG_Y_SAME = 0x20,
FLAG_OVERLAP_SIMPLE = 0x40,
FLAG_CUBIC = 0x80
};
const GlyphHeader &header;
hb_bytes_t bytes;
SimpleGlyph (const GlyphHeader &header_, hb_bytes_t bytes_) :
header (header_), bytes (bytes_) {}
unsigned int instruction_len_offset () const
{ return GlyphHeader::static_size + 2 * header.numberOfContours; }
unsigned int length (unsigned int instruction_len) const
{ return instruction_len_offset () + 2 + instruction_len; }
bool has_instructions_length () const
{
return instruction_len_offset () + 2 <= bytes.length;
}
unsigned int instructions_length () const
{
unsigned int instruction_length_offset = instruction_len_offset ();
if (unlikely (instruction_length_offset + 2 > bytes.length)) return 0;
const HBUINT16 &instructionLength = StructAtOffset<HBUINT16> (&bytes, instruction_length_offset);
/* Out of bounds of the current glyph */
if (unlikely (length (instructionLength) > bytes.length)) return 0;
return instructionLength;
}
const hb_bytes_t trim_padding () const
{
/* based on FontTools _g_l_y_f.py::trim */
const uint8_t *glyph = (uint8_t*) bytes.arrayZ;
const uint8_t *glyph_end = glyph + bytes.length;
/* simple glyph w/contours, possibly trimmable */
glyph += instruction_len_offset ();
if (unlikely (glyph + 2 >= glyph_end)) return hb_bytes_t ();
unsigned int num_coordinates = StructAtOffset<HBUINT16> (glyph - 2, 0) + 1;
unsigned int num_instructions = StructAtOffset<HBUINT16> (glyph, 0);
glyph += 2 + num_instructions;
unsigned int coord_bytes = 0;
unsigned int coords_with_flags = 0;
while (glyph < glyph_end)
{
uint8_t flag = *glyph;
glyph++;
unsigned int repeat = 1;
if (flag & FLAG_REPEAT)
{
if (unlikely (glyph >= glyph_end)) return hb_bytes_t ();
repeat = *glyph + 1;
glyph++;
}
unsigned int xBytes, yBytes;
xBytes = yBytes = 0;
if (flag & FLAG_X_SHORT) xBytes = 1;
else if ((flag & FLAG_X_SAME) == 0) xBytes = 2;
if (flag & FLAG_Y_SHORT) yBytes = 1;
else if ((flag & FLAG_Y_SAME) == 0) yBytes = 2;
coord_bytes += (xBytes + yBytes) * repeat;
coords_with_flags += repeat;
if (coords_with_flags >= num_coordinates) break;
}
if (unlikely (coords_with_flags != num_coordinates)) return hb_bytes_t ();
return bytes.sub_array (0, bytes.length + coord_bytes - (glyph_end - glyph));
}
/* zero instruction length */
void drop_hints ()
{
if (!has_instructions_length ()) return;
GlyphHeader &glyph_header = const_cast<GlyphHeader &> (header);
(HBUINT16 &) StructAtOffset<HBUINT16> (&glyph_header, instruction_len_offset ()) = 0;
}
void drop_hints_bytes (hb_bytes_t &dest_start, hb_bytes_t &dest_end) const
{
unsigned int instructions_len = instructions_length ();
unsigned int glyph_length = length (instructions_len);
dest_start = bytes.sub_array (0, glyph_length - instructions_len);
dest_end = bytes.sub_array (glyph_length, bytes.length - glyph_length);
}
void set_overlaps_flag ()
{
if (unlikely (!header.numberOfContours)) return;
unsigned flags_offset = length (instructions_length ());
if (unlikely (flags_offset + 1 > bytes.length)) return;
HBUINT8 &first_flag = (HBUINT8 &) StructAtOffset<HBUINT16> (&bytes, flags_offset);
first_flag = (uint8_t) first_flag | FLAG_OVERLAP_SIMPLE;
}
static bool read_flags (const HBUINT8 *&p /* IN/OUT */,
hb_array_t<contour_point_t> points_ /* IN/OUT */,
const HBUINT8 *end)
{
auto *points = points_.arrayZ;
unsigned count = points_.length;
for (unsigned int i = 0; i < count;)
{
if (unlikely (p + 1 > end)) return false;
uint8_t flag = *p++;
points[i++].flag = flag;
if (flag & FLAG_REPEAT)
{
if (unlikely (p + 1 > end)) return false;
unsigned int repeat_count = *p++;
unsigned stop = hb_min (i + repeat_count, count);
for (; i < stop; i++)
points[i].flag = flag;
}
}
return true;
}
static bool read_points (const HBUINT8 *&p /* IN/OUT */,
hb_array_t<contour_point_t> points_ /* IN/OUT */,
const HBUINT8 *end,
float contour_point_t::*m,
const simple_glyph_flag_t short_flag,
const simple_glyph_flag_t same_flag)
{
int v = 0;
for (auto &point : points_)
{
unsigned flag = point.flag;
if (flag & short_flag)
{
if (unlikely (p + 1 > end)) return false;
v += (bool(flag & same_flag) * 2 - 1) * *p++;
}
else
{
if (!(flag & same_flag))
{
if (unlikely (p + HBINT16::static_size > end)) return false;
v += *(const HBINT16 *) p;
p += HBINT16::static_size;
}
}
point.*m = v;
}
return true;
}
bool get_contour_points (contour_point_vector_t &points /* OUT */,
bool phantom_only = false) const
{
const HBUINT16 *endPtsOfContours = &StructAfter<HBUINT16> (header);
int num_contours = header.numberOfContours;
assert (num_contours > 0);
/* One extra item at the end, for the instruction-count below. */
if (unlikely (!bytes.check_range (&endPtsOfContours[num_contours]))) return false;
unsigned int num_points = endPtsOfContours[num_contours - 1] + 1;
unsigned old_length = points.length;
points.alloc (points.length + num_points + 4); // Allocate for phantom points, to avoid a possible copy
if (unlikely (!points.resize (points.length + num_points, false))) return false;
auto points_ = points.as_array ().sub_array (old_length);
if (!phantom_only)
hb_memset (points_.arrayZ, 0, sizeof (contour_point_t) * num_points);
if (phantom_only) return true;
for (int i = 0; i < num_contours; i++)
points_[endPtsOfContours[i]].is_end_point = true;
/* Skip instructions */
const HBUINT8 *p = &StructAtOffset<HBUINT8> (&endPtsOfContours[num_contours + 1],
endPtsOfContours[num_contours]);
if (unlikely ((const char *) p < bytes.arrayZ)) return false; /* Unlikely overflow */
const HBUINT8 *end = (const HBUINT8 *) (bytes.arrayZ + bytes.length);
if (unlikely (p >= end)) return false;
/* Read x & y coordinates */
return read_flags (p, points_, end)
&& read_points (p, points_, end, &contour_point_t::x,
FLAG_X_SHORT, FLAG_X_SAME)
&& read_points (p, points_, end, &contour_point_t::y,
FLAG_Y_SHORT, FLAG_Y_SAME);
}
static void encode_coord (int value,
unsigned &flag,
const simple_glyph_flag_t short_flag,
const simple_glyph_flag_t same_flag,
hb_vector_t<uint8_t> &coords /* OUT */)
{
if (value == 0)
{
flag |= same_flag;
}
else if (value >= -255 && value <= 255)
{
flag |= short_flag;
if (value > 0) flag |= same_flag;
else value = -value;
coords.arrayZ[coords.length++] = (uint8_t) value;
}
else
{
int16_t val = value;
coords.arrayZ[coords.length++] = val >> 8;
coords.arrayZ[coords.length++] = val & 0xff;
}
}
static void encode_flag (unsigned flag,
unsigned &repeat,
unsigned lastflag,
hb_vector_t<uint8_t> &flags /* OUT */)
{
if (flag == lastflag && repeat != 255)
{
repeat++;
if (repeat == 1)
{
/* We know there's room. */
flags.arrayZ[flags.length++] = flag;
}
else
{
unsigned len = flags.length;
flags.arrayZ[len-2] = flag | FLAG_REPEAT;
flags.arrayZ[len-1] = repeat;
}
}
else
{
repeat = 0;
flags.arrayZ[flags.length++] = flag;
}
}
bool compile_bytes_with_deltas (const contour_point_vector_t &all_points,
bool no_hinting,
hb_bytes_t &dest_bytes /* OUT */)
{
if (header.numberOfContours == 0 || all_points.length <= 4)
{
dest_bytes = hb_bytes_t ();
return true;
}
unsigned num_points = all_points.length - 4;
hb_vector_t<uint8_t> flags, x_coords, y_coords;
if (unlikely (!flags.alloc_exact (num_points))) return false;
if (unlikely (!x_coords.alloc_exact (2*num_points))) return false;
if (unlikely (!y_coords.alloc_exact (2*num_points))) return false;
unsigned lastflag = 255, repeat = 0;
int prev_x = 0, prev_y = 0;
for (unsigned i = 0; i < num_points; i++)
{
unsigned flag = all_points.arrayZ[i].flag;
flag &= FLAG_ON_CURVE | FLAG_OVERLAP_SIMPLE | FLAG_CUBIC;
int cur_x = roundf (all_points.arrayZ[i].x);
int cur_y = roundf (all_points.arrayZ[i].y);
encode_coord (cur_x - prev_x, flag, FLAG_X_SHORT, FLAG_X_SAME, x_coords);
encode_coord (cur_y - prev_y, flag, FLAG_Y_SHORT, FLAG_Y_SAME, y_coords);
encode_flag (flag, repeat, lastflag, flags);
prev_x = cur_x;
prev_y = cur_y;
lastflag = flag;
}
unsigned len_before_instrs = 2 * header.numberOfContours + 2;
unsigned len_instrs = instructions_length ();
unsigned total_len = len_before_instrs + flags.length + x_coords.length + y_coords.length;
if (!no_hinting)
total_len += len_instrs;
char *p = (char *) hb_malloc (total_len);
if (unlikely (!p)) return false;
const char *src = bytes.arrayZ + GlyphHeader::static_size;
char *cur = p;
hb_memcpy (p, src, len_before_instrs);
cur += len_before_instrs;
src += len_before_instrs;
if (!no_hinting)
{
hb_memcpy (cur, src, len_instrs);
cur += len_instrs;
}
hb_memcpy (cur, flags.arrayZ, flags.length);
cur += flags.length;
hb_memcpy (cur, x_coords.arrayZ, x_coords.length);
cur += x_coords.length;
hb_memcpy (cur, y_coords.arrayZ, y_coords.length);
dest_bytes = hb_bytes_t (p, total_len);
return true;
}
};
} /* namespace glyf_impl */
} /* namespace OT */
#endif /* OT_GLYF_SIMPLEGLYPH_HH */