harfbuzz/src/harfbuzz-buffer.c

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/*
* Copyright (C) 1998-2004 David Turner and Werner Lemberg
* Copyright (C) 2004,2007 Red Hat, Inc.
*
* This is part of HarfBuzz, an OpenType Layout engine 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
*/
#include "harfbuzz-impl.h"
#include "harfbuzz-buffer-private.h"
#include "harfbuzz-gsub-private.h"
#include "harfbuzz-gpos-private.h"
/* Here is how the buffer works internally:
*
* There are two string pointers: in_string and out_string. They
* always have same allocated size, but different length and positions.
*
* As an optimization, both in_string and out_string may point to the
* same piece of memory, which is owned by in_string. This remains the
* case as long as:
*
* - copy_glyph() is called
* - replace_glyph() is called with inplace=TRUE
* - add_output_glyph() and add_output_glyphs() are not called
*
* In that case swap(), and copy_glyph(), and replace_glyph() are all
* mostly no-op.
*
* As soon an add_output_glyph[s]() or replace_glyph() with inplace=FALSE is
* called, out_string is moved over to an alternate buffer (alt_string), and
* its current contents (out_length entries) are copied to the alt buffer.
* This should all remain transparent to the user. swap() then switches
* in_string and alt_string. alt_string is not allocated until its needed,
* but after that it's grown with in_string unconditionally.
*
* The buffer->separate_out boolean keeps status of whether out_string points
* to in_string (FALSE) or alt_string (TRUE).
*/
/* Internal API */
/*static XXX */ void
hb_buffer_ensure (hb_buffer_t *buffer,
unsigned int size)
{
HB_UInt new_allocated = buffer->allocated;
/* XXX err handling */
if (size > new_allocated)
{
HB_Error error;
while (size > new_allocated)
new_allocated += (new_allocated >> 1) + 8;
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if (buffer->positions)
buffer->positions = realloc (buffer->positions, new_allocated * sizeof (buffer->positions[0]));
buffer->in_string = realloc (buffer->in_string, new_allocated * sizeof (buffer->in_string[0]));
if (buffer->separate_out)
{
buffer->alt_string = realloc (buffer->alt_string, new_allocated * sizeof (buffer->alt_string[0]));
buffer->out_string = buffer->alt_string;
}
else
{
buffer->out_string = buffer->in_string;
if (buffer->alt_string)
{
free (buffer->alt_string);
buffer->alt_string = NULL;
}
}
buffer->allocated = new_allocated;
}
}
static HB_Error
hb_buffer_duplicate_out_buffer (HB_Buffer buffer)
{
if (!buffer->alt_string)
buffer->alt_string = malloc (buffer->allocated * sizeof (buffer->alt_string[0]));
buffer->out_string = buffer->alt_string;
memcpy (buffer->out_string, buffer->in_string, buffer->out_length * sizeof (buffer->out_string[0]));
buffer->separate_out = TRUE;
return HB_Err_Ok;
}
/* Public API */
hb_buffer_t *
hb_buffer_new (void)
{
hb_buffer_t *buffer;
buffer = malloc (sizeof (hb_buffer_t));
if (HB_UNLIKELY (!buffer))
return NULL;
buffer->allocated = 0;
buffer->in_string = NULL;
buffer->alt_string = NULL;
buffer->positions = NULL;
hb_buffer_clear (buffer);
return buffer;
}
void
hb_buffer_free (HB_Buffer buffer)
{
free (buffer->in_string);
free (buffer->alt_string);
free (buffer->positions);
free (buffer);
}
void
hb_buffer_clear (HB_Buffer buffer)
{
buffer->in_length = 0;
buffer->out_length = 0;
buffer->in_pos = 0;
buffer->out_pos = 0;
buffer->out_string = buffer->in_string;
buffer->separate_out = FALSE;
buffer->max_ligID = 0;
}
void
hb_buffer_add_glyph (HB_Buffer buffer,
HB_UInt glyph_index,
HB_UInt properties,
HB_UInt cluster)
{
HB_Error error;
HB_GlyphItem glyph;
hb_buffer_ensure (buffer, buffer->in_length + 1);
glyph = &buffer->in_string[buffer->in_length];
glyph->gindex = glyph_index;
glyph->properties = properties;
glyph->cluster = cluster;
glyph->component = 0;
glyph->ligID = 0;
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glyph->gproperty = HB_GLYPH_PROPERTY_UNKNOWN;
buffer->in_length++;
}
/* HarfBuzz-Internal API */
HB_INTERNAL void
_hb_buffer_clear_output (HB_Buffer buffer)
{
buffer->out_length = 0;
buffer->out_pos = 0;
buffer->out_string = buffer->in_string;
buffer->separate_out = FALSE;
}
HB_INTERNAL HB_Error
_hb_buffer_clear_positions (HB_Buffer buffer)
{
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_hb_buffer_clear_output (buffer);
if (!buffer->positions)
buffer->positions = malloc (buffer->allocated * sizeof (buffer->positions[0]));
memset (buffer->positions, 0, sizeof (buffer->positions[0]) * buffer->in_length);
return HB_Err_Ok;
}
HB_INTERNAL void
_hb_buffer_swap (HB_Buffer buffer)
{
HB_GlyphItem tmp_string;
int tmp_length;
int tmp_pos;
if (buffer->separate_out)
{
tmp_string = buffer->in_string;
buffer->in_string = buffer->out_string;
buffer->out_string = tmp_string;
buffer->alt_string = buffer->out_string;
}
tmp_length = buffer->in_length;
buffer->in_length = buffer->out_length;
buffer->out_length = tmp_length;
tmp_pos = buffer->in_pos;
buffer->in_pos = buffer->out_pos;
buffer->out_pos = tmp_pos;
}
/* The following function copies `num_out' elements from `glyph_data'
to `buffer->out_string', advancing the in array pointer in the structure
by `num_in' elements, and the out array pointer by `num_out' elements.
Finally, it sets the `length' field of `out' equal to
`pos' of the `out' structure.
If `component' is 0xFFFF, the component value from buffer->in_pos
will copied `num_out' times, otherwise `component' itself will
be used to fill the `component' fields.
If `ligID' is 0xFFFF, the ligID value from buffer->in_pos
will copied `num_out' times, otherwise `ligID' itself will
be used to fill the `ligID' fields.
The properties for all replacement glyphs are taken
from the glyph at position `buffer->in_pos'.
The cluster value for the glyph at position buffer->in_pos is used
for all replacement glyphs */
HB_INTERNAL HB_Error
_hb_buffer_add_output_glyphs (HB_Buffer buffer,
HB_UShort num_in,
HB_UShort num_out,
HB_UShort *glyph_data,
HB_UShort component,
HB_UShort ligID)
{
HB_Error error;
HB_UShort i;
HB_UInt properties;
HB_UInt cluster;
hb_buffer_ensure (buffer, buffer->out_pos + num_out);
if (!buffer->separate_out)
{
error = hb_buffer_duplicate_out_buffer (buffer);
if (error)
return error;
}
properties = buffer->in_string[buffer->in_pos].properties;
cluster = buffer->in_string[buffer->in_pos].cluster;
if (component == 0xFFFF)
component = buffer->in_string[buffer->in_pos].component;
if (ligID == 0xFFFF)
ligID = buffer->in_string[buffer->in_pos].ligID;
for (i = 0; i < num_out; i++)
{
HB_GlyphItem item = &buffer->out_string[buffer->out_pos + i];
item->gindex = glyph_data[i];
item->properties = properties;
item->cluster = cluster;
item->component = component;
item->ligID = ligID;
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item->gproperty = HB_GLYPH_PROPERTY_UNKNOWN;
}
buffer->in_pos += num_in;
buffer->out_pos += num_out;
buffer->out_length = buffer->out_pos;
return HB_Err_Ok;
}
HB_INTERNAL HB_Error
_hb_buffer_add_output_glyph (HB_Buffer buffer,
HB_UInt glyph_index,
HB_UShort component,
HB_UShort ligID)
{
HB_UShort glyph_data = glyph_index;
return _hb_buffer_add_output_glyphs (buffer, 1, 1,
&glyph_data, component, ligID);
}
HB_INTERNAL HB_Error
_hb_buffer_next_glyph (HB_Buffer buffer)
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{
HB_Error error;
if (buffer->separate_out)
{
hb_buffer_ensure (buffer, buffer->out_pos + 1);
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buffer->out_string[buffer->out_pos] = buffer->in_string[buffer->in_pos];
}
buffer->in_pos++;
buffer->out_pos++;
buffer->out_length = buffer->out_pos;
return HB_Err_Ok;
}
HB_INTERNAL HB_Error
_hb_buffer_replace_glyph (HB_Buffer buffer,
HB_UInt glyph_index)
{
if (!buffer->separate_out)
{
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buffer->out_string[buffer->out_pos].gindex = glyph_index;
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buffer->in_pos++;
buffer->out_pos++;
buffer->out_length = buffer->out_pos;
}
else
{
return _hb_buffer_add_output_glyph (buffer, glyph_index, 0xFFFF, 0xFFFF);
}
return HB_Err_Ok;
}
HB_INTERNAL HB_UShort
_hb_buffer_allocate_ligid (HB_Buffer buffer)
{
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return ++buffer->max_ligID;
}