harfbuzz/src/harfbuzz-buffer.c

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/* harfbuzz-buffer.c: Buffer of glyphs for substitution/positioning
*
* Copyright 2004,2007 Red Hat Software
*
* Portions Copyright 1996-2000 by
* David Turner, Robert Wilhelm, and Werner Lemberg.
*/
#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 HB_Error
hb_buffer_ensure( HB_Buffer buffer,
HB_UInt size )
{
HB_UInt new_allocated = buffer->allocated;
if (size > new_allocated)
{
HB_Error error;
while (size > new_allocated)
new_allocated += (new_allocated >> 1) + 8;
if ( buffer->positions )
{
if ( REALLOC_ARRAY( buffer->positions, new_allocated, HB_PositionRec ) )
return error;
}
if ( REALLOC_ARRAY( buffer->in_string, new_allocated, HB_GlyphItemRec ) )
return error;
if ( buffer->separate_out )
{
if ( REALLOC_ARRAY( buffer->alt_string, new_allocated, HB_GlyphItemRec ) )
return error;
buffer->out_string = buffer->alt_string;
}
else
{
buffer->out_string = buffer->in_string;
if ( buffer->alt_string )
{
if ( REALLOC_ARRAY( buffer->alt_string, new_allocated, HB_GlyphItemRec ) )
return error;
}
}
buffer->allocated = new_allocated;
}
return HB_Err_Ok;
}
static HB_Error
hb_buffer_duplicate_out_buffer( HB_Buffer buffer )
{
if ( !buffer->alt_string )
{
HB_Error error;
if ( ALLOC_ARRAY( buffer->alt_string, buffer->allocated, HB_GlyphItemRec ) )
return error;
}
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_Error
hb_buffer_new( HB_Buffer *pbuffer )
{
HB_Buffer buffer;
HB_Error error;
if ( ALLOC( buffer, sizeof( HB_BufferRec ) ) )
return error;
buffer->allocated = 0;
buffer->in_string = NULL;
buffer->alt_string = NULL;
buffer->positions = NULL;
hb_buffer_clear( buffer );
*pbuffer = buffer;
return HB_Err_Ok;
}
void
hb_buffer_free( HB_Buffer buffer )
{
FREE( buffer->in_string );
FREE( buffer->alt_string );
buffer->out_string = NULL;
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;
}
HB_Error
hb_buffer_add_glyph( HB_Buffer buffer,
HB_UInt glyph_index,
HB_UInt properties,
HB_UInt cluster )
{
HB_Error error;
HB_GlyphItem glyph;
error = hb_buffer_ensure( buffer, buffer->in_length + 1 );
if ( error )
return error;
glyph = &buffer->in_string[buffer->in_length];
glyph->gindex = glyph_index;
glyph->properties = properties;
glyph->cluster = cluster;
glyph->component = 0;
glyph->ligID = 0;
glyph->gproperties = HB_GLYPH_PROPERTIES_UNKNOWN;
buffer->in_length++;
return HB_Err_Ok;
}
/* 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 )
{
if ( !buffer->positions )
{
HB_Error error;
if ( ALLOC_ARRAY( buffer->positions, buffer->allocated, HB_PositionRec ) )
return error;
}
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;
error = hb_buffer_ensure( buffer, buffer->out_pos + num_out );
if ( error )
return error;
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;
item->gproperties = HB_GLYPH_PROPERTIES_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_copy_output_glyph ( HB_Buffer buffer )
{
HB_Error error;
error = hb_buffer_ensure( buffer, buffer->out_pos + 1 );
if ( error )
return error;
if ( buffer->separate_out )
{
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_output_glyph( HB_Buffer buffer,
HB_UInt glyph_index,
HB_Bool inplace )
{
HB_Error error;
if ( inplace )
{
error = _hb_buffer_copy_output_glyph ( buffer );
if ( error )
return error;
buffer->out_string[buffer->out_pos-1].gindex = glyph_index;
}
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 )
{
buffer->max_ligID++;
if (HB_UNLIKELY (buffer->max_ligID == 0))
buffer->max_ligID++;
return buffer->max_ligID;
}