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/* Pango
* pango-coverage.c: Coverage maps for fonts
*
* Copyright (C) 2000 Red Hat Software
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:coverage-maps
* @short_description:Unicode character range coverage storage
* @title:Coverage Maps
*
* It is often necessary in Pango to determine if a particular font can
* represent a particular character, and also how well it can represent
* that character. The #PangoCoverage is a data structure that is used
* to represent that information.
*/
#include "config.h"
#include <string.h>
#include "pango-coverage.h"
typedef struct _PangoBlockInfo PangoBlockInfo;
#define N_BLOCKS_INCREMENT 256
/* The structure of a PangoCoverage object is a two-level table, with blocks of size 256.
* each block is stored as a packed array of 2 bit values for each index, in LSB order.
*/
struct _PangoBlockInfo
{
guchar *data;
PangoCoverageLevel level; /* Used if data == NULL */
};
struct _PangoCoverage
{
guint ref_count;
int n_blocks;
PangoBlockInfo *blocks;
};
/**
* pango_coverage_new:
*
* Create a new #PangoCoverage
*
* Return value: the newly allocated #PangoCoverage,
* initialized to %PANGO_COVERAGE_NONE
* with a reference count of one, which
* should be freed with pango_coverage_unref().
**/
PangoCoverage *
pango_coverage_new (void)
{
PangoCoverage *coverage = g_slice_new (PangoCoverage);
coverage->n_blocks = N_BLOCKS_INCREMENT;
coverage->blocks = g_new0 (PangoBlockInfo, coverage->n_blocks);
coverage->ref_count = 1;
return coverage;
}
/**
* pango_coverage_copy:
* @coverage: a #PangoCoverage
*
* Copy an existing #PangoCoverage. (This function may now be unnecessary
* since we refcount the structure. File a bug if you use it.)
*
* Return value: (transfer full): the newly allocated #PangoCoverage,
* with a reference count of one, which should be freed
* with pango_coverage_unref().
**/
PangoCoverage *
pango_coverage_copy (PangoCoverage *coverage)
{
int i;
PangoCoverage *result;
g_return_val_if_fail (coverage != NULL, NULL);
result = g_slice_new (PangoCoverage);
result->n_blocks = coverage->n_blocks;
result->blocks = g_new (PangoBlockInfo, coverage->n_blocks);
result->ref_count = 1;
for (i=0; i<coverage->n_blocks; i++)
{
if (coverage->blocks[i].data)
{
result->blocks[i].data = g_new (guchar, 64);
memcpy (result->blocks[i].data, coverage->blocks[i].data, 64);
}
else
result->blocks[i].data = NULL;
result->blocks[i].level = coverage->blocks[i].level;
}
return result;
}
/**
* pango_coverage_ref:
* @coverage: a #PangoCoverage
*
* Increase the reference count on the #PangoCoverage by one
*
* Return value: @coverage
**/
PangoCoverage *
pango_coverage_ref (PangoCoverage *coverage)
{
g_return_val_if_fail (coverage != NULL, NULL);
g_atomic_int_inc ((int *) &coverage->ref_count);
return coverage;
}
/**
* pango_coverage_unref:
* @coverage: a #PangoCoverage
*
* Decrease the reference count on the #PangoCoverage by one.
* If the result is zero, free the coverage and all associated memory.
**/
void
pango_coverage_unref (PangoCoverage *coverage)
{
int i;
g_return_if_fail (coverage != NULL);
g_return_if_fail (coverage->ref_count > 0);
if (g_atomic_int_dec_and_test ((int *) &coverage->ref_count))
{
for (i=0; i<coverage->n_blocks; i++)
g_slice_free1 (64, coverage->blocks[i].data);
g_free (coverage->blocks);
g_slice_free (PangoCoverage, coverage);
}
}
/**
* pango_coverage_get:
* @coverage: a #PangoCoverage
* @index_: the index to check
*
* Determine whether a particular index is covered by @coverage
*
* Return value: the coverage level of @coverage for character @index_.
**/
PangoCoverageLevel
pango_coverage_get (PangoCoverage *coverage,
int index)
{
int block_index;
g_return_val_if_fail (coverage != NULL, PANGO_COVERAGE_NONE);
/* index should really have been defined unsigned. Work around
* it by just returning NONE.
*/
if (G_UNLIKELY (index < 0))
return PANGO_COVERAGE_NONE;
block_index = index / 256;
if (block_index >= coverage->n_blocks)
return PANGO_COVERAGE_NONE;
else
{
guchar *data = coverage->blocks[block_index].data;
if (data)
{
int i = index % 256;
int shift = (i % 4) * 2;
return (data[i/4] >> shift) & 0x3;
}
else
return coverage->blocks[block_index].level;
}
}
/**
* pango_coverage_set:
* @coverage: a #PangoCoverage
* @index_: the index to modify
* @level: the new level for @index_
*
* Modify a particular index within @coverage
**/
void
pango_coverage_set (PangoCoverage *coverage,
int index,
PangoCoverageLevel level)
{
int block_index, i;
guchar *data;
g_return_if_fail (coverage != NULL);
g_return_if_fail (index >= 0);
g_return_if_fail ((guint) level <= 3);
block_index = index / 256;
if (block_index >= coverage->n_blocks)
{
int old_n_blocks = coverage->n_blocks;
coverage->n_blocks =
N_BLOCKS_INCREMENT * ((block_index + N_BLOCKS_INCREMENT) / N_BLOCKS_INCREMENT);
coverage->blocks = g_renew (PangoBlockInfo, coverage->blocks, coverage->n_blocks);
memset (coverage->blocks + old_n_blocks, 0,
sizeof (PangoBlockInfo) * (coverage->n_blocks - old_n_blocks));
}
data = coverage->blocks[block_index].data;
if (!data)
{
guchar byte;
if (level == coverage->blocks[block_index].level)
return;
data = g_slice_alloc (64);
coverage->blocks[block_index].data = data;
byte = coverage->blocks[block_index].level |
(coverage->blocks[block_index].level << 2) |
(coverage->blocks[block_index].level << 4) |
(coverage->blocks[block_index].level << 6);
memset (data, byte, 64);
}
i = index % 256;
data[i/4] |= level << ((i % 4) * 2);
}
/**
* pango_coverage_max:
* @coverage: a #PangoCoverage
* @other: another #PangoCoverage
*
* Set the coverage for each index in @coverage to be the max (better)
* value of the current coverage for the index and the coverage for
* the corresponding index in @other.
**/
void
pango_coverage_max (PangoCoverage *coverage,
PangoCoverage *other)
{
int block_index, i;
int old_blocks;
g_return_if_fail (coverage != NULL);
old_blocks = MIN (coverage->n_blocks, other->n_blocks);
if (other->n_blocks > coverage->n_blocks)
{
coverage->n_blocks = other->n_blocks;
coverage->blocks = g_renew (PangoBlockInfo, coverage->blocks, coverage->n_blocks);
for (block_index = old_blocks; block_index < coverage->n_blocks; block_index++)
{
if (other->blocks[block_index].data)
{
coverage->blocks[block_index].data = g_new (guchar, 64);
memcpy (coverage->blocks[block_index].data, other->blocks[block_index].data, 64);
}
else
coverage->blocks[block_index].data = NULL;
coverage->blocks[block_index].level = other->blocks[block_index].level;
}
}
for (block_index = 0; block_index < old_blocks; block_index++)
{
if (!coverage->blocks[block_index].data && !other->blocks[block_index].data)
{
coverage->blocks[block_index].level = MAX (coverage->blocks[block_index].level, other->blocks[block_index].level);
}
else if (coverage->blocks[block_index].data && other->blocks[block_index].data)
{
guchar *data = coverage->blocks[block_index].data;
for (i=0; i<64; i++)
{
int byte1 = data[i];
int byte2 = other->blocks[block_index].data[i];
/* There are almost certainly some clever logical ops to do this */
data[i] =
MAX (byte1 & 0x3, byte2 & 0x3) |
MAX (byte1 & 0xc, byte2 & 0xc) |
MAX (byte1 & 0x30, byte2 & 0x30) |
MAX (byte1 & 0xc0, byte2 & 0xc0);
}
}
else
{
guchar *src, *dest;
int level, byte2;
if (coverage->blocks[block_index].data)
{
src = dest = coverage->blocks[block_index].data;
level = other->blocks[block_index].level;
}
else
{
src = other->blocks[block_index].data;
dest = g_new (guchar, 64);
coverage->blocks[block_index].data = dest;
level = coverage->blocks[block_index].level;
}
byte2 = level | (level << 2) | (level << 4) | (level << 6);
for (i=0; i<64; i++)
{
int byte1 = src[i];
/* There are almost certainly some clever logical ops to do this */
dest[i] =
MAX (byte1 & 0x3, byte2 & 0x3) |
MAX (byte1 & 0xc, byte2 & 0xc) |
MAX (byte1 & 0x30, byte2 & 0x30) |
MAX (byte1 & 0xc0, byte2 & 0xc0);
}
}
}
}
#define PANGO_COVERAGE_MAGIC 0xc89dbd5e
/**
* pango_coverage_to_bytes:
* @coverage: a #PangoCoverage
* @bytes: (out) (array length=n_bytes) (element-type guint8):
* location to store result (must be freed with g_free())
* @n_bytes: (out): location to store size of result
*
* Convert a #PangoCoverage structure into a flat binary format
**/
void
pango_coverage_to_bytes (PangoCoverage *coverage,
guchar **bytes,
int *n_bytes)
{
int i, j;
int size = 8 + 4 * coverage->n_blocks;
guchar *data;
int offset;
for (i=0; i<coverage->n_blocks; i++)
{
if (coverage->blocks[i].data)
size += 64;
}
data = g_malloc (size);
*(guint32 *)&data[0] = g_htonl (PANGO_COVERAGE_MAGIC); /* Magic */
*(guint32 *)&data[4] = g_htonl (coverage->n_blocks);
offset = 8;
for (i=0; i<coverage->n_blocks; i++)
{
guint32 header_val;
/* Check for solid blocks. This is a sort of random place
* to do the optimization, but we care most about getting
* it right when storing it somewhere persistant.
*/
if (coverage->blocks[i].data != NULL)
{
guchar *data = coverage->blocks[i].data;
guchar first_val = data[0];
if (first_val == 0 || first_val == 0xff)
{
for (j = 1 ; j < 64; j++)
if (data[j] != first_val)
break;
if (j == 64)
{
g_slice_free1 (64, data);
coverage->blocks[i].data = NULL;
coverage->blocks[i].level = first_val & 0x3;
}
}
}
if (coverage->blocks[i].data != NULL)
header_val = (guint32)-1;
else
header_val = coverage->blocks[i].level;
*(guint32 *)&data[offset] = g_htonl (header_val);
offset += 4;
if (coverage->blocks[i].data)
{
memcpy (data + offset, coverage->blocks[i].data, 64);
offset += 64;
}
}
*bytes = data;
*n_bytes = size;
}
static guint32
pango_coverage_get_uint32 (guchar **ptr)
{
guint32 val;
memcpy (&val, *ptr, 4);
*ptr += 4;
return g_ntohl (val);
}
/**
* pango_coverage_from_bytes:
* @bytes: (array length=n_bytes) (element-type guint8): binary data
* representing a #PangoCoverage
* @n_bytes: the size of @bytes in bytes
*
* Convert data generated from pango_coverage_to_bytes() back
* to a #PangoCoverage
*
* Return value: (transfer full) (nullable): a newly allocated
* #PangoCoverage, or %NULL if the data was invalid.
**/
PangoCoverage *
pango_coverage_from_bytes (guchar *bytes,
int n_bytes)
{
PangoCoverage *coverage = g_slice_new0 (PangoCoverage);
guchar *ptr = bytes;
int i;
coverage->ref_count = 1;
if (n_bytes < 8)
goto error;
if (pango_coverage_get_uint32 (&ptr) != PANGO_COVERAGE_MAGIC)
goto error;
coverage->n_blocks = pango_coverage_get_uint32 (&ptr);
coverage->blocks = g_new0 (PangoBlockInfo, coverage->n_blocks);
for (i = 0; i < coverage->n_blocks; i++)
{
guint val;
if (ptr + 4 > bytes + n_bytes)
goto error;
val = pango_coverage_get_uint32 (&ptr);
if (val == (guint32)-1)
{
if (ptr + 64 > bytes + n_bytes)
goto error;
coverage->blocks[i].data = g_new (guchar, 64);
memcpy (coverage->blocks[i].data, ptr, 64);
ptr += 64;
}
else
coverage->blocks[i].level = val;
}
return coverage;
error:
pango_coverage_unref (coverage);
return NULL;
}
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