mutter/cogl/cogl-bitmask.c

/*
 * Cogl
 *
 * An object oriented GL/GLES Abstraction/Utility Layer
 *
 * Copyright (C) 2010 Intel Corporation.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
 *
 *
 *
 * Authors:
 *   Neil Roberts <neil@linux.intel.com>
 */

#include "config.h"

#include <glib.h>
#include <string.h>

#include <test-fixtures/test-unit.h>

#include "cogl-bitmask.h"
#include "cogl-util.h"
#include "cogl-flags.h"

/* This code assumes that we can cast an unsigned long to a pointer
   and back without losing any data */
_COGL_STATIC_ASSERT (sizeof (unsigned long) <= sizeof (void *),
                     "This toolchain breaks Cogl's assumption that it can "
                     "safely cast an unsigned long to a pointer without "
                     "loosing data");

#define ARRAY_INDEX(bit_num) \
  ((bit_num) / (sizeof (unsigned long) * 8))
#define BIT_INDEX(bit_num) \
  ((bit_num) & (sizeof (unsigned long) * 8 - 1))
#define BIT_MASK(bit_num) \
  (1UL << BIT_INDEX (bit_num))

CoglBool
_cogl_bitmask_get_from_array (const CoglBitmask *bitmask,
                              unsigned int bit_num)
{
  GArray *array = (GArray *) *bitmask;

  /* If the index is off the end of the array then assume the bit is
     not set */
  if (bit_num >= sizeof (unsigned long) * 8 * array->len)
    return FALSE;
  else
    return !!(g_array_index (array, unsigned long, ARRAY_INDEX (bit_num)) &
              BIT_MASK (bit_num));
}

static void
_cogl_bitmask_convert_to_array (CoglBitmask *bitmask)
{
  GArray *array;
  /* Fetch the old values */
  unsigned long old_values = _cogl_bitmask_to_bits (bitmask);

  array = g_array_new (FALSE, /* not zero-terminated */
                       TRUE, /* do clear new entries */
                       sizeof (unsigned long));
  /* Copy the old values back in */
  g_array_append_val (array, old_values);

  *bitmask = (struct _CoglBitmaskImaginaryType *) array;
}

void
_cogl_bitmask_set_in_array (CoglBitmask *bitmask,
                            unsigned int bit_num,
                            CoglBool value)
{
  GArray *array;
  unsigned int array_index;
  unsigned long new_value_mask;

  /* If the bitmask is not already an array then we need to allocate one */
  if (!_cogl_bitmask_has_array (bitmask))
    _cogl_bitmask_convert_to_array (bitmask);

  array = (GArray *) *bitmask;

  array_index = ARRAY_INDEX (bit_num);
  /* Grow the array if necessary. This will clear the new data */
  if (array_index >= array->len)
    g_array_set_size (array, array_index + 1);

  new_value_mask = BIT_MASK (bit_num);

  if (value)
    g_array_index (array, unsigned long, array_index) |= new_value_mask;
  else
    g_array_index (array, unsigned long, array_index) &= ~new_value_mask;
}

void
_cogl_bitmask_set_bits (CoglBitmask *dst,
                        const CoglBitmask *src)
{
  if (_cogl_bitmask_has_array (src))
    {
      GArray *src_array, *dst_array;
      int i;

      if (!_cogl_bitmask_has_array (dst))
        _cogl_bitmask_convert_to_array (dst);

      dst_array = (GArray *) *dst;
      src_array = (GArray *) *src;

      if (dst_array->len < src_array->len)
        g_array_set_size (dst_array, src_array->len);

      for (i = 0; i < src_array->len; i++)
        g_array_index (dst_array, unsigned long, i) |=
          g_array_index (src_array, unsigned long, i);
    }
  else if (_cogl_bitmask_has_array (dst))
    {
      GArray *dst_array;

      dst_array = (GArray *) *dst;

      g_array_index (dst_array, unsigned long, 0) |=
        _cogl_bitmask_to_bits (src);
    }
  else
    *dst = _cogl_bitmask_from_bits (_cogl_bitmask_to_bits (dst) |
                                    _cogl_bitmask_to_bits (src));
}

void
_cogl_bitmask_set_range_in_array (CoglBitmask *bitmask,
                                  unsigned int n_bits,
                                  CoglBool value)
{
  GArray *array;
  unsigned int array_index, bit_index;

  if (n_bits == 0)
    return;

  /* If the bitmask is not already an array then we need to allocate one */
  if (!_cogl_bitmask_has_array (bitmask))
    _cogl_bitmask_convert_to_array (bitmask);

  array = (GArray *) *bitmask;

  /* Get the array index of the top most value that will be touched */
  array_index = ARRAY_INDEX (n_bits - 1);
  /* Get the bit index of the top most value */
  bit_index = BIT_INDEX (n_bits - 1);
  /* Grow the array if necessary. This will clear the new data */
  if (array_index >= array->len)
    g_array_set_size (array, array_index + 1);

  if (value)
    {
      /* Set the bits that are touching this index */
      g_array_index (array, unsigned long, array_index) |=
        ~0UL >> (sizeof (unsigned long) * 8 - 1 - bit_index);

      /* Set all of the bits in any lesser indices */
      memset (array->data, 0xff, sizeof (unsigned long) * array_index);
    }
  else
    {
      /* Clear the bits that are touching this index */
      g_array_index (array, unsigned long, array_index) &= ~1UL << bit_index;

      /* Clear all of the bits in any lesser indices */
      memset (array->data, 0x00, sizeof (unsigned long) * array_index);
    }
}

void
_cogl_bitmask_xor_bits (CoglBitmask *dst,
                        const CoglBitmask *src)
{
  if (_cogl_bitmask_has_array (src))
    {
      GArray *src_array, *dst_array;
      int i;

      if (!_cogl_bitmask_has_array (dst))
        _cogl_bitmask_convert_to_array (dst);

      dst_array = (GArray *) *dst;
      src_array = (GArray *) *src;

      if (dst_array->len < src_array->len)
        g_array_set_size (dst_array, src_array->len);

      for (i = 0; i < src_array->len; i++)
        g_array_index (dst_array, unsigned long, i) ^=
          g_array_index (src_array, unsigned long, i);
    }
  else if (_cogl_bitmask_has_array (dst))
    {
      GArray *dst_array;

      dst_array = (GArray *) *dst;

      g_array_index (dst_array, unsigned long, 0) ^=
        _cogl_bitmask_to_bits (src);
    }
  else
    *dst = _cogl_bitmask_from_bits (_cogl_bitmask_to_bits (dst) ^
                                    _cogl_bitmask_to_bits (src));
}

void
_cogl_bitmask_clear_all_in_array (CoglBitmask *bitmask)
{
  GArray *array = (GArray *) *bitmask;

  memset (array->data, 0, sizeof (unsigned long) * array->len);
}

void
_cogl_bitmask_foreach (const CoglBitmask *bitmask,
                       CoglBitmaskForeachFunc func,
                       void *user_data)
{
  if (_cogl_bitmask_has_array (bitmask))
    {
      GArray *array = (GArray *) *bitmask;
      const unsigned long *values = &g_array_index (array, unsigned long, 0);
      int bit_num;

      COGL_FLAGS_FOREACH_START (values, array->len, bit_num)
        {
          if (!func (bit_num, user_data))
            return;
        }
      COGL_FLAGS_FOREACH_END;
    }
  else
    {
      unsigned long mask = _cogl_bitmask_to_bits (bitmask);
      int bit_num;

      COGL_FLAGS_FOREACH_START (&mask, 1, bit_num)
        {
          if (!func (bit_num, user_data))
            return;
        }
      COGL_FLAGS_FOREACH_END;
    }
}

void
_cogl_bitmask_set_flags_array (const CoglBitmask *bitmask,
                               unsigned long *flags)
{
  const GArray *array = (const GArray *) *bitmask;
  int i;

  for (i = 0; i < array->len; i++)
    flags[i] |= g_array_index (array, unsigned long, i);
}

int
_cogl_bitmask_popcount_in_array (const CoglBitmask *bitmask)
{
  const GArray *array = (const GArray *) *bitmask;
  int pop = 0;
  int i;

  for (i = 0; i < array->len; i++)
    pop += _cogl_util_popcountl (g_array_index (array, unsigned long, i));

  return pop;
}

int
_cogl_bitmask_popcount_upto_in_array (const CoglBitmask *bitmask,
                                      int upto)
{
  const GArray *array = (const GArray *) *bitmask;

  if (upto >= array->len * sizeof (unsigned long) * 8)
    return _cogl_bitmask_popcount_in_array (bitmask);
  else
    {
      unsigned long top_mask;
      int array_index = ARRAY_INDEX (upto);
      int bit_index = BIT_INDEX (upto);
      int pop = 0;
      int i;

      for (i = 0; i < array_index; i++)
        pop += _cogl_util_popcountl (g_array_index (array, unsigned long, i));

      top_mask = g_array_index (array, unsigned long, array_index);

      return pop + _cogl_util_popcountl (top_mask & ((1UL << bit_index) - 1));
    }
}

typedef struct
{
  int n_bits;
  int *bits;
} CheckData;

static CoglBool
check_bit (int bit_num, void *user_data)
{
  CheckData *data = user_data;
  int i;

  for (i = 0; i < data->n_bits; i++)
    if (data->bits[i] == bit_num)
      {
        data->bits[i] = -1;
        return TRUE;
      }

  g_assert_not_reached ();

  return TRUE;
}

static void
verify_bits (const CoglBitmask *bitmask,
             ...)
{
  CheckData data;
  va_list ap, ap_copy;
  int i;

  va_start (ap, bitmask);
  G_VA_COPY (ap_copy, ap);

  for (data.n_bits = 0; va_arg (ap, int) != -1; data.n_bits++);

  data.bits = alloca (data.n_bits * (sizeof (int)));

  G_VA_COPY (ap, ap_copy);

  for (i = 0; i < data.n_bits; i++)
    data.bits[i] = va_arg (ap, int);

  _cogl_bitmask_foreach (bitmask, check_bit, &data);

  for (i = 0; i < data.n_bits; i++)
    g_assert_cmpint (data.bits[i], ==, -1);

  g_assert_cmpint (_cogl_bitmask_popcount (bitmask), ==, data.n_bits);

  for (i = 0; i < 1024; i++)
    {
      int upto_popcount = 0;
      int j;

      G_VA_COPY (ap, ap_copy);

      for (j = 0; j < data.n_bits; j++)
        if (va_arg (ap, int) < i)
          upto_popcount++;

      g_assert_cmpint (_cogl_bitmask_popcount_upto (bitmask, i),
                       ==,
                       upto_popcount);

      G_VA_COPY (ap, ap_copy);

      for (j = 0; j < data.n_bits; j++)
        if (va_arg (ap, int) == i)
          break;

      g_assert_cmpint (_cogl_bitmask_get (bitmask, i), ==, (j < data.n_bits));
    }
}

UNIT_TEST (check_bitmask_api,
           0 /* no requirements */,
           0 /* no failure cases */)
{
  CoglBitmask bitmask;
  CoglBitmask other_bitmask;
  /* A dummy bit to make it use arrays sometimes */
  int dummy_bit;
  int i;

  for (dummy_bit = -1; dummy_bit < 256; dummy_bit += 40)
    {
      _cogl_bitmask_init (&bitmask);
      _cogl_bitmask_init (&other_bitmask);

      if (dummy_bit != -1)
        _cogl_bitmask_set (&bitmask, dummy_bit, TRUE);

      verify_bits (&bitmask, dummy_bit, -1);

      _cogl_bitmask_set (&bitmask, 1, TRUE);
      _cogl_bitmask_set (&bitmask, 4, TRUE);
      _cogl_bitmask_set (&bitmask, 5, TRUE);

      verify_bits (&bitmask, 1, 4, 5, dummy_bit, -1);

      _cogl_bitmask_set (&bitmask, 4, FALSE);

      verify_bits (&bitmask, 1, 5, dummy_bit, -1);

      _cogl_bitmask_clear_all (&bitmask);

      verify_bits (&bitmask, -1);

      if (dummy_bit != -1)
        _cogl_bitmask_set (&bitmask, dummy_bit, TRUE);

      verify_bits (&bitmask, dummy_bit, -1);

      _cogl_bitmask_set (&bitmask, 1, TRUE);
      _cogl_bitmask_set (&bitmask, 4, TRUE);
      _cogl_bitmask_set (&bitmask, 5, TRUE);
      _cogl_bitmask_set (&other_bitmask, 5, TRUE);
      _cogl_bitmask_set (&other_bitmask, 6, TRUE);

      _cogl_bitmask_set_bits (&bitmask, &other_bitmask);

      verify_bits (&bitmask, 1, 4, 5, 6, dummy_bit, -1);
      verify_bits (&other_bitmask, 5, 6, -1);

      _cogl_bitmask_set (&bitmask, 6, FALSE);

      verify_bits (&bitmask, 1, 4, 5, dummy_bit, -1);

      _cogl_bitmask_xor_bits (&bitmask, &other_bitmask);

      verify_bits (&bitmask, 1, 4, 6, dummy_bit, -1);
      verify_bits (&other_bitmask, 5, 6, -1);

      _cogl_bitmask_set_range (&bitmask, 5, TRUE);

      verify_bits (&bitmask, 0, 1, 2, 3, 4, 6, dummy_bit, -1);

      _cogl_bitmask_set_range (&bitmask, 4, FALSE);

      verify_bits (&bitmask, 4, 6, dummy_bit, -1);

      _cogl_bitmask_destroy (&other_bitmask);
      _cogl_bitmask_destroy (&bitmask);
    }

  /* Extra tests for really long bitmasks */
  _cogl_bitmask_init (&bitmask);
  _cogl_bitmask_set_range (&bitmask, 400, TRUE);
  _cogl_bitmask_init (&other_bitmask);
  _cogl_bitmask_set (&other_bitmask, 5, TRUE);
  _cogl_bitmask_xor_bits (&bitmask, &other_bitmask);

  for (i = 0; i < 1024; i++)
    g_assert_cmpint (_cogl_bitmask_get (&bitmask, i),
                     ==,
                     (i == 5 ? FALSE :
                      i < 400 ? TRUE :
                      FALSE));

  _cogl_bitmask_set_range (&other_bitmask, 500, TRUE);
  _cogl_bitmask_set_bits (&bitmask, &other_bitmask);

  for (i = 0; i < 1024; i++)
    g_assert_cmpint (_cogl_bitmask_get (&bitmask, i), ==, (i < 500));
}