[pulseview.git] / pv / data / logicsnapshot.cpp

/*
 * This file is part of the PulseView project.
 *
 * Copyright (C) 2012 Joel Holdsworth <joel@airwebreathe.org.uk>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */

#include <extdef.h>

#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>

#include <boost/foreach.hpp>

#include "logicsnapshot.h"

using boost::lock_guard;
using boost::recursive_mutex;
using std::max;
using std::min;
using std::pair;

namespace pv {
namespace data {

const int LogicSnapshot::MipMapScalePower = 4;
const int LogicSnapshot::MipMapScaleFactor = 1 << MipMapScalePower;
const float LogicSnapshot::LogMipMapScaleFactor = logf(MipMapScaleFactor);
const uint64_t LogicSnapshot::MipMapDataUnit = 64*1024;	// bytes

LogicSnapshot::LogicSnapshot(const sr_datafeed_logic &logic,
                             const uint64_t expected_num_samples) :
	Snapshot(logic.unitsize),
	_last_append_sample(0)
{
	set_capacity(expected_num_samples);

	lock_guard<recursive_mutex> lock(_mutex);
	memset(_mip_map, 0, sizeof(_mip_map));
	append_payload(logic);
}

LogicSnapshot::~LogicSnapshot()
{
	lock_guard<recursive_mutex> lock(_mutex);
	BOOST_FOREACH(MipMapLevel &l, _mip_map)
		free(l.data);
}

uint64_t LogicSnapshot::unpack_sample(const uint8_t *ptr) const
{
	uint64_t value = 0;
	switch(_unit_size) {
	default:
		value |= ((uint64_t)ptr[7]) << 56;
		/* FALLTHRU */
	case 7:
		value |= ((uint64_t)ptr[6]) << 48;
		/* FALLTHRU */
	case 6:
		value |= ((uint64_t)ptr[5]) << 40;
		/* FALLTHRU */
	case 5:
		value |= ((uint64_t)ptr[4]) << 32;
		/* FALLTHRU */
	case 4:
		value |= ((uint32_t)ptr[3]) << 24;
		/* FALLTHRU */
	case 3:
		value |= ((uint32_t)ptr[2]) << 16;
		/* FALLTHRU */
	case 2:
		value |= ptr[1] << 8;
		/* FALLTHRU */
	case 1:
		value |= ptr[0];
		/* FALLTHRU */
	case 0:
		break;
	}
	return value;
}

void LogicSnapshot::pack_sample(uint8_t *ptr, uint64_t value)
{
	switch(_unit_size) {
	default:
		ptr[7] = value >> 56;
		/* FALLTHRU */
	case 7:
		ptr[6] = value >> 48;
		/* FALLTHRU */
	case 6:
		ptr[5] = value >> 40;
		/* FALLTHRU */
	case 5:
		ptr[4] = value >> 32;
		/* FALLTHRU */
	case 4:
		ptr[3] = value >> 24;
		/* FALLTHRU */
	case 3:
		ptr[2] = value >> 16;
		/* FALLTHRU */
	case 2:
		ptr[1] = value >> 8;
		/* FALLTHRU */
	case 1:
		ptr[0] = value;
		/* FALLTHRU */
	case 0:
		break;
	}
}

void LogicSnapshot::append_payload(
	const sr_datafeed_logic &logic)
{
	assert(_unit_size == logic.unitsize);
	assert((logic.length % _unit_size) == 0);

	lock_guard<recursive_mutex> lock(_mutex);

	append_data(logic.data, logic.length / _unit_size);

	// Generate the first mip-map from the data
	append_payload_to_mipmap();
}

void LogicSnapshot::get_samples(uint8_t *const data,
	int64_t start_sample, int64_t end_sample) const
{
	assert(data);
	assert(start_sample >= 0);
	assert(start_sample <= (int64_t)_sample_count);
	assert(end_sample >= 0);
	assert(end_sample <= (int64_t)_sample_count);
	assert(start_sample <= end_sample);

	lock_guard<recursive_mutex> lock(_mutex);

	const size_t size = (end_sample - start_sample) * _unit_size;
	memcpy(data, (const uint8_t*)_data + start_sample, size);
}

void LogicSnapshot::reallocate_mipmap_level(MipMapLevel &m)
{
	const uint64_t new_data_length = ((m.length + MipMapDataUnit - 1) /
		MipMapDataUnit) * MipMapDataUnit;
	if (new_data_length > m.data_length)
	{
		m.data_length = new_data_length;

		// Padding is added to allow for the uint64_t write word
		m.data = realloc(m.data, new_data_length * _unit_size +
			sizeof(uint64_t));
	}
}

void LogicSnapshot::append_payload_to_mipmap()
{
	MipMapLevel &m0 = _mip_map[0];
	uint64_t prev_length;
	const uint8_t *src_ptr;
	uint8_t *dest_ptr;
	uint64_t accumulator;
	unsigned int diff_counter;

	// Expand the data buffer to fit the new samples
	prev_length = m0.length;
	m0.length = _sample_count / MipMapScaleFactor;

	// Break off if there are no new samples to compute
	if (m0.length == prev_length)
		return;

	reallocate_mipmap_level(m0);

	dest_ptr = (uint8_t*)m0.data + prev_length * _unit_size;

	// Iterate through the samples to populate the first level mipmap
	const uint8_t *const end_src_ptr = (uint8_t*)_data +
		m0.length * _unit_size * MipMapScaleFactor;
	for (src_ptr = (uint8_t*)_data +
		prev_length * _unit_size * MipMapScaleFactor;
		src_ptr < end_src_ptr;)
	{
		// Accumulate transitions which have occurred in this sample
		accumulator = 0;
		diff_counter = MipMapScaleFactor;
		while (diff_counter-- > 0)
		{
			const uint64_t sample = unpack_sample(src_ptr);
			accumulator |= _last_append_sample ^ sample;
			_last_append_sample = sample;
			src_ptr += _unit_size;
		}

		pack_sample(dest_ptr, accumulator);
		dest_ptr += _unit_size;
	}

	// Compute higher level mipmaps
	for (unsigned int level = 1; level < ScaleStepCount; level++)
	{
		MipMapLevel &m = _mip_map[level];
		const MipMapLevel &ml = _mip_map[level-1];

		// Expand the data buffer to fit the new samples
		prev_length = m.length;
		m.length = ml.length / MipMapScaleFactor;

		// Break off if there are no more samples to computed
		if (m.length == prev_length)
			break;

		reallocate_mipmap_level(m);

		// Subsample the level lower level
		src_ptr = (uint8_t*)ml.data +
			_unit_size * prev_length * MipMapScaleFactor;
		const uint8_t *const end_dest_ptr =
			(uint8_t*)m.data + _unit_size * m.length;
		for (dest_ptr = (uint8_t*)m.data +
			_unit_size * prev_length;
			dest_ptr < end_dest_ptr;
			dest_ptr += _unit_size)
		{
			accumulator = 0;
			diff_counter = MipMapScaleFactor;
			while (diff_counter-- > 0)
			{
				accumulator |= unpack_sample(src_ptr);
				src_ptr += _unit_size;
			}

			pack_sample(dest_ptr, accumulator);
		}
	}
}

uint64_t LogicSnapshot::get_sample(uint64_t index) const
{
	assert(_data);
	assert(index < _sample_count);

	return unpack_sample((uint8_t*)_data + index * _unit_size);
}

void LogicSnapshot::get_subsampled_edges(
	std::vector<EdgePair> &edges,
	uint64_t start, uint64_t end,
	float min_length, int sig_index)
{
	uint64_t index = start;
	unsigned int level;
	bool last_sample;
	bool fast_forward;

	assert(end <= get_sample_count());
	assert(start <= end);
	assert(min_length > 0);
	assert(sig_index >= 0);
	assert(sig_index < 64);

	lock_guard<recursive_mutex> lock(_mutex);

	const uint64_t block_length = (uint64_t)max(min_length, 1.0f);
	const unsigned int min_level = max((int)floorf(logf(min_length) /
		LogMipMapScaleFactor) - 1, 0);
	const uint64_t sig_mask = 1ULL << sig_index;

	// Store the initial state
	last_sample = (get_sample(start) & sig_mask) != 0;
	edges.push_back(pair<int64_t, bool>(index++, last_sample));

	while (index + block_length <= end)
	{
		//----- Continue to search -----//
		level = min_level;

		// We cannot fast-forward if there is no mip-map data at
		// at the minimum level.
		fast_forward = (_mip_map[level].data != NULL);

		if (min_length < MipMapScaleFactor)
		{
			// Search individual samples up to the beginning of
			// the next first level mip map block
			const uint64_t final_index = min(end,
				pow2_ceil(index, MipMapScalePower));

			for (; index < final_index &&
				(index & ~(~0 << MipMapScalePower)) != 0;
				index++)
			{
				const bool sample =
					(get_sample(index) & sig_mask) != 0;

				// If there was a change we cannot fast forward
				if (sample != last_sample) {
					fast_forward = false;
					break;
				}
			}
		}
		else
		{
			// If resolution is less than a mip map block,
			// round up to the beginning of the mip-map block
			// for this level of detail
			const int min_level_scale_power =
				(level + 1) * MipMapScalePower;
			index = pow2_ceil(index, min_level_scale_power);
			if (index >= end)
				break;

			// We can fast forward only if there was no change
			const bool sample =
				(get_sample(index) & sig_mask) != 0;
			if (last_sample != sample)
				fast_forward = false;
		}

		if (fast_forward) {

			// Fast forward: This involves zooming out to higher
			// levels of the mip map searching for changes, then
			// zooming in on them to find the point where the edge
			// begins.

			// Slide right and zoom out at the beginnings of mip-map
			// blocks until we encounter a change
			while (1) {
				const int level_scale_power =
					(level + 1) * MipMapScalePower;
				const uint64_t offset =
					index >> level_scale_power;

				// Check if we reached the last block at this
				// level, or if there was a change in this block
				if (offset >= _mip_map[level].length ||
					(get_subsample(level, offset) &
						sig_mask))
					break;

				if ((offset & ~(~0 << MipMapScalePower)) == 0) {
					// If we are now at the beginning of a
					// higher level mip-map block ascend one
					// level
					if (level + 1 >= ScaleStepCount ||
						!_mip_map[level + 1].data)
						break;

					level++;
				} else {
					// Slide right to the beginning of the
					// next mip map block
					index = pow2_ceil(index + 1,
						level_scale_power);
				}
			}

			// Zoom in, and slide right until we encounter a change,
			// and repeat until we reach min_level
			while (1) {
				assert(_mip_map[level].data);

				const int level_scale_power =
					(level + 1) * MipMapScalePower;
				const uint64_t offset =
					index >> level_scale_power;

				// Check if we reached the last block at this
				// level, or if there was a change in this block
				if (offset >= _mip_map[level].length ||
					(get_subsample(level, offset) &
						sig_mask)) {
					// Zoom in unless we reached the minimum
					// zoom
					if (level == min_level)
						break;

					level--;
				} else {
					// Slide right to the beginning of the
					// next mip map block
					index = pow2_ceil(index + 1,
						level_scale_power);
				}
			}

			// If individual samples within the limit of resolution,
			// do a linear search for the next transition within the
			// block
			if (min_length < MipMapScaleFactor) {
				for (; index < end; index++) {
					const bool sample = (get_sample(index) &
						sig_mask) != 0;
					if (sample != last_sample)
						break;
				}
			}
		}

		//----- Store the edge -----//

		// Take the last sample of the quanization block
		const int64_t final_index = index + block_length;
		if (index + block_length > end)
			break;

		// Store the final state
		const bool final_sample =
			(get_sample(final_index - 1) & sig_mask) != 0;
		edges.push_back(pair<int64_t, bool>(index, final_sample));

		index = final_index;
		last_sample = final_sample;
	}

	// Add the final state
	const bool end_sample = get_sample(end) & sig_mask;
	if (last_sample != end_sample)
		edges.push_back(pair<int64_t, bool>(end, end_sample));
	edges.push_back(pair<int64_t, bool>(end + 1, end_sample));
}

uint64_t LogicSnapshot::get_subsample(int level, uint64_t offset) const
{
	assert(level >= 0);
	assert(_mip_map[level].data);
	return unpack_sample((uint8_t*)_mip_map[level].data +
		_unit_size * offset);
}

uint64_t LogicSnapshot::pow2_ceil(uint64_t x, unsigned int power)
{
	const uint64_t p = 1 << power;
	return (x + p - 1) / p * p;
}

} // namespace data
} // namespace pv
Commit	Line	Data
28a4c9c5	1	/*
b3f22de0	2	* This file is part of the PulseView project.
28a4c9c5 JH	3	*
	4	* Copyright (C) 2012 Joel Holdsworth <joel@airwebreathe.org.uk>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	19	*/
	20
cef18fc6	21	#include <extdef.h>
28a4c9c5	22
f556bc6a	23	#include <assert.h>
4ceab49a	24	#include <string.h>
b36d8550	25	#include <stdlib.h>
4ceab49a JH	26	#include <math.h>
	27
	28	#include <boost/foreach.hpp>
	29
1b1ec774	30	#include "logicsnapshot.h"
f556bc6a	31
819f4c25 JH	32	using boost::lock_guard;
	33	using boost::recursive_mutex;
	34	using std::max;
	35	using std::min;
	36	using std::pair;
28a4c9c5	37
51e77110	38	namespace pv {
1b1ec774	39	namespace data {
51e77110	40
1b1ec774 JH	41	const int LogicSnapshot::MipMapScalePower = 4;
	42	const int LogicSnapshot::MipMapScaleFactor = 1 << MipMapScalePower;
	43	const float LogicSnapshot::LogMipMapScaleFactor = logf(MipMapScaleFactor);
	44	const uint64_t LogicSnapshot::MipMapDataUnit = 64*1024; // bytes
4ceab49a	45
27d7c96b DK	46	LogicSnapshot::LogicSnapshot(const sr_datafeed_logic &logic,
27d7c96b DK	47	const uint64_t expected_num_samples) :
1b1ec774	48	Snapshot(logic.unitsize),
4ceab49a	49	_last_append_sample(0)
f556bc6a	50	{
27d7c96b DK	51	set_capacity(expected_num_samples);
27d7c96b DK	52
7d29656f	53	lock_guard<recursive_mutex> lock(_mutex);
4ceab49a	54	memset(_mip_map, 0, sizeof(_mip_map));
f556bc6a JH	55	append_payload(logic);
	56	}
	57
1b1ec774	58	LogicSnapshot::~LogicSnapshot()
4ceab49a	59	{
7d29656f	60	lock_guard<recursive_mutex> lock(_mutex);
4ceab49a JH	61	BOOST_FOREACH(MipMapLevel &l, _mip_map)
	62	free(l.data);
	63	}
	64
8cb71705 MC	65	uint64_t LogicSnapshot::unpack_sample(const uint8_t *ptr) const
	66	{
	67	uint64_t value = 0;
	68	switch(_unit_size) {
	69	default:
	70	value \|= ((uint64_t)ptr[7]) << 56;
	71	/* FALLTHRU */
	72	case 7:
	73	value \|= ((uint64_t)ptr[6]) << 48;
	74	/* FALLTHRU */
	75	case 6:
	76	value \|= ((uint64_t)ptr[5]) << 40;
	77	/* FALLTHRU */
	78	case 5:
	79	value \|= ((uint64_t)ptr[4]) << 32;
	80	/* FALLTHRU */
	81	case 4:
	82	value \|= ((uint32_t)ptr[3]) << 24;
	83	/* FALLTHRU */
	84	case 3:
	85	value \|= ((uint32_t)ptr[2]) << 16;
	86	/* FALLTHRU */
	87	case 2:
	88	value \|= ptr[1] << 8;
	89	/* FALLTHRU */
	90	case 1:
	91	value \|= ptr[0];
	92	/* FALLTHRU */
	93	case 0:
	94	break;
	95	}
	96	return value;
	97	}
	98
	99	void LogicSnapshot::pack_sample(uint8_t *ptr, uint64_t value)
	100	{
	101	switch(_unit_size) {
	102	default:
	103	ptr[7] = value >> 56;
	104	/* FALLTHRU */
	105	case 7:
	106	ptr[6] = value >> 48;
	107	/* FALLTHRU */
	108	case 6:
	109	ptr[5] = value >> 40;
	110	/* FALLTHRU */
	111	case 5:
	112	ptr[4] = value >> 32;
	113	/* FALLTHRU */
	114	case 4:
	115	ptr[3] = value >> 24;
	116	/* FALLTHRU */
	117	case 3:
	118	ptr[2] = value >> 16;
	119	/* FALLTHRU */
	120	case 2:
	121	ptr[1] = value >> 8;
	122	/* FALLTHRU */
	123	case 1:
	124	ptr[0] = value;
	125	/* FALLTHRU */
	126	case 0:
	127	break;
	128	}
129	}
130
1b1ec774	131	void LogicSnapshot::append_payload(
28a4c9c5 JH	132	const sr_datafeed_logic &logic)
28a4c9c5 JH	133	{
f556bc6a	134	assert(_unit_size == logic.unitsize);
5cef1ea3	135	assert((logic.length % _unit_size) == 0);
f556bc6a	136
7d29656f JH	137	lock_guard<recursive_mutex> lock(_mutex);
7d29656f JH	138
5cef1ea3	139	append_data(logic.data, logic.length / _unit_size);
4ceab49a JH	140
	141	// Generate the first mip-map from the data
	142	append_payload_to_mipmap();
	143	}
	144
ed990f11 JH	145	void LogicSnapshot::get_samples(uint8_t *const data,
	146	int64_t start_sample, int64_t end_sample) const
	147	{
	148	assert(data);
	149	assert(start_sample >= 0);
0fbda3c2	150	assert(start_sample <= (int64_t)_sample_count);
ed990f11	151	assert(end_sample >= 0);
0fbda3c2	152	assert(end_sample <= (int64_t)_sample_count);
ed990f11 JH	153	assert(start_sample <= end_sample);
	154
	155	lock_guard<recursive_mutex> lock(_mutex);
	156
	157	const size_t size = (end_sample - start_sample) * _unit_size;
	158	memcpy(data, (const uint8_t*)_data + start_sample, size);
	159	}
	160
023887ca	161	void LogicSnapshot::reallocate_mipmap_level(MipMapLevel &m)
4ceab49a JH	162	{
	163	const uint64_t new_data_length = ((m.length + MipMapDataUnit - 1) /
	164	MipMapDataUnit) * MipMapDataUnit;
333d5bbc	165	if (new_data_length > m.data_length)
4ceab49a JH	166	{
4ceab49a JH	167	m.data_length = new_data_length;
8fe60279 JH	168
	169	// Padding is added to allow for the uint64_t write word
	170	m.data = realloc(m.data, new_data_length * _unit_size +
	171	sizeof(uint64_t));
4ceab49a JH	172	}
	173	}
	174
1b1ec774	175	void LogicSnapshot::append_payload_to_mipmap()
4ceab49a JH	176	{
	177	MipMapLevel &m0 = _mip_map[0];
	178	uint64_t prev_length;
	179	const uint8_t *src_ptr;
	180	uint8_t *dest_ptr;
	181	uint64_t accumulator;
	182	unsigned int diff_counter;
	183
	184	// Expand the data buffer to fit the new samples
	185	prev_length = m0.length;
77bff0b1	186	m0.length = _sample_count / MipMapScaleFactor;
4ceab49a JH	187
4ceab49a JH	188	// Break off if there are no new samples to compute
333d5bbc	189	if (m0.length == prev_length)
4ceab49a JH	190	return;
4ceab49a JH	191
023887ca	192	reallocate_mipmap_level(m0);
4ceab49a JH	193
	194	dest_ptr = (uint8_t)m0.data + prev_length _unit_size;
	195
	196	// Iterate through the samples to populate the first level mipmap
023887ca	197	const uint8_t const end_src_ptr = (uint8_t)_data +
4ceab49a	198	m0.length * _unit_size * MipMapScaleFactor;
333d5bbc	199	for (src_ptr = (uint8_t*)_data +
4ceab49a JH	200	prev_length * _unit_size * MipMapScaleFactor;
	201	src_ptr < end_src_ptr;)
	202	{
	203	// Accumulate transitions which have occurred in this sample
	204	accumulator = 0;
	205	diff_counter = MipMapScaleFactor;
333d5bbc	206	while (diff_counter-- > 0)
4ceab49a	207	{
8cb71705	208	const uint64_t sample = unpack_sample(src_ptr);
4ceab49a JH	209	accumulator \|= _last_append_sample ^ sample;
	210	_last_append_sample = sample;
	211	src_ptr += _unit_size;
	212	}
	213
8cb71705	214	pack_sample(dest_ptr, accumulator);
4ceab49a JH	215	dest_ptr += _unit_size;
	216	}
	217
	218	// Compute higher level mipmaps
333d5bbc	219	for (unsigned int level = 1; level < ScaleStepCount; level++)
4ceab49a JH	220	{
	221	MipMapLevel &m = _mip_map[level];
	222	const MipMapLevel &ml = _mip_map[level-1];
	223
	224	// Expand the data buffer to fit the new samples
	225	prev_length = m.length;
	226	m.length = ml.length / MipMapScaleFactor;
	227
	228	// Break off if there are no more samples to computed
333d5bbc	229	if (m.length == prev_length)
4ceab49a JH	230	break;
4ceab49a JH	231
023887ca	232	reallocate_mipmap_level(m);
4ceab49a JH	233
	234	// Subsample the level lower level
	235	src_ptr = (uint8_t*)ml.data +
	236	_unit_size * prev_length * MipMapScaleFactor;
023887ca	237	const uint8_t *const end_dest_ptr =
4ceab49a	238	(uint8_t)m.data + _unit_size m.length;
333d5bbc	239	for (dest_ptr = (uint8_t*)m.data +
4ceab49a JH	240	_unit_size * prev_length;
	241	dest_ptr < end_dest_ptr;
	242	dest_ptr += _unit_size)
	243	{
	244	accumulator = 0;
	245	diff_counter = MipMapScaleFactor;
333d5bbc	246	while (diff_counter-- > 0)
4ceab49a	247	{
8cb71705	248	accumulator \|= unpack_sample(src_ptr);
4ceab49a JH	249	src_ptr += _unit_size;
	250	}
	251
8cb71705	252	pack_sample(dest_ptr, accumulator);
4ceab49a JH	253	}
4ceab49a JH	254	}
28a4c9c5	255	}
2858b391	256
1b1ec774	257	uint64_t LogicSnapshot::get_sample(uint64_t index) const
2858b391 JH	258	{
2858b391 JH	259	assert(_data);
3f96c34a	260	assert(index < _sample_count);
2858b391	261
8cb71705	262	return unpack_sample((uint8_t)_data + index _unit_size);
2858b391 JH	263	}
2858b391 JH	264
1b1ec774	265	void LogicSnapshot::get_subsampled_edges(
2858b391	266	std::vector<EdgePair> &edges,
60b0c2da	267	uint64_t start, uint64_t end,
0b02e057	268	float min_length, int sig_index)
2858b391	269	{
60b0c2da JH	270	uint64_t index = start;
60b0c2da JH	271	unsigned int level;
7d0d64f9 JH	272	bool last_sample;
7d0d64f9 JH	273	bool fast_forward;
0b02e057	274
0b02e057	275	assert(end <= get_sample_count());
2858b391	276	assert(start <= end);
0b02e057	277	assert(min_length > 0);
2858b391	278	assert(sig_index >= 0);
80d50141	279	assert(sig_index < 64);
2858b391	280
7d29656f JH	281	lock_guard<recursive_mutex> lock(_mutex);
7d29656f JH	282
60b0c2da JH	283	const uint64_t block_length = (uint64_t)max(min_length, 1.0f);
60b0c2da JH	284	const unsigned int min_level = max((int)floorf(logf(min_length) /
0b02e057	285	LogMipMapScaleFactor) - 1, 0);
7d0d64f9	286	const uint64_t sig_mask = 1ULL << sig_index;
2858b391	287
7d0d64f9 JH	288	// Store the initial state
	289	last_sample = (get_sample(start) & sig_mask) != 0;
	290	edges.push_back(pair<int64_t, bool>(index++, last_sample));
2858b391	291
333d5bbc	292	while (index + block_length <= end)
2858b391	293	{
7d0d64f9	294	//----- Continue to search -----//
0b02e057	295	level = min_level;
f06ab143 JH	296
	297	// We cannot fast-forward if there is no mip-map data at
	298	// at the minimum level.
	299	fast_forward = (_mip_map[level].data != NULL);
2858b391	300
333d5bbc	301	if (min_length < MipMapScaleFactor)
0b02e057 JH	302	{
	303	// Search individual samples up to the beginning of
	304	// the next first level mip map block
7d0d64f9	305	const uint64_t final_index = min(end,
0b02e057 JH	306	pow2_ceil(index, MipMapScalePower));
0b02e057 JH	307
333d5bbc	308	for (; index < final_index &&
0b02e057 JH	309	(index & ~(~0 << MipMapScalePower)) != 0;
	310	index++)
	311	{
	312	const bool sample =
	313	(get_sample(index) & sig_mask) != 0;
7d0d64f9 JH	314
7d0d64f9 JH	315	// If there was a change we cannot fast forward
333d5bbc	316	if (sample != last_sample) {
7d0d64f9	317	fast_forward = false;
0b02e057	318	break;
7d0d64f9	319	}
0b02e057 JH	320	}
	321	}
	322	else
	323	{
	324	// If resolution is less than a mip map block,
	325	// round up to the beginning of the mip-map block
	326	// for this level of detail
	327	const int min_level_scale_power =
	328	(level + 1) * MipMapScalePower;
	329	index = pow2_ceil(index, min_level_scale_power);
333d5bbc	330	if (index >= end)
0b02e057 JH	331	break;
0b02e057 JH	332
7d0d64f9 JH	333	// We can fast forward only if there was no change
	334	const bool sample =
	335	(get_sample(index) & sig_mask) != 0;
f06ab143 JH	336	if (last_sample != sample)
f06ab143 JH	337	fast_forward = false;
0b02e057 JH	338	}
0b02e057 JH	339
333d5bbc	340	if (fast_forward) {
7d0d64f9 JH	341
	342	// Fast forward: This involves zooming out to higher
	343	// levels of the mip map searching for changes, then
	344	// zooming in on them to find the point where the edge
	345	// begins.
	346
	347	// Slide right and zoom out at the beginnings of mip-map
	348	// blocks until we encounter a change
333d5bbc	349	while (1) {
7d0d64f9 JH	350	const int level_scale_power =
	351	(level + 1) * MipMapScalePower;
	352	const uint64_t offset =
	353	index >> level_scale_power;
7d0d64f9 JH	354
	355	// Check if we reached the last block at this
	356	// level, or if there was a change in this block
333d5bbc	357	if (offset >= _mip_map[level].length \|\|
7d0d64f9 JH	358	(get_subsample(level, offset) &
7d0d64f9 JH	359	sig_mask))
0b02e057 JH	360	break;
0b02e057 JH	361
333d5bbc	362	if ((offset & ~(~0 << MipMapScalePower)) == 0) {
7d0d64f9 JH	363	// If we are now at the beginning of a
	364	// higher level mip-map block ascend one
	365	// level
333d5bbc	366	if (level + 1 >= ScaleStepCount \|\|
7d0d64f9 JH	367	!_mip_map[level + 1].data)
	368	break;
	369
	370	level++;
	371	} else {
	372	// Slide right to the beginning of the
	373	// next mip map block
	374	index = pow2_ceil(index + 1,
	375	level_scale_power);
	376	}
0b02e057	377	}
7d0d64f9 JH	378
	379	// Zoom in, and slide right until we encounter a change,
	380	// and repeat until we reach min_level
333d5bbc	381	while (1) {
7d0d64f9 JH	382	assert(_mip_map[level].data);
	383
	384	const int level_scale_power =
	385	(level + 1) * MipMapScalePower;
	386	const uint64_t offset =
	387	index >> level_scale_power;
7d0d64f9 JH	388
	389	// Check if we reached the last block at this
	390	// level, or if there was a change in this block
333d5bbc	391	if (offset >= _mip_map[level].length \|\|
7d0d64f9 JH	392	(get_subsample(level, offset) &
	393	sig_mask)) {
	394	// Zoom in unless we reached the minimum
	395	// zoom
333d5bbc	396	if (level == min_level)
7d0d64f9 JH	397	break;
	398
	399	level--;
	400	} else {
	401	// Slide right to the beginning of the
	402	// next mip map block
	403	index = pow2_ceil(index + 1,
	404	level_scale_power);
	405	}
0b02e057	406	}
0b02e057	407
7d0d64f9 JH	408	// If individual samples within the limit of resolution,
	409	// do a linear search for the next transition within the
	410	// block
333d5bbc UH	411	if (min_length < MipMapScaleFactor) {
333d5bbc UH	412	for (; index < end; index++) {
7d0d64f9 JH	413	const bool sample = (get_sample(index) &
7d0d64f9 JH	414	sig_mask) != 0;
333d5bbc	415	if (sample != last_sample)
7d0d64f9 JH	416	break;
7d0d64f9 JH	417	}
0b02e057 JH	418	}
	419	}
	420
7d0d64f9 JH	421	//----- Store the edge -----//
	422
	423	// Take the last sample of the quanization block
	424	const int64_t final_index = index + block_length;
333d5bbc	425	if (index + block_length > end)
7d0d64f9 JH	426	break;
	427
	428	// Store the final state
	429	const bool final_sample =
	430	(get_sample(final_index - 1) & sig_mask) != 0;
	431	edges.push_back(pair<int64_t, bool>(index, final_sample));
	432
	433	index = final_index;
	434	last_sample = final_sample;
2858b391 JH	435	}
	436
	437	// Add the final state
175d6573 JH	438	const bool end_sample = get_sample(end) & sig_mask;
	439	if (last_sample != end_sample)
	440	edges.push_back(pair<int64_t, bool>(end, end_sample));
	441	edges.push_back(pair<int64_t, bool>(end + 1, end_sample));
2858b391	442	}
0b02e057	443
1b1ec774	444	uint64_t LogicSnapshot::get_subsample(int level, uint64_t offset) const
b2bcbe51 JH	445	{
	446	assert(level >= 0);
	447	assert(_mip_map[level].data);
8cb71705	448	return unpack_sample((uint8_t*)_mip_map[level].data +
b2bcbe51 JH	449	_unit_size * offset);
	450	}
	451
1b1ec774	452	uint64_t LogicSnapshot::pow2_ceil(uint64_t x, unsigned int power)
0b02e057	453	{
60b0c2da JH	454	const uint64_t p = 1 << power;
60b0c2da JH	455	return (x + p - 1) / p * p;
0b02e057	456	}
51e77110	457
1b1ec774	458	} // namespace data
51e77110	459	} // namespace pv