/*
* Copyright 2020 sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
* Author: Pau Espin Pedrol <pespin@sysmocom.de>
*
* SPDX-License-Identifier: 0BSD
*
    Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted.
    THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
    INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
    AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
    PERFORMANCE OF THIS SOFTWARE.
*/

#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <stddef.h>
#include <osmocom/core/talloc.h>

#include "shm.h"

//#define ENCDECDEBUG

/* Convert offsets to pointers */
struct ipc_shm_stream *ipc_shm_decode_stream(void *tall_ctx, struct ipc_shm_raw_region *root_raw,
					     struct ipc_shm_raw_stream *stream_raw)
{
	unsigned int i;
	struct ipc_shm_stream *stream;
	stream = talloc_zero(tall_ctx, struct ipc_shm_stream);
	stream = talloc_zero_size(tall_ctx, sizeof(struct ipc_shm_stream) +
						    sizeof(struct ipc_shm_raw_smpl_buf *) * stream_raw->num_buffers);
	if (!stream)
		return NULL;
	stream->num_buffers = stream_raw->num_buffers;
	stream->buffer_size = stream_raw->buffer_size;
	stream->raw = stream_raw;
	for (i = 0; i < stream->num_buffers; i++) {
#ifdef ENCDECDEBUG
		fprintf(stderr, "decode: smpl_buf %d at offset %u\n", i, stream_raw->buffer_offset[i]);
#endif
		stream->buffers[i] =
			(struct ipc_shm_raw_smpl_buf *)(((uint8_t *)root_raw) + stream_raw->buffer_offset[i]);
	}
	return stream;
}

struct ipc_shm_channel *ipc_shm_decode_channel(void *tall_ctx, struct ipc_shm_raw_region *root_raw,
					       struct ipc_shm_raw_channel *chan_raw)
{
	struct ipc_shm_channel *chan;
	chan = talloc_zero(tall_ctx, struct ipc_shm_channel);
	if (!chan)
		return NULL;
#ifdef ENCDECDEBUG
	fprintf(stderr, "decode: streams at offset %u and %u\n", chan_raw->dl_buf_offset, chan_raw->ul_buf_offset);
#endif
	chan->dl_stream = ipc_shm_decode_stream(
		chan, root_raw, (struct ipc_shm_raw_stream *)(((uint8_t *)root_raw) + chan_raw->dl_buf_offset));
	chan->ul_stream = ipc_shm_decode_stream(
		chan, root_raw, (struct ipc_shm_raw_stream *)(((uint8_t *)root_raw) + chan_raw->ul_buf_offset));
	return chan;
}
struct ipc_shm_region *ipc_shm_decode_region(void *tall_ctx, struct ipc_shm_raw_region *root_raw)
{
	unsigned int i;
	struct ipc_shm_region *root;
	root = talloc_zero_size(tall_ctx,
				sizeof(struct ipc_shm_region) + sizeof(struct ipc_shm_channel *) * root_raw->num_chans);
	if (!root)
		return NULL;

	root->num_chans = root_raw->num_chans;
	for (i = 0; i < root->num_chans; i++) {
#ifdef ENCDECDEBUG
		fprintf(stderr, "decode: channel %d at offset %u\n", i, root_raw->chan_offset[i]);
#endif
		root->channels[i] = ipc_shm_decode_channel(
			root, root_raw,
			(struct ipc_shm_raw_channel *)(((uint8_t *)root_raw) + root_raw->chan_offset[i]));
	}
	return root;
}

unsigned int ipc_shm_encode_smpl_buf(struct ipc_shm_raw_region *root_raw, struct ipc_shm_raw_smpl_buf *smpl_buf_raw,
				     uint32_t buffer_size)
{
	uint8_t *start = (uint8_t *)smpl_buf_raw;
	unsigned int offset = sizeof(struct ipc_shm_raw_smpl_buf);
	offset = (((uintptr_t)offset + 7) & ~0x07ULL);
#ifdef ENCDECDEBUG
	fprintf(stderr, "encode: smpl_buf at offset %lu\n", (start - (uint8_t *)root_raw));
#endif
	offset += buffer_size * sizeof(uint16_t) * 2; /* samples */
	return offset;
}

unsigned int ipc_shm_encode_stream(struct ipc_shm_raw_region *root_raw, struct ipc_shm_raw_stream *stream_raw,
				   uint32_t num_buffers, uint32_t buffer_size)
{
	unsigned int i;
	ptrdiff_t start = (ptrdiff_t)stream_raw;
	unsigned int offset = sizeof(struct ipc_shm_raw_stream) + sizeof(uint32_t) * num_buffers;
	offset = (((uintptr_t)offset + 7) & ~0x07ULL);
#ifdef ENCDECDEBUG
	fprintf(stderr, "encode: stream at offset %lu\n", (start - (ptrdiff_t)root_raw));
#endif
	if (root_raw) {
		stream_raw->num_buffers = num_buffers;
		stream_raw->buffer_size = buffer_size;
		stream_raw->read_next = 0;
		stream_raw->write_next = 0;
	}
	for (i = 0; i < num_buffers; i++) {
		if (root_raw)
			stream_raw->buffer_offset[i] = (start + offset - (ptrdiff_t)root_raw);
		offset +=
			ipc_shm_encode_smpl_buf(root_raw, (struct ipc_shm_raw_smpl_buf *)(start + offset), buffer_size);
	}
	return offset;
}
unsigned int ipc_shm_encode_channel(struct ipc_shm_raw_region *root_raw, struct ipc_shm_raw_channel *chan_raw,
				    uint32_t num_buffers, uint32_t buffer_size)
{
	uint8_t *start = (uint8_t *)chan_raw;
	unsigned int offset = sizeof(struct ipc_shm_raw_channel);
	offset = (((uintptr_t)offset + 7) & ~0x07ULL);
#ifdef ENCDECDEBUG
	fprintf(stderr, "encode: channel at offset %lu\n", (start - (uint8_t *)root_raw));
#endif
	if (root_raw)
		chan_raw->dl_buf_offset = (start + offset - (uint8_t *)root_raw);
	offset += ipc_shm_encode_stream(root_raw, (struct ipc_shm_raw_stream *)(start + offset), num_buffers,
					buffer_size);
	if (root_raw)
		chan_raw->ul_buf_offset = (start + offset - (uint8_t *)root_raw);
	offset += ipc_shm_encode_stream(root_raw, (struct ipc_shm_raw_stream *)(start + offset), num_buffers,
					buffer_size);
	return offset;
}
/* if root_raw is NULL, then do a dry run, aka only calculate final offset */
unsigned int ipc_shm_encode_region(struct ipc_shm_raw_region *root_raw, uint32_t num_chans, uint32_t num_buffers,
				   uint32_t buffer_size)
{
	unsigned i;
	uintptr_t start = (uintptr_t)root_raw;
	unsigned int offset = sizeof(struct ipc_shm_raw_region) + sizeof(uint32_t) * num_chans;
	offset = (((uintptr_t)offset + 7) & ~0x07ULL);

	if (root_raw)
		root_raw->num_chans = num_chans;
	for (i = 0; i < num_chans; i++) {
		uint32_t ofs = (start + offset - (uintptr_t)root_raw);
		if (root_raw)
			root_raw->chan_offset[i] = (start + offset - (uintptr_t)root_raw);
#ifdef ENCDECDEBUG
		fprintf(stderr, "encode: channel %d chan_offset[i]=%u\n", i, ofs);
#endif
		offset += ipc_shm_encode_channel(root_raw, (struct ipc_shm_raw_channel *)(start + offset), num_buffers,
						 buffer_size);
	}
	//TODO: pass maximum size and verify we didn't go through
	return offset;
}