/*
Copyright (C) 2014-2025, Youssef Touil <youssef@airspy.com>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to use,
copy, modify, merge, and distribute the Software exclusively as part of the 
Airspy ecosystem, which includes Airspy-branded hardware, official tools, and
associated software directly approved or maintained by the original authors.

Any redistribution, publication, sublicensing, or commercial use outside the
Airspy ecosystem is strictly prohibited without prior written consent from the 
copyright holders.

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software used within the Airspy ecosystem.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE, PROVIDED SUCH USE REMAINS WITHIN THE AIRSPY ECOSYSTEM.
*/

#include "iqconverter_float.h"
#include <stdlib.h>
#include <string.h>

#include <stdio.h>

#if defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR)
  #include <malloc.h>
  #define _aligned_malloc __mingw_aligned_malloc
  #define _aligned_free  __mingw_aligned_free
  #define _inline inline
  #define FIR_STANDARD
#elif defined(__APPLE__)
  #include <malloc/malloc.h>
  #define _aligned_malloc(size, alignment) malloc(size)
  #define _aligned_free(mem) free(mem)
  #define _inline inline
  #define FIR_STANDARD
#elif defined(__FreeBSD__)
  #if defined(__x86_64__) || defined(__i386__)
    #define USE_SSE2
    #include <immintrin.h>
  #endif
  #define _inline inline
  #define _aligned_free(mem) free(mem)
void *_aligned_malloc(size_t size, size_t alignment)
{
    void *result;
    if (posix_memalign(&result, alignment, size) == 0)
        return result;
    return 0;
}
#elif defined(__GNUC__) && !defined(__MINGW64_VERSION_MAJOR)
  #include <malloc.h>
  #define _aligned_malloc(size, alignment) memalign(alignment, size)
  #define _aligned_free(mem) free(mem)
  #define _inline inline
#else
	#if (_MSC_VER >= 1800)
		//#define USE_SSE2
		//#include <immintrin.h>
	#endif
#endif

#define SIZE_FACTOR 32
#define DEFAULT_ALIGNMENT 16
#define HPF_COEFF 0.01f

#if defined(_MSC_VER)
	#define ALIGNED __declspec(align(DEFAULT_ALIGNMENT))
#else
	#define ALIGNED
#endif

iqconverter_float_t *iqconverter_float_create(const float *hb_kernel, int len)
{
	int i, j;
	size_t buffer_size;
	iqconverter_float_t *cnv = (iqconverter_float_t *) _aligned_malloc(sizeof(iqconverter_float_t), DEFAULT_ALIGNMENT);

	cnv->len = len / 2 + 1;
	cnv->hbc = hb_kernel[len / 2];

	buffer_size = cnv->len * sizeof(float);

	cnv->fir_kernel = (float *) _aligned_malloc(buffer_size, DEFAULT_ALIGNMENT);
	cnv->fir_queue = (float *) _aligned_malloc(buffer_size * SIZE_FACTOR, DEFAULT_ALIGNMENT);
	cnv->delay_line = (float *) _aligned_malloc(buffer_size / 2, DEFAULT_ALIGNMENT);

	iqconverter_float_reset(cnv);

	for (i = 0, j = 0; i < cnv->len; i++, j += 2)
	{
		cnv->fir_kernel[i] = hb_kernel[j];
	} 

	return cnv;
}

void iqconverter_float_free(iqconverter_float_t *cnv)
{
	_aligned_free(cnv->fir_kernel);
	_aligned_free(cnv->fir_queue);
	_aligned_free(cnv->delay_line);
	_aligned_free(cnv);
}

void iqconverter_float_reset(iqconverter_float_t *cnv)
{
	cnv->avg = 0.0f;
	cnv->fir_index = 0;
	cnv->delay_index = 0;
	memset(cnv->delay_line, 0, cnv->len * sizeof(float) / 2);
	memset(cnv->fir_queue, 0, cnv->len * sizeof(float) * SIZE_FACTOR);
}

static _inline float process_fir_taps(const float *kernel, const float *queue, int len)
{
	int i;

#ifdef USE_SSE2

	__m128 acc = _mm_set_ps(0, 0, 0, 0);

#else

	float sum = 0.0f;

#endif

	if (len >= 8)
	{
		int it = len >> 3;

#ifdef USE_SSE2

		for (i = 0; i < it; i++)
		{
			__m128 head1 = _mm_loadu_ps(queue);
			__m128 kern1 = _mm_load_ps(kernel);
			__m128 head2 = _mm_loadu_ps(queue + 4);
			__m128 kern2 = _mm_load_ps(kernel + 4);

			__m128 mul1 = _mm_mul_ps(kern1, head1);
			__m128 mul2 = _mm_mul_ps(kern2, head2);

			mul1 = _mm_add_ps(mul1, mul2);

			acc = _mm_add_ps(acc, mul1);

			queue += 8;
			kernel += 8;
		}

#else

		for (i = 0; i < it; i++)
		{
			sum += kernel[0] * queue[0]
				+ kernel[1] * queue[1]
				+ kernel[2] * queue[2]
				+ kernel[3] * queue[3]
				+ kernel[4] * queue[4]
				+ kernel[5] * queue[5]
				+ kernel[6] * queue[6]
				+ kernel[7] * queue[7];

			queue += 8;
			kernel += 8;
		}

#endif
		len &= 7;
	}

	if (len >= 4)
	{

#ifdef USE_SSE2

		__m128 head = _mm_loadu_ps(queue);
		__m128 kern = _mm_load_ps(kernel);
		__m128 mul = _mm_mul_ps(kern, head);
		acc = _mm_add_ps(acc, mul);

#else

		sum += kernel[0] * queue[0]
			+ kernel[1] * queue[1]
			+ kernel[2] * queue[2]
			+ kernel[3] * queue[3];

#endif

		kernel += 4;
		queue += 4;
		len &= 3;
	}

#ifdef USE_SSE2

	__m128 t = _mm_add_ps(acc, _mm_movehl_ps(acc, acc));
	acc = _mm_add_ss(t, _mm_shuffle_ps(t, t, 1));

#ifdef __FreeBSD__
	float sum = acc[0];
#else
	float sum = acc.m128_f32[0];
#endif

#endif

	if (len >= 2)
	{
		sum += kernel[0] * queue[0]
			+ kernel[1] * queue[1];

		//kernel += 2;
		//queue += 2;
		//len &= 1;
	}

	//if (len >= 1)
	//{
	//	sum += kernel[0] * queue[0];
	//}

	return sum;
}

static void fir_interleaved_4(iqconverter_float_t *cnv, float *samples, int len)
{
	int i;
	int fir_index = cnv->fir_index;
	int fir_len = cnv->len;
	float *fir_kernel = cnv->fir_kernel;
	float *fir_queue = cnv->fir_queue;
	float *queue;
	float acc;

	for (i = 0; i < len; i += 2)
	{
		queue = fir_queue + fir_index;

		queue[0] = samples[i];

		acc = fir_kernel[0] * (queue[0] + queue[4 - 1])
			+ fir_kernel[1] * (queue[1] + queue[4 - 2]);

		samples[i] = acc;

		if (--fir_index < 0)
		{
			fir_index = fir_len * (SIZE_FACTOR - 1);
			memcpy(fir_queue + fir_index + 1, fir_queue, (fir_len - 1) * sizeof(float));
		}
	}

	cnv->fir_index = fir_index;
}

static void fir_interleaved_8(iqconverter_float_t *cnv, float *samples, int len)
{
	int i;
	int fir_index = cnv->fir_index;
	int fir_len = cnv->len;
	float *fir_kernel = cnv->fir_kernel;
	float *fir_queue = cnv->fir_queue;
	float *queue;
	float acc;

	for (i = 0; i < len; i += 2)
	{
		queue = fir_queue + fir_index;

		queue[0] = samples[i];

		acc = fir_kernel[0] * (queue[0] + queue[8 - 1])
			+ fir_kernel[1] * (queue[1] + queue[8 - 2])
			+ fir_kernel[2] * (queue[2] + queue[8 - 3])
			+ fir_kernel[3] * (queue[3] + queue[8 - 4]);

		samples[i] = acc;

		if (--fir_index < 0)
		{
			fir_index = fir_len * (SIZE_FACTOR - 1);
			memcpy(fir_queue + fir_index + 1, fir_queue, (fir_len - 1) * sizeof(float));
		}
	}

	cnv->fir_index = fir_index;
}

static void fir_interleaved_12(iqconverter_float_t *cnv, float *samples, int len)
{
	int i;
	int fir_index = cnv->fir_index;
	int fir_len = cnv->len;
	float *fir_kernel = cnv->fir_kernel;
	float *fir_queue = cnv->fir_queue;
	float *queue;
	float acc = 0;

	for (i = 0; i < len; i += 2)
	{
		queue = fir_queue + fir_index;

		queue[0] = samples[i];

		acc = fir_kernel[0]  * (queue[0]  + queue[12 - 1])
			+ fir_kernel[1]  * (queue[1]  + queue[12 - 2])
			+ fir_kernel[2]  * (queue[2]  + queue[12 - 3])
			+ fir_kernel[3]  * (queue[3]  + queue[12 - 4])
			+ fir_kernel[4]  * (queue[4]  + queue[12 - 5])
			+ fir_kernel[5]  * (queue[5]  + queue[12 - 6]);

		samples[i] = acc;

		if (--fir_index < 0)
		{
			fir_index = fir_len * (SIZE_FACTOR - 1);
			memcpy(fir_queue + fir_index + 1, fir_queue, (fir_len - 1) * sizeof(float));
		}
	}

	cnv->fir_index = fir_index;
}

static void fir_interleaved_24(iqconverter_float_t *cnv, float *samples, int len)
{
	int i;
	int fir_index = cnv->fir_index;
	int fir_len = cnv->len;
	float *fir_kernel = cnv->fir_kernel;
	float *fir_queue = cnv->fir_queue;
	float *queue;
	float acc = 0;

	for (i = 0; i < len; i += 2)
	{
		queue = fir_queue + fir_index;

		queue[0] = samples[i];

		acc = fir_kernel[0]  * (queue[0]  + queue[24 - 1])
			+ fir_kernel[1]  * (queue[1]  + queue[24 - 2])
			+ fir_kernel[2]  * (queue[2]  + queue[24 - 3])
			+ fir_kernel[3]  * (queue[3]  + queue[24 - 4])
			+ fir_kernel[4]  * (queue[4]  + queue[24 - 5])
			+ fir_kernel[5]  * (queue[5]  + queue[24 - 6])
			+ fir_kernel[6]  * (queue[6]  + queue[24 - 7])
			+ fir_kernel[7]  * (queue[7]  + queue[24 - 8])
			+ fir_kernel[8]  * (queue[8]  + queue[24 - 9])
			+ fir_kernel[9]  * (queue[9]  + queue[24 - 10])
			+ fir_kernel[10] * (queue[10] + queue[24 - 11])
			+ fir_kernel[11] * (queue[11] + queue[24 - 12]);

		samples[i] = acc;

		if (--fir_index < 0)
		{
			fir_index = fir_len * (SIZE_FACTOR - 1);
			memcpy(fir_queue + fir_index + 1, fir_queue, (fir_len - 1) * sizeof(float));
		}
	}

	cnv->fir_index = fir_index;
}

static void fir_interleaved_generic(iqconverter_float_t *cnv, float *samples, int len)
{
	int i;
	int fir_index = cnv->fir_index;
	int fir_len = cnv->len;
	float *fir_kernel = cnv->fir_kernel;
	float *fir_queue = cnv->fir_queue;
	float *queue;

	for (i = 0; i < len; i += 2)
	{
		queue = fir_queue + fir_index;

		queue[0] = samples[i];

		samples[i] = process_fir_taps(fir_kernel, queue, fir_len);

		if (--fir_index < 0)
		{
			fir_index = fir_len * (SIZE_FACTOR - 1);
			memcpy(fir_queue + fir_index + 1, fir_queue, (fir_len - 1) * sizeof(float));
		}
	}

	cnv->fir_index = fir_index;
}

static void fir_interleaved(iqconverter_float_t *cnv, float *samples, int len)
{
	switch (cnv->len)
	{
	case 4:
		fir_interleaved_4(cnv, samples, len);
		break;
	case 8:
		fir_interleaved_8(cnv, samples, len);
		break;
	case 12:
		fir_interleaved_12(cnv, samples, len);
		break;
	case 24:
		fir_interleaved_24(cnv, samples, len);
		break;
	default:
		fir_interleaved_generic(cnv, samples, len);
		break;
	}
}

static void delay_interleaved(iqconverter_float_t *cnv, float *samples, int len)
{
	int i;
	ALIGNED int index;
	ALIGNED int half_len;
	ALIGNED float res;
	
	half_len = cnv->len >> 1;
	index = cnv->delay_index;

	for (i = 0; i < len; i += 2)
	{
		res = cnv->delay_line[index];
		cnv->delay_line[index] = samples[i];
		samples[i] = res;

		if (++index >= half_len)
		{
			index = 0;
		}
	}
	
	cnv->delay_index = index;
}

#define SCALE (0.01f)

static void remove_dc(iqconverter_float_t *cnv, float *samples, int len)
{
	int i;
	ALIGNED float avg = cnv->avg;

	for (i = 0; i < len; i++)
	{
		samples[i] -= avg;
		avg += SCALE * samples[i];
	}

	cnv->avg = avg;
}

static void translate_fs_4(iqconverter_float_t *cnv, float *samples, int len)
{
	int i;
	ALIGNED float hbc = cnv->hbc;

#ifdef USE_SSE2

	float *buf = samples;
	ALIGNED __m128 vec;
	ALIGNED __m128 rot = _mm_set_ps(hbc, 1.0f, -hbc, -1.0f);

	for (i = 0; i < len / 4; i++, buf +=4)
	{
		vec = _mm_loadu_ps(buf);
		vec = _mm_mul_ps(vec, rot);
		_mm_storeu_ps(buf, vec);
	}

#else

	int j;

	for (i = 0; i < len / 4; i++)
	{
		j = i << 2;
		samples[j + 0] = -samples[j + 0];
		samples[j + 1] = -samples[j + 1] * hbc;
		//samples[j + 2] = samples[j + 2];
		samples[j + 3] = samples[j + 3] * hbc;
	}

#endif

	fir_interleaved(cnv, samples, len);
	delay_interleaved(cnv, samples + 1, len);
}

void iqconverter_float_process(iqconverter_float_t *cnv, float *samples, int len)
{
	remove_dc(cnv, samples, len);
	translate_fs_4(cnv, samples, len);
}
