/*
 *     low frequency Digital-Function-Generator
 *     Lookup table generator code
 *
 *   Copyright (C) 2007  Michael Buesch <m@bues.ch>
 *
 *   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.
 */

#include <stdio.h>
#include <math.h>
#include <strings.h>
#include <ctype.h>


#undef M_PI
#define M_PI		3.14159265358979323846264338327


/* Make sure buf is long enough! */
static void toupper_str(char *buf, const char *str)
{
	while (*str) {
		*buf = toupper(*str);
		buf++;
		str++;
	}
	*buf = 0;
}

static void generate_sine_table(void)
{
	double i;
	double step;
	double s;
	unsigned int val;
	int cnt = 0;

	printf("/* Sine function table */\n");
	printf("extern const uint8_t PROGMEM table_sine[];\n");
	printf("const uint8_t PROGMEM table_sine[] = {");

	/* sin() takes radians as arg. 2pi rad == 360deg */
	step = (M_PI * 2) / (0xFF + 1);
	for (i = 0; i < (M_PI * 2) - step; i += step) {
		s = sin(i);
		s += 1;
		s *= 0xFF / 2;
		val = round(s);
		if (cnt % 8 == 0)
			printf("\n\t0x%02X,", val & 0xFF);
		else
			printf(" 0x%02X,", val & 0xFF);
		cnt++;
	}
	printf("\n};\n");
}

static void generate_triangle_table(void)
{
	int i;
	unsigned int val;

	printf("/* Triangle function table */\n");
	printf("extern const uint8_t PROGMEM table_triang[];\n");
	printf("const uint8_t PROGMEM table_triang[] = {");

	for (i = 0, val = 0; i < 0xFF + 1; i++) {
		if (i % 8 == 0)
			printf("\n\t0x%02X,", val & 0xFF);
		else
			printf(" 0x%02X,", val & 0xFF);
		if (val == 0xFE) {
			val++;
		} else {
			if (i < 128)
				val += 2;
			else
				val -= 2;
		}
	}
	printf("\n};\n");
}

static void gen_chartab(const char *name, const char *template)
{
	int i, column;
	unsigned int val;
	char upper_name[128];

	static unsigned int char_ascii = 0;

	toupper_str(upper_name, name);
	printf("/* Character table: %s */\n", upper_name);
	printf("extern const uint8_t PROGMEM table_char_%s[];\n", name);
	printf("const uint8_t PROGMEM table_char_%s[] = {\n\t", name);

	column = 0;
	val = 0;
	for (i = 0; i < 40; i++) {
		if (template[i] != ' ')
			val |= (1 << (4 - column));
		column++;
		if (column == 5) {
			printf("0x%02X, ", val & 0xFF);
			column = 0;
			val = 0;
		}
	}
	printf("\n};\n");
	printf("#define ASCII_%s  %u\n\n", upper_name, char_ascii);

	char_ascii++;
}

static void generate_char_tables(void)
{
	const char *t;

	t =
	"#    "
	" #   "
	"  #  "
	"  #  "
	" #   "
	"#    "
	"#    "
	" #   ";
	gen_chartab("sine", t);

	t =
	"#    "
	"#####"
	"    #"
	"    #"
	"    #"
	"#####"
	"#    "
	"#    ";
	gen_chartab("square", t);

	t =
	"#    "
	" #   "
	"  #  "
	"   # "
	"  #  "
	" #   "
	"#    "
	"     ";
	gen_chartab("tri", t);

	t =
	"#    "
	" #   "
	"  #  "
	"   # "
	"#####"
	" #   "
	"  #  "
	"   # ";
	gen_chartab("saw", t);
}

int main(int argc, char **argv)
{
	printf("/******************************************\n");
	printf(" ** THIS FILE IS GENERATED. DO NOT EDIT! **\n");
	printf(" ******************************************/\n");
	printf("\n");
	printf("#include <avr/pgmspace.h>\n");
	printf("\n");
	printf("\n");

	generate_sine_table();
	printf("\n\n\n");

	generate_triangle_table();
	printf("\n\n\n");

	generate_char_tables();
	printf("\n\n\n");
}