/*!
 * \file lifeutil.c
 *
 * \brief Support routines for Conway's Game of Life.
 *
 * $Copyright: (C) 2003 Tony Finch <dot@dotat.at> $
 *
 * $dotat: life/lifeutil.c,v 1.6 2003/12/17 10:02:19 fanf2 Exp $
 */

#include <err.h>
#include <stdio.h>
#include <stdlib.h>

#include "life.h"

void
life_alloc(life_ctx *ctx, size_t size) {
	free(ctx->old);
	ctx->old = NULL;
	if(ctx->size > size)
		return;
	ctx->old = ctx->space;
	ctx->size = size;
	ctx->space = malloc(sizeof(life_cells) * size);
	ctx->new = ctx->space;
	if(ctx->space == NULL)
		err(1, "malloc");
}

void
life_init(life_ctx *ctx, void *aux,
    life_pos minx, life_pos miny, life_pos maxx, life_pos maxy) {
	ctx->cells = ctx->end = ctx->new = NULL;
	ctx->workdone = ctx->generation = 0;
	ctx->space = ctx->old = NULL;
	ctx->size = 0;
	ctx->minx = minx; ctx->miny = miny;
	ctx->maxx = maxx; ctx->maxy = maxy;
	ctx->aux = aux;
	life_alloc(ctx, 1024);
}

void
life_debug(life_ctx *ctx) {
	life_cells *this;
	unsigned long population;
	int bit;

	this = ctx->cells;
	population = 0;
	do {
		if(this->pos < 0)
			printf("%12d\n", this->pos);
		else {
			printf("%12d %08x\n", this->pos, this->bmp);
			for(bit = 0; bit < WORDSIZE; bit++)
				if(this->bmp & 1 << bit)
					++population;
		}
	} while(this++->pos != -1);
	printf("population %lu\n", population);
}

void
life_step(life_ctx *ctx) {
	size_t required;

	ctx->end = life(ctx->cells, ctx->new, ctx);
	ctx->workdone += ctx->end - ctx->new;
	ctx->generation++;
	life_draw_flush(ctx);

	ctx->cells = ctx->new;
	required = (ctx->end - ctx->new) * 3;
	if(ctx->end + required < ctx->space + ctx->size)
		ctx->new = ctx->end;
	else if(ctx->space + required < ctx->cells)
		ctx->new = ctx->space;
	else
		life_alloc(ctx, ctx->size * 4);
}

void
life_draw(life_ctx *ctx) {
	life_cells *this;
	life_pos y;

	life_draw_clear(ctx);
	for(this = ctx->cells; this->pos != -1; this++)
		if(this->pos < 0)
			y = this->pos;
		else
			life_draw_bmp(ctx, this->pos, y, 0, this->bmp);
	life_draw_flush(ctx);
}

void
life_draw_bmp_cellwise(life_ctx *ctx,
    life_pos x, life_pos y, life_bmp old, life_bmp new) {
	life_bmp dead, live, mask;
	int bit, width;

	if(y < ctx->miny || y >= ctx->maxy)
		return;
	x -= ctx->minx; y -= ctx->miny;
	width = ctx->maxx - ctx->minx;
	dead = old & ~new; live = ~old & new;
	if(x + WORDSIZE >= width) {
		if(x >= width)
			return;
		mask = ~0 >> (x + WORDSIZE - width);
		dead &= mask;
		live &= mask;
	} else if(x < 0) {
		if(x + WORDSIZE < 0)
			return;
		mask = ~0 << -x;
		dead &= mask;
		live &= mask;
	}
	if(dead == 0 && live == 0)
		return;
	for(bit = 0; bit < WORDSIZE; bit++)
		if(dead & 1<<bit)
			life_draw_dead(ctx, x+bit, y);
		else if(live & 1<<bit)
			life_draw_live(ctx, x+bit, y);
}

life_pos
life_maxy(life_ctx *ctx) {
	life_cells *p = ctx->end - 2;
	while(p->pos > 0)
		p--;
	return(p->pos + 1);
}

/* EOF lifeutil.c */