#include <stdint.h>
#include <string.h>
#include <stdlib.h>

#include "pixmap.h"
#include "pixmap_impl.h"

struct packed_pixmap {
    struct pixmap pixmap;
    unsigned int width;
    unsigned int height;
    uint8_t * pixels;
};

static unsigned int
line_size(unsigned int width) {
    return width/8 + ((width % 8)==0 ? 0 : 1);
}

static void
packed_pixmap_clear(struct pixmap * p) {
    struct packed_pixmap * this = (struct packed_pixmap *)p;
    memset(this->pixels, 0, this->height*line_size(this->width)*sizeof(uint8_t));
}

/* Draw a point on the pixmap.
 */
static void
packed_pixmap_set_pixel(struct pixmap * p, unsigned int x, unsigned int y, int v) {
    struct packed_pixmap * this = (struct packed_pixmap *)p;
    if (x < this->width && y < this->height) {
	uint8_t mask = 1;
	mask <<= x % 8;
	if (v)
	    this->pixels[line_size(this->width)*y + x/8] |= mask;
	else
	    this->pixels[line_size(this->width)*y + x/8] &= ~mask;
    }
}

static int
packed_pixmap_get_pixel(const struct pixmap * p, unsigned int x, unsigned int y) {
    struct packed_pixmap * this = (struct packed_pixmap *)p;
    if (x < this->width && y < this->height) {
	uint8_t mask = 1;
	mask <<= x % 8;
	return (this->pixels[line_size(this->width)*y + x/8] & mask);
    }
    return 0;
}

static unsigned int
packed_pixmap_get_width(const struct pixmap * p) {
    struct packed_pixmap * this = (struct packed_pixmap *)p;
    return this->width;
}

static unsigned int
packed_pixmap_get_height(const struct pixmap * p) {
    struct packed_pixmap * this = (struct packed_pixmap *)p;
    return this->height;
}

static size_t
packed_pixmap_get_memory_size(const struct pixmap * p) {
    struct packed_pixmap * this = (struct packed_pixmap *)p;
    return this->height * line_size(this->width) * sizeof(uint8_t);
}

static void
packed_pixmap_destroy(struct pixmap * this) {
    free(this);
}

struct pixmap *
packed_pixmap_new(unsigned int width, unsigned int height, uint8_t * buf) {
    static const struct pixmap_vtable vtable = {
	.clear = packed_pixmap_clear,
	.set_pixel = packed_pixmap_set_pixel,
	.get_pixel = packed_pixmap_get_pixel,
	.get_width = packed_pixmap_get_width,
	.get_height = packed_pixmap_get_height,
	.get_memory_size = packed_pixmap_get_memory_size,
	.destroy = packed_pixmap_destroy,
    };

    struct packed_pixmap * this = malloc(sizeof(struct packed_pixmap) + height*line_size(width)*sizeof(uint8_t));
    if (this) {
	this->pixmap.vtable = & vtable;
	this->width = width;
	this->height = height;
	this->pixels = buf;
	memset(this->pixels, 0, height*line_size(width)*sizeof(uint8_t));
    }
    return &(this->pixmap);
}