/*
Copyright (c) 2014 Richard van Roy (pluizer)

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

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

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.
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include "cdynvector.h"

static void* smalloc(size_t size)
{
	void* ptr = malloc(size);
	if (!ptr)
	{
		fprintf(stderr, "Out of memory!");
		exit(-1);
	}
	return ptr;
}

static void* srealloc(void* old, size_t size)
{
	void* ptr = realloc(old, size);
	if (!ptr)
	{
		fprintf(stderr, "Out of memory!");
		exit(-1);
	}
	return ptr;
}

typedef struct _DV_IndexStack
{
	unsigned* data;
	unsigned size_hint;
	unsigned size;
} DV_IndexStack;

DV_IndexStack* new_index_stack(unsigned size_hint)
{
	DV_IndexStack* is = smalloc(sizeof(DV_IndexStack));
	is->data = smalloc(sizeof(unsigned) * size_hint);
	is->size_hint = size_hint;
	is->size = 0;
	return is;
}

void free_index_stack(DV_IndexStack* is)
{
	free(is->data);
	free(is);
}

void index_stack_grow(DV_IndexStack* is)
{
	is->size_hint *= 2;
	is->data = srealloc(is->data, sizeof(unsigned) * is->size_hint);
}

void index_stack_push(DV_IndexStack* is, unsigned index)
{
	if (is->size >= is->size_hint)
	{
		index_stack_grow(is);
	}
	is->data[is->size++] = index;
}

int index_stack_empty(DV_IndexStack* is)
{
	return !is->size;
}

unsigned index_stack_pop(DV_IndexStack* is)
{
	assert(!index_stack_empty(is));
	return is->data[--is->size];
}

DV_Vector* dv_vector_new(unsigned chunk_size, unsigned size_hint)
{
	DV_Vector* dv = smalloc(sizeof(DV_Vector));
	assert(dv);
	dv->indices = smalloc(sizeof(unsigned)*size_hint);
	memset(dv->indices, 0, sizeof(unsigned)*size_hint);
	dv->available_stack = new_index_stack(size_hint);
	dv->last_stack = new_index_stack(size_hint);
	dv->size = 0;
	dv->size_hint = size_hint;
	dv->chunk_size = chunk_size;
	dv->data = smalloc(dv->chunk_size  * size_hint);
	memset(dv->data, 0, dv->chunk_size * size_hint);
	return dv;
}

void dv_vector_free(DV_Vector* dv)
{
	free(dv->data);
	free(dv->indices);
	free_index_stack(dv->available_stack);
	free_index_stack(dv->last_stack);
	free(dv);
}

unsigned vector_grow(DV_Vector* dv)
{
	unsigned old_max = dv->size_hint;
	dv->size_hint *= 2;
	dv->data = srealloc(dv->data, 
			    dv->chunk_size * dv->size_hint);
	dv->indices = srealloc(dv->indices, sizeof(unsigned) * dv->size_hint);
	memset(dv->indices+old_max, 0, sizeof(unsigned)*old_max);
	return dv->size_hint - old_max;
}


unsigned dv_vector_push(DV_Vector* dv, void* chunk, unsigned* grown_by)
{
	unsigned index = index_stack_empty(dv->available_stack) 
		? dv->size : index_stack_pop(dv->available_stack);
	
	*grown_by = 0;

	/* vector full */
	if (dv->size >= dv->size_hint)
	{
		*grown_by = vector_grow(dv);
	}

	memcpy(dv->data+(dv->size*dv->chunk_size), chunk, dv->chunk_size);
	dv->indices[index] = dv->size;
	dv->size++;
	index_stack_push(dv->last_stack, index);
	return index;
}

void dv_vector_remove(DV_Vector* dv, unsigned index)
{
	dv->size--;
	if (dv->indices[index] != dv->size)
	{
		memcpy(dv->data+(dv->chunk_size * dv->indices[index]),
		       dv->data+(dv->chunk_size * (dv->size)),
		       dv->chunk_size);
		unsigned last = index_stack_pop(dv->last_stack);
		dv->indices[last] = dv->indices[index];
	} else {
		index_stack_pop(dv->last_stack);
	}
	index_stack_push(dv->available_stack, index);
}

void dv_vector_change(DV_Vector* dv, unsigned index, void* chunk)
{
	memcpy(dv->data+(dv->chunk_size * dv->indices[index]),
	       chunk,
	       dv->chunk_size);
}

void* dv_vector_ref(DV_Vector* dv, unsigned index)
{
	return dv->data+(dv->chunk_size * dv->indices[index]);
}

unsigned dv_vector_chunk_size(DV_Vector* dv)
{
	return dv->chunk_size;
}

unsigned dv_vector_size(DV_Vector* dv)
{
	return dv->size;
}

unsigned dv_vector_current_capacity(DV_Vector* dv)
{
	return dv->size_hint;
}

void* dv_vector_data(DV_Vector* dv)
{
	return dv->data;
}