#include "pool.h"

#include "posix.h"

#ifndef GIT_WIN32

#include <unistd.h>

#endif

struct git_pool_page {

	git_pool_page *next;

	uint32_t size;

	uint32_t avail;

	GIT_ALIGN(char data[GIT_FLEX_ARRAY], 8);

};

static void *pool_alloc_page(git_pool *pool, uint32_t size);

uint32_t git_pool__system_page_size(void)

{

	static uint32_t size = 0;

	if (!size) {

		size_t page_size;

		if (git__page_size(&page_size) < 0)

			page_size = 4096;

		/* allow space for malloc overhead */

		size = page_size - (2 * sizeof(void *)) - sizeof(git_pool_page);

	}

	return size;

}

#ifndef GIT_DEBUG_POOL

void git_pool_init(git_pool *pool, uint32_t item_size)

{

	assert(pool);

	assert(item_size >= 1);

	memset(pool, 0, sizeof(git_pool));

	pool->item_size = item_size;

	pool->page_size = git_pool__system_page_size();

}

void git_pool_clear(git_pool *pool)

{

	git_pool_page *scan, *next;

	for (scan = pool->pages; scan != NULL; scan = next) {

		next = scan->next;

		git__free(scan);

	}

	pool->pages = NULL;

}

static void *pool_alloc_page(git_pool *pool, uint32_t size)

{

	git_pool_page *page;

	const uint32_t new_page_size = (size <= pool->page_size) ? pool->page_size : size;

	size_t alloc_size;

	if (GIT_ADD_SIZET_OVERFLOW(&alloc_size, new_page_size, sizeof(git_pool_page)) ||

		!(page = git__malloc(alloc_size)))

		return NULL;

	page->size = new_page_size;

	page->avail = new_page_size - size;

	page->next = pool->pages;

	pool->pages = page;

	return page->data;

}

static void *pool_alloc(git_pool *pool, uint32_t size)

{

	git_pool_page *page = pool->pages;

	void *ptr = NULL;

	if (!page || page->avail < size)

		return pool_alloc_page(pool, size);

	ptr = &page->data[page->size - page->avail];

	page->avail -= size;

	return ptr;

}

uint32_t git_pool__open_pages(git_pool *pool)

{

	uint32_t ct = 0;

	git_pool_page *scan;

	for (scan = pool->pages; scan != NULL; scan = scan->next) ct++;

	return ct;

}

bool git_pool__ptr_in_pool(git_pool *pool, void *ptr)

{

	git_pool_page *scan;

	for (scan = pool->pages; scan != NULL; scan = scan->next)

		if ((void *)scan->data <= ptr &&

			(void *)(((char *)scan->data) + scan->size) > ptr)

			return true;

	return false;

}

#else

static int git_pool__ptr_cmp(const void * a, const void * b)

{

	if(a > b) {

		return 1;

	}

	if(a < b) {

		return -1;

	}

	else {

		return 0;

	}

}

void git_pool_init(git_pool *pool, uint32_t item_size)

{

	assert(pool);

	assert(item_size >= 1);

	memset(pool, 0, sizeof(git_pool));

	pool->item_size = item_size;

	pool->page_size = git_pool__system_page_size();

	git_vector_init(&pool->allocations, 100, git_pool__ptr_cmp);

}

void git_pool_clear(git_pool *pool)

{

	git_vector_free_deep(&pool->allocations);

}

static void *pool_alloc(git_pool *pool, uint32_t size) {

	void *ptr = NULL;

	if((ptr = git__malloc(size)) == NULL) {

		return NULL;

	}

	git_vector_insert_sorted(&pool->allocations, ptr, NULL);

	return ptr;

}

bool git_pool__ptr_in_pool(git_pool *pool, void *ptr)

{

	size_t pos;

	return git_vector_bsearch(&pos, &pool->allocations, ptr) != GIT_ENOTFOUND;

}

#endif

void git_pool_swap(git_pool *a, git_pool *b)

{

	git_pool temp;

	if (a == b)

		return;

	memcpy(&temp, a, sizeof(temp));

	memcpy(a, b, sizeof(temp));

	memcpy(b, &temp, sizeof(temp));

}

static uint32_t alloc_size(git_pool *pool, uint32_t count)

{

	const uint32_t align = sizeof(void *) - 1;

	if (pool->item_size > 1) {

		const uint32_t item_size = (pool->item_size + align) & ~align;

		return item_size * count;

	}

	return (count + align) & ~align;

}

void *git_pool_malloc(git_pool *pool, uint32_t items)

{

	return pool_alloc(pool, alloc_size(pool, items));

}

void *git_pool_mallocz(git_pool *pool, uint32_t items)

{

	const uint32_t size = alloc_size(pool, items);

	void *ptr = pool_alloc(pool, size);

	if (ptr)

		memset(ptr, 0x0, size);

	return ptr;

}

char *git_pool_strndup(git_pool *pool, const char *str, size_t n)

{

	char *ptr = NULL;

	assert(pool && str && pool->item_size == sizeof(char));

	if ((uint32_t)(n + 1) < n)

		return NULL;

	if ((ptr = git_pool_malloc(pool, (uint32_t)(n + 1))) != NULL) {

		memcpy(ptr, str, n);

		ptr[n] = '\0';

	}

	return ptr;

}

char *git_pool_strdup(git_pool *pool, const char *str)

{

	assert(pool && str && pool->item_size == sizeof(char));

	return git_pool_strndup(pool, str, strlen(str));

}

char *git_pool_strdup_safe(git_pool *pool, const char *str)

{

	return str ? git_pool_strdup(pool, str) : NULL;

}

char *git_pool_strcat(git_pool *pool, const char *a, const char *b)

{

	void *ptr;

	size_t len_a, len_b;

	assert(pool && pool->item_size == sizeof(char));

	len_a = a ? strlen(a) : 0;

	len_b = b ? strlen(b) : 0;

	if ((ptr = git_pool_malloc(pool, (uint32_t)(len_a + len_b + 1))) != NULL) {

		if (len_a)

			memcpy(ptr, a, len_a);

		if (len_b)

			memcpy(((char *)ptr) + len_a, b, len_b);

		*(((char *)ptr) + len_a + len_b) = '\0';

	}

	return ptr;

}