/*

 * File: z-virt.c

 * Purpose: Memory management routines

 *

 * Copyright (c) 1997 Ben Harrison.

 *

 * This work is free software; you can redistribute it and/or modify it

 * under the terms of either:

 *

 * a) the GNU General Public License as published by the Free Software

 *    Foundation, version 2, or

 *

 * b) the "Angband licence":

 *    This software may be copied and distributed for educational, research,

 *    and not for profit purposes provided that this copyright and statement

 *    are included in all such copies.  Other copyrights may also apply.

 */

#include "z-virt.h"

#include "z-util.h"



/*

 * Hooks for platform-specific memory allocation.

 */

static mem_alloc_hook ralloc_aux;

static mem_free_hook rnfree_aux;

static mem_realloc_hook realloc_aux;





/*

 * Set the hooks for the memory system.

 */

bool mem_set_hooks(mem_alloc_hook alloc, mem_free_hook free, mem_realloc_hook realloc)

{

	/* Error-check */

	if (!alloc || !free || !realloc) return FALSE;



	/* Set up hooks */

	ralloc_aux = alloc;

	rnfree_aux = free;

	realloc_aux = realloc;



	return TRUE;

}





/*

 * Allocate `len` bytes of memory.

 *

 * Returns:

 *  - NULL if `len` == 0; or

 *  - a pointer to a block of memory of at least `len` bytes

 *

 * Doesn't return on out of memory.

 */

void *mem_alloc(size_t len)

{

	void *mem;



	/* Allow allocation of "zero bytes" */

	if (len == 0) return (NULL);



	/* Allocate some memory */

	if (ralloc_aux) mem = (*ralloc_aux)(len);

	else            mem = malloc(len);



	/* Handle OOM */

	if (!mem) quit("Out of Memory!");



	return mem;

}





/*

 * Free the memory pointed to by `p`.

 *

 * Returns NULL.

 */

void *mem_free(void *p)

{

	/* Easy to free nothing */

	if (!p) return (NULL);



	/* Free memory */

	if (rnfree_aux) (*rnfree_aux)(p);

	else            free(p);



	/* Done */

	return (NULL);

}





/*

 * Allocate `len` bytes of memory, copying whatever is in `p` with it.

 *

 * Returns:

 *  - NULL if `len` == 0 or `p` is NULL; or

 *  - a pointer to a block of memory of at least `len` bytes

 *

 * Doesn't return on out of memory.

 */

void *mem_realloc(void *p, size_t len)

{

	void *mem;



	/* Fail gracefully */

	if (!p || len == 0) return (NULL);



	if (realloc_aux) mem = (*realloc_aux)(p, len);

	else             mem = realloc(p, len);



	/* Handle OOM */

	if (!mem) quit("Out of Memory!");



	return mem;

}







/*

 * Duplicates an existing string `str`, allocating as much memory as necessary.

 */

char *string_make(const char *str)

{

	char *res;

	size_t siz;



	/* Error-checking */

	if (!str) return NULL;



	/* Allocate space for the string (including terminator) */

	siz = strlen(str) + 1;

	res = mem_alloc(siz);



	/* Copy the string (with terminator) */

	my_strcpy(res, str, siz);



	return res;

}





/*

 * Un-allocate a string allocated above.

 */

#undef string_free

char *string_free(char *str)

{

	/* Kill the buffer of chars we must have allocated above */

	return mem_free(str);

}