elinks/src/util/memlist.c

/** These routines represent handling of struct memory_list.
 * @file */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdarg.h>
#include <stdlib.h>

#include "elinks.h"

#include "util/error.h"
#include "util/memlist.h"
#include "util/memory.h"


/**
 * @struct memory_list
 * memory_list is used to track information about all allocated memory
 * belonging to something. Then we can free it when we won't need it
 * anymore, but the one who allocated it won't be able to get control
 * back in order to free it himself.
 */

#define ML_SIZE(n) (sizeof(struct memory_list) + (n) * sizeof(void *))

/** Create a memory list. If @a p is NULL or allocation fails, it will
 * return NULL.
 * It always stops at first NULL element.
 * @relates memory_list */
#if defined(DEBUG_MEMLIST) && defined(HAVE_VARIADIC_MACROS)
struct memory_list *
debug_getml(unsigned char *file, int line, void *p, ...)
#else
struct memory_list *
getml(void *p, ...)
#endif
{
	struct memory_list *ml;
	va_list ap;
	void *q;
	int n = 1;

	/* If first element is NULL, there's no need to allocate memory, so
	 * just return. */
	if (!p) return NULL;

	/* How many elements ? */
	va_start(ap, p);
	while ((q = va_arg(ap, void *))) n++;
	va_end(ap);

	/* Allocate space for memory list. */
	ml = mem_alloc(ML_SIZE(n));
	if (!ml) return NULL;

	/* First element. */
	ml->n = 1;
	ml->p[0] = p;

	/* Next ones. */
	va_start(ap, p);
	while ((q = va_arg(ap, void *))) ml->p[ml->n++] = q;
	va_end(ap);

	/* The end. */
	return ml;
}

/** Add elements to a memory list.
 * If memory list exists, it enlarges it, else it creates it.
 * if there's no elements or first element is NULL, it does nothing.
 * It always stops at first NULL element.
 * @relates memory_list */
#if defined(DEBUG_MEMLIST) && defined(HAVE_VARIADIC_MACROS)
void
debug_add_to_ml(unsigned char *file, int line, struct memory_list **ml, ...)
#else
void
add_to_ml(struct memory_list **ml, ...)
#endif
{
	va_list ap;
	void *q;
	int n = 0;

	/* How many new elements ? */
	va_start(ap, ml);
	while ((q = va_arg(ap, void *))) n++;
	va_end(ap);

	/* None, so just return. */
	if (!n) {
#ifdef DEBUG_MEMLIST
#ifdef HAVE_VARIADIC_MACROS
		errline = line, errfile = file;
#else
		errline = 0, errfile = "?";
#endif
		elinks_error("add_to_ml(%p, NULL, ...)", ml);
#endif
		return;
	}

	if (!*ml) {
		/* If getml() wasn't called before or returned NULL,
		 * then we create it. */
		*ml = mem_alloc(ML_SIZE(n));
		if (!*ml) return;

		(*ml)->n = 0;
	} else {
		/* Enlarge existing ml. */
		struct memory_list *nml;

		nml = mem_realloc(*ml, ML_SIZE(n + (*ml)->n));
		if (!nml) return;

		*ml = nml;
	}

	/* Set ml with new elements and update count. */
	va_start(ap, ml);
	while ((q = va_arg(ap, void *))) (*ml)->p[(*ml)->n++] = q;
	va_end(ap);
}

/** @relates memory_list */
#ifdef DEBUG_MEMLIST
void
debug_add_one_to_ml(unsigned char *file, int line, struct memory_list **ml, void *p)
#else
void
add_one_to_ml(struct memory_list **ml, void *p)
#endif
{
	/* None, so just return. */
	if (!p) {
#ifdef DEBUG_MEMLIST
		errline = line, errfile = file;
		elinks_error("add_one_to_ml(%p, NULL)", ml);
#endif
		return;
	}

	if (!*ml) {
		/* If getml() wasn't called before or returned NULL,
		 * then we create it. */
		*ml = mem_alloc(ML_SIZE(1));
		if (!*ml) return;

		(*ml)->n = 0;
	} else {
		/* Enlarge existing ml. */
		struct memory_list *nml;

		nml = mem_realloc(*ml, ML_SIZE(1 + (*ml)->n));
		if (!nml) return;

		*ml = nml;
	}

	/* Set ml with new element and update count. */
	(*ml)->p[(*ml)->n++] = p;
}


/** Free elements and memory list.
 * It returns safely if passed a NULL pointer.
 * @relates memory_list */
void
freeml(struct memory_list *ml)
{
	int i;

	if (!ml) return;

	for (i = 0; i < ml->n; i++)
		mem_free(ml->p[i]);

	mem_free(ml);
}

#undef ML_SIZE