radare2/libr/util/cache.c

/* radare - LGPL - Copyright 2013-2020 - pancake */

// XXX: should use the same code as libr/io/cache.c
// one malloc per write
#include <r_util.h>
// TODO: optimize reallocs.. store RBuffer info.. wait. extend r_buf_ for that?

R_API RCache *r_cache_new(void) {
	RCache *c = R_NEW0 (RCache);
	if (!c) {
		return NULL;
	}
	c->buf = NULL;
	c->base = 0;
	c->len = 0;
	return c;
}

R_API void r_cache_free(RCache *c) {
	if (c) {
		free (c->buf);
	}
	free (c);
}

R_API const ut8 *r_cache_get(RCache *c, ut64 addr, int *len) {
	if (!c->buf) {
		return NULL;
	}
	if (len) {
		*len = c->base - addr;
	}
	if (addr < c->base) {
		return NULL;
	}
	if (addr > (c->base + c->len)) {
		return NULL;
	}
	if (len) {
		*len = c->len - (addr - c->base);
	}
	// eprintf ("4 - %d\n", (addr-c->base));
	return c->buf + (addr - c->base);
}

R_API int r_cache_set(RCache *c, ut64 addr, const ut8 *buf, int len) {
	if (!c) {
		return 0;
	}
	if (!c->buf) {
		c->buf = malloc (len);
		if (!c->buf) {
			return 0;
		}
		memcpy (c->buf, buf, len);
		c->base = addr;
		c->len = len;
	} else if (addr < c->base) {
		ut8 *b;
		int baselen = (c->base - addr);
		int newlen = baselen + ((len > c->len)? len: c->base);
		// XXX expensive heap usage. must simplify
		b = malloc (newlen);
		if (!b) {
			return 0;
		}
		memset (b, 0xff, newlen);
		memcpy (b + baselen, c->buf, c->len);
		memcpy (b, buf, len);
		free (c->buf);
		c->buf = b;
		c->base = addr;
		c->len = newlen;
	} else if ((addr + len) > (c->base + c->len)) {
		ut8 *b;
		int baselen = (addr - c->base);
		int newlen = baselen + len;
		b = realloc (c->buf, newlen);
		if (!b) {
			return 0;
		}
		memcpy (b + baselen, buf, len);
		c->buf = b;
		c->len = newlen;
	} else {
		memcpy (c->buf, buf, len);
	}
	return c->len;
}

R_API void r_cache_flush(RCache *c) {
	if (c) {
		c->base = 0;
		c->len = 0;
		R_FREE (c->buf);
	}
}