* Split out a fair bit of avahi-core into avahi-common for use by the client library

git-svn-id: file:///home/lennart/svn/public/avahi/trunk@98 941a03a8-eaeb-0310-b9a0-b1bbd8fe43fe

1 files changed, 0 insertions, 744 deletions

diff --git a/avahi-core/dns.c b/avahi-core/dns.c
deleted file mode 100644
index 9e19c9e..0000000
--- a/avahi-core/dns.c
+++ /dev/null
@@ -1,744 +0,0 @@
-/* $Id$ */
-
-/***
-  This file is part of avahi.
- 
-  avahi is free software; you can redistribute it and/or modify it
-  under the terms of the GNU Lesser General Public License as
-  published by the Free Software Foundation; either version 2.1 of the
-  License, or (at your option) any later version.
- 
-  avahi is distributed in the hope that it will be useful, but WITHOUT
-  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
-  or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
-  Public License for more details.
- 
-  You should have received a copy of the GNU Lesser General Public
-  License along with avahi; if not, write to the Free Software
-  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
-  USA.
-***/
-
-#ifdef HAVE_CONFIG_H
-#include <config.h>
-#endif
-
-#include <netinet/in.h>
-
-#include <stdlib.h>
-#include <string.h>
-#include <stdio.h>
-
-#include "dns.h"
-#include "util.h"
-
-AvahiDnsPacket* avahi_dns_packet_new(guint mtu) {
-    AvahiDnsPacket *p;
-    guint max_size;
-
-    if (mtu <= 0)
-        max_size = AVAHI_DNS_PACKET_MAX_SIZE;
-    else if (mtu >= AVAHI_DNS_PACKET_EXTRA_SIZE)
-        max_size = mtu - AVAHI_DNS_PACKET_EXTRA_SIZE;
-    else
-        max_size = 0;
-
-    if (max_size < AVAHI_DNS_PACKET_HEADER_SIZE)
-        max_size = AVAHI_DNS_PACKET_HEADER_SIZE;
-    
-    p = g_malloc(sizeof(AvahiDnsPacket) + max_size);
-    p->size = p->rindex = AVAHI_DNS_PACKET_HEADER_SIZE;
-    p->max_size = max_size;
-    p->name_table = NULL;
-
-    memset(AVAHI_DNS_PACKET_DATA(p), 0, p->size);
-    return p;
-}
-
-AvahiDnsPacket* avahi_dns_packet_new_query(guint mtu) {
-    AvahiDnsPacket *p;
-
-    p = avahi_dns_packet_new(mtu);
-    avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
-    return p;
-}
-
-AvahiDnsPacket* avahi_dns_packet_new_response(guint mtu, gboolean aa) {
-    AvahiDnsPacket *p;
-
-    p = avahi_dns_packet_new(mtu);
-    avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(1, 0, aa, 0, 0, 0, 0, 0, 0, 0));
-    return p;
-}
-
-AvahiDnsPacket* avahi_dns_packet_new_reply(AvahiDnsPacket* p, guint mtu, gboolean copy_queries, gboolean aa) {
-    AvahiDnsPacket *r;
-    g_assert(p);
-
-    r = avahi_dns_packet_new_response(mtu, aa);
-
-    if (copy_queries) {
-        guint n, saved_rindex;
-
-        saved_rindex = p->rindex;
-        p->rindex = AVAHI_DNS_PACKET_HEADER_SIZE;
-        
-        for (n = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_QDCOUNT); n > 0; n--) {
-            AvahiKey *k;
-            gboolean unicast_response;
-
-            if ((k = avahi_dns_packet_consume_key(p, &unicast_response))) {
-                avahi_dns_packet_append_key(r, k, unicast_response);
-                avahi_key_unref(k);
-            }
-        }
-
-        p->rindex = saved_rindex;
-
-        avahi_dns_packet_set_field(r, AVAHI_DNS_FIELD_QDCOUNT, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_QDCOUNT));
-    }
-
-    avahi_dns_packet_set_field(r, AVAHI_DNS_FIELD_ID, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ID));
-
-    avahi_dns_packet_set_field(r, AVAHI_DNS_FIELD_FLAGS,
-                               (avahi_dns_packet_get_field(r, AVAHI_DNS_FIELD_FLAGS) & ~AVAHI_DNS_FLAG_OPCODE) |
-                               (avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & AVAHI_DNS_FLAG_OPCODE));
-
-    return r;
-} 
-
-
-void avahi_dns_packet_free(AvahiDnsPacket *p) {
-    g_assert(p);
-
-    if (p->name_table)
-        g_hash_table_destroy(p->name_table);
-    
-    g_free(p);
-}
-
-void avahi_dns_packet_set_field(AvahiDnsPacket *p, guint index, guint16 v) {
-    g_assert(p);
-    g_assert(index < AVAHI_DNS_PACKET_HEADER_SIZE);
-    
-    ((guint16*) AVAHI_DNS_PACKET_DATA(p))[index] = g_htons(v);
-}
-
-guint16 avahi_dns_packet_get_field(AvahiDnsPacket *p, guint index) {
-    g_assert(p);
-    g_assert(index < AVAHI_DNS_PACKET_HEADER_SIZE);
-
-    return g_ntohs(((guint16*) AVAHI_DNS_PACKET_DATA(p))[index]);
-}
-
-void avahi_dns_packet_inc_field(AvahiDnsPacket *p, guint index) {
-    g_assert(p);
-
-    avahi_dns_packet_set_field(p, index, avahi_dns_packet_get_field(p, index) + 1);
-}   
-
-guint8* avahi_dns_packet_append_name(AvahiDnsPacket *p, const gchar *name) {
-    guint8 *d, *saved_ptr = NULL;
-    guint saved_size;
-    
-    g_assert(p);
-    g_assert(name);
-
-    saved_size = p->size;
-    saved_ptr = avahi_dns_packet_extend(p, 0);
-    
-    while (*name) {
-        guint8* prev;
-        const gchar *pname;
-        gchar label[64];
-
-        /* Check whether we can compress this name. */
-
-        if (p->name_table && (prev = g_hash_table_lookup(p->name_table, name))) {
-            guint index;
-            
-            g_assert(prev >= AVAHI_DNS_PACKET_DATA(p));
-            index = (guint) (prev - AVAHI_DNS_PACKET_DATA(p));
-
-            g_assert(index < p->size);
-
-            if (index < 0x4000) {
-                guint16 *t;
-                if (!(t = (guint16*) avahi_dns_packet_extend(p, sizeof(guint16))))
-                    return NULL;
-
-                *t = g_htons((0xC000 | index));
-                return saved_ptr;
-            }
-        }
-
-        pname = name;
-        
-        if (!(avahi_unescape_label(&name, label, sizeof(label))))
-            goto fail;
-
-        if (!(d = avahi_dns_packet_append_string(p, label)))
-            goto fail;
-
-        if (!p->name_table)
-            /* This works only for normalized domain names */
-            p->name_table = g_hash_table_new_full((GHashFunc) g_str_hash, (GEqualFunc) g_str_equal, g_free, NULL);
-
-        g_hash_table_insert(p->name_table, g_strdup(pname), d);
-    }
-
-    if (!(d = avahi_dns_packet_extend(p, 1)))
-        goto fail;
-    
-    *d = 0;
-
-    return saved_ptr;
-
-fail:
-    p->size = saved_size;
-    return NULL;
-}
-
-guint8* avahi_dns_packet_append_uint16(AvahiDnsPacket *p, guint16 v) {
-    guint8 *d;
-    g_assert(p);
-    
-    if (!(d = avahi_dns_packet_extend(p, sizeof(guint16))))
-        return NULL;
-    
-    *((guint16*) d) = g_htons(v);
-    return d;
-}
-
-guint8 *avahi_dns_packet_append_uint32(AvahiDnsPacket *p, guint32 v) {
-    guint8 *d;
-    g_assert(p);
-
-    if (!(d = avahi_dns_packet_extend(p, sizeof(guint32))))
-        return NULL;
-    
-    *((guint32*) d) = g_htonl(v);
-
-    return d;
-}
-
-guint8 *avahi_dns_packet_append_bytes(AvahiDnsPacket  *p, gconstpointer b, guint l) {
-    guint8* d;
-
-    g_assert(p);
-    g_assert(b);
-    g_assert(l);
-
-    if (!(d = avahi_dns_packet_extend(p, l)))
-        return NULL;
-
-    memcpy(d, b, l);
-    return d;
-}
-
-guint8* avahi_dns_packet_append_string(AvahiDnsPacket *p, const gchar *s) {
-    guint8* d;
-    guint k;
-    
-    g_assert(p);
-    g_assert(s);
-
-    if ((k = strlen(s)) >= 255)
-        k = 255;
-    
-    if (!(d = avahi_dns_packet_extend(p, k+1)))
-        return NULL;
-
-    *d = (guint8) k;
-    memcpy(d+1, s, k);
-
-    return d;
-}
-
-guint8 *avahi_dns_packet_extend(AvahiDnsPacket *p, guint l) {
-    guint8 *d;
-    
-    g_assert(p);
-
-    if (p->size+l > p->max_size)
-        return NULL;
-    
-    d = AVAHI_DNS_PACKET_DATA(p) + p->size;
-    p->size += l;
-    
-    return d;
-}
-
-gint avahi_dns_packet_check_valid(AvahiDnsPacket *p) {
-    guint16 flags;
-    g_assert(p);
-
-    if (p->size < 12)
-        return -1;
-
-    flags = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS);
-
-    if (flags & AVAHI_DNS_FLAG_OPCODE || flags & AVAHI_DNS_FLAG_RCODE)
-        return -1;
-
-    return 0;
-}
-
-gint avahi_dns_packet_is_query(AvahiDnsPacket *p) {
-    g_assert(p);
-    
-    return !(avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & AVAHI_DNS_FLAG_QR);
-}
-
-static gint consume_labels(AvahiDnsPacket *p, guint index, gchar *ret_name, guint l) {
-    gint ret = 0;
-    int compressed = 0;
-    int first_label = 1;
-    g_assert(p && ret_name && l);
-    
-    for (;;) {
-        guint8 n;
-
-        if (index+1 > p->size)
-            return -1;
-
-        n = AVAHI_DNS_PACKET_DATA(p)[index];
-
-        if (!n) {
-            index++;
-            if (!compressed)
-                ret++;
-
-            if (l < 1)
-                return -1;
-            *ret_name = 0;
-            
-            return ret;
-            
-        } else if (n <= 63) {
-            /* Uncompressed label */
-            index++;
-            if (!compressed)
-                ret++;
-        
-            if (index + n > p->size)
-                return -1;
-
-            if ((guint) n + 1 > l)
-                return -1;
-
-            if (!first_label) {
-                *(ret_name++) = '.';
-                l--;
-            } else
-                first_label = 0;
-
-            if (!(avahi_escape_label(AVAHI_DNS_PACKET_DATA(p) + index, n, &ret_name, &l)))
-                return -1;
-
-            index += n;
-            
-            if (!compressed)
-                ret += n;
-        } else if ((n & 0xC0) == 0xC0) {
-            /* Compressed label */
-
-            if (index+2 > p->size)
-                return -1;
-
-            index = ((guint) (AVAHI_DNS_PACKET_DATA(p)[index] & ~0xC0)) << 8 | AVAHI_DNS_PACKET_DATA(p)[index+1];
-
-            if (!compressed)
-                ret += 2;
-            
-            compressed = 1;
-        } else
-            return -1;
-    }
-}
-
-gint avahi_dns_packet_consume_name(AvahiDnsPacket *p, gchar *ret_name, guint l) {
-    gint r;
-    
-    if ((r = consume_labels(p, p->rindex, ret_name, l)) < 0)
-        return -1;
-
-    p->rindex += r;
-    return 0;
-}
-
-gint avahi_dns_packet_consume_uint16(AvahiDnsPacket *p, guint16 *ret_v) {
-    g_assert(p);
-    g_assert(ret_v);
-
-    if (p->rindex + sizeof(guint16) > p->size)
-        return -1;
-
-    *ret_v = g_ntohs(*((guint16*) (AVAHI_DNS_PACKET_DATA(p) + p->rindex)));
-    p->rindex += sizeof(guint16);
-
-    return 0;
-}
-
-gint avahi_dns_packet_consume_uint32(AvahiDnsPacket *p, guint32 *ret_v) {
-    g_assert(p);
-    g_assert(ret_v);
-
-    if (p->rindex + sizeof(guint32) > p->size)
-        return -1;
-
-    *ret_v = g_ntohl(*((guint32*) (AVAHI_DNS_PACKET_DATA(p) + p->rindex)));
-    p->rindex += sizeof(guint32);
-    
-    return 0;
-}
-
-gint avahi_dns_packet_consume_bytes(AvahiDnsPacket *p, gpointer ret_data, guint l) {
-    g_assert(p);
-    g_assert(ret_data);
-    g_assert(l > 0);
-    
-    if (p->rindex + l > p->size)
-        return -1;
-
-    memcpy(ret_data, AVAHI_DNS_PACKET_DATA(p) + p->rindex, l);
-    p->rindex += l;
-
-    return 0;
-}
-
-gint avahi_dns_packet_consume_string(AvahiDnsPacket *p, gchar *ret_string, guint l) {
-    guint k;
-    
-    g_assert(p);
-    g_assert(ret_string);
-    g_assert(l > 0);
-
-    if (p->rindex >= p->size)
-        return -1;
-
-    k = AVAHI_DNS_PACKET_DATA(p)[p->rindex];
-
-    if (p->rindex+1+k > p->size)
-        return -1;
-
-    if (l > k+1)
-        l = k+1;
-
-    memcpy(ret_string, AVAHI_DNS_PACKET_DATA(p)+p->rindex+1, l-1);
-    ret_string[l-1] = 0;
-
-    
-    p->rindex += 1+k;
-
-    return 0;
-    
-}
-
-gconstpointer avahi_dns_packet_get_rptr(AvahiDnsPacket *p) {
-    g_assert(p);
-    
-    if (p->rindex > p->size)
-        return NULL;
-
-    return AVAHI_DNS_PACKET_DATA(p) + p->rindex;
-}
-
-gint avahi_dns_packet_skip(AvahiDnsPacket *p, guint length) {
-    g_assert(p);
-
-    if (p->rindex + length > p->size)
-        return -1;
-
-    p->rindex += length;
-    return 0;
-}
-
-AvahiRecord* avahi_dns_packet_consume_record(AvahiDnsPacket *p, gboolean *ret_cache_flush) {
-    gchar name[257], buf[257];
-    guint16 type, class;
-    guint32 ttl;
-    guint16 rdlength;
-    AvahiRecord *r = NULL;
-    gconstpointer start;
-
-    g_assert(p);
-    g_assert(ret_cache_flush);
-
-/*     g_message("consume_record()"); */
-
-    if (avahi_dns_packet_consume_name(p, name, sizeof(name)) < 0 ||
-        avahi_dns_packet_consume_uint16(p, &type) < 0 ||
-        avahi_dns_packet_consume_uint16(p, &class) < 0 ||
-        avahi_dns_packet_consume_uint32(p, &ttl) < 0 ||
-        avahi_dns_packet_consume_uint16(p, &rdlength) < 0 ||
-        p->rindex + rdlength > p->size)
-        goto fail;
-
-/*     g_message("name = %s, rdlength = %u", name, rdlength); */
-
-    *ret_cache_flush = !!(class & AVAHI_DNS_CACHE_FLUSH);
-    class &= ~AVAHI_DNS_CACHE_FLUSH;
-    
-    start = avahi_dns_packet_get_rptr(p);
-    
-    r = avahi_record_new_full(name, class, type);
-    
-    switch (type) {
-        case AVAHI_DNS_TYPE_PTR:
-        case AVAHI_DNS_TYPE_CNAME:
-
-/*             g_message("ptr"); */
-            
-            if (avahi_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
-                goto fail;
-
-            r->data.ptr.name = g_strdup(buf);
-            break;
-
-            
-        case AVAHI_DNS_TYPE_SRV:
-
-/*             g_message("srv"); */
-            
-            if (avahi_dns_packet_consume_uint16(p, &r->data.srv.priority) < 0 ||
-                avahi_dns_packet_consume_uint16(p, &r->data.srv.weight) < 0 ||
-                avahi_dns_packet_consume_uint16(p, &r->data.srv.port) < 0 ||
-                avahi_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
-                goto fail;
-            
-            r->data.srv.name = g_strdup(buf);
-            break;
-
-        case AVAHI_DNS_TYPE_HINFO:
-            
-/*             g_message("hinfo"); */
-
-            if (avahi_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
-                goto fail;
-
-            r->data.hinfo.cpu = g_strdup(buf);
-
-            if (avahi_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
-                goto fail;
-
-            r->data.hinfo.os = g_strdup(buf);
-            break;
-
-        case AVAHI_DNS_TYPE_TXT:
-
-/*             g_message("txt"); */
-
-            if (rdlength > 0) {
-                r->data.txt.string_list = avahi_string_list_parse(avahi_dns_packet_get_rptr(p), rdlength);
-                
-                if (avahi_dns_packet_skip(p, rdlength) < 0)
-                    goto fail;
-            } else
-                r->data.txt.string_list = NULL;
-            
-            break;
-
-        case AVAHI_DNS_TYPE_A:
-
-/*             g_message("A"); */
-
-            if (avahi_dns_packet_consume_bytes(p, &r->data.a.address, sizeof(AvahiIPv4Address)) < 0)
-                goto fail;
-            
-            break;
-
-        case AVAHI_DNS_TYPE_AAAA:
-
-/*             g_message("aaaa"); */
-            
-            if (avahi_dns_packet_consume_bytes(p, &r->data.aaaa.address, sizeof(AvahiIPv6Address)) < 0)
-                goto fail;
-            
-            break;
-            
-        default:
-
-/*             g_message("generic"); */
-            
-            if (rdlength > 0) {
-
-                r->data.generic.data = g_memdup(avahi_dns_packet_get_rptr(p), rdlength);
-                
-                if (avahi_dns_packet_skip(p, rdlength) < 0)
-                    goto fail;
-            }
-
-            break;
-    }
-
-/*     g_message("%i == %u ?", (guint8*) avahi_dns_packet_get_rptr(p) - (guint8*) start, rdlength); */
-    
-    /* Check if we read enough data */
-    if ((guint8*) avahi_dns_packet_get_rptr(p) - (guint8*) start != rdlength)
-        goto fail;
-    
-    r->ttl = ttl;
-
-    return r;
-
-fail:
-    if (r)
-        avahi_record_unref(r);
-
-    return NULL;
-}
-
-AvahiKey* avahi_dns_packet_consume_key(AvahiDnsPacket *p, gboolean *ret_unicast_response) {
-    gchar name[256];
-    guint16 type, class;
-
-    g_assert(p);
-    g_assert(ret_unicast_response);
-
-    if (avahi_dns_packet_consume_name(p, name, sizeof(name)) < 0 ||
-        avahi_dns_packet_consume_uint16(p, &type) < 0 ||
-        avahi_dns_packet_consume_uint16(p, &class) < 0)
-        return NULL;
-
-    *ret_unicast_response = !!(class & AVAHI_DNS_UNICAST_RESPONSE);
-    class &= ~AVAHI_DNS_UNICAST_RESPONSE;
-
-    return avahi_key_new(name, class, type);
-}
-
-guint8* avahi_dns_packet_append_key(AvahiDnsPacket *p, AvahiKey *k, gboolean unicast_response) {
-    guint8 *t;
-    guint size;
-    
-    g_assert(p);
-    g_assert(k);
-
-    size = p->size;
-    
-    if (!(t = avahi_dns_packet_append_name(p, k->name)) ||
-        !avahi_dns_packet_append_uint16(p, k->type) ||
-        !avahi_dns_packet_append_uint16(p, k->class | (unicast_response ? AVAHI_DNS_UNICAST_RESPONSE : 0))) {
-        p->size = size;
-        return NULL;
-    }
-
-    return t;
-}
-
-guint8* avahi_dns_packet_append_record(AvahiDnsPacket *p, AvahiRecord *r, gboolean cache_flush, guint max_ttl) {
-    guint8 *t, *l, *start;
-    guint size;
-
-    g_assert(p);
-    g_assert(r);
-
-    size = p->size;
-
-    if (!(t = avahi_dns_packet_append_name(p, r->key->name)) ||
-        !avahi_dns_packet_append_uint16(p, r->key->type) ||
-        !avahi_dns_packet_append_uint16(p, cache_flush ? (r->key->class | AVAHI_DNS_CACHE_FLUSH) : (r->key->class &~ AVAHI_DNS_CACHE_FLUSH)) ||
-        !avahi_dns_packet_append_uint32(p, (max_ttl && r->ttl > max_ttl) ? max_ttl : r->ttl) ||
-        !(l = avahi_dns_packet_append_uint16(p, 0)))
-        goto fail;
-
-    start = avahi_dns_packet_extend(p, 0);
-
-    switch (r->key->type) {
-        
-        case AVAHI_DNS_TYPE_PTR:
-        case AVAHI_DNS_TYPE_CNAME :
-
-            if (!(avahi_dns_packet_append_name(p, r->data.ptr.name)))
-                goto fail;
-            
-            break;
-
-        case AVAHI_DNS_TYPE_SRV:
-
-            if (!avahi_dns_packet_append_uint16(p, r->data.srv.priority) ||
-                !avahi_dns_packet_append_uint16(p, r->data.srv.weight) ||
-                !avahi_dns_packet_append_uint16(p, r->data.srv.port) ||
-                !avahi_dns_packet_append_name(p, r->data.srv.name))
-                goto fail;
-
-            break;
-
-        case AVAHI_DNS_TYPE_HINFO:
-            if (!avahi_dns_packet_append_string(p, r->data.hinfo.cpu) ||
-                !avahi_dns_packet_append_string(p, r->data.hinfo.os))
-                goto fail;
-
-            break;
-
-        case AVAHI_DNS_TYPE_TXT: {
-
-            guint8 *data;
-            guint size;
-
-            size = avahi_string_list_serialize(r->data.txt.string_list, NULL, 0);
-
-/*             g_message("appending string: %u %p", size, r->data.txt.string_list); */
-
-            if (!(data = avahi_dns_packet_extend(p, size)))
-                goto fail;
-
-            avahi_string_list_serialize(r->data.txt.string_list, data, size);
-            break;
-        }
-
-
-        case AVAHI_DNS_TYPE_A:
-
-            if (!avahi_dns_packet_append_bytes(p, &r->data.a.address, sizeof(r->data.a.address)))
-                goto fail;
-            
-            break;
-
-        case AVAHI_DNS_TYPE_AAAA:
-            
-            if (!avahi_dns_packet_append_bytes(p, &r->data.aaaa.address, sizeof(r->data.aaaa.address)))
-                goto fail;
-            
-            break;
-            
-        default:
-
-            if (r->data.generic.size &&
-                avahi_dns_packet_append_bytes(p, r->data.generic.data, r->data.generic.size))
-                goto fail;
-
-            break;
-    }
-
-
-
-    
-    size = avahi_dns_packet_extend(p, 0) - start;
-    g_assert(size <= 0xFFFF);
-
-/*     g_message("appended %u", size); */
-
-    * (guint16*) l = g_htons((guint16) size);
-    
-    return t;
-
-
-fail:
-    p->size = size;
-    return NULL;
-}
-
-gboolean avahi_dns_packet_is_empty(AvahiDnsPacket *p) {
-    g_assert(p);
-
-    return p->size <= AVAHI_DNS_PACKET_HEADER_SIZE;
-}
-
-guint avahi_dns_packet_space(AvahiDnsPacket *p) {
-    g_assert(p);
-
-    g_assert(p->size <= p->max_size);
-    
-    return p->max_size - p->size;
-}