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emem.h

/* emem.h
 * Definitions for Wireshark memory management and garbage collection
 * Ronnie Sahlberg 2005
 *
 * $Id: emem.h 18937 2006-08-17 08:17:48Z sahlberg $
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#ifndef __EMEM_H__
#define __EMEM_H__

#include "gnuc_format_check.h"

/* Functions for handling memory allocation and garbage collection with 
 * a packet lifetime scope.
 * These functions are used to allocate memory that will only remain persistent
 * until Wireshark starts dissecting the next packet in the list.
 * Everytime Wireshark starts decoding the next packet all memory allocated
 * through these functions will be released back to the free pool.
 *
 * These functions are very fast and offer automatic garbage collection:
 * Everytime a new packet is dissected, all memory allocations done in
 * the previous packet is freed.
 */
/* Initialize packet-lifetime memory allocation pool. This function is called 
 * once when [t]Wireshark is initialized to set up the required structures.
 */
void ep_init_chunk(void);

/* Allocate memory with a packet lifetime scope */
void *ep_alloc(size_t size);
#define ep_new(type) ((type*)ep_alloc(sizeof(type)))

/* Allocate memory with a packet lifetime scope and fill it with zeros*/
void* ep_alloc0(size_t size);
#define ep_new0(type) ((type*)ep_alloc0(sizeof(type)))

/* Duplicate a string with a packet lifetime scope */
gchar* ep_strdup(const gchar* src);

/* Duplicate at most n characters of a string with a packet lifetime scope */
gchar* ep_strndup(const gchar* src, size_t len);

/* Duplicate a buffer with a packet lifetime scope */
void* ep_memdup(const void* src, size_t len);

/* Create a formatted string with a packet lifetime scope */
gchar* ep_strdup_vprintf(const gchar* fmt, va_list ap);
gchar* ep_strdup_printf(const gchar* fmt, ...)
    GNUC_FORMAT_CHECK(printf, 1, 2);

/* allocates with a packet lifetime scope an array of type made of num elements */
#define ep_alloc_array(type,num) (type*)ep_alloc(sizeof(type)*(num))

/* 
 * Splits a string into a maximum of max_tokens pieces, using the given
 * delimiter. If max_tokens is reached, the remainder of string is appended
 * to the last token. Consecutive delimiters are treated as a single delimiter.
 *
 * the vector and all the strings are allocated with packet lifetime scope
 */
gchar** ep_strsplit(const gchar* string, const gchar* delimiter, int max_tokens);

/* release all memory allocated in the previous packet dissector */
void ep_free_all(void);


/* a stack implemented using ephemeral allocators */

typedef struct _ep_stack_frame_t** ep_stack_t;

struct _ep_stack_frame_t {
    void* payload;
    struct _ep_stack_frame_t* below;
    struct _ep_stack_frame_t* above;
};

/*
 * creates an empty stack with a packet lifetime scope
 */
ep_stack_t ep_stack_new(void);

/*
 * pushes item into stack, returns item
 */
void* ep_stack_push(ep_stack_t stack, void* item);

/*
 * pops an item from the stack
 */
void* ep_stack_pop(ep_stack_t stack);

/*
 * returns the item on top of the stack without popping it
 */
#define ep_stack_peek(stack) ((*(stack))->payload)


/* Functions for handling memory allocation and garbage collection with 
 * a capture lifetime scope.
 * These functions are used to allocate memory that will only remain persistent
 * until Wireshark opens a new capture or capture file.
 * Everytime Wireshark starts a new capture or opens a new capture file
 * all the data allocated through these functions will be released back 
 * to the free pool.
 *
 * These functions are very fast and offer automatic garbage collection.
 */
/* Initialize capture-lifetime memory allocation pool. This function is called 
 * once when [t]Wireshark is initialized to set up the required structures.
 */
void se_init_chunk(void);

/* Allocate memory with a capture lifetime scope */
void *se_alloc(size_t size);

/* Allocate memory with a capture lifetime scope and fill it with zeros*/
void* se_alloc0(size_t size);

/* Duplicate a string with a capture lifetime scope */
gchar* se_strdup(const gchar* src);

/* Duplicate at most n characters of a string with a capture lifetime scope */
gchar* se_strndup(const gchar* src, size_t len);

/* Duplicate a buffer with a capture lifetime scope */
void* se_memdup(const void* src, size_t len);

/* Create a formatted string with a capture lifetime scope */
gchar* se_strdup_vprintf(const gchar* fmt, va_list ap);
gchar* se_strdup_printf(const gchar* fmt, ...)
    GNUC_FORMAT_CHECK(printf, 1, 2);

/* allocates with a capture lifetime scope an array of type made of num elements */
#define se_alloc_array(type,num) (type*)se_alloc(sizeof(type)*(num))

/* release all memory allocated */
void se_free_all(void);




/**************************************************************
 * binary trees 
 **************************************************************/
#define EMEM_TREE_RB_COLOR_RED            0x00
#define EMEM_TREE_RB_COLOR_BLACK    0x01
typedef struct _emem_tree_node_t {
      struct _emem_tree_node_t *parent;
      struct _emem_tree_node_t *left;
      struct _emem_tree_node_t *right;
      union {
            guint32 rb_color;
      } u;
      guint32 key32;
      void *data;
} emem_tree_node_t;

/* Right now we only do basic red/black trees   but in the future we might want
 * to try something different, such as a tree where each node keeps track
 * of how many times it has been looked up, and letting often looked up
 * nodes bubble upwards in the tree using rotate_right/left.
 * That would probably be good for things like nfs filehandles 
 */
#define EMEM_TREE_TYPE_RED_BLACK    1
typedef struct _emem_tree_t {
      struct _emem_tree_t *next;
      int type;
      char *name;    /* just a string to make debugging easier */
      emem_tree_node_t *tree;
      void *(*malloc)(size_t);
} emem_tree_t;

/* list of all trees with se allocation scope so that they can all be reset 
 * automatically when we free all se memory
 */
extern emem_tree_t *se_trees;


/* *******************************************************************
 * Tree functions for SE memory allocation scope
 * ******************************************************************* */
/* This function is used to create a se based tree with monitoring.
 * When the SE heap is released back to the system the pointer to the 
 * tree is automatically reset to NULL.
 *
 * type is : EMEM_TREE_TYPE_RED_BLACK for a standard red/black tree.
 */
emem_tree_t *se_tree_create(int type, char *name);

/* This function is similar to the se_tree_create() call but with the
 * difference that when the se memory is release everything including the 
 * pointer to the tree itself will be released.
 * This tree will not be just reset to zero  it will be completely forgotten
 * by the allocator.
 * Use this function for when you want to store the pointer to a tree inside
 * another structure that is also se allocated so that when the structure is
 * released, the tree will be completely released as well.
 */
emem_tree_t *se_tree_create_non_persistent(int type, char *name);

/* se_tree_insert32 
 * Insert data into the tree and key it by a 32bit integer value
 */
#define se_tree_insert32 emem_tree_insert32

/* se_tree_lookup32 
 * Retreive the data at the search key. the search key is a 32bit integer value
 */
#define se_tree_lookup32 emem_tree_lookup32

/* se_tree_lookup32_le
 * Retreive the data for the largest key that is less than or equal
 * to the search key.
 */
#define se_tree_lookup32_le emem_tree_lookup32_le

/* se_tree_insert32_array
 * Insert data into the tree and key it by a 32bit integer value
 */
#define se_tree_insert32_array emem_tree_insert32_array

/* se_tree_lookup32_array
 * Lookup data from the tree that is index by an array
 */
#define se_tree_lookup32_array emem_tree_lookup32_array



/* Create a new string based hash table */
#define se_tree_create_string() se_tree_create(SE_TREE_TYPE_RED_BLACK)

/* Insert a new value under a string key */
#define se_tree_insert_string emem_tree_insert_string

/* Lookup the value under a string key */
#define se_tree_lookup_string emem_tree_lookup_string


/* *******************************************************************
 * Tree functions for PE memory allocation scope
 * ******************************************************************* */
/* These trees have PErmanent allocation scope and will never be released
 */
emem_tree_t *pe_tree_create(int type, char *name);
#define pe_tree_insert32 emem_tree_insert32
#define pe_tree_lookup32 emem_tree_lookup32
#define pe_tree_lookup32_le emem_tree_lookup32_le
#define pe_tree_insert32_array emem_tree_insert32_array
#define pe_tree_lookup32_array emem_tree_lookup32_array
#define pe_tree_insert_string emem_tree_insert_string
#define pe_tree_lookup_string emem_tree_lookup_string



/* ******************************************************************
 * Real tree functions
 * ****************************************************************** */

/* This function is used to insert a node indexed by a guint32 key value.
 * The data pointer should be allocated by the appropriate storage scope
 * so that it will be released at the same time as the tree itself is 
 * destroyed.
 */
void emem_tree_insert32(emem_tree_t *se_tree, guint32 key, void *data);

/* This function will look up a node in the tree indexed by a guint32 integer
 * value.
 */
void *emem_tree_lookup32(emem_tree_t *se_tree, guint32 key);

/* This function will look up a node in the tree indexed by a guint32 integer
 * value.
 * The function will return the node that has the largest key that is 
 * equal to or smaller than the search key, or NULL if no such key was
 * found.
 */
void *emem_tree_lookup32_le(emem_tree_t *se_tree, guint32 key);

typedef struct _emem_tree_key_t {
      guint32 length;               /*length in guint32 words */
      guint32 *key;
} emem_tree_key_t;

/* This function is used to insert a node indexed by a sequence of guint32 
 * key values.
 * The data pointer should be allocated by SE allocators so that the
 * data will be released at the same time as the tree itself is destroyed.
 *
 * If you use ...32_array() calls you MUST make sure that every single node
 * you add to a specific tree always has a key of exactly the same number of 
 * keylen words or things will most likely crash. Or at least that every single
 * item that sits behind the same top level node always have exactly the same
 * number of words.
 *
 * One way to guarantee this is the way that NFS does this for the
 * nfs_name_snoop_known  tree which holds filehandles for both v2 and v3.
 * v2 filehandles are always 32 bytes (8 words) while v3 filehandles can have
 * any length (though 32bytes are most common).
 * The NFS dissector handles this by providing a guint32 containing the length
 * as the very first item in this vector :
 *
 *                emem_tree_key_t fhkey[3];
 *
 *                fhlen=nns->fh_length;
 *                fhkey[0].length=1;
 *                fhkey[0].key=&fhlen;
 *                fhkey[1].length=fhlen/4;
 *                fhkey[1].key=nns->fh;
 *                fhkey[2].length=0;
 */
void emem_tree_insert32_array(emem_tree_t *se_tree, emem_tree_key_t *key, void *data);

/* This function will look up a node in the tree indexed by a sequence of
 * guint32 integer values.
 */
void *emem_tree_lookup32_array(emem_tree_t *se_tree, emem_tree_key_t *key);

/* Insert a new value under a string key */
void emem_tree_insert_string(emem_tree_t* h, const gchar* k, void* v);

/* Lookup the value under a string key */
void* emem_tree_lookup_string(emem_tree_t* h, const gchar* k);









#endif /* emem.h */

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