/*
  * $Id$
  *
  * adding/removing headers or any other data chunk from a message
  */
 
 #ifndef data_lump_h
 #define data_lump_h
 
 
 enum { LUMP_NOP=0, LUMP_DEL, LUMP_ADD };
 
 struct lump{
 	int type; /* VIA, OTHER, UNSPEC(=0), ... */
 	int op;   /* DEL, ADD, NOP, UNSPEC(=0) */
 	
 	union{
 		int offset; /* used for DEL, MODIFY */
 		char * value; /* used for ADD */
 	}u;
 	int len; /* length of this header field */
 	
 	
 	struct lump* before; /* list of headers to be inserted in front of the
 								current one */
 	struct lump* after; /* list of headers to be inserted immediately after
 							  the current one */
 	
 	struct lump* next;
 };
 
 /*
  * hdrs must be kept sorted after their offset (DEL, NOP, UNSPEC)
  * and/or their position (ADD). E.g.:
  *  - to delete header Z insert it in to the list according to its offset 
  *   and with op=DELETE
  * - if you want to add a new header X after a  header Y, insert Y in the list
  *   with op NOP and after it X (op ADD).
  * - if you want X before Y, insert X in Y's before list.
  * - if you want X to be the first header just put it first in hdr_lst.
  *  -if you want to replace Y with X, insert Y with op=DELETE and then X with
  *  op=ADD.
  * before and after must contain only ADD ops!
  * 
  * Difference between "after" & "next" when ADDing:
  * "after" forces the new header immediately after the current one while
  * "next" means another header can be inserted between them.
  * 
  */
 
 
 
 /* adds a header to the end */
 struct lump* append_new_lump(struct lump** list, char* new_hdr,
 							 int len, int type);
 /* inserts a header to the beginning */
 struct lump* insert_new_lump(struct lump** list, char* new_hdr,
 							  int len, int type);
 struct lump* insert_new_lump_after(struct lump* after,
 									char* new_hdr, int len, int type);
 struct lump* insert_new_lump_before(struct lump* before, char* new_hdr,
 									int len,int type);
 
 
 /* removes an already existing header */
 struct lump* del_lump(struct lump** list, int offset, int len, int type);
 /* set an anchor */
 struct lump* anchor_lump(struct lump** list, int offset, int len, int type);
 
 
 /* frees the content of a lump struct */
 void free_lump(struct lump* l);
 /*frees an entire lump list, recursively */
 void free_lump_list(struct lump* lump_list);
 
 #endif