#include	"mail.h"/* Find the specified record. * Called by mail_delete(), mail_fetch(), and mail_store(). */int_mail_find(MAIL *mail, const char *key, int writelock){	off_t	offset, nextoffset;		/* Calculate hash value for this key, then calculate byte		   offset of correspondin g chain ptr in hash table.		   This is where our search starts. */			/* calc offset in hash table for this key */	mail->chainoff = (_mail_hash(mail, key) * PTR_SZ) + mail->hashoff;	mail->ptroff = mail->chainoff;			/* Here's where we lock this hash chain.  It's the			   caller's responsibility to unlock it when done.			   Note we lock and unlock only the first byte. */	if (writelock) {		if (writew_lock(mail->idxfd, mail->chainoff, SEEK_SET, 1) < 0)			err_dump("writew_lock error");	} else {		if (readw_lock(mail->idxfd, mail->chainoff, SEEK_SET, 1) < 0)			err_dump("readw_lock error");	}			/* Get the offset in the index file of first record			   on the hash chain (can be 0) */	offset = _mail_readptr(mail, mail->ptroff);	while (offset != 0) {		nextoffset = _mail_readidx(mail, offset,REALIDX);		if (strcmp(mail->keybuf, key) == 0)			break;		/* found a match */		mail->ptroff = offset;	/* offset of this (unequal) record */		offset = nextoffset;	/* next one to compare */	}	if (offset == 0)		return(-1);		/* error, record not found */		/* We have a match.  We're guaranteed that mail->ptroff contains		   the offset of the chain ptr that points to this matching		   index record.  _mail_dodelete() uses this fact.  (The chain		   ptr that points to this matching record could be in an		   index record or in the hash table.) */	return(0);}