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/* ========================================================================
* Copyright 1988-2007 University of Washington
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
*
* ========================================================================
*/
/*
* Program: File descriptor string routines
*
* Author: Mark Crispin
* Networks and Distributed Computing
* Computing & Communications
* University of Washington
* Administration Building, AG-44
* Seattle, WA 98195
* Internet: MRC@CAC.Washington.EDU
*
* Date: 15 April 1997
* Last Edited: 4 April 2007
*/
#include "mail.h"
#include "osdep.h"
#include "misc.h"
#include "fdstring.h"
/* String driver for fd stringstructs */
static void fd_string_init (STRING *s,void *data,unsigned long size);
static char fd_string_next (STRING *s);
static void fd_string_setpos (STRING *s,unsigned long i);
STRINGDRIVER fd_string = {
fd_string_init, /* initialize string structure */
fd_string_next, /* get next byte in string structure */
fd_string_setpos /* set position in string structure */
};
/* Initialize string structure for fd stringstruct
* Accepts: string structure
* pointer to string
* size of string
*/
static void fd_string_init (STRING *s,void *data,unsigned long size)
{
FDDATA *d = (FDDATA *) data;
/* note fd */
s->data = (void *) (unsigned long) d->fd;
s->data1 = d->pos; /* note file offset */
s->size = size; /* note size */
s->curpos = s->chunk = d->chunk;
s->chunksize = (unsigned long) d->chunksize;
s->offset = 0; /* initial position */
/* and size of data */
s->cursize = min (s->chunksize,size);
/* move to that position in the file */
lseek (d->fd,d->pos,L_SET);
read (d->fd,s->chunk,(size_t) s->cursize);
}
/* Get next character from fd stringstruct
* Accepts: string structure
* Returns: character, string structure chunk refreshed
*/
static char fd_string_next (STRING *s)
{
char c = *s->curpos++; /* get next byte */
SETPOS (s,GETPOS (s)); /* move to next chunk */
return c; /* return the byte */
}
/* Set string pointer position for fd stringstruct
* Accepts: string structure
* new position
*/
static void fd_string_setpos (STRING *s,unsigned long i)
{
if (i > s->size) i = s->size; /* don't permit setting beyond EOF */
s->offset = i; /* set new offset */
s->curpos = s->chunk; /* reset position */
/* set size of data */
if (s->cursize = min (s->chunksize,SIZE (s))) {
/* move to that position in the file */
lseek ((long) s->data,s->data1 + s->offset,L_SET);
read ((long) s->data,s->curpos,(size_t) s->cursize);
}
}
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