152 lines
3.7 KiB
C
152 lines
3.7 KiB
C
/* ****************************************************************************
|
|
* stream/builtin/limited.c -- built-in limited stream.
|
|
* Copyright (C) 2017 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
|
|
*
|
|
* This file is part of libcasio.
|
|
* libcasio 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 3.0 of the License,
|
|
* or (at your option) any later version.
|
|
*
|
|
* libcasio 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 libcasio; if not, see <http://www.gnu.org/licenses/>.
|
|
* ************************************************************************* */
|
|
#include "builtin.h"
|
|
|
|
/* Cookie structure. */
|
|
|
|
typedef struct {
|
|
char _magic[8];
|
|
casio_stream_t *_stream;
|
|
size_t _left;
|
|
} limited_cookie_t;
|
|
|
|
/* ---
|
|
* Callbacks.
|
|
* --- */
|
|
|
|
/**
|
|
* casio_limited_read:
|
|
* Read from a limited stream.
|
|
*
|
|
* @arg vcookie the cookie (uncasted).
|
|
* @arg data the data pointer.
|
|
* @arg size the data size.
|
|
* @arg timeout the timeout (in ms).
|
|
* @return the error code (0 if ok).
|
|
*/
|
|
|
|
CASIO_LOCAL int casio_limited_read(void *vcookie, unsigned char *dest,
|
|
size_t size, unsigned int timeout)
|
|
{
|
|
int err; limited_cookie_t *cookie = (void*)vcookie;
|
|
size_t left;
|
|
|
|
if (size > cookie->_left) {
|
|
/* First, skip the required bytes. */
|
|
|
|
left = cookie->_left;
|
|
cookie->_left = 0;
|
|
if ((err = casio_skip(cookie->_stream, left)))
|
|
return (err);
|
|
|
|
/* Once the skip is done successfully, we return that we
|
|
* have an EOF. */
|
|
|
|
return (casio_error_eof);
|
|
}
|
|
|
|
if ((err = casio_read(cookie->_stream, dest, size, timeout))) {
|
|
cookie->_left = 0; /* XXX: depends on the error? */
|
|
return (err);
|
|
}
|
|
cookie->_left -= size;
|
|
return (0);
|
|
}
|
|
|
|
/**
|
|
* casio_limited_close:
|
|
* Close a limited stream.
|
|
*
|
|
* @arg vcookie the cookie (uncasted).
|
|
* @return the error code (0 if ok).
|
|
*/
|
|
|
|
CASIO_LOCAL int casio_limited_close(void *vcookie)
|
|
{
|
|
casio_free(vcookie);
|
|
return (0);
|
|
}
|
|
|
|
/* Callbacks. */
|
|
|
|
CASIO_LOCAL const casio_streamfuncs_t casio_limited_callbacks = {
|
|
(casio_stream_close_t *)casio_limited_close,
|
|
(casio_stream_read_t *)casio_limited_read,
|
|
NULL, NULL,
|
|
NULL, NULL, NULL, NULL
|
|
};
|
|
|
|
/* ---
|
|
* Main functions.
|
|
* --- */
|
|
|
|
/**
|
|
* casio_open_limited:
|
|
* Open a limited stream.
|
|
*
|
|
* @arg stream the stream to make.
|
|
* @arg original the original stream.
|
|
* @arg size the size the limited buffer is limited to.
|
|
* @return the error (0 if ok).
|
|
*/
|
|
|
|
int CASIO_EXPORT casio_open_limited(casio_stream_t **stream,
|
|
casio_stream_t *original, size_t size)
|
|
{
|
|
limited_cookie_t *cookie = NULL;
|
|
|
|
/* FIXME: check original stream */
|
|
/* allocate the cookie */
|
|
|
|
cookie = casio_alloc(1, sizeof(limited_cookie_t));
|
|
if (!cookie)
|
|
return (casio_error_alloc);
|
|
|
|
/* Fill the cookie. */
|
|
|
|
memcpy(cookie->_magic, "LIMITED\x7F", 8);
|
|
cookie->_stream = original;
|
|
cookie->_left = size;
|
|
|
|
/* Initialize da stream. */
|
|
|
|
return (casio_open_stream(stream,
|
|
casio_get_openmode(original) & CASIO_OPENMODE_READ,
|
|
cookie, &casio_limited_callbacks, 0));
|
|
}
|
|
|
|
/**
|
|
* casio_empty_limited:
|
|
* Empty a limited stream.
|
|
*
|
|
* @arg stream the stream to empty.
|
|
* @return the error code (0 if ok).
|
|
*/
|
|
|
|
int CASIO_EXPORT casio_empty_limited(casio_stream_t *stream)
|
|
{
|
|
int err; limited_cookie_t *cookie = (void*)casio_get_cookie(stream);
|
|
|
|
if (!cookie || memcmp(cookie->_magic, "LIMITED\x7F", 8))
|
|
return (casio_error_op);
|
|
err = casio_skip(cookie->_stream, cookie->_left);
|
|
cookie->_left = 0;
|
|
return (err);
|
|
}
|