121 lines
2.8 KiB
C
121 lines
2.8 KiB
C
/* ****************************************************************************
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* stream/csum32.c -- built-in stream for making a 32-bit checksum.
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* Copyright (C) 2017 Thomas "Cakeisalie5" Touhey <thomas@touhey.fr>
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*
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* This file is part of libcasio.
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* libcasio is free software; you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 3.0 of the License,
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* or (at your option) any later version.
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*
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* libcasio is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with libcasio; if not, see <http://www.gnu.org/licenses/>.
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* ************************************************************************* */
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#include "stream.h"
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/* ---
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* Cookie structure.
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* --- */
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struct thecookie {
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tio_stream_t *_stream;
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casio_uint32_t *_checksum;
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};
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/* ---
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* Callbacks.
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* --- */
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/**
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* csum32_read:
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* Read from this stream.
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*
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* @arg cookie the cookie.
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* @arg data the data pointer.
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* @arg size the data size.
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* @arg timeout the timeout.
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* @return the error code (0 if ok).
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*/
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CASIO_LOCAL int csum32_read(struct thecookie *cookie,
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unsigned char *dest, size_t count)
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{
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int err;
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/* Make the call. */
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err = tio_read(cookie->_stream, dest, count);
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if (err) return (err);
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/* Make the checksum. */
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*cookie->_checksum = casio_checksum32(dest, count, *cookie->_checksum);
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return (0);
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}
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/**
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* csum32_close:
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* Close the stream.
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*
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* @arg cookie the cookie.
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* @return the error code (0 if ok).
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*/
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CASIO_LOCAL void csum32_close(struct thecookie *cookie)
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{
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casio_free(cookie);
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}
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/* Callbacks. */
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CASIO_LOCAL tio_functions_t const csum32_callbacks = {
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(tio_close_t *)&csum32_close,
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(tio_read_t *)&csum32_read,
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NULL, NULL
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};
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/* ---
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* Main functions.
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* --- */
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/**
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* casio_open_csum32:
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* Open a 32-bit checksum stream.
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*
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* @arg stream the stream to make.
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* @arg original the original stream.
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* @arg csum the checksum pointer.
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* @return the error code (0 if ok).
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*/
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int CASIO_EXPORT casio_open_csum32(tio_stream_t **stream,
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tio_stream_t *original, casio_uint32_t *csum)
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{
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struct thecookie *cookie = NULL;
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unsigned int openmode;
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if (!tio_isreadable(original))
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return (casio_error_op);
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/* Allocate the cookie. */
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cookie = casio_alloc(1, sizeof(struct thecookie));
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if (!cookie)
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return (casio_error_alloc);
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/* Fill the cookie. */
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cookie->_stream = original;
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cookie->_checksum = csum;
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/* Initialize and return da stream. */
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return (casio_tio_error(tio_open(stream, original, cookie,
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TIO_OPENFLAG_READ, &csum32_callbacks, 0)));
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}
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