129 lines
3.6 KiB
C
129 lines
3.6 KiB
C
/* ****************************************************************************
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* mcsfile/decode/cas/cell.c -- decode a CAS matrix/list/variable.
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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 "../decode.h"
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/* ---
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* Internal function.
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* --- */
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/**
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* decode_cell:
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* Read a cell.
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*
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* @arg buffer the buffer to read from.
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* @arg cell the cell to fill.
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* @arg x the abscissa of the cell.
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* @arg y the ordinate of the cell.
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* @return the error code (0 if ok).
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*/
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CASIO_LOCAL int decode_cell(casio_stream_t *buffer, casio_mcscell_t *cell,
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unsigned int *x, unsigned int *y)
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{
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unsigned char csum = 0, checksum;
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casio_uint16_t fx, fy;
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casio_casbcd_t wkg;
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cell->casio_mcscell_flags = casio_mcscellflag_used;
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/* read position */
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DREAD(fx) *x = be16toh(fx) - 1;
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DREAD(fy) *y = be16toh(fy) - 1;
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csum = casio_checksum_cas(&fx, sizeof(casio_uint16_t), csum);
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csum = casio_checksum_cas(&fy, sizeof(casio_uint16_t), csum);
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/* read the parts */
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DREAD(wkg)
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csum = casio_checksum_cas(&wkg, sizeof(casio_casbcd_t), csum);
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if (casio_bcd_fromcas(&cell->casio_mcscell_real, &wkg)) {
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READ(&wkg, sizeof(casio_casbcd_t))
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csum = casio_checksum_cas(&wkg, sizeof(casio_casbcd_t), csum);
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casio_bcd_fromcas(&cell->casio_mcscell_imgn, &wkg);
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}
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/* read and check the checksum */
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DREAD(checksum)
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if (csum != checksum)
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return (casio_error_csum);
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/* no prob'! */
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return (0);
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}
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/* ---
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* Cell-reading CAS part decoding functions.
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* --- */
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/**
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* casio_decode_caspart_matrix:
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* Decode a CAS matrix part.
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*
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* @arg handle the handle to contribute to.
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* @arg buffer the buffer to read from.
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* @return the error code (0 if ok).
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*/
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int CASIO_EXPORT casio_decode_caspart_matrix(casio_mcsfile_t *handle,
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casio_stream_t *buffer)
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{
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int err; casio_mcscell_t cell;
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unsigned int y, x;
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/* read the cell */
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err = decode_cell(buffer, &cell, &x, &y);
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if (err) return (err);
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/* save the cell (FIXME: secure) */
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handle->casio_mcsfile_cells[y][x] = cell;
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/* check if its the last cell */
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if (y == handle->casio_mcsfile_head.casio_mcshead_height - 1
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&& x == handle->casio_mcsfile_head.casio_mcshead_width - 1)
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handle->casio_mcsfile_head.casio_mcshead_flags &=
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~casio_mcsflag_unfinished;
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/* no error! */
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return (0);
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}
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/**
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* casio_decode_caspart_var:
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* Decode a CAS variable part.
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*
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* @arg handle the handle to contribute to.
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* @arg buffer the buffer to read from.
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* @return the error code (0 if ok).
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*/
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int CASIO_EXPORT casio_decode_caspart_var(casio_mcsfile_t *handle,
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casio_stream_t *buffer)
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{
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int err; unsigned int x, y;
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/* read and save the cell */
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err = decode_cell(buffer, &handle->casio_mcsfile_var, &x, &y);
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if (err) return (err);
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if (x != 1 || y != 1) return (casio_error_magic);
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/* no error! */
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handle->casio_mcsfile_head.casio_mcshead_flags &=
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~casio_mcsflag_unfinished;
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return (0);
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}
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