350 lines
10 KiB
C
350 lines
10 KiB
C
/*------------------------------------------------------------------------
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* Copyright 2007-2010 (c) Jeff Brown <spadix@users.sourceforge.net>
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*
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* This file is part of the ZBar Bar Code Reader.
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*
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* The ZBar Bar Code Reader is free software; you can redistribute it
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* and/or modify it under the terms of the GNU Lesser Public License as
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* published by the Free Software Foundation; either version 2.1 of
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* the License, or (at your option) any later version.
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*
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* The ZBar Bar Code Reader is distributed in the hope that it will be
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* useful, but WITHOUT ANY WARRANTY; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser Public License for more details.
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*
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* You should have received a copy of the GNU Lesser Public License
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* along with the ZBar Bar Code Reader; if not, write to the Free
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* Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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* Boston, MA 02110-1301 USA
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*
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* http://sourceforge.net/projects/zbar
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*------------------------------------------------------------------------*/
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#ifndef _DECODER_H_
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#define _DECODER_H_
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#include <zbar_config.h>
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#include <stdlib.h> /* realloc */
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#include <limits.h>
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#include <zbar.h>
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#include "debug.h"
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#define NUM_CFGS (ZBAR_CFG_MAX_LEN - ZBAR_CFG_MIN_LEN + 1)
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#ifdef ENABLE_EAN
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# include "decoder/ean.h"
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#endif
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#ifdef ENABLE_I25
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# include "decoder/i25.h"
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#endif
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#ifdef ENABLE_DATABAR
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# include "decoder/databar.h"
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#endif
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#ifdef ENABLE_CODABAR
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# include "decoder/codabar.h"
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#endif
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#ifdef ENABLE_CODE39
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# include "decoder/code39.h"
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#endif
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#ifdef ENABLE_CODE93
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# include "decoder/code93.h"
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#endif
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#ifdef ENABLE_CODE128
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# include "decoder/code128.h"
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#endif
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#ifdef ENABLE_PDF417
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# include "decoder/pdf417.h"
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#endif
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#ifdef ENABLE_QRCODE
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# include "decoder/qr_finder.h"
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#endif
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/* size of bar width history (implementation assumes power of two) */
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#ifndef DECODE_WINDOW
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# define DECODE_WINDOW 16
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#endif
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/* initial data buffer allocation */
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#ifndef BUFFER_MIN
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# define BUFFER_MIN 0x20
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#endif
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/* maximum data buffer allocation
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* (longer symbols are rejected)
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*/
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#ifndef BUFFER_MAX
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# define BUFFER_MAX 0x100
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#endif
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/* buffer allocation increment */
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#ifndef BUFFER_INCR
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# define BUFFER_INCR 0x10
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#endif
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#define CFG(dcode, cfg) ((dcode).configs[(cfg) - ZBAR_CFG_MIN_LEN])
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#define TEST_CFG(config, cfg) (((config) >> (cfg)) & 1)
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#define MOD(mod) (1 << (mod))
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/* symbology independent decoder state */
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struct zbar_decoder_s {
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unsigned char idx; /* current width index */
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unsigned w[DECODE_WINDOW]; /* window of last N bar widths */
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zbar_symbol_type_t type; /* type of last decoded data */
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zbar_symbol_type_t lock; /* buffer lock */
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unsigned modifiers; /* symbology modifier */
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int direction; /* direction of last decoded data */
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unsigned s6; /* 6-element character width */
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/* everything above here is automatically reset */
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unsigned buf_alloc; /* dynamic buffer allocation */
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unsigned buflen; /* binary data length */
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unsigned char *buf; /* decoded characters */
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void *userdata; /* application data */
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zbar_decoder_handler_t *handler; /* application callback */
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/* symbology specific state */
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#ifdef ENABLE_EAN
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ean_decoder_t ean; /* EAN/UPC parallel decode attempts */
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#endif
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#ifdef ENABLE_I25
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i25_decoder_t i25; /* Interleaved 2 of 5 decode state */
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#endif
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#ifdef ENABLE_DATABAR
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databar_decoder_t databar; /* DataBar decode state */
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#endif
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#ifdef ENABLE_CODABAR
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codabar_decoder_t codabar; /* Codabar decode state */
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#endif
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#ifdef ENABLE_CODE39
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code39_decoder_t code39; /* Code 39 decode state */
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#endif
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#ifdef ENABLE_CODE93
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code93_decoder_t code93; /* Code 93 decode state */
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#endif
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#ifdef ENABLE_CODE128
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code128_decoder_t code128; /* Code 128 decode state */
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#endif
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#ifdef ENABLE_PDF417
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pdf417_decoder_t pdf417; /* PDF417 decode state */
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#endif
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#ifdef ENABLE_QRCODE
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qr_finder_t qrf; /* QR Code finder state */
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#endif
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};
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/* return current element color */
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static inline char get_color (const zbar_decoder_t *dcode)
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{
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return(dcode->idx & 1);
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}
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/* retrieve i-th previous element width */
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static inline unsigned get_width (const zbar_decoder_t *dcode,
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unsigned char offset)
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{
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return(dcode->w[(dcode->idx - offset) & (DECODE_WINDOW - 1)]);
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}
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/* retrieve bar+space pair width starting at offset i */
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static inline unsigned pair_width (const zbar_decoder_t *dcode,
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unsigned char offset)
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{
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return(get_width(dcode, offset) + get_width(dcode, offset + 1));
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}
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/* calculate total character width "s"
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* - start of character identified by context sensitive offset
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* (<= DECODE_WINDOW - n)
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* - size of character is n elements
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*/
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static inline unsigned calc_s (const zbar_decoder_t *dcode,
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unsigned char offset,
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unsigned char n)
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{
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/* FIXME check that this gets unrolled for constant n */
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unsigned s = 0;
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while(n--)
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s += get_width(dcode, offset++);
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return(s);
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}
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/* fixed character width decode assist
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* bar+space width are compared as a fraction of the reference dimension "x"
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* - +/- 1/2 x tolerance
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* - measured total character width (s) compared to symbology baseline (n)
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* (n = 7 for EAN/UPC, 11 for Code 128)
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* - bar+space *pair width* "e" is used to factor out bad "exposures"
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* ("blooming" or "swelling" of dark or light areas)
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* => using like-edge measurements avoids these issues
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* - n should be > 3
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*/
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static inline int decode_e (unsigned e,
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unsigned s,
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unsigned n)
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{
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/* result is encoded number of units - 2
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* (for use as zero based index)
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* or -1 if invalid
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*/
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unsigned char E = ((e * n * 2 + 1) / s - 3) / 2;
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return((E >= n - 3) ? -1 : E);
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}
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/* sort three like-colored elements and return ordering
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*/
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static inline unsigned decode_sort3 (zbar_decoder_t *dcode,
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int i0)
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{
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unsigned w0 = get_width(dcode, i0);
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unsigned w2 = get_width(dcode, i0 + 2);
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unsigned w4 = get_width(dcode, i0 + 4);
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if(w0 < w2) {
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if(w2 < w4)
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return((i0 << 8) | ((i0 + 2) << 4) | (i0 + 4));
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if(w0 < w4)
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return((i0 << 8) | ((i0 + 4) << 4) | (i0 + 2));
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return(((i0 + 4) << 8) | (i0 << 4) | (i0 + 2));
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}
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if(w4 < w2)
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return(((i0 + 4) << 8) | ((i0 + 2) << 4) | i0);
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if(w0 < w4)
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return(((i0 + 2) << 8) | (i0 << 4) | (i0 + 4));
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return(((i0 + 2) << 8) | ((i0 + 4) << 4) | i0);
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}
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/* sort N like-colored elements and return ordering
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*/
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static inline unsigned decode_sortn (zbar_decoder_t *dcode,
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int n,
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int i0)
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{
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unsigned mask = 0, sort = 0;
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int i;
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for(i = n - 1; i >= 0; i--) {
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unsigned wmin = UINT_MAX;
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int jmin = -1, j;
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for(j = n - 1; j >= 0; j--) {
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if((mask >> j) & 1)
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continue;
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unsigned w = get_width(dcode, i0 + j * 2);
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if(wmin >= w) {
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wmin = w;
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jmin = j;
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}
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}
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zassert(jmin >= 0, 0, "sortn(%d,%d) jmin=%d",
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n, i0, jmin);
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sort <<= 4;
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mask |= 1 << jmin;
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sort |= i0 + jmin * 2;
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}
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return(sort);
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}
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/* acquire shared state lock */
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static inline char acquire_lock (zbar_decoder_t *dcode,
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zbar_symbol_type_t req)
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{
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if(dcode->lock) {
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dbprintf(2, " [locked %d]\n", dcode->lock);
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return(1);
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}
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dcode->lock = req;
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return(0);
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}
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/* check and release shared state lock */
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static inline char release_lock (zbar_decoder_t *dcode,
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zbar_symbol_type_t req)
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{
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zassert(dcode->lock == req, 1, "lock=%d req=%d\n",
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dcode->lock, req);
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dcode->lock = 0;
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return(0);
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}
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/* ensure output buffer has sufficient allocation for request */
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static inline char size_buf (zbar_decoder_t *dcode,
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unsigned len)
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{
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unsigned char *buf;
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if(len <= BUFFER_MIN)
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return(0);
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if(len < dcode->buf_alloc)
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/* FIXME size reduction heuristic? */
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return(0);
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if(len > BUFFER_MAX)
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return(1);
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if(len < dcode->buf_alloc + BUFFER_INCR) {
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len = dcode->buf_alloc + BUFFER_INCR;
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if(len > BUFFER_MAX)
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len = BUFFER_MAX;
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}
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buf = realloc(dcode->buf, len);
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if(!buf)
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return(1);
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dcode->buf = buf;
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dcode->buf_alloc = len;
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return(0);
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}
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static inline void *zbar_decoder_get_userdata (const zbar_decoder_t *dcode)
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{
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return(dcode->userdata);
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}
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static inline void zbar_decoder_set_userdata (zbar_decoder_t *dcode,
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void *userdata)
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{
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dcode->userdata = userdata;
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}
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static inline zbar_symbol_type_t zbar_decoder_get_type (const zbar_decoder_t *dcode)
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{
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return(dcode->type);
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}
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static inline unsigned int zbar_decoder_get_modifiers (const zbar_decoder_t *dcode)
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{
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return(dcode->modifiers);
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}
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static inline zbar_color_t zbar_decoder_get_color (const zbar_decoder_t *dcode)
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{
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return(get_color(dcode));
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}
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static inline const char *zbar_decoder_get_data (const zbar_decoder_t *dcode)
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{
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return((char*)dcode->buf);
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}
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static inline unsigned int zbar_decoder_get_data_length (const zbar_decoder_t *dcode)
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{
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return(dcode->buflen);
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}
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static inline int zbar_decoder_get_direction (const zbar_decoder_t *dcode)
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{
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return(dcode->direction);
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}
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static inline zbar_decoder_handler_t *
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zbar_decoder_set_handler (zbar_decoder_t *dcode,
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zbar_decoder_handler_t *handler)
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{
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zbar_decoder_handler_t *result = dcode->handler;
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dcode->handler = handler;
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return(result);
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}
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extern const char *_zbar_decoder_buf_dump (unsigned char *buf,
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unsigned int buflen);
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#endif
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