Zoltan Hudak / zbar

A streamlined version (for embedded use) of Jeff Brown's ZBar library. Visit <http://zbar.sourceforge.net> for more details.

Dependents:   BarcodeReader_F103

decoder.h@1:4f5c042a2d34, 2020-01-10 (annotated)

Committer:
hudakz
Date:
Fri Jan 10 22:06:18 2020 +0000
Revision:
1:4f5c042a2d34
Parent:
0:e33621169e44 
Streamlined barcode reader library.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
hudakz 0:e33621169e44 1 /*------------------------------------------------------------------------
hudakz 0:e33621169e44 2 * Copyright 2007-2009 (c) Jeff Brown <spadix@users.sourceforge.net>
hudakz 0:e33621169e44 3 *
hudakz 0:e33621169e44 4 * This file is part of the ZBar Bar Code Reader.
hudakz 0:e33621169e44 5 *
hudakz 0:e33621169e44 6 * The ZBar Bar Code Reader is free software; you can redistribute it
hudakz 0:e33621169e44 7 * and/or modify it under the terms of the GNU Lesser Public License as
hudakz 0:e33621169e44 8 * published by the Free Software Foundation; either version 2.1 of
hudakz 0:e33621169e44 9 * the License, or (at your option) any later version.
hudakz 0:e33621169e44 10 *
hudakz 0:e33621169e44 11 * The ZBar Bar Code Reader is distributed in the hope that it will be
hudakz 0:e33621169e44 12 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
hudakz 0:e33621169e44 13 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
hudakz 0:e33621169e44 14 * GNU Lesser Public License for more details.
hudakz 0:e33621169e44 15 *
hudakz 0:e33621169e44 16 * You should have received a copy of the GNU Lesser Public License
hudakz 0:e33621169e44 17 * along with the ZBar Bar Code Reader; if not, write to the Free
hudakz 0:e33621169e44 18 * Software Foundation, Inc., 51 Franklin St, Fifth Floor,
hudakz 0:e33621169e44 19 * Boston, MA 02110-1301 USA
hudakz 0:e33621169e44 20 *
hudakz 0:e33621169e44 21 * http://sourceforge.net/projects/zbar
hudakz 0:e33621169e44 22 *------------------------------------------------------------------------*/
hudakz 0:e33621169e44 23 #ifndef _DECODER_H_
hudakz 0:e33621169e44 24 #define _DECODER_H_
hudakz 0:e33621169e44 25
hudakz 0:e33621169e44 26 #include "config.h"
hudakz 0:e33621169e44 27 #include <stdlib.h> /* realloc */
hudakz 0:e33621169e44 28
hudakz 0:e33621169e44 29 #include <zbar.h>
hudakz 0:e33621169e44 30
hudakz 0:e33621169e44 31 #define NUM_CFGS (ZBAR_CFG_MAX_LEN - ZBAR_CFG_MIN_LEN + 1)
hudakz 0:e33621169e44 32
hudakz 0:e33621169e44 33 #ifdef ENABLE_EAN
hudakz 0:e33621169e44 34 # include "decoder/ean.h"
hudakz 0:e33621169e44 35 #endif
hudakz 0:e33621169e44 36 #ifdef ENABLE_I25
hudakz 0:e33621169e44 37 # include "decoder/i25.h"
hudakz 0:e33621169e44 38 #endif
hudakz 0:e33621169e44 39 #ifdef ENABLE_CODE39
hudakz 0:e33621169e44 40 # include "decoder/code39.h"
hudakz 0:e33621169e44 41 #endif
hudakz 0:e33621169e44 42 #ifdef ENABLE_CODE128
hudakz 0:e33621169e44 43 # include "decoder/code128.h"
hudakz 0:e33621169e44 44 #endif
hudakz 0:e33621169e44 45 #ifdef ENABLE_PDF417
hudakz 0:e33621169e44 46 # include "decoder/pdf417.h"
hudakz 0:e33621169e44 47 #endif
hudakz 0:e33621169e44 48 #ifdef ENABLE_QRCODE
hudakz 0:e33621169e44 49 # include "decoder/qr_finder.h"
hudakz 0:e33621169e44 50 #endif
hudakz 0:e33621169e44 51
hudakz 0:e33621169e44 52 /* size of bar width history (implementation assumes power of two) */
hudakz 0:e33621169e44 53 #ifndef DECODE_WINDOW
hudakz 0:e33621169e44 54 # define DECODE_WINDOW 16
hudakz 0:e33621169e44 55 #endif
hudakz 0:e33621169e44 56
hudakz 0:e33621169e44 57 /* initial data buffer allocation */
hudakz 0:e33621169e44 58 #ifndef BUFFER_MIN
hudakz 0:e33621169e44 59 # define BUFFER_MIN 0x20
hudakz 0:e33621169e44 60 #endif
hudakz 0:e33621169e44 61
hudakz 0:e33621169e44 62 /* maximum data buffer allocation
hudakz 0:e33621169e44 63 * (longer symbols are rejected)
hudakz 0:e33621169e44 64 */
hudakz 0:e33621169e44 65 #ifndef BUFFER_MAX
hudakz 0:e33621169e44 66 # define BUFFER_MAX 0x100
hudakz 0:e33621169e44 67 #endif
hudakz 0:e33621169e44 68
hudakz 0:e33621169e44 69 /* buffer allocation increment */
hudakz 0:e33621169e44 70 #ifndef BUFFER_INCR
hudakz 0:e33621169e44 71 # define BUFFER_INCR 0x10
hudakz 0:e33621169e44 72 #endif
hudakz 0:e33621169e44 73
hudakz 0:e33621169e44 74 #define CFG(dcode, cfg) ((dcode).configs[(cfg) - ZBAR_CFG_MIN_LEN])
hudakz 0:e33621169e44 75 #define TEST_CFG(config, cfg) (((config) >> (cfg)) & 1)
hudakz 0:e33621169e44 76
hudakz 0:e33621169e44 77 /* symbology independent decoder state */
hudakz 0:e33621169e44 78 struct zbar_decoder_s {
hudakz 0:e33621169e44 79 unsigned char idx; /* current width index */
hudakz 0:e33621169e44 80 unsigned w[DECODE_WINDOW]; /* window of last N bar widths */
hudakz 0:e33621169e44 81 zbar_symbol_type_t type; /* type of last decoded data */
hudakz 0:e33621169e44 82 zbar_symbol_type_t lock; /* buffer lock */
hudakz 0:e33621169e44 83
hudakz 0:e33621169e44 84 /* everything above here is automatically reset */
hudakz 0:e33621169e44 85 unsigned buf_alloc; /* dynamic buffer allocation */
hudakz 0:e33621169e44 86 unsigned buflen; /* binary data length */
hudakz 0:e33621169e44 87 unsigned char *buf; /* decoded characters */
hudakz 0:e33621169e44 88 void *userdata; /* application data */
hudakz 0:e33621169e44 89 zbar_decoder_handler_t *handler; /* application callback */
hudakz 0:e33621169e44 90
hudakz 0:e33621169e44 91 /* symbology specific state */
hudakz 0:e33621169e44 92 #ifdef ENABLE_EAN
hudakz 0:e33621169e44 93 ean_decoder_t ean; /* EAN/UPC parallel decode attempts */
hudakz 0:e33621169e44 94 #endif
hudakz 0:e33621169e44 95 #ifdef ENABLE_I25
hudakz 0:e33621169e44 96 i25_decoder_t i25; /* Interleaved 2 of 5 decode state */
hudakz 0:e33621169e44 97 #endif
hudakz 0:e33621169e44 98 #ifdef ENABLE_CODE39
hudakz 0:e33621169e44 99 code39_decoder_t code39; /* Code 39 decode state */
hudakz 0:e33621169e44 100 #endif
hudakz 0:e33621169e44 101 #ifdef ENABLE_CODE128
hudakz 0:e33621169e44 102 code128_decoder_t code128; /* Code 128 decode state */
hudakz 0:e33621169e44 103 #endif
hudakz 0:e33621169e44 104 #ifdef ENABLE_PDF417
hudakz 0:e33621169e44 105 pdf417_decoder_t pdf417; /* PDF417 decode state */
hudakz 0:e33621169e44 106 #endif
hudakz 0:e33621169e44 107 #ifdef ENABLE_QRCODE
hudakz 0:e33621169e44 108 qr_finder_t qrf; /* QR Code finder state */
hudakz 0:e33621169e44 109 #endif
hudakz 0:e33621169e44 110 };
hudakz 0:e33621169e44 111
hudakz 0:e33621169e44 112 /* return current element color */
hudakz 0:e33621169e44 113 static inline char get_color (const zbar_decoder_t *dcode)
hudakz 0:e33621169e44 114 {
hudakz 0:e33621169e44 115 return(dcode->idx & 1);
hudakz 0:e33621169e44 116 }
hudakz 0:e33621169e44 117
hudakz 0:e33621169e44 118 /* retrieve i-th previous element width */
hudakz 0:e33621169e44 119 static inline unsigned get_width (const zbar_decoder_t *dcode,
hudakz 0:e33621169e44 120 unsigned char offset)
hudakz 0:e33621169e44 121 {
hudakz 0:e33621169e44 122 return(dcode->w[(dcode->idx - offset) & (DECODE_WINDOW - 1)]);
hudakz 0:e33621169e44 123 }
hudakz 0:e33621169e44 124
hudakz 0:e33621169e44 125 /* retrieve bar+space pair width starting at offset i */
hudakz 0:e33621169e44 126 static inline unsigned pair_width (const zbar_decoder_t *dcode,
hudakz 0:e33621169e44 127 unsigned char offset)
hudakz 0:e33621169e44 128 {
hudakz 0:e33621169e44 129 return(get_width(dcode, offset) + get_width(dcode, offset + 1));
hudakz 0:e33621169e44 130 }
hudakz 0:e33621169e44 131
hudakz 0:e33621169e44 132 /* calculate total character width "s"
hudakz 0:e33621169e44 133 * - start of character identified by context sensitive offset
hudakz 0:e33621169e44 134 * (<= DECODE_WINDOW - n)
hudakz 0:e33621169e44 135 * - size of character is n elements
hudakz 0:e33621169e44 136 */
hudakz 0:e33621169e44 137 static inline unsigned calc_s (const zbar_decoder_t *dcode,
hudakz 0:e33621169e44 138 unsigned char offset,
hudakz 0:e33621169e44 139 unsigned char n)
hudakz 0:e33621169e44 140 {
hudakz 0:e33621169e44 141 /* FIXME check that this gets unrolled for constant n */
hudakz 0:e33621169e44 142 unsigned s = 0;
hudakz 0:e33621169e44 143 while(n--)
hudakz 0:e33621169e44 144 s += get_width(dcode, offset++);
hudakz 0:e33621169e44 145 return(s);
hudakz 0:e33621169e44 146 }
hudakz 0:e33621169e44 147
hudakz 0:e33621169e44 148 /* fixed character width decode assist
hudakz 0:e33621169e44 149 * bar+space width are compared as a fraction of the reference dimension "x"
hudakz 0:e33621169e44 150 * - +/- 1/2 x tolerance
hudakz 0:e33621169e44 151 * - measured total character width (s) compared to symbology baseline (n)
hudakz 0:e33621169e44 152 * (n = 7 for EAN/UPC, 11 for Code 128)
hudakz 0:e33621169e44 153 * - bar+space *pair width* "e" is used to factor out bad "exposures"
hudakz 0:e33621169e44 154 * ("blooming" or "swelling" of dark or light areas)
hudakz 0:e33621169e44 155 * => using like-edge measurements avoids these issues
hudakz 0:e33621169e44 156 * - n should be > 3
hudakz 0:e33621169e44 157 */
hudakz 0:e33621169e44 158 static inline int decode_e (unsigned e,
hudakz 0:e33621169e44 159 unsigned s,
hudakz 0:e33621169e44 160 unsigned n)
hudakz 0:e33621169e44 161 {
hudakz 0:e33621169e44 162 /* result is encoded number of units - 2
hudakz 0:e33621169e44 163 * (for use as zero based index)
hudakz 0:e33621169e44 164 * or -1 if invalid
hudakz 0:e33621169e44 165 */
hudakz 0:e33621169e44 166 unsigned char E = ((e * n * 2 + 1) / s - 3) / 2;
hudakz 0:e33621169e44 167 return((E >= n - 3) ? -1 : E);
hudakz 0:e33621169e44 168 }
hudakz 0:e33621169e44 169
hudakz 0:e33621169e44 170 /* acquire shared state lock */
hudakz 0:e33621169e44 171 static inline char get_lock (zbar_decoder_t *dcode,
hudakz 0:e33621169e44 172 zbar_symbol_type_t req)
hudakz 0:e33621169e44 173 {
hudakz 0:e33621169e44 174 if(dcode->lock)
hudakz 0:e33621169e44 175 return(1);
hudakz 0:e33621169e44 176 dcode->lock = req;
hudakz 0:e33621169e44 177 return(0);
hudakz 0:e33621169e44 178 }
hudakz 0:e33621169e44 179
hudakz 0:e33621169e44 180 /* ensure output buffer has sufficient allocation for request */
hudakz 0:e33621169e44 181 static inline char size_buf (zbar_decoder_t *dcode,
hudakz 0:e33621169e44 182 unsigned len)
hudakz 0:e33621169e44 183 {
hudakz 0:e33621169e44 184 if(len < dcode->buf_alloc)
hudakz 0:e33621169e44 185 /* FIXME size reduction heuristic? */
hudakz 0:e33621169e44 186 return(0);
hudakz 0:e33621169e44 187 if(len > BUFFER_MAX)
hudakz 0:e33621169e44 188 return(1);
hudakz 0:e33621169e44 189 if(len < dcode->buf_alloc + BUFFER_INCR) {
hudakz 0:e33621169e44 190 len = dcode->buf_alloc + BUFFER_INCR;
hudakz 0:e33621169e44 191 if(len > BUFFER_MAX)
hudakz 0:e33621169e44 192 len = BUFFER_MAX;
hudakz 0:e33621169e44 193 }
hudakz 0:e33621169e44 194 unsigned char *buf = realloc(dcode->buf, len);
hudakz 0:e33621169e44 195 if(!buf)
hudakz 0:e33621169e44 196 return(1);
hudakz 0:e33621169e44 197 dcode->buf = buf;
hudakz 0:e33621169e44 198 dcode->buf_alloc = len;
hudakz 0:e33621169e44 199 return(0);
hudakz 0:e33621169e44 200 }
hudakz 0:e33621169e44 201
hudakz 0:e33621169e44 202 extern const char *_zbar_decoder_buf_dump (unsigned char *buf,
hudakz 0:e33621169e44 203 unsigned int buflen);
hudakz 0:e33621169e44 204
hudakz 0:e33621169e44 205 #endif