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Diffstat (limited to 'zbar/decoder.h')
| -rw-r--r-- | zbar/decoder.h | 292 |
1 files changed, 292 insertions, 0 deletions
diff --git a/zbar/decoder.h b/zbar/decoder.h new file mode 100644 index 0000000..260dc43 --- /dev/null +++ b/zbar/decoder.h @@ -0,0 +1,292 @@ +/*------------------------------------------------------------------------ + * Copyright 2007-2010 (c) Jeff Brown <spadix@users.sourceforge.net> + * + * This file is part of the ZBar Bar Code Reader. + * + * The ZBar Bar Code Reader is free software; you can redistribute it + * and/or modify it under the terms of the GNU Lesser Public License as + * published by the Free Software Foundation; either version 2.1 of + * the License, or (at your option) any later version. + * + * The ZBar Bar Code Reader 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 Public License for more details. + * + * You should have received a copy of the GNU Lesser Public License + * along with the ZBar Bar Code Reader; if not, write to the Free + * Software Foundation, Inc., 51 Franklin St, Fifth Floor, + * Boston, MA 02110-1301 USA + * + * http://sourceforge.net/projects/zbar + *------------------------------------------------------------------------*/ +#ifndef _DECODER_H_ +#define _DECODER_H_ + +#include "config.h" +#include <limits.h> +#include <stdlib.h> /* realloc */ + +#include <zbar.h> + +#include "debug.h" + +#define NUM_CFGS (ZBAR_CFG_MAX_LEN - ZBAR_CFG_MIN_LEN + 1) + +#if ENABLE_EAN == 1 +#include "decoder/ean.h" +#endif +#if ENABLE_I25 == 1 +#include "decoder/i25.h" +#endif +#if ENABLE_DATABAR == 1 +#include "decoder/databar.h" +#endif +#if ENABLE_CODABAR == 1 +#include "decoder/codabar.h" +#endif +#if ENABLE_CODE39 == 1 +#include "decoder/code39.h" +#endif +#if ENABLE_CODE93 == 1 +#include "decoder/code93.h" +#endif +#if ENABLE_CODE128 == 1 +#include "decoder/code128.h" +#endif +#if ENABLE_PDF417 == 1 +#include "decoder/pdf417.h" +#endif +#if ENABLE_QRCODE == 1 +#include "decoder/qr_finder.h" +#endif +#if ENABLE_SQCODE == 1 +#include "decoder/sq_finder.h" +#endif + +/* size of bar width history (implementation assumes power of two) */ +#ifndef DECODE_WINDOW +#define DECODE_WINDOW 16 +#endif + +/* initial data buffer allocation */ +#ifndef BUFFER_MIN +#define BUFFER_MIN 0x20 +#endif + +/* maximum data buffer allocation + * (longer symbols are rejected) + */ +#ifndef BUFFER_MAX +#define BUFFER_MAX 0x100 +#endif + +/* buffer allocation increment */ +#ifndef BUFFER_INCR +#define BUFFER_INCR 0x10 +#endif + +#define CFG(dcode, cfg) ((dcode).configs[(cfg)-ZBAR_CFG_MIN_LEN]) +#define TEST_CFG(config, cfg) (((config) >> (cfg)) & 1) +#define MOD(mod) (1 << (mod)) + +/* symbology independent decoder state */ +struct zbar_decoder_s { + unsigned char idx; /* current width index */ + unsigned w[DECODE_WINDOW]; /* window of last N bar widths */ + zbar_symbol_type_t type; /* type of last decoded data */ + zbar_symbol_type_t lock; /* buffer lock */ + unsigned modifiers; /* symbology modifier */ + int direction; /* direction of last decoded data */ + unsigned s6; /* 6-element character width */ + + /* everything above here is automatically reset */ + unsigned buf_alloc; /* dynamic buffer allocation */ + unsigned buflen; /* binary data length */ + unsigned char *buf; /* decoded characters */ + void *userdata; /* application data */ + zbar_decoder_handler_t *handler; /* application callback */ + + /* symbology specific state */ +#if ENABLE_EAN == 1 + ean_decoder_t ean; /* EAN/UPC parallel decode attempts */ +#endif +#if ENABLE_I25 == 1 + i25_decoder_t i25; /* Interleaved 2 of 5 decode state */ +#endif +#if ENABLE_DATABAR == 1 + databar_decoder_t databar; /* DataBar decode state */ +#endif +#if ENABLE_CODABAR == 1 + codabar_decoder_t codabar; /* Codabar decode state */ +#endif +#if ENABLE_CODE39 == 1 + code39_decoder_t code39; /* Code 39 decode state */ +#endif +#if ENABLE_CODE93 == 1 + code93_decoder_t code93; /* Code 93 decode state */ +#endif +#if ENABLE_CODE128 == 1 + code128_decoder_t code128; /* Code 128 decode state */ +#endif +#if ENABLE_PDF417 == 1 + pdf417_decoder_t pdf417; /* PDF417 decode state */ +#endif +#if ENABLE_QRCODE == 1 + qr_finder_t qrf; /* QR Code finder state */ +#endif +#if ENABLE_SQCODE == 1 + sq_finder_t sqf; /* SQ Code finder state */ +#endif +}; + +/* return current element color */ +static inline char get_color(const zbar_decoder_t *dcode) +{ + return (dcode->idx & 1); +} + +/* retrieve i-th previous element width */ +static inline unsigned get_width(const zbar_decoder_t *dcode, + unsigned char offset) +{ + return (dcode->w[(dcode->idx - offset) & (DECODE_WINDOW - 1)]); +} + +/* retrieve bar+space pair width starting at offset i */ +static inline unsigned pair_width(const zbar_decoder_t *dcode, + unsigned char offset) +{ + return (get_width(dcode, offset) + get_width(dcode, offset + 1)); +} + +/* calculate total character width "s" + * - start of character identified by context sensitive offset + * (<= DECODE_WINDOW - n) + * - size of character is n elements + */ +static inline unsigned calc_s(const zbar_decoder_t *dcode, unsigned char offset, + unsigned char n) +{ + /* FIXME check that this gets unrolled for constant n */ + unsigned s = 0; + while (n--) + s += get_width(dcode, offset++); + return (s); +} + +/* fixed character width decode assist + * bar+space width are compared as a fraction of the reference dimension "x" + * - +/- 1/2 x tolerance + * - measured total character width (s) compared to symbology baseline (n) + * (n = 7 for EAN/UPC, 11 for Code 128) + * - bar+space *pair width* "e" is used to factor out bad "exposures" + * ("blooming" or "swelling" of dark or light areas) + * => using like-edge measurements avoids these issues + * - n should be > 3 + */ +static inline int decode_e(unsigned e, unsigned s, unsigned n) +{ + /* result is encoded number of units - 2 + * (for use as zero based index) + * or -1 if invalid + */ + unsigned char E = ((e * n * 2 + 1) / s - 3) / 2; + return ((E >= n - 3) ? -1 : E); +} + +/* sort three like-colored elements and return ordering + */ +static inline unsigned decode_sort3(zbar_decoder_t *dcode, int i0) +{ + unsigned w0 = get_width(dcode, i0); + unsigned w2 = get_width(dcode, i0 + 2); + unsigned w4 = get_width(dcode, i0 + 4); + if (w0 < w2) { + if (w2 < w4) + return ((i0 << 8) | ((i0 + 2) << 4) | (i0 + 4)); + if (w0 < w4) + return ((i0 << 8) | ((i0 + 4) << 4) | (i0 + 2)); + return (((i0 + 4) << 8) | (i0 << 4) | (i0 + 2)); + } + if (w4 < w2) + return (((i0 + 4) << 8) | ((i0 + 2) << 4) | i0); + if (w0 < w4) + return (((i0 + 2) << 8) | (i0 << 4) | (i0 + 4)); + return (((i0 + 2) << 8) | ((i0 + 4) << 4) | i0); +} + +/* sort N like-colored elements and return ordering + */ +static inline unsigned decode_sortn(zbar_decoder_t *dcode, int n, int i0) +{ + unsigned mask = 0, sort = 0; + int i; + for (i = n - 1; i >= 0; i--) { + unsigned wmin = UINT_MAX; + int jmin = -1, j; + for (j = n - 1; j >= 0; j--) { + unsigned w; + if ((mask >> j) & 1) + continue; + w = get_width(dcode, i0 + j * 2); + if (wmin >= w) { + wmin = w; + jmin = j; + } + } + zassert(jmin >= 0, 0, "sortn(%d,%d) jmin=%d", n, i0, jmin); + sort <<= 4; + mask |= 1 << jmin; + sort |= i0 + jmin * 2; + } + return (sort); +} + +/* acquire shared state lock */ +static inline char acquire_lock(zbar_decoder_t *dcode, zbar_symbol_type_t req) +{ + if (dcode->lock) { + dbprintf(2, " [locked %d]\n", dcode->lock); + return (1); + } + dcode->lock = req; + return (0); +} + +/* check and release shared state lock */ +static inline char release_lock(zbar_decoder_t *dcode, zbar_symbol_type_t req) +{ + zassert(dcode->lock == req, 1, "lock=%d req=%d\n", dcode->lock, req); + dcode->lock = 0; + return (0); +} + +/* ensure output buffer has sufficient allocation for request */ +static inline char size_buf(zbar_decoder_t *dcode, unsigned len) +{ + unsigned char *buf; + if (len <= BUFFER_MIN) + return (0); + if (len < dcode->buf_alloc) + /* FIXME size reduction heuristic? */ + return (0); + if (len > BUFFER_MAX) + return (1); + if (len < dcode->buf_alloc + BUFFER_INCR) { + len = dcode->buf_alloc + BUFFER_INCR; + if (len > BUFFER_MAX) + len = BUFFER_MAX; + } + buf = realloc(dcode->buf, len); + if (!buf) + return (1); + dcode->buf = buf; + dcode->buf_alloc = len; + return (0); +} + +extern const char *_zbar_decoder_buf_dump(unsigned char *buf, + unsigned int buflen); + +#endif |