A streamlined version (for embedded use) of Jeff Brown's ZBar library. Visit <http://zbar.sourceforge.net> for more details.
Dependents: BarcodeReader_F103
Diff: decoder/ean.c
- Revision:
- 0:e33621169e44
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/decoder/ean.c Fri Jan 10 20:29:52 2020 +0000 @@ -0,0 +1,646 @@ +/*------------------------------------------------------------------------ + * Copyright 2007-2009 (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 + *------------------------------------------------------------------------*/ + +#include "../config.h" +#include <zbar.h> +#include "../decoder.h" + +#ifdef ENABLE_EAN + +#ifdef DEBUG_EAN +# define DEBUG_LEVEL (DEBUG_EAN) +#endif +#include "../debug.h" + +/* partial decode symbol location */ +typedef enum symbol_partial_e { + EAN_LEFT = 0x0000, + EAN_RIGHT = 0x1000, +} symbol_partial_t; + +/* convert compact encoded D2E1E2 to character (bit4 is parity) */ +static const unsigned char digits[] = { /* E1 E2 */ + 0x06, 0x10, 0x04, 0x13, /* 2 2-5 */ + 0x19, 0x08, 0x11, 0x05, /* 3 2-5 (d2 <= thr) */ + 0x09, 0x12, 0x07, 0x15, /* 4 2-5 (d2 <= thr) */ + 0x16, 0x00, 0x14, 0x03, /* 5 2-5 */ + 0x18, 0x01, 0x02, 0x17, /* E1E2=43,44,33,34 (d2 > thr) */ +}; + +static const unsigned char parity_decode[] = { + 0xf0, /* [xx] BBBBBB = RIGHT half EAN-13 */ + + /* UPC-E check digit encoding */ + 0xff, + 0xff, + 0x0f, /* [07] BBBAAA = 0 */ + 0xff, + 0x1f, /* [0b] BBABAA = 1 */ + 0x2f, /* [0d] BBAABA = 2 */ + 0xf3, /* [0e] BBAAAB = 3 */ + 0xff, + 0x4f, /* [13] BABBAA = 4 */ + 0x7f, /* [15] BABABA = 7 */ + 0xf8, /* [16] BABAAB = 8 */ + 0x5f, /* [19] BAABBA = 5 */ + 0xf9, /* [1a] BAABAB = 9 */ + 0xf6, /* [1c] BAAABB = 6 */ + 0xff, + + /* LEFT half EAN-13 leading digit */ + 0xff, + 0x6f, /* [23] ABBBAA = 6 */ + 0x9f, /* [25] ABBABA = 9 */ + 0xf5, /* [26] ABBAAB = 5 */ + 0x8f, /* [29] ABABBA = 8 */ + 0xf7, /* [2a] ABABAB = 7 */ + 0xf4, /* [2c] ABAABB = 4 */ + 0xff, + 0x3f, /* [31] AABBBA = 3 */ + 0xf2, /* [32] AABBAB = 2 */ + 0xf1, /* [34] AABABB = 1 */ + 0xff, + 0xff, + 0xff, + 0xff, + 0x0f, /* [3f] AAAAAA = 0 */ +}; + +#ifdef DEBUG_EAN +static unsigned char debug_buf[0x18]; + +static inline const unsigned char *dsprintbuf(ean_decoder_t *ean) +{ + int i; + for(i = 0; i < 7; i++) + debug_buf[i] = ((ean->buf[0] < 0 || ean->buf[i] < 0) + ? '-' + : ean->buf[i] + '0'); + debug_buf[i] = ' '; + for(; i < 13; i++) + debug_buf[i + 1] = ((ean->buf[7] < 0 || ean->buf[i] < 0) + ? '-' + : ean->buf[i] + '0'); + debug_buf[i + 1] = ' '; + for(; i < 18; i++) + debug_buf[i + 2] = ((ean->buf[13] < 0 || ean->buf[i] < 0) + ? '-' + : ean->buf[i] + '0'); + debug_buf[i + 2] = '\0'; + return(debug_buf); +} +#endif + +/* evaluate previous N (>= 2) widths as auxiliary pattern, + * using preceding 4 as character width + */ +static inline signed char aux_end (zbar_decoder_t *dcode, + unsigned char fwd) +{ + /* reference width from previous character */ + unsigned s = calc_s(dcode, 4 + fwd, 4); + + /* check quiet zone */ + unsigned qz = get_width(dcode, 0); + if(!fwd && qz && qz < s * 3 / 4) { + dprintf(2, " [invalid quiet]"); + return(-1); + } + + dprintf(2, " ("); + signed char code = 0; + unsigned char i; + for(i = 1 - fwd; i < 3 + fwd; i++) { + unsigned e = get_width(dcode, i) + get_width(dcode, i + 1); + dprintf(2, " %d", e); + code = (code << 2) | decode_e(e, s, 7); + if(code < 0) { + dprintf(2, " [invalid end guard]"); + return(-1); + } + } + dprintf(2, ") s=%d aux=%x", s, code); + return(code); +} + +/* determine possible auxiliary pattern + * using current 4 as possible character + */ +static inline signed char aux_start (zbar_decoder_t *dcode) +{ + /* FIXME NB add-on has no guard in reverse */ + unsigned e2 = get_width(dcode, 5) + get_width(dcode, 6); + if(decode_e(e2, dcode->ean.s4, 7)) { + dprintf(2, " [invalid any]"); + return(/*FIXME (get_color(dcode) == ZBAR_SPACE) ? STATE_ADDON : */-1); + } + + unsigned e1 = get_width(dcode, 4) + get_width(dcode, 5); + unsigned char E1 = decode_e(e1, dcode->ean.s4, 7); + + if(get_color(dcode) == ZBAR_BAR) { + /* check for quiet-zone */ + unsigned qz = get_width(dcode, 7); + if(!qz || qz >= dcode->ean.s4 * 3 / 4) { + if(!E1) { + dprintf(2, " [valid normal]"); + return(0); /* normal symbol start */ + } + else if(E1 == 1) { + dprintf(2, " [valid add-on]"); + return(STATE_ADDON); /* add-on symbol start */ + } + } + dprintf(2, " [invalid start]"); + return(-1); + } + + if(!E1) { + /* attempting decode from SPACE => validate center guard */ + unsigned e3 = get_width(dcode, 6) + get_width(dcode, 7); + if(!decode_e(e3, dcode->ean.s4, 7)) { + dprintf(2, " [valid center]"); + return(0); /* start after center guard */ + } + } + dprintf(2, " [invalid center]"); + return(/*STATE_ADDON*/-1); +} + +/* attempt to decode previous 4 widths (2 bars and 2 spaces) as a character */ +static inline signed char decode4 (zbar_decoder_t *dcode) +{ + /* calculate similar edge measurements */ + unsigned e1 = ((get_color(dcode) == ZBAR_BAR) + ? get_width(dcode, 0) + get_width(dcode, 1) + : get_width(dcode, 2) + get_width(dcode, 3)); + unsigned e2 = get_width(dcode, 1) + get_width(dcode, 2); + dprintf(2, "\n e1=%d e2=%d", e1, e2); + + /* create compacted encoding for direct lookup */ + signed char code = ((decode_e(e1, dcode->ean.s4, 7) << 2) | + decode_e(e2, dcode->ean.s4, 7)); + if(code < 0) + return(-1); + dprintf(2, " code=%x", code); + + /* 4 combinations require additional determinant (D2) + E1E2 == 34 (0110) + E1E2 == 43 (1001) + E1E2 == 33 (0101) + E1E2 == 44 (1010) + */ + if((1 << code) & 0x0660) { + /* use sum of bar widths */ + unsigned d2 = ((get_color(dcode) == ZBAR_BAR) + ? get_width(dcode, 0) + get_width(dcode, 2) + : get_width(dcode, 1) + get_width(dcode, 3)); + d2 *= 7; + unsigned char mid = (((1 << code) & 0x0420) + ? 3 /* E1E2 in 33,44 */ + : 4); /* E1E2 in 34,43 */ + unsigned char alt = d2 > (mid * dcode->ean.s4); + if(alt) + code = ((code >> 1) & 3) | 0x10; /* compress code space */ + dprintf(2, " (d2=%d(%d) alt=%d)", d2, mid * dcode->ean.s4, alt); + } + dprintf(2, " char=%02x", digits[(unsigned char)code]); + zassert(code < 0x14, -1, "code=%02x e1=%x e2=%x s4=%x color=%x\n", + code, e1, e2, dcode->ean.s4, get_color(dcode)); + return(code); +} + +static inline zbar_symbol_type_t ean_part_end4 (ean_pass_t *pass, + unsigned char fwd) +{ + /* extract parity bits */ + unsigned char par = ((pass->raw[1] & 0x10) >> 1 | + (pass->raw[2] & 0x10) >> 2 | + (pass->raw[3] & 0x10) >> 3 | + (pass->raw[4] & 0x10) >> 4); + + dprintf(2, " par=%x", par); + if(par && par != 0xf) + /* invalid parity combination */ + return(ZBAR_NONE); + + if(!par == fwd) { + /* reverse sampled digits */ + unsigned char tmp = pass->raw[1]; + pass->raw[1] = pass->raw[4]; + pass->raw[4] = tmp; + tmp = pass->raw[2]; + pass->raw[2] = pass->raw[3]; + pass->raw[3] = tmp; + } + + dprintf(2, "\n"); + dprintf(1, "decode4=%x%x%x%x\n", + pass->raw[1] & 0xf, pass->raw[2] & 0xf, + pass->raw[3] & 0xf, pass->raw[4] & 0xf); + if(!par) + return(ZBAR_EAN8 | EAN_RIGHT); + return(ZBAR_EAN8 | EAN_LEFT); +} + +static inline zbar_symbol_type_t ean_part_end7 (ean_decoder_t *ean, + ean_pass_t *pass, + unsigned char fwd) +{ + /* calculate parity index */ + unsigned char par = ((fwd) + ? ((pass->raw[1] & 0x10) << 1 | + (pass->raw[2] & 0x10) | + (pass->raw[3] & 0x10) >> 1 | + (pass->raw[4] & 0x10) >> 2 | + (pass->raw[5] & 0x10) >> 3 | + (pass->raw[6] & 0x10) >> 4) + : ((pass->raw[1] & 0x10) >> 4 | + (pass->raw[2] & 0x10) >> 3 | + (pass->raw[3] & 0x10) >> 2 | + (pass->raw[4] & 0x10) >> 1 | + (pass->raw[5] & 0x10) | + (pass->raw[6] & 0x10) << 1)); + + /* lookup parity combination */ + pass->raw[0] = parity_decode[par >> 1]; + if(par & 1) + pass->raw[0] >>= 4; + pass->raw[0] &= 0xf; + dprintf(2, " par=%02x(%x)", par, pass->raw[0]); + + if(pass->raw[0] == 0xf) + /* invalid parity combination */ + return(ZBAR_NONE); + + if(!par == fwd) { + /* reverse sampled digits */ + unsigned char i; + for(i = 1; i < 4; i++) { + unsigned char tmp = pass->raw[i]; + pass->raw[i] = pass->raw[7 - i]; + pass->raw[7 - i] = tmp; + } + } + + dprintf(2, "\n"); + dprintf(1, "decode=%x%x%x%x%x%x%x(%02x)\n", + pass->raw[0] & 0xf, pass->raw[1] & 0xf, + pass->raw[2] & 0xf, pass->raw[3] & 0xf, + pass->raw[4] & 0xf, pass->raw[5] & 0xf, + pass->raw[6] & 0xf, par); + + if(TEST_CFG(ean->ean13_config, ZBAR_CFG_ENABLE)) { + if(!par) + return(ZBAR_EAN13 | EAN_RIGHT); + if(par & 0x20) + return(ZBAR_EAN13 | EAN_LEFT); + } + if(par && !(par & 0x20)) + return(ZBAR_UPCE); + + return(ZBAR_NONE); +} + +/* update state for one of 4 parallel passes */ +static inline zbar_symbol_type_t decode_pass (zbar_decoder_t *dcode, + ean_pass_t *pass) +{ + pass->state++; + unsigned char idx = pass->state & STATE_IDX; + unsigned char fwd = pass->state & 1; + + if(get_color(dcode) == ZBAR_SPACE && + (idx == 0x10 || idx == 0x11) && + TEST_CFG(dcode->ean.ean8_config, ZBAR_CFG_ENABLE) && + !aux_end(dcode, fwd)) { + dprintf(2, " fwd=%x", fwd); + zbar_symbol_type_t part = ean_part_end4(pass, fwd); + pass->state = -1; + return(part); + } + + if(!(idx & 0x03) && idx <= 0x14) { + if(!dcode->ean.s4) + return(0); + /* validate guard bars before decoding first char of symbol */ + if(!pass->state) { + pass->state = aux_start(dcode); + if(pass->state < 0) + return(0); + idx = pass->state & STATE_IDX; + } + signed char code = decode4(dcode); + if(code < 0) + pass->state = -1; + else { + dprintf(2, "\n raw[%x]=%02x =>", idx >> 2, + digits[(unsigned char)code]); + pass->raw[(idx >> 2) + 1] = digits[(unsigned char)code]; + dprintf(2, " raw=%d%d%d%d%d%d%d", + pass->raw[0] & 0xf, pass->raw[1] & 0xf, + pass->raw[2] & 0xf, pass->raw[3] & 0xf, + pass->raw[4] & 0xf, pass->raw[5] & 0xf, + pass->raw[6] & 0xf); + } + } + + if(get_color(dcode) == ZBAR_SPACE && + (idx == 0x18 || idx == 0x19)) { + zbar_symbol_type_t part = ZBAR_NONE; + dprintf(2, " fwd=%x", fwd); + if(!aux_end(dcode, fwd)) + part = ean_part_end7(&dcode->ean, pass, fwd); + pass->state = -1; + return(part); + } + return(0); +} + +static inline signed char ean_verify_checksum (ean_decoder_t *ean, + int n) +{ + unsigned char chk = 0; + unsigned char i; + for(i = 0; i < n; i++) { + unsigned char d = ean->buf[i]; + zassert(d < 10, -1, "i=%x d=%x chk=%x %s\n", i, d, chk, + _zbar_decoder_buf_dump((void*)ean->buf, 18)); + chk += d; + if((i ^ n) & 1) { + chk += d << 1; + if(chk >= 20) + chk -= 20; + } + if(chk >= 10) + chk -= 10; + } + zassert(chk < 10, -1, "chk=%x n=%x %s", chk, n, + _zbar_decoder_buf_dump((void*)ean->buf, 18)); + if(chk) + chk = 10 - chk; + unsigned char d = ean->buf[n]; + zassert(d < 10, -1, "n=%x d=%x chk=%x %s\n", n, d, chk, + _zbar_decoder_buf_dump((void*)ean->buf, 18)); + if(chk != d) { + dprintf(1, "\nchecksum mismatch %d != %d (%s)\n", + chk, d, dsprintbuf(ean)); + return(-1); + } + return(0); +} + +static inline unsigned char isbn10_calc_checksum (ean_decoder_t *ean) +{ + unsigned int chk = 0; + unsigned char w; + for(w = 10; w > 1; w--) { + unsigned char d = ean->buf[13 - w]; + zassert(d < 10, '?', "w=%x d=%x chk=%x %s\n", w, d, chk, + _zbar_decoder_buf_dump((void*)ean->buf, 18)); + chk += d * w; + } + chk = chk % 11; + if(!chk) + return('0'); + chk = 11 - chk; + if(chk < 10) + return(chk + '0'); + return('X'); +} + +static inline void ean_expand_upce (ean_decoder_t *ean, + ean_pass_t *pass) +{ + int i = 0; + /* parity encoded digit is checksum */ + ean->buf[12] = pass->raw[i++]; + + unsigned char decode = pass->raw[6] & 0xf; + ean->buf[0] = 0; + ean->buf[1] = 0; + ean->buf[2] = pass->raw[i++] & 0xf; + ean->buf[3] = pass->raw[i++] & 0xf; + ean->buf[4] = (decode < 3) ? decode : pass->raw[i++] & 0xf; + ean->buf[5] = (decode < 4) ? 0 : pass->raw[i++] & 0xf; + ean->buf[6] = (decode < 5) ? 0 : pass->raw[i++] & 0xf; + ean->buf[7] = 0; + ean->buf[8] = 0; + ean->buf[9] = (decode < 3) ? pass->raw[i++] & 0xf : 0; + ean->buf[10] = (decode < 4) ? pass->raw[i++] & 0xf : 0; + ean->buf[11] = (decode < 5) ? pass->raw[i++] & 0xf : decode; +} + +static inline zbar_symbol_type_t integrate_partial (ean_decoder_t *ean, + ean_pass_t *pass, + zbar_symbol_type_t part) +{ + /* copy raw data into holding buffer */ + /* if same partial is not consistent, reset others */ + dprintf(2, " integrate part=%x (%s)", part, dsprintbuf(ean)); + signed char i, j; + if(part & ZBAR_ADDON) { + /* FIXME TBD */ + for(i = (part == ZBAR_ADDON5) ? 4 : 1; i >= 0; i--) { + unsigned char digit = pass->raw[i] & 0xf; + if(ean->addon && ean->buf[i + 13] != digit) { + /* partial mismatch - reset collected parts */ + ean->left = ean->right = ean->addon = ZBAR_NONE; + } + ean->buf[i + 13] = digit; + } + ean->addon = part; + } + else { + if((ean->left && ((part & ZBAR_SYMBOL) != ean->left)) || + (ean->right && ((part & ZBAR_SYMBOL) != ean->right))) { + /* partial mismatch - reset collected parts */ + dprintf(2, " rst(type %x %x)", ean->left, ean->right); + ean->left = ean->right = ean->addon = ZBAR_NONE; + } + + if(part & EAN_RIGHT) { + part &= ZBAR_SYMBOL; + j = (part == ZBAR_EAN13) ? 12 : 7; + for(i = (part == ZBAR_EAN13) ? 6 : 4; i; i--, j--) { + unsigned char digit = pass->raw[i] & 0xf; + if(ean->right && ean->buf[j] != digit) { + /* partial mismatch - reset collected parts */ + dprintf(2, " rst(right)"); + ean->left = ean->right = ean->addon = ZBAR_NONE; + } + ean->buf[j] = digit; + } + ean->right = part; + } + else if(part != ZBAR_UPCE) /* EAN_LEFT */ { + j = (part == ZBAR_EAN13) ? 6 : 3; + for(i = (part == ZBAR_EAN13) ? 6 : 4; j >= 0; i--, j--) { + unsigned char digit = pass->raw[i] & 0xf; + if(ean->left && ean->buf[j] != digit) { + /* partial mismatch - reset collected parts */ + dprintf(2, " rst(left)"); + ean->left = ean->right = ean->addon = ZBAR_NONE; + } + ean->buf[j] = digit; + } + ean->left = part; + } + else /* ZBAR_UPCE */ + ean_expand_upce(ean, pass); + } + + if((part & ZBAR_SYMBOL) != ZBAR_UPCE) { + part = (ean->left & ean->right); + if(!part) + part = ZBAR_PARTIAL; + } + + if(((part == ZBAR_EAN13 || + part == ZBAR_UPCE) && ean_verify_checksum(ean, 12)) || + (part == ZBAR_EAN8 && ean_verify_checksum(ean, 7))) + /* invalid parity */ + part = ZBAR_NONE; + + if(part == ZBAR_EAN13) { + /* special case EAN-13 subsets */ + if(!ean->buf[0] && TEST_CFG(ean->upca_config, ZBAR_CFG_ENABLE)) + part = ZBAR_UPCA; + else if(ean->buf[0] == 9 && ean->buf[1] == 7) { + /* ISBN-10 has priority over ISBN-13(?) */ + if(ean->buf[2] == 8 && + TEST_CFG(ean->isbn10_config, ZBAR_CFG_ENABLE)) + part = ZBAR_ISBN10; + else if((ean->buf[2] == 8 || ean->buf[2] == 9) && + TEST_CFG(ean->isbn13_config, ZBAR_CFG_ENABLE)) + part = ZBAR_ISBN13; + } + } + else if(part == ZBAR_UPCE) { + if(TEST_CFG(ean->upce_config, ZBAR_CFG_ENABLE)) { + /* UPC-E was decompressed for checksum verification, + * but user requested compressed result + */ + ean->buf[0] = ean->buf[1] = 0; + for(i = 2; i < 8; i++) + ean->buf[i] = pass->raw[i - 1] & 0xf; + ean->buf[i] = pass->raw[0] & 0xf; + } + else if(TEST_CFG(ean->upca_config, ZBAR_CFG_ENABLE)) + /* UPC-E reported as UPC-A has priority over EAN-13 */ + part = ZBAR_UPCA; + else if(TEST_CFG(ean->ean13_config, ZBAR_CFG_ENABLE)) + part = ZBAR_EAN13; + else + part = ZBAR_NONE; + } + + if(part > ZBAR_PARTIAL) + part |= ean->addon; + + dprintf(2, " %x/%x=%x", ean->left, ean->right, part); + return(part); +} + +/* copy result to output buffer */ +static inline void postprocess (zbar_decoder_t *dcode, + zbar_symbol_type_t sym) +{ + ean_decoder_t *ean = &dcode->ean; + zbar_symbol_type_t base = sym & ZBAR_SYMBOL; + int i = 0, j = 0; + if(base > ZBAR_PARTIAL) { + if(base == ZBAR_UPCA) + i = 1; + else if(base == ZBAR_UPCE) { + i = 1; + base--; + } + else if(base == ZBAR_ISBN13) + base = ZBAR_EAN13; + else if(base == ZBAR_ISBN10) + i = 3; + + if(base == ZBAR_ISBN10 || + !TEST_CFG(ean_get_config(ean, sym), ZBAR_CFG_EMIT_CHECK)) + base--; + + for(; j < base && ean->buf[i] >= 0; i++, j++) + dcode->buf[j] = ean->buf[i] + '0'; + + if((sym & ZBAR_SYMBOL) == ZBAR_ISBN10 && j == 9 && + TEST_CFG(ean->isbn10_config, ZBAR_CFG_EMIT_CHECK)) + /* recalculate ISBN-10 check digit */ + dcode->buf[j++] = isbn10_calc_checksum(ean); + } + if(sym & ZBAR_ADDON) + for(i = 13; ean->buf[i] >= 0; i++, j++) + dcode->buf[j] = ean->buf[i] + '0'; + dcode->buflen = j; + dcode->buf[j] = '\0'; +} + +zbar_symbol_type_t _zbar_decode_ean (zbar_decoder_t *dcode) +{ + /* process upto 4 separate passes */ + zbar_symbol_type_t sym = ZBAR_NONE; + unsigned char pass_idx = dcode->idx & 3; + + /* update latest character width */ + dcode->ean.s4 -= get_width(dcode, 4); + dcode->ean.s4 += get_width(dcode, 0); + + unsigned char i; + for(i = 0; i < 4; i++) { + ean_pass_t *pass = &dcode->ean.pass[i]; + if(pass->state >= 0 || + i == pass_idx) + { + dprintf(2, " ean[%x/%x]: idx=%x st=%d s=%d", + pass_idx, i, dcode->idx, pass->state, dcode->ean.s4); + zbar_symbol_type_t part = decode_pass(dcode, pass); + if(part) { + /* update accumulated data from new partial decode */ + sym = integrate_partial(&dcode->ean, pass, part); + if(sym) { + /* this pass valid => _reset_ all passes */ + dprintf(2, " sym=%x", sym); + dcode->ean.pass[0].state = dcode->ean.pass[1].state = -1; + dcode->ean.pass[2].state = dcode->ean.pass[3].state = -1; + if(sym > ZBAR_PARTIAL) { + if(!get_lock(dcode, ZBAR_EAN13)) + postprocess(dcode, sym); + else { + dprintf(1, " [locked %d]", dcode->lock); + sym = ZBAR_PARTIAL; + } + } + } + } + dprintf(2, "\n"); + } + } + return(sym); +} + +#endif