code39.c

00001 /*------------------------------------------------------------------------
00002  *  Copyright 2008-2009 (c) Jeff Brown <spadix@users.sourceforge.net>
00003  *
00004  *  This file is part of the ZBar Bar Code Reader.
00005  *
00006  *  The ZBar Bar Code Reader is free software; you can redistribute it
00007  *  and/or modify it under the terms of the GNU Lesser Public License as
00008  *  published by the Free Software Foundation; either version 2.1 of
00009  *  the License, or (at your option) any later version.
00010  *
00011  *  The ZBar Bar Code Reader is distributed in the hope that it will be
00012  *  useful, but WITHOUT ANY WARRANTY; without even the implied warranty
00013  *  of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00014  *  GNU Lesser Public License for more details.
00015  *
00016  *  You should have received a copy of the GNU Lesser Public License
00017  *  along with the ZBar Bar Code Reader; if not, write to the Free
00018  *  Software Foundation, Inc., 51 Franklin St, Fifth Floor,
00019  *  Boston, MA  02110-1301  USA
00020  *
00021  *  http://sourceforge.net/projects/zbar
00022  *------------------------------------------------------------------------*/
00023 
00024 #include "../config.h"
00025 #include <string.h>     /* memmove */
00026 
00027 #ifdef ENABLE_CODE39
00028 
00029 #include <zbar.h>
00030 #include "../decoder.h"
00031 
00032 #ifdef DEBUG_CODE39
00033 # define DEBUG_LEVEL DEBUG_CODE39
00034 #endif
00035 #include "../debug.h"
00036 
00037 #define NUM_CHARS (0x2c)
00038 
00039 static const unsigned char code39_hi[32] = {
00040     0x80 | 0x00,  /* 2 next */
00041     0x40 | 0x02,  /* 4 */
00042     0x80 | 0x06,  /* 2 next */
00043     0xc0 | 0x08,  /* 2 skip */
00044     0x40 | 0x0a,  /* 4 */
00045     0x80 | 0x0e,  /* 2 next */
00046     0xc0 | 0x10,  /* 2 skip */
00047     0x00 | 0x12,  /* direct */
00048 
00049     0x80 | 0x13,  /* 2 next */
00050     0xc0 | 0x15,  /* 2 skip */
00051     0x80 | 0x17,  /* 2 next */
00052     0xff,
00053     0xc0 | 0x19,  /* 2 skip */
00054     0x00 | 0x1b,  /* direct */
00055     0xff,
00056     0xff,
00057 
00058     0x40 | 0x1c,  /* 4 */
00059     0x80 | 0x20,  /* 2 next */
00060     0xc0 | 0x22,  /* 2 skip */
00061     0x00 | 0x24,  /* direct */
00062     0x80 | 0x25,  /* 2 next */
00063     0xff,
00064     0x00 | 0x27,  /* direct */
00065     0xff,
00066 
00067     0xc0 | 0x28,  /* 2 skip */
00068     0x00 | 0x2a,  /* direct */
00069     0xff,
00070     0xff,
00071     0x00 | 0x2b,  /* direct */
00072     0xff,
00073     0xff,
00074     0xff,
00075 };
00076 
00077 typedef struct char39_s {
00078     unsigned char chk, rev, fwd;
00079 } char39_t;
00080 
00081 static const char39_t code39_encodings[NUM_CHARS] = {
00082     { 0x07, 0x1a, 0x20 }, /* 00 */
00083     { 0x0d, 0x10, 0x03 }, /* 01 */
00084     { 0x13, 0x17, 0x22 }, /* 02 */
00085     { 0x16, 0x1d, 0x23 }, /* 03 */
00086     { 0x19, 0x0d, 0x05 }, /* 04 */
00087     { 0x1c, 0x13, 0x06 }, /* 05 */
00088     { 0x25, 0x07, 0x0c }, /* 06 */
00089     { 0x2a, 0x2a, 0x27 }, /* 07 */
00090     { 0x31, 0x04, 0x0e }, /* 08 */
00091     { 0x34, 0x00, 0x0f }, /* 09 */
00092     { 0x43, 0x15, 0x25 }, /* 0a */
00093     { 0x46, 0x1c, 0x26 }, /* 0b */
00094     { 0x49, 0x0b, 0x08 }, /* 0c */
00095     { 0x4c, 0x12, 0x09 }, /* 0d */
00096     { 0x52, 0x19, 0x2b }, /* 0e */
00097     { 0x58, 0x0f, 0x00 }, /* 0f */
00098     { 0x61, 0x02, 0x11 }, /* 10 */
00099     { 0x64, 0x09, 0x12 }, /* 11 */
00100     { 0x70, 0x06, 0x13 }, /* 12 */
00101     { 0x85, 0x24, 0x16 }, /* 13 */
00102     { 0x8a, 0x29, 0x28 }, /* 14 */
00103     { 0x91, 0x21, 0x18 }, /* 15 */
00104     { 0x94, 0x2b, 0x19 }, /* 16 */
00105     { 0xa2, 0x28, 0x29 }, /* 17 */
00106     { 0xa8, 0x27, 0x2a }, /* 18 */
00107     { 0xc1, 0x1f, 0x1b }, /* 19 */
00108     { 0xc4, 0x26, 0x1c }, /* 1a */
00109     { 0xd0, 0x23, 0x1d }, /* 1b */
00110     { 0x03, 0x14, 0x1e }, /* 1c */
00111     { 0x06, 0x1b, 0x1f }, /* 1d */
00112     { 0x09, 0x0a, 0x01 }, /* 1e */
00113     { 0x0c, 0x11, 0x02 }, /* 1f */
00114     { 0x12, 0x18, 0x21 }, /* 20 */
00115     { 0x18, 0x0e, 0x04 }, /* 21 */
00116     { 0x21, 0x01, 0x0a }, /* 22 */
00117     { 0x24, 0x08, 0x0b }, /* 23 */
00118     { 0x30, 0x05, 0x0d }, /* 24 */
00119     { 0x42, 0x16, 0x24 }, /* 25 */
00120     { 0x48, 0x0c, 0x07 }, /* 26 */
00121     { 0x60, 0x03, 0x10 }, /* 27 */
00122     { 0x81, 0x1e, 0x14 }, /* 28 */
00123     { 0x84, 0x25, 0x15 }, /* 29 */
00124     { 0x90, 0x22, 0x17 }, /* 2a */
00125     { 0xc0, 0x20, 0x1a }, /* 2b */
00126 };
00127 
00128 static const unsigned char code39_characters[NUM_CHARS] =
00129     "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-. $/+%*";
00130 
00131 static inline unsigned char code39_decode1 (unsigned char enc,
00132                                             unsigned e,
00133                                             unsigned s)
00134 {
00135     unsigned char E = decode_e(e, s, 36);
00136     if(E > 7)
00137         return(0xff);
00138     enc <<= 1;
00139     if(E > 2) {
00140         enc |= 1;
00141         dprintf(2, "1");
00142     }
00143     else
00144         dprintf(2, "0");
00145     return(enc);
00146 }
00147 
00148 static inline signed char code39_decode9 (zbar_decoder_t *dcode)
00149 {
00150     code39_decoder_t *dcode39 = &dcode->code39;
00151 
00152     dprintf(2, " s=%d ", dcode39->s9);
00153     if(dcode39->s9 < 9)
00154         return(-1);
00155 
00156     /* threshold bar width ratios */
00157     unsigned char i, enc = 0;
00158     for(i = 0; i < 5; i++) {
00159         enc = code39_decode1(enc, get_width(dcode, i), dcode39->s9);
00160         if(enc == 0xff)
00161             return(-1);
00162     }
00163     zassert(enc < 0x20, -1, " enc=%x s9=%x\n", enc, dcode39->s9);
00164 
00165     /* lookup first 5 encoded widths for coarse decode */
00166     unsigned char idx = code39_hi[enc];
00167     if(idx == 0xff)
00168         return(-1);
00169 
00170     /* encode remaining widths (NB first encoded width is lost) */
00171     for(; i < 9; i++) {
00172         enc = code39_decode1(enc, get_width(dcode, i), dcode39->s9);
00173         if(enc == 0xff)
00174             return(-1);
00175     }
00176 
00177     if((idx & 0xc0) == 0x80)
00178         idx = (idx & 0x3f) + ((enc >> 3) & 1);
00179     else if((idx & 0xc0) == 0xc0)
00180         idx = (idx & 0x3f) + ((enc >> 2) & 1);
00181     else if(idx & 0xc0)
00182         idx = (idx & 0x3f) + ((enc >> 2) & 3);
00183     zassert(idx < 0x2c, -1, " idx=%x enc=%x s9=%x\n", idx, enc, dcode39->s9);
00184 
00185     const char39_t *c = &code39_encodings[idx];
00186     dprintf(2, " i=%02x chk=%02x c=%02x/%02x", idx, c->chk, c->fwd, c->rev);
00187     if(enc != c->chk)
00188         return(-1);
00189 
00190     dcode39->width = dcode39->s9;
00191     return((dcode39->direction) ? c->rev : c->fwd);
00192 }
00193 
00194 static inline signed char code39_decode_start (zbar_decoder_t *dcode)
00195 {
00196     code39_decoder_t *dcode39 = &dcode->code39;
00197 
00198     signed char c = code39_decode9(dcode);
00199     if(c == 0x19)
00200         dcode39->direction ^= 1;
00201     else if(c != 0x2b) {
00202         dprintf(2, "\n");
00203         return(ZBAR_NONE);
00204     }
00205 
00206     /* check leading quiet zone - spec is 10x */
00207     unsigned quiet = get_width(dcode, 9);
00208     if(quiet && quiet < dcode39->s9 / 2) {
00209         dprintf(2, " [invalid quiet]\n");
00210         return(ZBAR_NONE);
00211     }
00212 
00213     dcode39->element = 9;
00214     dcode39->character = 0;
00215     dprintf(1, " dir=%x [valid start]\n", dcode39->direction);
00216     return(ZBAR_PARTIAL);
00217 }
00218 
00219 static inline void code39_postprocess (zbar_decoder_t *dcode)
00220 {
00221     code39_decoder_t *dcode39 = &dcode->code39;
00222     int i;
00223     if(dcode39->direction) {
00224         /* reverse buffer */
00225         dprintf(2, " (rev)");
00226         for(i = 0; i < dcode39->character / 2; i++) {
00227             unsigned j = dcode39->character - 1 - i;
00228             char code = dcode->buf[i];
00229             dcode->buf[i] = dcode->buf[j];
00230             dcode->buf[j] = code;
00231         }
00232     }
00233     for(i = 0; i < dcode39->character; i++)
00234         dcode->buf[i] = ((dcode->buf[i] < 0x2b)
00235                          ? code39_characters[(unsigned)dcode->buf[i]]
00236                          : '?');
00237     dcode->buflen = i;
00238     dcode->buf[i] = '\0';
00239 }
00240 
00241 zbar_symbol_type_t _zbar_decode_code39 (zbar_decoder_t *dcode)
00242 {
00243     code39_decoder_t *dcode39 = &dcode->code39;
00244 
00245     /* update latest character width */
00246     dcode39->s9 -= get_width(dcode, 9);
00247     dcode39->s9 += get_width(dcode, 0);
00248 
00249     if(dcode39->character < 0) {
00250         if(get_color(dcode) != ZBAR_BAR)
00251             return(ZBAR_NONE);
00252         dprintf(2, "      code39:");
00253         return((zbar_symbol_type_t)code39_decode_start(dcode));
00254     }
00255 
00256     if(++dcode39->element < 9)
00257         return(ZBAR_NONE);
00258 
00259     dprintf(2, "      code39[%c%02d+%x]",
00260             (dcode39->direction) ? '<' : '>',
00261             dcode39->character, dcode39->element);
00262 
00263     if(dcode39->element == 10) {
00264         unsigned space = get_width(dcode, 0);
00265         if(dcode39->character &&
00266            dcode->buf[dcode39->character - 1] == 0x2b) {  /* STOP */
00267             /* trim STOP character */
00268             dcode39->character--;
00269             zbar_symbol_type_t sym = ZBAR_CODE39;
00270 
00271             /* trailing quiet zone check */
00272             if(space && space < dcode39->width / 2) {
00273                 dprintf(2, " [invalid qz]\n");
00274                 sym = ZBAR_NONE;
00275             }
00276             else if(dcode39->character < CFG(*dcode39, ZBAR_CFG_MIN_LEN) ||
00277                     (CFG(*dcode39, ZBAR_CFG_MAX_LEN) > 0 &&
00278                      dcode39->character > CFG(*dcode39, ZBAR_CFG_MAX_LEN))) {
00279                 dprintf(2, " [invalid len]\n");
00280                 sym = ZBAR_NONE;
00281             }
00282             else {
00283                 /* FIXME checksum (needs config enable) */
00284                 code39_postprocess(dcode);
00285                 dprintf(2, " [valid end]\n");
00286             }
00287             dcode39->character = -1;
00288             if(!sym)
00289                 dcode->lock = ZBAR_NONE;
00290             return(sym);
00291         }
00292         if(space > dcode39->width / 2) {
00293             /* inter-character space check failure */
00294             dcode->lock = ZBAR_NONE;
00295             dcode39->character = -1;
00296             dprintf(2, " ics>%d [invalid ics]", dcode39->width);
00297         }
00298         dcode39->element = ZBAR_NONE;
00299         dprintf(2, "\n");
00300         return(ZBAR_NONE);
00301     }
00302 
00303     signed char c = code39_decode9(dcode);
00304     dprintf(2, " c=%d", c);
00305 
00306     /* lock shared resources */
00307     if(!dcode39->character && get_lock(dcode, ZBAR_CODE39)) {
00308         dcode39->character = -1;
00309         dprintf(1, " [locked %d]\n", dcode->lock);
00310         return(ZBAR_PARTIAL);
00311     }
00312 
00313     if(c < 0 ||
00314        ((dcode39->character >= BUFFER_MIN) &&
00315         size_buf(dcode, dcode39->character + 1))) {
00316         dprintf(1, (c < 0) ? " [aborted]\n" : " [overflow]\n");
00317         dcode->lock = ZBAR_NONE;
00318         dcode39->character = -1;
00319         return(ZBAR_NONE);
00320     }
00321     else {
00322         zassert(c < 0x2c, ZBAR_NONE, "c=%02x s9=%x\n", c, dcode39->s9);
00323         dprintf(2, "\n");
00324     }
00325 
00326     dcode->buf[dcode39->character++] = c;
00327 
00328     return(ZBAR_NONE);
00329 }
00330 
00331 #endif