Diff: decoder/i25.c

Revision:

0:e33621169e44

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/decoder/i25.c	Fri Jan 10 20:29:52 2020 +0000
@@ -0,0 +1,238 @@
+/*------------------------------------------------------------------------
+ *  Copyright 2008-2009 (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 <string.h>     /* memmove */
+
+#ifdef ENABLE_I25
+
+#include <zbar.h>
+#include "../decoder.h"
+
+#ifdef DEBUG_I25
+# define DEBUG_LEVEL (DEBUG_I25)
+#endif
+#include "../debug.h"
+
+static inline unsigned char i25_decode1 (unsigned char enc,
+                                         unsigned e,
+                                         unsigned s)
+{
+    unsigned char E = decode_e(e, s, 45);
+    if(E > 7)
+        return(0xff);
+    enc <<= 1;
+    if(E > 2)
+        enc |= 1;
+    return(enc);
+}
+
+static inline unsigned char i25_decode10 (zbar_decoder_t *dcode,
+                                          unsigned char offset)
+{
+    i25_decoder_t *dcode25 = &dcode->i25;
+    dprintf(2, " s=%d", dcode25->s10);
+    if(dcode25->s10 < 10)
+        return(0xff);
+
+    /* threshold bar width ratios */
+    unsigned char enc = 0, par = 0;
+    signed char i;
+    for(i = 8; i >= 0; i -= 2) {
+        unsigned char j = offset + ((dcode25->direction) ? i : 8 - i);
+        enc = i25_decode1(enc, get_width(dcode, j), dcode25->s10);
+        if(enc == 0xff)
+            return(0xff);
+        if(enc & 1)
+            par++;
+    }
+
+    dprintf(2, " enc=%02x par=%x", enc, par);
+
+    /* parity check */
+    if(par != 2) {
+        dprintf(2, " [bad parity]");
+        return(0xff);
+    }
+
+    /* decode binary weights */
+    enc &= 0xf;
+    if(enc & 8) {
+        if(enc == 12)
+            enc = 0;
+        else if(--enc > 9) {
+            dprintf(2, " [invalid encoding]");
+            return(0xff);
+        }
+    }
+
+    dprintf(2, " => %x", enc);
+    return(enc);
+}
+
+static inline signed char i25_decode_start (zbar_decoder_t *dcode)
+{
+    i25_decoder_t *dcode25 = &dcode->i25;
+    if(dcode25->s10 < 10)
+        return(ZBAR_NONE);
+
+    unsigned char enc = 0;
+    unsigned char i = 10;
+    enc = i25_decode1(enc, get_width(dcode, i++), dcode25->s10);
+    enc = i25_decode1(enc, get_width(dcode, i++), dcode25->s10);
+    enc = i25_decode1(enc, get_width(dcode, i++), dcode25->s10);
+
+    if((get_color(dcode) == ZBAR_BAR)
+       ? enc != 4
+       : (enc = i25_decode1(enc, get_width(dcode, i++), dcode25->s10))) {
+        dprintf(4, "      i25: s=%d enc=%x [invalid]\n", dcode25->s10, enc);
+        return(ZBAR_NONE);
+    }
+
+    /* check leading quiet zone - spec is 10n(?)
+     * we require 5.25n for w=2n to 6.75n for w=3n
+     * (FIXME should really factor in w:n ratio)
+     */
+    unsigned quiet = get_width(dcode, i++);
+    if(quiet && quiet < dcode25->s10 * 3 / 8) {
+        dprintf(3, "      i25: s=%d enc=%x q=%d [invalid qz]\n",
+                dcode25->s10, enc, quiet);
+        return(ZBAR_NONE);
+    }
+
+    dcode25->direction = get_color(dcode);
+    dcode25->element = 1;
+    dcode25->character = 0;
+    return(ZBAR_PARTIAL);
+}
+
+static inline signed char i25_decode_end (zbar_decoder_t *dcode)
+{
+    i25_decoder_t *dcode25 = &dcode->i25;
+
+    /* check trailing quiet zone */
+    unsigned quiet = get_width(dcode, 0);
+    if((quiet && quiet < dcode25->width * 3 / 8) ||
+       decode_e(get_width(dcode, 1), dcode25->width, 45) > 2 ||
+       decode_e(get_width(dcode, 2), dcode25->width, 45) > 2) {
+        dprintf(3, " s=%d q=%d [invalid qz]\n", dcode25->width, quiet);
+        return(ZBAR_NONE);
+    }
+
+    /* check exit condition */
+    unsigned char E = decode_e(get_width(dcode, 3), dcode25->width, 45);
+    if((!dcode25->direction)
+       ? E - 3 > 4
+       : (E > 2 ||
+          decode_e(get_width(dcode, 4), dcode25->width, 45) > 2))
+        return(ZBAR_NONE);
+
+    if(dcode25->direction) {
+        /* reverse buffer */
+        dprintf(2, " (rev)");
+        int i;
+        for(i = 0; i < dcode25->character / 2; i++) {
+            unsigned j = dcode25->character - 1 - i;
+            char c = dcode->buf[i];
+            dcode->buf[i] = dcode->buf[j];
+            dcode->buf[j] = c;
+        }
+    }
+
+    if(dcode25->character < CFG(*dcode25, ZBAR_CFG_MIN_LEN) ||
+       (CFG(*dcode25, ZBAR_CFG_MAX_LEN) > 0 &&
+        dcode25->character > CFG(*dcode25, ZBAR_CFG_MAX_LEN))) {
+        dprintf(2, " [invalid len]\n");
+        dcode->lock = 0;
+        dcode25->character = -1;
+        return(ZBAR_NONE);
+    }
+
+    dcode->buflen = dcode25->character;
+    dcode->buf[dcode25->character] = '\0';
+    dprintf(2, " [valid end]\n");
+    dcode25->character = -1;
+    return(ZBAR_I25);
+}
+
+zbar_symbol_type_t _zbar_decode_i25 (zbar_decoder_t *dcode)
+{
+    i25_decoder_t *dcode25 = &dcode->i25;
+
+    /* update latest character width */
+    dcode25->s10 -= get_width(dcode, 10);
+    dcode25->s10 += get_width(dcode, 0);
+
+    if(dcode25->character < 0 &&
+       !i25_decode_start(dcode))
+        return(ZBAR_NONE);
+
+    if(--dcode25->element == 6 - dcode25->direction)
+        return(i25_decode_end(dcode));
+    else if(dcode25->element)
+        return(ZBAR_NONE);
+
+    /* FIXME check current character width against previous */
+    dcode25->width = dcode25->s10;
+
+    dprintf(2, "      i25[%c%02d+%x]",
+            (dcode25->direction) ? '<' : '>',
+            dcode25->character, dcode25->element);
+
+    /* lock shared resources */
+    if(!dcode25->character && get_lock(dcode, ZBAR_I25)) {
+        dcode25->character = -1;
+        dprintf(2, " [locked %d]\n", dcode->lock);
+        return(ZBAR_PARTIAL);
+    }
+
+    unsigned char c = i25_decode10(dcode, 1);
+    dprintf(2, " c=%x", c);
+
+    if(c > 9 ||
+       ((dcode25->character >= BUFFER_MIN) &&
+        size_buf(dcode, dcode25->character + 2))) {
+        dprintf(2, (c > 9) ? " [aborted]\n" : " [overflow]\n");
+        dcode->lock = 0;
+        dcode25->character = -1;
+        return(ZBAR_NONE);
+    }
+    dcode->buf[dcode25->character++] = c + '0';
+
+    c = i25_decode10(dcode, 0);
+    dprintf(2, " c=%x", c);
+    if(c > 9) {
+        dprintf(2, " [aborted]\n");
+        dcode->lock = 0;
+        dcode25->character = -1;
+        return(ZBAR_NONE);
+    }
+    else
+        dprintf(2, "\n");
+
+    dcode->buf[dcode25->character++] = c + '0';
+    dcode25->element = 10;
+    return((dcode25->character == 2) ? ZBAR_PARTIAL : ZBAR_NONE);
+}
+
+#endif