/*------------------------------------------------------------------------
 *  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
