/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/**

 * textcat.c -- routines for categorizing text

 *

 * Copyright (C) 2003 WiseGuys Internet B.V.

 *

 * THE BSD LICENSE

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 * notice, this list of conditions and the following disclaimer.

 *

 * - Redistributions in binary form must reproduce the above copyright

 * notice, this list of conditions and the following disclaimer in the

 * documentation and/or other materials provided with the

 * distribution.

 *

 * - Neither the name of the WiseGuys Internet B.V. nor the names of

 * its contributors may be used to endorse or promote products derived

 * from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 *

 * DESCRIPTION

 *

 * These routines use the N-gram fingerprinting technique as described

 * in Cavnar and Trenkle, (1994.), N-Gram-Based Text Categorization.

 * (cf. http://www.nonlineardynamics.com/trenkle/)

 *

 * REVISION HISTORY

 *

 * Mar 27, 2003 frank@wise-guys.nl -- created

 *

 * IMPROVEMENTS:

 * - If two n-grams have the same frequency count, choose the shortest

 * - Use a better similarity measure (the article suggests Wilcoxon rank test)

 * - The profiles are matched one by one, which results in redundant lookups.

 * - Make the thingy reentrant as well as thread-safe. (Reentrancy is abandoned

 *   by the use of the output buffer in textcat_t.)

 */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include <stdlib.h>

#include <string.h>

#include "common_impl.h"

#include "fingerprint.h"

#include "textcat.h"

#include "constants.h"

typedef struct

{

    void **fprint;

    unsigned char *fprint_disable;

    uint4 size;

    uint4 maxsize;

    uint4 mindocsize;

    char output[MAXOUTPUTSIZE];

    candidate_t *tmp_candidates;

    boole utfaware;

} textcat_t;

static int cmpcandidates(const void *a, const void *b)

{

    const candidate_t *x = (const candidate_t *)a;

    const candidate_t *y = (const candidate_t *)b;

    return (x->score - y->score);

}

extern void textcat_Done(void *handle)

{

    textcat_t *h = (textcat_t *) handle;

    uint4 i;

    for (i = 0; i < h->size; i++)

    {

        fp_Done(h->fprint[i]);

    }

    if (h->tmp_candidates != NULL)

    {

        textcat_ReleaseClassifyFullOutput(h, h->tmp_candidates);

    }

    free(h->fprint);

    free(h->fprint_disable);

    free(h);

}

extern int textcat_SetProperty(void *handle, textcat_Property property,

                               sint4 value)

{

    textcat_t *h = (textcat_t *) handle;

    switch (property)

    {

    case TCPROP_UTF8AWARE:

        if ((value == TC_TRUE) || (value == TC_FALSE))

        {

            h->utfaware = value;

            return 0;

        }

        return -2;

        break;

    case TCPROP_MINIMUM_DOCUMENT_SIZE:

        if (value > 0)

        {

            h->mindocsize = value;

            return 0;

        }

        return -2;

        break;

    default:

        break;

    }

    return -1;

}

/** Replaces older function */

extern void *textcat_Init(const char *conffile)

{

    return special_textcat_Init(conffile, DEFAULT_FINGERPRINTS_PATH);

}

/**

 * Originaly this function had only one parameter (conffile) it has been modified since OOo use

 * Basicaly prefix is the directory path where fingerprints are stored

 */

extern void *special_textcat_Init(const char *conffile, const char *prefix)

{

    textcat_t *h;

    char *finger_print_file_name;

    size_t finger_print_file_name_size;

    size_t prefix_size;

    char line[1024];

    FILE *fp;

    fp = fopen(conffile, "r");

    if (!fp)

    {

#ifdef VERBOSE

        fprintf(stderr, "Failed to open config file '%s'\n", conffile);

#endif

        return NULL;

    }

    h = (textcat_t *) malloc(sizeof(textcat_t));

    h->size = 0;

    h->maxsize = 16;

    h->mindocsize = MINDOCSIZE;

    h->fprint = (void **)malloc(sizeof(void *) * h->maxsize);

    h->fprint_disable =

        (unsigned char *)malloc(sizeof(unsigned char) * h->maxsize);

    /* added to store the state of languages */

    h->tmp_candidates = NULL;

    h->utfaware = TC_TRUE;

    prefix_size = strlen(prefix);

    finger_print_file_name_size = prefix_size + 1;

    finger_print_file_name =

        (char *)malloc(sizeof(char) * (finger_print_file_name_size + 1024));

    finger_print_file_name[0] = '\0';

    strcat(finger_print_file_name, prefix);

    while (wg_getline(line, 1024, fp))

    {

        char *p;

        char *segment[4];

        /*** Skip comments ***/

        if ((p = strchr(line, '#')))

        {

            *p = '\0';

        }

        if (wg_split(segment, line, line, 4) < 2)

        {

            continue;

        }

        /*** Ensure enough space ***/

        if (h->size == h->maxsize)

        {

            h->maxsize *= 2;

            h->fprint =

                (void **)realloc(h->fprint, sizeof(void *) * h->maxsize);

            h->fprint_disable =

                (unsigned char *)realloc(h->fprint_disable,

                                         sizeof(unsigned char) * h->maxsize);

        }

        /*** Load data ***/

        if ((h->fprint[h->size] = fp_Init(segment[1])) == NULL)

        {

            goto BAILOUT;

        }

        while (prefix_size + strlen(segment[0]) > finger_print_file_name_size)

        {

            char *tmp;

            size_t tmp_size = finger_print_file_name_size * 2;

            tmp =

                (char *)realloc(finger_print_file_name,

                                sizeof(char) * (tmp_size + 1));

            if (tmp == NULL)

            {

                goto BAILOUT;

            }

            else

            {

                finger_print_file_name = tmp;

                finger_print_file_name_size = tmp_size;

            }

        }

        finger_print_file_name[prefix_size] = '\0';

        strcat(finger_print_file_name, segment[0]);

        if (fp_Read(h->fprint[h->size], finger_print_file_name, 400) == 0)

            goto BAILOUT;

        h->fprint_disable[h->size] = 0xF0;  /* 0xF0 is the code for enabled

                                               languages, 0x0F is for disabled 

                                             */

        h->size++;

    }

    free(finger_print_file_name);

    fclose(fp);

    return h;

  BAILOUT:

    free(finger_print_file_name);

    fclose(fp);

    textcat_Done(h);

    return NULL;

}

extern candidate_t *textcat_GetClassifyFullOutput(void *handle)

{

    textcat_t *h = (textcat_t *) handle;

    return (candidate_t *) malloc(sizeof(candidate_t) * h->size);

}

extern void textcat_ReleaseClassifyFullOutput(void *handle,

                                              candidate_t * candidates)

{

    if (candidates != NULL)

    {

        free(candidates);

    }

}

extern char *textcat_Classify(void *handle, const char *buffer, size_t size)

{

    textcat_t *h = (textcat_t *) handle;

    char *result = h->output;

    uint4 i, cnt;

    if (h->tmp_candidates == NULL)

    {

        h->tmp_candidates = textcat_GetClassifyFullOutput(h);

    }

    cnt = textcat_ClassifyFull(h, buffer, size, h->tmp_candidates);

    switch (cnt)

    {

    case TEXTCAT_RESULT_UNKNOWN:

        result = TEXTCAT_RESULT_UNKNOWN_STR;

        break;

    case TEXTCAT_RESULT_SHORT:

        result = TEXTCAT_RESULT_SHORT_STR;

        break;

    default:

        {

            const char *plimit = result + MAXOUTPUTSIZE;

            char *p = result;

            *p = '\0';

            for (i = 0; i < cnt; i++)

            {

                p = wg_strgmov(p, "[", plimit);

                p = wg_strgmov(p, h->tmp_candidates[i].name, plimit);

                p = wg_strgmov(p, "]", plimit);

            }

        }

    }

    return result;

}

extern int textcat_ClassifyFull(void *handle, const char *buffer, size_t size,

                                candidate_t * candidates)

{

    textcat_t *h = (textcat_t *) handle;

    uint4 i, cnt = 0;

    int minscore = MAXSCORE;

    int threshold = minscore;

    void *unknown;

    unknown = fp_Init(NULL);

    fp_SetProperty(unknown, TCPROP_UTF8AWARE, h->utfaware);

    fp_SetProperty(unknown, TCPROP_MINIMUM_DOCUMENT_SIZE, h->mindocsize);

    if (fp_Create(unknown, buffer, size, MAXNGRAMS) == 0)

    {

        /*** Too little information ***/

        fp_Done(unknown);

        return TEXTCAT_RESULT_SHORT;

    }

    /*** Calculate the score for each category. ***/

    for (i = 0; i < h->size; i++)

    {

        int score;

        if (h->fprint_disable[i] & 0x0F)

        {                       /* if this language is disabled */

            score = MAXSCORE;

        }

        else

        {

            score = fp_Compare(h->fprint[i], unknown, threshold);

            /* printf("Score for %s : %i\n", fp_Name(h->fprint[i]), score); */

        }

        candidates[i].score = score;

        candidates[i].name = fp_Name(h->fprint[i]);

        if (score < minscore)

        {

            minscore = score;

            threshold = (int)((double)score * THRESHOLDVALUE);

        }

    }

    /*** Find the best performers ***/

    for (i = 0, cnt = 0; i < h->size; i++)

    {

        if (candidates[i].score < threshold)

        {

            if (++cnt == MAXCANDIDATES + 1)

            {

                break;

            }

            memcpy(&candidates[cnt - 1], &candidates[i], sizeof(candidate_t));

        }

    }

    fp_Done(unknown);

    /*** The verdict ***/

    if (cnt == MAXCANDIDATES + 1)

    {

        return TEXTCAT_RESULT_UNKNOWN;

    }

    else

    {

        qsort(candidates, cnt, sizeof(candidate_t), cmpcandidates);

        return cnt;

    }

}

extern const char *textcat_Version(void)

{

    return EXTTEXTCAT_VERSION;

}

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */