/*
 * Fanalyze - Commandline tool for analyzing similarities between multiple files
 * Programmed and designed by Matti 'ccr' Hamalainen
 * (C) Copyright 2018-2019 Tecnic Software productions (TNSP)
 *
 * Please read file 'COPYING' for information on license and distribution.
 */
#include "dmtool.h"
#include "dmlib.h"
#include "dmargs.h"
#include "dmfile.h"

#define SET_MAX_FILES          64
#define SET_MAX_ELEMS          256
#define SET_MAX_VARIANTS       4

#define SET_MAX_GREP_VALUES    64
#define SET_MAX_GREP_LIST      64

#define SET_MAX_SEQUENCES      1024
#define SET_MAX_PLACES         1024


/* Typedefs
 */
typedef struct
{
    Uint8 stats[SET_MAX_ELEMS];
    Uint8 variants, data;
    int interest[SET_MAX_VARIANTS];
    int interestF[SET_MAX_VARIANTS];
} DMCompElem;


typedef struct
{
    int count;
    Uint8 value;
} DMStatValue;


typedef struct
{
    DMStatValue cv[SET_MAX_ELEMS];
} DMStats;


typedef struct
{
    char *filename;
    Uint8 *data;
    size_t size;
    DMStats stats;
    BOOL analyzed;
} DMSourceFile;


typedef struct
{
    DMSourceFile *file;  // pointer to file struct where match was found
    size_t offs;         // offset to match in file data
} DMMatchPlace;


typedef struct
{
    size_t len;     // length of the matching sequence
    Uint8 *data;    // "const" pointer to data in one file, don't free()

    int nfiles;     // number of separate files match was found
    int nplaces;    // number of places where match was found
    DMMatchPlace places[SET_MAX_PLACES];
} DMMatchSeq;


enum
{
    DMGV_UINT8 = 0,
    DMGV_UINT16_LE,
    DMGV_UINT16_BE,
    DMGV_UINT32_LE,
    DMGV_UINT32_BE,

    DMGV_last
};


enum
{
    DMGS_HEX = 0,
    DMGS_DEC,
    DMGS_last
};


typedef struct
{
    int type;
    int disp;
    int nvalues;
    Uint32 values[SET_MAX_GREP_LIST];
    BOOL vwildcards[SET_MAX_GREP_LIST];
} DMGrepValue;


typedef struct
{
    char *name;
    Uint32 nmax;
    unsigned int bsize;
} DMGrepType;


static const DMGrepType dmGrepTypes[DMGV_last] =
{
    { "8bit (byte)"      , (1ULL <<  8) - 1, 1 },
    { "16bit (word) LE"  , (1ULL << 16) - 1, 2 },
    { "16bit (word) BE"  , (1ULL << 16) - 1, 2 },
    { "32bit (word) LE"  , (1ULL << 32) - 1, 4 },
    { "32bit (word) BE"  , (1ULL << 32) - 1, 4 },
};


typedef struct
{
    char *name;
    char *fmtPrefix;
    char *fmt;
} DMGrepDisp;


static const DMGrepDisp dmGrepDisp[DMGS_last] =
{
    { "hex", "0", "x" },
    { "dec", "" , "d" },
};


enum
{
    FA_ANALYZE,
    FA_GREP,
    FA_OFFSET,
    FA_MATCHES,
};


/* Global variables
 */
int            setMode = FA_ANALYZE;
int            nsrcFiles = 0;              // Number of source files
DMSourceFile   srcFiles[SET_MAX_FILES];    // Source file names
DMStats        totalStats;
int            nsetGrepValues = 0;
DMGrepValue    setGrepValues[SET_MAX_GREP_VALUES];
size_t         optMinMatchLen = 8;

DMMatchSeq dmSequences[SET_MAX_SEQUENCES];
int ndmSequences = 0;


/* Arguments
 */
static const DMOptArg optList[] =
{
    {  0, '?', "help",        "Show this help", OPT_NONE },
    {  1, 'v', "verbose",     "Be more verbose", OPT_NONE },
    {  2, 'g', "grep",        "Binary grep <val>[,<val2>...][:<le|be>[8|16|32]]", OPT_ARGREQ },
    {  3, 'o', "offset",      "Show data in offset <offs>[,<offs2>...][:<le|be>[8|16|32][d|x]]", OPT_ARGREQ },
    {  4, 'm', "match",       "Find matching sequences minimum of <n> bytes long", OPT_NONE },
    {  5, 'n', "minmatch",    "Minimum match sequence length", OPT_ARGREQ },
};

static const int optListN = sizeof(optList) / sizeof(optList[0]);


void argShowHelp()
{
    dmPrintBanner(stdout, dmProgName, "[options] <input file #1> <input file #2> [...]");
    dmArgsPrintHelp(stdout, optList, optListN, 0);

    fprintf(stdout,
    "\n"
    "Fanalyze is a simplistic commandline tool to assist analysis of similarities\n"
    "between multiple files of same format (but different content). It provides\n"
    "automatic analysis (default operating mode), binary grep functionality (-g)\n"
    "and offset data display (-o)\n"
    "\n"
    "Value lists for grep function can contain wildcard '?' (or '#') which\n"
    "matches any value of the specified (or inferred) type. For example:\n"
    "-g 0x0f,7,5,?,5,?,? will match sequence of bytes 0f 07 05 ?? 05 ?? ??\n"
    "and -g 0xe,0x1001,?,2023:le16 will match le16 value 000e 1001 ???? 07e7\n"
    "\n"
    "NOTICE! Matching sequences search (-m) is considered unfinished and\n"
    "under development.\n"
    );
}


BOOL dmGetData(const int type, const DMSourceFile *file, const size_t offs, Uint32 *mval)
{
    Uint8 *data = file->data + offs;
    if (offs + dmGrepTypes[type].bsize >= file->size)
    {
        *mval = 0;
        return FALSE;
    }

    switch (type)
    {
        case DMGV_UINT8:
            *mval = *((Uint8 *) data);
            break;

        case DMGV_UINT16_LE:
            *mval = DM_LE16_TO_NATIVE(*((Uint16 *) data));
            break;

        case DMGV_UINT16_BE:
            *mval = DM_BE16_TO_NATIVE(*((Uint16 *) data));
            break;

        case DMGV_UINT32_LE:
            *mval = DM_LE32_TO_NATIVE(*((Uint32 *) data));
            break;

        case DMGV_UINT32_BE:
            *mval = DM_BE32_TO_NATIVE(*((Uint32 *) data));
            break;

        default:
            *mval = 0;
            return FALSE;
    }
    return TRUE;
}


void dmPrintGrepValueList(const DMGrepValue *node, const BOOL match, DMSourceFile *file, const size_t offs)
{
    char mfmt[16];

    snprintf(mfmt, sizeof(mfmt), "%%%s%d%s%%s",
        dmGrepDisp[node->disp].fmtPrefix,
        dmGrepTypes[node->type].bsize * 2,
        dmGrepDisp[node->disp].fmt);

    for (int n = 0; n < node->nvalues; n++)
    {
        const char *veol = (n + 1 < node->nvalues) ? " " : "\n";

        if (match)
        {
            Uint32 mval;
            dmGetData(node->type, file, offs + n, &mval);
            dmPrint(1, mfmt, mval, veol);
        }
        else
        {
            if (node->vwildcards[n])
                dmPrint(1, "?%s", veol);
            else
                dmPrint(1, mfmt, node->values[n], veol);
        }
    }
}


int argParseGrepValue(const char *arg, const int mode)
{
    const char *specsep = strchr(arg, ':');
    char *vspec, *vstr, *vsep;
    DMGrepValue val;
    int ret = DMERR_OK;
    BOOL more;

    memset(&val, 0, sizeof(val));

    if (setMode != FA_ANALYZE && setMode != mode)
    {
        dmErrorMsg("Options specifying multiple operating modes can't be used.\n");
        return DMERR_INVALID_ARGS;
    }
    setMode = mode;

    // Do we have spec?
    if (specsep != NULL)
    {
        vspec = dm_strdup_trim(specsep + 1, DM_TRIM_BOTH);
        vstr = dm_strndup_trim(arg, specsep - arg, DM_TRIM_BOTH);
    }
    else
    {
        vspec = NULL;
        vstr = dm_strdup(arg);
    }

    // Parse spec if any
    if (vspec != NULL)
    {
        BOOL vendianess = TRUE;
        char *vtmp = vspec;

        // Get endianess specifier, if any
        if (dm_strncasecmp(vtmp, "le", 2) == 0)
        {
            vendianess = TRUE;
            vtmp += 2;
        }
        else
        if (dm_strncasecmp(vtmp, "be", 2) == 0)
        {
            vendianess = FALSE;
            vtmp += 2;
        }

        // Get value bit size
        if (strncmp(vtmp, "8", 1) == 0)
        {
            val.type = DMGV_UINT8;
            vtmp += 1;
        }
        else
        if (strncmp(vtmp, "16", 2) == 0)
        {
            val.type = vendianess ? DMGV_UINT16_LE : DMGV_UINT16_BE;
            vtmp += 2;
        }
        else
        if (strncmp(vtmp, "32", 2) == 0)
        {
            val.type = vendianess ? DMGV_UINT32_LE : DMGV_UINT32_BE;
            vtmp += 2;
        }
        else
        {
            ret = dmError(DMERR_INVALID_ARGS,
                "Invalid grep type '%s'.\n",
                vspec);
            goto out;
        }

        switch (tolower(*vtmp))
        {
            case 'd':
                val.disp = DMGS_DEC;
                break;

            case 'x': case 'h':
                val.disp = DMGS_HEX;
                break;

            case 0:
                break;

            default:
                ret = dmError(DMERR_INVALID_ARGS,
                    "Invalid grep view type '%s'.\n",
                    vspec);
                goto out;
        }
    }

    // Get list of values
    char *vtmp = vstr;
    do
    {
        if (val.nvalues >= SET_MAX_GREP_LIST)
        {
            ret = dmError(DMERR_BOUNDS,
                "Too many greplist values specified '%s'.\n",
                vstr);
            goto out;
        }

        if ((vsep = strchr(vtmp, ',')) != NULL)
        {
            *vsep = 0;
            more = TRUE;
        }
        else
            more = FALSE;

        if (vtmp[0] == '#' || vtmp[0] == '?')
        {
            val.vwildcards[val.nvalues] = TRUE;
            if (mode == FA_OFFSET)
            {
                ret = dmError(DMERR_INVALID_ARGS,
                    "Offset mode does not allow wildcard values.\n");
                goto out;
            }
        }
        else
        if (!dmGetIntVal(vtmp, &val.values[val.nvalues], NULL))
        {
            ret = dmError(DMERR_INVALID_ARGS,
                "Not a valid integer value '%s'.\n",
                vtmp);
            goto out;
        }

        val.nvalues++;

        if (more)
            vtmp = vsep + 1;
    } while (more);

    if (val.vwildcards[0])
    {
        ret = dmError(DMERR_INVALID_ARGS,
            "First grep value can not be a wildcard.\n");
        goto out;
    }

    if (mode == FA_GREP)
    {
        // Check if we need to guess size
        if (val.type < 0)
        {
            for (int n = DMGV_last; n >= 0; n--)
            {
                const DMGrepType *def = &dmGrepTypes[n];
                if (val.values[0] <= def->nmax)
                    val.type = n;
            }
        }

        if (val.type < 0)
        {
            ret = dmError(DMERR_INVALID_ARGS,
                "Could not guess value type for '%s'.\n",
                arg);
            goto out;
        }

        // Check range
        for (int n = 0; n < val.nvalues; n++)
        if (!val.vwildcards[n] && val.values[n] > dmGrepTypes[val.type].nmax)
        {
            ret = dmError(DMERR_INVALID_ARGS,
                "Integer value %d <= %d <= %d out of range for type %s.\n",
                val.values[n], 0, dmGrepTypes[val.type].nmax,
                dmGrepTypes[val.type].name);

            goto out;
        }
    }
    else
    if (mode == FA_OFFSET)
    {
        if (val.type < 0)
            val.type = DMGV_UINT8;
    }

    if (nsetGrepValues < SET_MAX_GREP_VALUES)
    {
        DMGrepValue *node = &setGrepValues[nsetGrepValues++];
        memcpy(node, &val, sizeof(val));

        if (mode == FA_GREP)
        {
            dmPrint(1, "Grep %s: ",
                dmGrepTypes[val.type].name);

            dmPrintGrepValueList(node, FALSE, NULL, 0);
        }
    }
    else
    {
        ret = dmError(DMERR_BOUNDS,
            "Too many values specified (max %d).",
            SET_MAX_GREP_VALUES);
    }

out:
    dmFree(vspec);
    dmFree(vstr);
    return ret;
}


BOOL argHandleOpt(const int optN, char *optArg, char *currArg)
{
    (void) optArg;

    switch (optN)
    {
        case 0:
            argShowHelp();
            exit(0);
            break;

        case 1:
            dmVerbosity++;
            break;

        case 2:
            return argParseGrepValue(optArg, FA_GREP) == DMERR_OK;

        case 3:
            return argParseGrepValue(optArg, FA_OFFSET) == DMERR_OK;

        case 4:
            setMode = FA_MATCHES;
            break;

        case 5:
            optMinMatchLen = atoi(optArg);
            if (optMinMatchLen < 2 || optMinMatchLen > 16*1024)
            {
                dmErrorMsg("Invalid minimum match length '%s'.\n",
                    optArg);
                return FALSE;
            }
            return TRUE;

        default:
            dmErrorMsg("Unknown argument '%s'.\n", currArg);
            return FALSE;
    }

    return TRUE;
}


BOOL argHandleNonOpt(char *currArg)
{
    if (nsrcFiles < SET_MAX_FILES)
    {
        DMSourceFile *file = &srcFiles[nsrcFiles++];
        file->filename = currArg;
        return TRUE;
    }
    else
    {
        dmErrorMsg("Maximum number of input files exceeded (%d).\n",
            SET_MAX_FILES);
        return TRUE;
    }
}


void dmInitStats(DMStats *stats)
{
    for (size_t n = 0; n < SET_MAX_ELEMS; n++)
    {
        stats->cv[n].count = 0;
        stats->cv[n].value = n;
    }
}


int dmCompareStatFunc(const void *va, const void *vb)
{
    const DMStatValue *pa = va, *pb = vb;
    return pb->count - pa->count;
}


void dmPrintStats(DMStats *stats, const int nmax, const size_t size)
{
    qsort(&stats->cv, SET_MAX_ELEMS, sizeof(DMStatValue), dmCompareStatFunc);

    for (int n = 0; n < nmax; n++)
    {
        printf("$%02x (%d = %1.2f%%), ",
            stats->cv[n].value,
            stats->cv[n].count,
            ((float) stats->cv[n].count * 100.0f) / (float) size);
    }
    printf("\n\n");
}


BOOL dmAddMatchSequence(Uint8 *data, const size_t len, DMSourceFile *file, size_t offs)
{
    DMMatchSeq *seq = NULL;

    // Check for existing match sequence
    for (int n = 0; n < ndmSequences; n++)
    {
        DMMatchSeq *node = &dmSequences[n];
        if (node->len >= len &&
            memcmp(node->data + node->len - len, data, len) == 0)
        {
            seq = node;
            break;
        }
    }

    if (seq == NULL)
    {
        // No sequence found, add a new one
        if (ndmSequences + 1 >= SET_MAX_SEQUENCES)
        {
            dmErrorMsg("Too many matching sequences found.\n");
            return FALSE;
        }

        seq = &dmSequences[ndmSequences++];
    }
    else
    {
        // Check for existing place
        for (int n = 0; n < seq->nplaces; n++)
        {
            DMMatchPlace *place = &seq->places[n];
            if (place->file == file &&
                place->offs + seq->len == offs + len)
                return TRUE;
        }
    }

    seq->data = data;
    seq->len = len;

    // Add another file + offset
    if (seq->nplaces < SET_MAX_PLACES)
    {
        DMMatchPlace *place = &seq->places[seq->nplaces++];
        place->file = file;
        place->offs = offs;

        return TRUE;
    }
    else
        return FALSE;
}


int dmCompareMatchPlaces(const void *pa, const void *pb)
{
    const DMMatchPlace *va = (DMMatchPlace *) pa,
        *vb = (DMMatchPlace *) pb;

    return va->offs - vb->offs;
}


int main(int argc, char *argv[])
{
    DMCompElem *compBuf = NULL;
    size_t compBufSize = 0, totalSize = 0;
    int res;

    memset(&dmSequences, 0, sizeof(dmSequences));

    dmInitProg("fanalyze", "Simple tool for file format analysis",
        "0.4", NULL, NULL);
    dmVerbosity = 0;

    dmInitStats(&totalStats);

    // Parse arguments
    if (!dmArgsProcess(argc, argv, optList, optListN,
        argHandleOpt, argHandleNonOpt, OPTH_BAILOUT))
        exit(1);

    if (nsrcFiles < 1)
    {
        dmErrorMsg("Nothing to do. (try --help)\n");
        goto out;
    }

    // Read input files
    for (int nfile = 0; nfile < nsrcFiles; nfile++)
    {
        DMSourceFile *file = &srcFiles[nfile];
        if ((res = dmReadDataFile(NULL, file->filename, &file->data, &file->size)) != DMERR_OK)
        {
            dmErrorMsg("Could not read '%s': %s\n",
                file->filename, dmErrorStr(res));
            goto out;
        }

        dmPrint(2, "Input #%d: '%s', %" DM_PRIu_SIZE_T " bytes.\n",
            nfile + 1, file->filename, file->size);

        if (!compBufSize || file->size < compBufSize)
            compBufSize = file->size;

        totalSize += file->size;
        dmInitStats(&file->stats);
    }


    //
    // Check what operating mode we are in
    //
    if (setMode == FA_GREP)
    {
        for (int nfile = 0; nfile < nsrcFiles; nfile++)
        {
            DMSourceFile *file = &srcFiles[nfile];
            dmPrint(0, "\n%s\n", file->filename);

            for (int n = 0; n < nsetGrepValues; n++)
            {
                DMGrepValue *node = &setGrepValues[n];
                const DMGrepType *def = &dmGrepTypes[node->type];

                for (size_t offs = 0; offs + (def->bsize * node->nvalues) < file->size; offs++)
                {
                    BOOL match = TRUE;
                    for (int n = 0; n < node->nvalues; n++)
                    if (!node->vwildcards[n])
                    {
                        Uint32 mval;
                        dmGetData(node->type, file, offs + n, &mval);

                        if (mval != node->values[n])
                        {
                            match = FALSE;
                            break;
                        }
                    }

                    if (match)
                    {
                        dmPrint(0, "%08x : ", offs);
                        dmPrintGrepValueList(node, TRUE, file, offs);
                    }
                }
            }
        }
    }
    else
    if (setMode == FA_OFFSET)
    {
        for (int nfile = 0; nfile < nsrcFiles; nfile++)
        {
            DMSourceFile *file = &srcFiles[nfile];
            dmPrint(1, "#%03d: %s\n", nfile + 1, file->filename);
        }

        printf("  offset :");
        for (int nfile = 0; nfile < nsrcFiles; nfile++)
            printf("    %03d   ", nfile + 1);
        printf("\n");

        printf("==========");
        for (int nfile = 0; nfile < nsrcFiles; nfile++)
            printf("===========");
        printf("\n");

        for (int n = 0; n < nsetGrepValues; n++)
        {
            DMGrepValue *node = &setGrepValues[n];
            const DMGrepType *def = &dmGrepTypes[node->type];

            for (int nv = 0; nv < node->nvalues; nv++)
            {
                printf("%08x : ", node->values[nv]);

                for (int nfile = 0; nfile < nsrcFiles; nfile++)
                {
                    DMSourceFile *file = &srcFiles[nfile];
                    Uint32 mval;
                    char mstr[32];
                    int npad, nwidth;

                    if (dmGetData(node->type, file, node->values[nv], &mval))
                    {
                        char mfmt[16];
                        nwidth = def->bsize * 2;
                        snprintf(mfmt, sizeof(mfmt), "%%0%d%s",
                            nwidth, dmGrepDisp[node->disp].fmt);

                        snprintf(mstr, sizeof(mstr), mfmt, mval);
                    }
                    else
                    {
                        strcpy(mstr, "----");
                        nwidth = 4;
                    }

                    npad = (10 - nwidth) / 2;
                    for (int q = 0; q < npad; q++)
                        fputc(' ', stdout);

                    fputs(mstr, stdout);

                    for (int q = 0; q < npad; q++)
                        fputc(' ', stdout);
                }

                printf("  [%s]\n",
                    dmGrepDisp[node->disp].name);
            }
        }
    }
    else
    if (setMode == FA_ANALYZE)
    {
        // Allocate comparision buffer
        // XXX: integer overflow?
        dmPrint(2, "Allocating %d element (%d bytes) comparision buffer.\n",
            compBufSize, compBufSize * sizeof(DMCompElem));

        if ((compBuf = dmCalloc(compBufSize, sizeof(DMCompElem))) == NULL)
        {
            dmErrorMsg("Out of memory. Could not allocate comparision buffer!\n");
            goto out;
        }

        //
        // Basic file data comparision
        //
        dmPrint(2, "Analyzing ..\n");
        for (int nfile = 0; nfile < nsrcFiles; nfile++)
        {
            DMSourceFile *file = &srcFiles[nfile];

            for (size_t offs = 0; offs < file->size; offs++)
            {
                Uint8 bv = file->data[offs];
                totalStats.cv[bv].count++;
                file->stats.cv[bv].count++;
            }

            for (size_t offs = 0; offs < compBufSize; offs++)
            {
                Uint8 data = offs < file->size ? file->data[offs] : 0;
                compBuf[offs].stats[data]++;
            }
        }

        for (size_t offs = 0; offs < compBufSize; offs++)
        {
            DMCompElem *el = &compBuf[offs];
            for (int n = 0; n < SET_MAX_ELEMS; n++)
            {
                if (el->stats[n] > 0)
                {
                    el->variants++;
                    el->data = n;
                }
            }
        }

        //
        // Display results
        //
        for (size_t offs = 0, n = 0; offs < compBufSize; offs++)
        {
            DMCompElem *el = &compBuf[offs];
            BOOL var = el->variants > 1;

            if (n == 0)
                printf("%08" DM_PRIx_SIZE_T " | ", offs);

            if (var)
                printf("[%2d] ", el->variants);
            else
                printf(" %02x  ", el->data);

            if (++n >= 16)
            {
                printf("\n");
                n = 0;
            }
        }

        printf("\n");

        //
        // Attempt further analysis
        //
        for (int nfile = 0; nfile < nsrcFiles; nfile++)
        {
            DMSourceFile *file = &srcFiles[nfile];
            size_t len = file->size > compBufSize ? compBufSize : file->size;
            for (size_t offs = 0; offs + 4 < len; offs++)
            {
                DMCompElem *elem = &compBuf[offs];

                for (int variant = SET_MAX_VARIANTS - 1; variant >= 0; variant--)
                {
                    size_t nmax = (variant < 2) ? sizeof(Uint16) : sizeof(Uint32);
                    Uint32 tmp = 0;

                    for (size_t n = 0; n < nmax; n++)
                    {
                        size_t boffs = (variant & 1) ? n : nmax - n;

                        tmp <<= 8;
                        tmp |= file->data[offs + boffs];
                    }

                    if (file->size - tmp < 32)
                    {
                        elem->interest[variant] += 32 - (file->size - tmp);
                        elem->interestF[variant]++;
                    }
                }
            }
        }

        printf("\nMore findings:\n");
        for (size_t offs = 0; offs + 4 < compBufSize; offs++)
        {
            DMCompElem *elem = &compBuf[offs];

            for (int variant = 0; variant < SET_MAX_VARIANTS; variant++)
            if (elem->interestF[variant] > 0)
            {
                printf("%08" DM_PRIx_SIZE_T " | V%d : %d / %d\n",
                offs, variant,
                elem->interestF[variant], elem->interest[variant]);
            }
        }

        printf("\nGlobal most used bytes:\n");
        dmPrintStats(&totalStats, 16, totalSize);

        for (int nfile = 0; nfile < nsrcFiles; nfile++)
        {
            DMSourceFile *file = &srcFiles[nfile];
            printf("Most used bytes for '%s':\n", file->filename);
            dmPrintStats(&file->stats, 16, file->size);
        }

    }
    else
    if (setMode == FA_MATCHES)
    {
        //
        // Attempt to find matching sequences of N+
        //
        dmPrint(0, "Attempting to find matching sequences of %" DM_PRIu_SIZE_T" bytes or more\n",
            optMinMatchLen);

        for (int nfile1 = 0; nfile1 < nsrcFiles; nfile1++)
        {
            DMSourceFile *file1 = &srcFiles[nfile1];

            for (int nfile2 = 0; nfile2 < nsrcFiles; nfile2++)
            if (nfile2 != nfile1 && !file1->analyzed)
            {
                DMSourceFile *file2 = &srcFiles[nfile2];

                // Find longest possible matching sequence in file2, if any
                for (size_t moffs1 = 0; moffs1 + optMinMatchLen < file1->size;)
                {
                    size_t cnt = 0;
                    for (size_t moffs2 = 0; moffs2 + optMinMatchLen < file2->size; moffs2++)
                    {
                        for (cnt = 0; moffs1 + cnt + optMinMatchLen < file1->size &&
                            moffs2 + cnt + optMinMatchLen < file2->size; cnt++)
                        {
                            if (file1->data[moffs1 + cnt] != file2->data[moffs2 + cnt])
                                break;
                        }

                        if (cnt >= optMinMatchLen)
                        {
                            // Match found
                            if (!dmAddMatchSequence(file1->data + moffs1, cnt, file1, moffs1) ||
                                !dmAddMatchSequence(file2->data + moffs2, cnt, file2, moffs2))
                                goto done;

                            moffs1 += cnt;
                        }
                    }

                    if (cnt < optMinMatchLen)
                        moffs1++;
                }
            }
            file1->analyzed = TRUE;
        }

done:

        for (int nmatch = 0; nmatch < ndmSequences; nmatch++)
        {
            DMMatchSeq *seq = &dmSequences[nmatch];

            qsort(&seq->places, seq->nplaces, sizeof(DMMatchPlace),
                dmCompareMatchPlaces);
        }

        //
        // Display results
        //
        dmPrint(0, "Found %d matching sequence groups of %" DM_PRIu_SIZE_T " bytes minimum.\n",
            ndmSequences, optMinMatchLen);

        for (int nmatch = 0; nmatch < ndmSequences; nmatch++)
        {
            DMMatchSeq *seq = &dmSequences[nmatch];

            printf("\nSeq of %" DM_PRIu_SIZE_T " bytes in %d places (%d files)\n",
                seq->len, seq->nplaces, seq->nfiles);

            if (dmVerbosity > 0)
            {
                int n = 0;
                for (size_t offs = 0; offs < seq->len; offs++)
                {
                    if (n == 0)
                        printf("    ");

                    printf("%02x%s",
                        seq->data[offs],
                        offs + 1 < seq->len ? " " : "");

                    if (++n >= 16)
                    {
                        printf("\n");
                        n = 0;
                    }
                }
                if (n > 0)
                    printf("\n");
            }

            for (int nplace = 0; nplace < seq->nplaces; nplace++)
            {
                DMMatchPlace *place = &seq->places[nplace];
                printf("    %08" DM_PRIx_SIZE_T "-%08" DM_PRIx_SIZE_T ": %s\n",
                    place->offs,
                    place->offs + seq->len - 1,
                    place->file->filename);

            }
        }
    }
    else
    {
        dmErrorMsg("Invalid operating mode?\n");
    }

out:
    for (int nfile = 0; nfile < nsrcFiles; nfile++)
    {
        DMSourceFile *file = &srcFiles[nfile];
        dmFree(file->data);
    }

    return 0;
}