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/**** Einfache Levenshtein-Distanz (p0=q0=r0=1) ****/ |
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/**** mit Berücksichtigung von Wildcards ****/ |
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/**** (geschwindigkeitsoptimiertes C-Programm) ****/ |
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/**** Autor : Jörg Michael, Hannover ****/ |
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/**** Datum : 22. Dezember 1993 ****/ |
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|
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/**** modus = ' ': normale Levenshtein-Distanz ****/ |
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/**** modus = '+': keine Unterscheidung ****/ |
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/**** Klein-/Großschreibung ****/ |
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/**** modus = '*': wie '+', aber zusätzlich ****/ |
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/**** "symmetrisches" Verhalten ****/ |
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/**** gemäß der im Text beschrie- ****/ |
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/**** benen Vorformatierung ****/ |
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|
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#ifdef __cplusplus |
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extern "C" { |
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#endif |
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#include "EXTERN.h" |
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#include "perl.h" |
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#include "XSUB.h" |
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#ifdef __cplusplus |
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} |
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|
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#endif |
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#define maxlen 51 |
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char *strchr(); |
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|
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int |
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formatierung(char ziel[], char wort[], int n, char modus) |
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/**** Wandelt "wort" in GROSSschreibung ****/ |
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/**** um und expandiert Umlaute ****/ |
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/**** (n = Zeichenzahl von "ziel") ****/ |
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/**** Zurückgegeben wird: strlen (ziel) ****/ |
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{ |
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int i, k; |
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char c, *s; |
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|
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i = 0; |
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k = 0; |
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while ((c = wort[i++]) != 0 && k < n - 1) { |
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if (isupper(c) || isdigit(c)) { |
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ziel[k++] = c; |
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} else if (islower(c)) { |
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ziel[k++] = c - 'a' + 'A'; |
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} else { |
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s = strchr("ÄAEäAEÖOEöOEÜUEüUEßSS", c); |
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if (s != NULL) { |
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ziel[k++] = *(s + 1); |
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if (k < n - 1) { |
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ziel[k++] = *(s + 2); |
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} |
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} else if (modus == '*' && c != '?') { |
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/**** Aufeinanderfolgende '*' ****/ |
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/**** zu einem zusammenziehen ****/ |
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if (k == 0 || ziel[k - 1] != '*') { |
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ziel[k++] = '*'; |
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} |
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} else { |
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ziel[k++] = c; |
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} |
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} |
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} |
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ziel[k] = 0; |
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return (k); |
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} |
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|
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int |
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WLD(wort, muster, modus, limit) |
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char *wort; |
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char *muster; |
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char modus; |
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int limit; |
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{ |
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register int spmin, p, q, r, lm, lw, d1, d2, i, k, x1, x2, x3; |
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char c, mm[maxlen], ww[maxlen]; |
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int d[maxlen]; |
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|
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if (limit == 0) { |
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limit = maxlen; |
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} |
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if (modus == '+' || modus == '*') { |
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lw = formatierung(ww, wort, maxlen, modus); |
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lm = formatierung(mm, muster, maxlen, modus); |
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|
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if (modus == '*' && lw < lm - 1 |
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&& strchr(ww, '*') != NULL) { |
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/**** Wort und Muster tauschen ****/ |
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wort = mm; |
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muster = ww; |
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strcpy(ww + lw, "*"); |
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i = lw; |
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lw = lm; |
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lm = i + 1; |
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/**** Limit neu setzen ****/ |
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i = (int) (i / 3); |
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if (i < limit) { |
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limit = i; |
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} |
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} else { |
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wort = ww; |
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muster = mm; |
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} |
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} else { |
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lw = strlen(wort); |
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lm = strlen(muster); |
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if (lw >= maxlen) |
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lw = (maxlen - 1); |
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if (lm >= maxlen) |
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lm = (maxlen - 1); |
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} |
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|
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/**** Anfangswerte berechnen ****/ |
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if (*muster == '*') { |
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for (k = 0; k <= lw; k++) { |
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d[k] = 0; |
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} |
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} else { |
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d[0] = (*muster == 0) ? 0 : 1; |
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i = (*muster == '?') ? 0 : 1; |
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for (k = 1; k <= lw; k++) { |
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if (*muster == *(wort + k - 1)) { |
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i = 0; |
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} |
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d[k] = k - 1 + i; |
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} |
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} |
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|
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spmin = (d[0] == 0 || lw == 0) ? d[0] : d[1]; |
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if (spmin > limit) { |
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return (maxlen); |
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} |
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/**** Distanzmatrix durchrechnen ****/ |
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for (i = 2; i <= lm; i++) { |
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c = *(muster + i - 1); |
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p = (c == '*' || c == '?') ? 0 : 1; |
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q = (c == '*') ? 0 : 1; |
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r = (c == '*') ? 0 : 1; |
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d2 = d[0]; |
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d[0] = d2 + q; |
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spmin = d[0]; |
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|
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for (k = 1; k <= lw; k++) { |
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/**** d[k] = Minimum dreier Zahlen ****/ |
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d1 = d2; |
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d2 = d[k]; |
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x1 = d1 + ((c == *(wort + k - 1)) ? 0 : p); |
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x2 = d2 + q; |
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x3 = d[k - 1] + r; |
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|
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if (x1 < x2) { |
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x2 = x1; |
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} |
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d[k] = (x2 < x3) ? x2 : x3; |
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|
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if (d[k] < spmin) { |
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spmin = d[k]; |
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} |
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} |
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|
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if (spmin > limit) { |
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return (maxlen); |
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} |
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} |
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return ((d[lw] <= limit) ? d[lw] : maxlen); |
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} |