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| 1 | /* raided from http://www.dcc.uchile.cl/~rbaeza/handbook/algs/7/713b.srch.c.html |
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| 2 | aparently distributed by Addison-Wesley Publishing Co. Inc, http://aw.com/ |
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| 3 | */ |
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| 4 | |
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| 5 | #include <string.h> |
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| 6 | #define MAXCHAR 256 |
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| 7 | |
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| 8 | const char *bmh_search(const unsigned char *pat, const unsigned char *text, |
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| 9 | int n) |
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| 10 | { |
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| 11 | int i, j, m, k, skip[MAXCHAR]; |
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| 12 | |
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| 13 | m = strlen((char *)pat); |
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| 14 | if (m == 0) |
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| 15 | return (char *)text; |
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| 16 | |
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| 17 | for (k=0; k<MAXCHAR; ++k) |
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| 18 | skip[k] = m; |
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| 19 | for (k=0; k<m-1; k++) |
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| 20 | skip[pat[k]] = m-k-1; |
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| 21 | |
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| 22 | for (k=m-1; k < n; k += skip[text[k] & (MAXCHAR-1)]) { |
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| 23 | for (j=m-1, i=k; j>=0 && text[i] == pat[j]; --j) |
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| 24 | --i; |
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| 25 | if (j == -1) |
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| 26 | return (char *)(text+i+1); |
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| 27 | } |
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| 28 | |
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| 29 | return NULL; |
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| 30 | } |
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