diff options
Diffstat (limited to 'ccl.c')
| -rw-r--r-- | ccl.c | 80 |
1 files changed, 80 insertions, 0 deletions
@@ -33,6 +33,23 @@ #include "flexdef.h" +/* return true if the chr is in the ccl. Takes negation into account. */ +static bool +ccl_contains (const int cclp, const int ch) +{ + int ind, len, i; + + len = ccllen[cclp]; + ind = cclmap[cclp]; + + for (i = 0; i < len; ++i) + if (ccltbl[ind + i] == ch) + return !cclng[cclp]; + + return cclng[cclp]; +} + + /* ccladd - add a single character to a ccl */ void ccladd (cclp, ch) @@ -71,6 +88,69 @@ void ccladd (cclp, ch) ccltbl[newpos] = ch; } +/* dump_cclp - same thing as list_character_set, but for cclps. */ + +static void dump_cclp (FILE* file, int cclp) +{ + register int i; + + putc ('[', file); + + for (i = 0; i < csize; ++i) { + if (ccl_contains(cclp, i)){ + register int start_char = i; + + putc (' ', file); + + fputs (readable_form (i), file); + + while (++i < csize && ccl_contains(cclp,i)) ; + + if (i - 1 > start_char) + /* this was a run */ + fprintf (file, "-%s", + readable_form (i - 1)); + + putc (' ', file); + } + } + + putc (']', file); +} + + + +/* ccl_set_diff - create a new ccl as the set difference of the two given ccls. */ +int +ccl_set_diff (int a, int b) +{ + int d, ch; + + /* create new class */ + d = cclinit(); + + /* In order to handle negation, we spin through all possible chars, + * addding each char in a that is not in b. + * (This could be O(n^2), but n is small and bounded.) + */ + for ( ch = 0; ch < csize; ++ch ) + if (ccl_contains (a, ch) && !ccl_contains(b, ch)) + ccladd (d, ch); + + /* debug */ + if (0){ + fprintf(stderr, "ccl_set_diff ("); + fprintf(stderr, "\n "); + dump_cclp (stderr, a); + fprintf(stderr, "\n "); + dump_cclp (stderr, b); + fprintf(stderr, "\n "); + dump_cclp (stderr, d); + fprintf(stderr, "\n)\n"); + } + return d; +} + /* cclinit - return an empty ccl */ |