diff options
Diffstat (limited to 'man_hash.c')
| -rw-r--r-- | man_hash.c | 55 |
1 files changed, 40 insertions, 15 deletions
@@ -21,13 +21,33 @@ #include <sys/types.h> #include <assert.h> +#include <ctype.h> #include <limits.h> #include <stdlib.h> #include <string.h> #include "libman.h" -static u_char table[26 * 6]; +#define HASH_DEPTH 6 + +#define HASH_ROW(x) do { \ + if ('.' == (x)) \ + (x) = 26; \ + else if (isupper((u_char)(x))) \ + (x) -= 65; \ + else \ + (x) -= 97; \ + (x) *= HASH_DEPTH; \ + } while (/* CONSTCOND */ 0) + +/* + * Lookup table is indexed first by lower-case first letter (plus one + * for the period, which is stored in the last row), then by lower or + * uppercase second letter. Buckets correspond to the index of the + * macro (the integer value of the enum stored as a char to save a bit + * of space). + */ +static u_char table[27 * HASH_DEPTH]; /* * XXX - this hash has global scope, so if intended for use as a library @@ -40,39 +60,44 @@ man_hash_init(void) memset(table, UCHAR_MAX, sizeof(table)); + assert(/* CONSTCOND */ MAN_MAX < UCHAR_MAX); + for (i = 0; i < MAN_MAX; i++) { x = man_macronames[i][0]; - assert((x >= 65 && x <= 90) || - (x >= 97 && x <= 122)); - x -= (x <= 90) ? 65 : 97; - x *= 6; + assert(isalpha((u_char)x) || '.' == x); - for (j = 0; j < 6; j++) + HASH_ROW(x); + + for (j = 0; j < HASH_DEPTH; j++) if (UCHAR_MAX == table[x + j]) { table[x + j] = (u_char)i; break; } - assert(j < 6); + + assert(j < HASH_DEPTH); } } -int + +enum mant man_hash_find(const char *tmp) { - int x, i, tok; + int x, y, i; + enum mant tok; - if (0 == (x = tmp[0])) + if ('\0' == (x = tmp[0])) return(MAN_MAX); - if ( ! ((x >= 65 && x <= 90) || (x >= 97 && x <= 122))) + if ( ! (isalpha((u_char)x) || '.' == x)) return(MAN_MAX); - x -= (x <= 90) ? 65 : 97; - x *= 6; + HASH_ROW(x); - for (i = 0; i < 6; i++) { - if (UCHAR_MAX == (tok = table[x + i])) + for (i = 0; i < HASH_DEPTH; i++) { + if (UCHAR_MAX == (y = table[x + i])) return(MAN_MAX); + + tok = (enum mant)y; if (0 == strcmp(tmp, man_macronames[tok])) return(tok); } |