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author | Larry Wall <lwall@jpl-devvax.jpl.nasa.gov> | 1987-12-18 00:00:00 +0000 |
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committer | Larry Wall <lwall@jpl-devvax.jpl.nasa.gov> | 1987-12-18 00:00:00 +0000 |
commit | 8d063cd8450e59ea1c611a2f4f5a21059a2804f1 (patch) | |
tree | 9bba34a99f94e47746e40ffe1419151779d8a4fc /x2p/hash.c | |
download | perl-8d063cd8450e59ea1c611a2f4f5a21059a2804f1.tar.gz |
a "replacement" for awk and sedperl-1.0
[ Perl is kind of designed to make awk and sed semi-obsolete. This posting
will include the first 10 patches after the main source. The following
description is lifted from Larry's manpage. --r$ ]
Perl is a interpreted language optimized for scanning arbitrary text
files, extracting information from those text files, and printing
reports based on that information. It's also a good language for many
system management tasks. The language is intended to be practical
(easy to use, efficient, complete) rather than beautiful (tiny,
elegant, minimal). It combines (in the author's opinion, anyway) some
of the best features of C, sed, awk, and sh, so people familiar with
those languages should have little difficulty with it. (Language
historians will also note some vestiges of csh, Pascal, and even
BASIC-PLUS.) Expression syntax corresponds quite closely to C
expression syntax. If you have a problem that would ordinarily use sed
or awk or sh, but it exceeds their capabilities or must run a little
faster, and you don't want to write the silly thing in C, then perl may
be for you. There are also translators to turn your sed and awk
scripts into perl scripts.
Diffstat (limited to 'x2p/hash.c')
-rw-r--r-- | x2p/hash.c | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/x2p/hash.c b/x2p/hash.c new file mode 100644 index 0000000000..db32c4c5fe --- /dev/null +++ b/x2p/hash.c @@ -0,0 +1,237 @@ +/* $Header: hash.c,v 1.0 87/12/18 13:07:18 root Exp $ + * + * $Log: hash.c,v $ + * Revision 1.0 87/12/18 13:07:18 root + * Initial revision + * + */ + +#include <stdio.h> +#include "EXTERN.h" +#include "handy.h" +#include "util.h" +#include "a2p.h" + +STR * +hfetch(tb,key) +register HASH *tb; +char *key; +{ + register char *s; + register int i; + register int hash; + register HENT *entry; + + if (!tb) + return Nullstr; + for (s=key, i=0, hash = 0; + /* while */ *s; + s++, i++, hash *= 5) { + hash += *s * coeff[i]; + } + entry = tb->tbl_array[hash & tb->tbl_max]; + for (; entry; entry = entry->hent_next) { + if (entry->hent_hash != hash) /* strings can't be equal */ + continue; + if (strNE(entry->hent_key,key)) /* is this it? */ + continue; + return entry->hent_val; + } + return Nullstr; +} + +bool +hstore(tb,key,val) +register HASH *tb; +char *key; +STR *val; +{ + register char *s; + register int i; + register int hash; + register HENT *entry; + register HENT **oentry; + + if (!tb) + return FALSE; + for (s=key, i=0, hash = 0; + /* while */ *s; + s++, i++, hash *= 5) { + hash += *s * coeff[i]; + } + + oentry = &(tb->tbl_array[hash & tb->tbl_max]); + i = 1; + + for (entry = *oentry; entry; i=0, entry = entry->hent_next) { + if (entry->hent_hash != hash) /* strings can't be equal */ + continue; + if (strNE(entry->hent_key,key)) /* is this it? */ + continue; + safefree((char*)entry->hent_val); + entry->hent_val = val; + return TRUE; + } + entry = (HENT*) safemalloc(sizeof(HENT)); + + entry->hent_key = savestr(key); + entry->hent_val = val; + entry->hent_hash = hash; + entry->hent_next = *oentry; + *oentry = entry; + + if (i) { /* initial entry? */ + tb->tbl_fill++; + if ((tb->tbl_fill * 100 / (tb->tbl_max + 1)) > FILLPCT) + hsplit(tb); + } + + return FALSE; +} + +#ifdef NOTUSED +bool +hdelete(tb,key) +register HASH *tb; +char *key; +{ + register char *s; + register int i; + register int hash; + register HENT *entry; + register HENT **oentry; + + if (!tb) + return FALSE; + for (s=key, i=0, hash = 0; + /* while */ *s; + s++, i++, hash *= 5) { + hash += *s * coeff[i]; + } + + oentry = &(tb->tbl_array[hash & tb->tbl_max]); + entry = *oentry; + i = 1; + for (; entry; i=0, oentry = &entry->hent_next, entry = entry->hent_next) { + if (entry->hent_hash != hash) /* strings can't be equal */ + continue; + if (strNE(entry->hent_key,key)) /* is this it? */ + continue; + safefree((char*)entry->hent_val); + safefree(entry->hent_key); + *oentry = entry->hent_next; + safefree((char*)entry); + if (i) + tb->tbl_fill--; + return TRUE; + } + return FALSE; +} +#endif + +hsplit(tb) +HASH *tb; +{ + int oldsize = tb->tbl_max + 1; + register int newsize = oldsize * 2; + register int i; + register HENT **a; + register HENT **b; + register HENT *entry; + register HENT **oentry; + + a = (HENT**) saferealloc((char*)tb->tbl_array, newsize * sizeof(HENT*)); + bzero((char*)&a[oldsize], oldsize * sizeof(HENT*)); /* zero second half */ + tb->tbl_max = --newsize; + tb->tbl_array = a; + + for (i=0; i<oldsize; i++,a++) { + if (!*a) /* non-existent */ + continue; + b = a+oldsize; + for (oentry = a, entry = *a; entry; entry = *oentry) { + if ((entry->hent_hash & newsize) != i) { + *oentry = entry->hent_next; + entry->hent_next = *b; + if (!*b) + tb->tbl_fill++; + *b = entry; + continue; + } + else + oentry = &entry->hent_next; + } + if (!*a) /* everything moved */ + tb->tbl_fill--; + } +} + +HASH * +hnew() +{ + register HASH *tb = (HASH*)safemalloc(sizeof(HASH)); + + tb->tbl_array = (HENT**) safemalloc(8 * sizeof(HENT*)); + tb->tbl_fill = 0; + tb->tbl_max = 7; + hiterinit(tb); /* so each() will start off right */ + bzero((char*)tb->tbl_array, 8 * sizeof(HENT*)); + return tb; +} + +#ifdef NOTUSED +hshow(tb) +register HASH *tb; +{ + fprintf(stderr,"%5d %4d (%2d%%)\n", + tb->tbl_max+1, + tb->tbl_fill, + tb->tbl_fill * 100 / (tb->tbl_max+1)); +} +#endif + +hiterinit(tb) +register HASH *tb; +{ + tb->tbl_riter = -1; + tb->tbl_eiter = Null(HENT*); + return tb->tbl_fill; +} + +HENT * +hiternext(tb) +register HASH *tb; +{ + register HENT *entry; + + entry = tb->tbl_eiter; + do { + if (entry) + entry = entry->hent_next; + if (!entry) { + tb->tbl_riter++; + if (tb->tbl_riter > tb->tbl_max) { + tb->tbl_riter = -1; + break; + } + entry = tb->tbl_array[tb->tbl_riter]; + } + } while (!entry); + + tb->tbl_eiter = entry; + return entry; +} + +char * +hiterkey(entry) +register HENT *entry; +{ + return entry->hent_key; +} + +STR * +hiterval(entry) +register HENT *entry; +{ + return entry->hent_val; +} |