plan9fox/sys/src/libhtml/strinttab.c
2011-03-30 19:35:09 +03:00

66 lines
1.3 KiB
C

#include <u.h>
#include <libc.h>
#include <draw.h>
#include <html.h>
#include "impl.h"
// Do case-insensitive lookup of key[0:keylen] in t[0:n] (key part),
// returning 1 if found, 0 if not.
// Array t must be sorted in increasing lexicographic order of key.
// If found, return corresponding val in *pans.
int
_lookup(StringInt* t, int n, Rune* key, int keylen, int* pans)
{
int min;
int max;
int try;
int cmpresult;
min = 0;
max = n - 1;
while(min <= max) {
try = (min + max)/2;
cmpresult = _Strncmpci(key, keylen, t[try].key);
if(cmpresult > 0)
min = try + 1;
else if(cmpresult < 0)
max = try - 1;
else {
*pans = t[try].val;
return 1;
}
}
return 0;
}
// Return first key in t[0:n] that corresponds to val,
// nil if none.
Rune*
_revlookup(StringInt* t, int n, int val)
{
int i;
for(i = 0; i < n; i++)
if(t[i].val == val)
return t[i].key;
return nil;
}
// Make a StringInt table out of a[0:n], mapping each string
// to its index. Check that entries are in alphabetical order.
StringInt*
_makestrinttab(Rune** a, int n)
{
StringInt* ans;
int i;
ans = (StringInt*)emalloc(n * sizeof(StringInt));
for(i = 0; i < n; i++) {
ans[i].key = a[i];
ans[i].val = i;
assert(i == 0 || runestrcmp(a[i], a[i - 1]) >= 0);
}
return ans;
}