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sync with Nasal CVS (added a sort() builtin)

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andy 2007-04-06 14:52:06 +00:00
parent a354c841f1
commit dcb3da9f28
1 changed files with 55 additions and 0 deletions
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55
simgear/nasal/lib.c
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@ -479,6 +479,60 @@ static naRef f_bind(naContext c, naRef me, int argc, naRef* args)
return func;
}
/* We use the "SortRec" gadget for two reasons: first, because ANSI
* qsort() doesn't give us a mechanism for passing a "context" pointer
* to the comparison routine we have to store one in every sorted
* record. Second, using an index into the original vector here
* allows us to make the sort stable in the event of a zero returned
* from the Nasal comparison function. */
struct SortData { naContext ctx, subc; struct SortRec* recs;
naRef* elems; int n; naRef fn; };
struct SortRec { struct SortData* sd; int i; };
static int sortcmp(struct SortRec* a, struct SortRec* b)
{
struct SortData* sd = a->sd;
naRef args[2], d;
args[0] = sd->elems[a->i];
args[1] = sd->elems[b->i];
d = naCall(sd->subc, sd->fn, 2, args, naNil(), naNil());
if(naGetError(sd->subc)) {
naFree(sd->recs);
naRethrowError(sd->subc);
} else if(!naIsNum(d = naNumValue(d))) {
naFree(sd->recs);
naRuntimeError(sd->ctx, "sort() comparison returned non-number");
}
return (d.num > 0) ? 1 : ((d.num < 0) ? -1 : (a->i - b->i));
}
static naRef f_sort(naContext c, naRef me, int argc, naRef* args)
{
int i;
struct SortData sd;
naRef out;
if(argc != 2 || !naIsVector(args[0]) || !naIsFunc(args[1]))
naRuntimeError(c, "bad/missing argument to sort()");
sd.subc = naSubContext(c);
sd.elems = PTR(args[0]).vec->rec->array;
sd.n = PTR(args[0]).vec->rec->size;
sd.fn = args[1];
sd.recs = naAlloc(sizeof(struct SortRec) * sd.n);
for(i=0; i<sd.n; i++) {
sd.recs[i].sd = &sd;
sd.recs[i].i = i;
}
qsort(sd.recs, sd.n, sizeof(sd.recs[0]),
(int(*)(const void*,const void*))sortcmp);
out = naNewVector(c);
naVec_setsize(out, sd.n);
for(i=0; i<sd.n; i++)
PTR(out).vec->rec->array[i] = sd.elems[sd.recs[i].i];
naFree(sd.recs);
naFreeContext(sd.subc);
return out;
}
static naCFuncItem funcs[] = {
{ "size", f_size },
{ "keys", f_keys },
@ -506,6 +560,7 @@ static naCFuncItem funcs[] = {
{ "split", f_split },
{ "rand", f_rand },
{ "bind", f_bind },
{ "sort", f_sort },
{ 0 }
};