/*
* Look up a key in a dictionary. Store a pointer to the value slot
* where found, or to the (value) slot for inserting.
* See idict.h for the possible return values.
*/
int
dict_find(const ref * pdref, const ref * pkey,
ref ** ppvalue /* result is stored here */ )
{
dict *pdict = pdref->value.pdict;
uint size = npairs(pdict);
register int etype;
uint nidx;
ref_packed kpack;
uint hash;
int ktype;
const gs_memory_t *mem = dict_mem(pdict);
/* Compute hash. The only types we bother with are strings, */
/* names, and (unlikely, but worth checking for) integers. */
switch (r_type(pkey)) {
case t_name:
nidx = name_index(mem, pkey);
nh:
hash = dict_name_index_hash(nidx);
kpack = packed_name_key(nidx);
ktype = t_name;
break;
case t_string: /* convert to a name first */
{
ref nref;
int code;
if (!r_has_attr(pkey, a_read))
return_error(gs_error_invalidaccess);
code = name_ref(mem, pkey->value.bytes, r_size(pkey), &nref, 1);
if (code < 0)
return code;
nidx = name_index(mem, &nref);
}
goto nh;
case t_real:
/*
* Make sure that equal reals and integers hash the same.
*/
{
int expt, i;
double mant = frexp(pkey->value.realval, &expt);
/*
* The value is mant * 2^expt, where 0.5 <= mant < 1,
* or else expt == mant == 0.
*/
if (expt < sizeof(long) * 8 || pkey->value.realval == min_long)
i = (int)pkey->value.realval;
else
i = (int)(mant * min_long); /* MSVC 6.00.8168.0 cannot compile this */
hash = (uint)i * 30503; /* with -O2 as a single expression */
}
goto ih;
case t_integer:
hash = (uint)pkey->value.intval * 30503;
ih:
kpack = packed_key_impossible;
ktype = -1;
nidx = 0; /* only to pacify gcc */
break;
case t_null: /* not allowed as a key */
return_error(gs_error_typecheck);
default:
hash = r_btype(pkey) * 99; /* yech */
kpack = packed_key_impossible;
ktype = -1;
nidx = 0; /* only to pacify gcc */
}
/* Search the dictionary */
if (dict_is_packed(pdict)) {
const ref_packed *pslot = 0;
# define found *ppvalue = packed_search_value_pointer; return 1
# define deleted if (pslot == 0) pslot = kp
# define missing goto miss
# include "idicttpl.h"
# undef missing
# undef deleted
# undef found
/*
* Double wraparound, dict is full.
* Note that even if there was an empty slot (pslot != 0),
* we must return dictfull if length = maxlength.
*/
if (pslot == 0 || d_length(pdict) == d_maxlength(pdict))
return_error(gs_error_dictfull);
*ppvalue = pdict->values.value.refs + (pslot - kbot);
return 0;
miss: /* Key is missing, not double wrap. See above re dictfull. */
if (d_length(pdict) == d_maxlength(pdict))
return_error(gs_error_dictfull);
if (pslot == 0)
pslot = kp;
*ppvalue = pdict->values.value.refs + (pslot - kbot);
return 0;
} else {
ref *kbot = pdict->keys.value.refs;
register ref *kp;
ref *pslot = 0;
int wrap = 0;
for (kp = kbot + dict_hash_mod(hash, size) + 2;;) {
--kp;
if ((etype = r_type(kp)) == ktype) { /* Fast comparison if both keys are names */
if (name_index(mem, kp) == nidx) {
*ppvalue = pdict->values.value.refs + (kp - kbot);
return 1;
}
} else if (etype == t_null) { /* Empty, deleted, or wraparound. */
/* Figure out which. */
if (kp == kbot) { /* wrap */
if (wrap++) { /* wrapped twice */
if (pslot == 0)
return_error(gs_error_dictfull);
break;
}
kp += size + 1;
} else if (r_has_attr(kp, a_executable)) { /* Deleted entry, save the slot. */
if (pslot == 0)
pslot = kp;
} else /* key not found */
break;
} else {
if (obj_eq(mem, kp, pkey)) {
*ppvalue = pdict->values.value.refs + (kp - kbot);
return 1;
}
}
}
if (d_length(pdict) == d_maxlength(pdict))
return_error(gs_error_dictfull);
*ppvalue = pdict->values.value.refs +
((pslot != 0 ? pslot : kp) - kbot);
return 0;
}
}
/*
* Look up a name on the dictionary stack.
* Return the pointer to the value if found, 0 if not.
*/
ref *
dstack_find_name_by_index(dict_stack_t * pds, uint nidx)
{
ds_ptr pdref = pds->stack.p;
/* Since we know the hash function is the identity function, */
/* there's no point in allocating a separate variable for it. */
#define hash dict_name_index_hash(nidx)
ref_packed kpack = packed_name_key(nidx);
do {
dict *pdict = pdref->value.pdict;
uint size = npairs(pdict);
const gs_memory_t *mem = dict_mem(pdict);
#ifdef DEBUG
if (gs_debug_c('D')) {
ref dnref;
name_index_ref(mem, nidx, &dnref);
dlputs("[D]lookup ");
debug_print_name(mem, &dnref);
dprintf3(" in 0x%lx(%u/%u)\n",
(ulong) pdict, dict_length(pdref),
dict_maxlength(pdref));
}
#endif
#define INCR_DEPTH(pdref)\
INCR(depth[min(MAX_STATS_DEPTH, pds->stack.p - pdref)])
if (dict_is_packed(pdict)) {
packed_search_1(INCR_DEPTH(pdref),
return packed_search_value_pointer,
DO_NOTHING, goto miss);
packed_search_2(INCR_DEPTH(pdref),
return packed_search_value_pointer,
DO_NOTHING, break);
miss:;
} else {
ref *kbot = pdict->keys.value.refs;
register ref *kp;
int wrap = 0;
/* Search the dictionary */
for (kp = kbot + dict_hash_mod(hash, size) + 2;;) {
--kp;
if (r_has_type(kp, t_name)) {
if (name_index(mem, kp) == nidx) {
INCR_DEPTH(pdref);
return pdict->values.value.refs + (kp - kbot);
}
} else if (r_has_type(kp, t_null)) { /* Empty, deleted, or wraparound. */
/* Figure out which. */
if (!r_has_attr(kp, a_executable))
break;
if (kp == kbot) { /* wrap */
if (wrap++)
break; /* 2 wraps */
kp += size + 1;
}
}
}
}
#undef INCR_DEPTH
}
