void op_zprevious(mval *v)
{
int4 n;
int min_reg_index, reg_index, res;
mname_entry gvname;
mval tmpmval, *datamval;
enum db_acc_method acc_meth;
boolean_t found, ok_to_change_currkey;
gd_binding *gd_map_start, *map, *prev_map;
gd_addr *gd_targ;
gvnh_reg_t *gvnh_reg;
DCL_THREADGBL_ACCESS;
SETUP_THREADGBL_ACCESS;
assert(gv_currkey->prev || !TREF(gv_last_subsc_null));
if (gv_currkey->prev)
{ /* If last subscript is a NULL subscript, modify gv_currkey such that a gvcst_search of the resulting gv_currkey
* will find the last available subscript. But in case of dba_usr, (the custom implementation of $ZPREVIOUS which
* is overloaded for DDP now but could be more in the future) it is better to hand over gv_currkey as it is so
* the custom implementation can decide what to do with it.
*/
acc_meth = REG_ACC_METH(gv_cur_region);
ok_to_change_currkey = (dba_usr != acc_meth);
if (TREF(gv_last_subsc_null) && ok_to_change_currkey)
{ /* Replace the last subscript with the highest possible subscript value i.e. the byte sequence
* 0xFF (STR_SUB_MAXVAL), 0xFF, 0xFF ... as much as possible i.e. until gv_currkey->top permits.
* This subscript is guaranteed to be NOT present in the database since a user who tried to set this
* exact subscripted global would have gotten a GVSUBOFLOW error (because GT.M sets aside a few bytes
* of padding space). And yet this is guaranteed to collate AFTER any existing subscript. Therefore we
* can safely do a gvcst_zprevious on this key to get at the last existing key in the database.
*
* With standard null collation, the last subscript will be 0x01
* Without standard null collation, the last subscript will be 0xFF
* Assert that is indeed the case as this will be used to restore the replaced subscript at the end.
*/
assert(gv_cur_region->std_null_coll || (STR_SUB_PREFIX == gv_currkey->base[gv_currkey->prev]));
assert(!gv_cur_region->std_null_coll || (SUBSCRIPT_STDCOL_NULL == gv_currkey->base[gv_currkey->prev]));
assert(KEY_DELIMITER == gv_currkey->base[gv_currkey->prev + 1]);
assert(gv_currkey->end == gv_currkey->prev + 2);
assert(gv_currkey->end < gv_currkey->top); /* need "<" (not "<=") to account for terminating 0x00 */
GVZPREVIOUS_APPEND_MAX_SUBS_KEY(gv_currkey, gv_target);
}
if ((dba_bg == acc_meth) || (dba_mm == acc_meth))
{
gvnh_reg = TREF(gd_targ_gvnh_reg);
if (NULL == gvnh_reg)
found = (gv_target->root ? gvcst_zprevious() : FALSE);
else
INVOKE_GVCST_SPR_XXX(gvnh_reg, found = gvcst_spr_zprevious());
} else if (dba_cm == acc_meth)
found = gvcmx_zprevious();
else
found = gvusr_zprevious();
v->mvtype = 0; /* so stp_gcol (if invoked below) can free up space currently occupied (BYPASSOK)
* by this to-be-overwritten mval */
if (found)
{
gv_altkey->prev = gv_currkey->prev;
if (!IS_STP_SPACE_AVAILABLE(MAX_KEY_SZ))
{
if ((0xFF != gv_altkey->base[gv_altkey->prev])
&& (SUBSCRIPT_STDCOL_NULL != gv_altkey->base[gv_altkey->prev]))
n = MAX_FORM_NUM_SUBLEN;
else
{
n = gv_altkey->end - gv_altkey->prev;
assert(n > 0);
}
v->str.len = 0; /* so stp_gcol (if invoked) can free up space currently occupied by this (BYPASSOK)
* to-be-overwritten mval */
ENSURE_STP_FREE_SPACE(n);
}
v->str.addr = (char *)stringpool.free;
v->str.len = MAX_KEY_SZ;
stringpool.free = gvsub2str(&gv_altkey->base[gv_altkey->prev], &(v->str), FALSE);
v->str.len = INTCAST((char *)stringpool.free - v->str.addr);
assert(v->str.addr < (char *)stringpool.top && v->str.addr >= (char *)stringpool.base);
assert(v->str.addr + v->str.len <= (char *)stringpool.top &&
v->str.addr + v->str.len >= (char *)stringpool.base);
} else
v->str.len = 0;
v->mvtype = MV_STR; /* initialize mvtype now that mval has been otherwise completely set up */
if (TREF(gv_last_subsc_null) && ok_to_change_currkey)
{ /* Restore gv_currkey to what it was at function entry time */
gv_currkey->base[gv_currkey->prev + 1] = KEY_DELIMITER;
if (gv_cur_region->std_null_coll)
gv_currkey->base[gv_currkey->prev] = SUBSCRIPT_STDCOL_NULL;
assert(gv_cur_region->std_null_coll || (STR_SUB_PREFIX == gv_currkey->base[gv_currkey->prev]));
gv_currkey->end = gv_currkey->prev + 2;
gv_currkey->base[gv_currkey->end] = KEY_DELIMITER;
}
assert(KEY_DELIMITER == gv_currkey->base[gv_currkey->end]);
} else
{ /* the following section is for $ZPREVIOUS(^gname) */
assert(2 <= gv_currkey->end);
assert(gv_currkey->end < (MAX_MIDENT_LEN + 2)); /* until names are not in midents */
assert(KEY_DELIMITER == gv_currkey->base[gv_currkey->end]);
assert(KEY_DELIMITER == gv_currkey->base[gv_currkey->end - 1]);
gd_targ = TREF(gd_targ_addr);
gd_map_start = gd_targ->maps;
map = gv_srch_map(gd_targ, (char *)&gv_currkey->base[0], gv_currkey->end - 1);
assert(map > (gd_map_start + 1));
/* If ^gname starts at "map" start search from map-1 since $ZPREVIOUS(^gname) is sought */
BACK_OFF_ONE_MAP_ENTRY_IF_EDGECASE(gv_currkey->base, gv_currkey->end - 1, map);
found = FALSE;
/* The first map entry corresponds to local locks. The second map entry does not contain any globals.
* Therefore, any search for globals needs to only look after these maps. Hence the "gd_map_start + 1" below.
*/
for ( ; map > gd_map_start + 1; map = prev_map)
{
prev_map = map - 1;
gv_cur_region = map->reg.addr;
if (!gv_cur_region->open)
gv_init_reg(gv_cur_region);
change_reg();
acc_meth = REG_ACC_METH(gv_cur_region);
/* search region, entries in directory tree could have empty GVT in which case move on to previous entry */
for ( ; ; )
{
assert(0 == gv_currkey->prev); /* or else gvcst_zprevious could get confused */
if ((dba_bg == acc_meth) || (dba_mm == acc_meth))
{
gv_target = cs_addrs->dir_tree;
found = gvcst_zprevious();
} else if (dba_cm == acc_meth)
found = gvcmx_zprevious();
else
found = gvusr_zprevious();
if ('#' == gv_altkey->base[0]) /* don't want to give any hidden ^#* global, e.g "^#t" */
found = FALSE;
if (!found)
break;
assert(1 < gv_altkey->end);
assert(gv_altkey->end < (MAX_MIDENT_LEN + 2)); /* until names are not in midents */
res = memcmp(gv_altkey->base, prev_map->gvkey.addr, gv_altkey->end);
assert((0 != res) || (gv_altkey->end <= prev_map->gvkey_len));
if (0 > res)
{ /* The global name we found is less than the maximum value in the previous map
* so this name is not part of the current map for sure. Move on to previous map.
*/
found = FALSE;
break;
}
gvname.var_name.addr = (char *)gv_altkey->base;
gvname.var_name.len = gv_altkey->end - 1;
if (dba_cm == acc_meth)
break;
COMPUTE_HASH_MNAME(&gvname);
GV_BIND_NAME_AND_ROOT_SEARCH(gd_targ, &gvname, gvnh_reg); /* updates "gv_currkey" */
assert((NULL != gvnh_reg->gvspan) || (gv_cur_region == map->reg.addr));
if (NULL != gvnh_reg->gvspan)
{ /* gv_target would NOT have been initialized by GV_BIND_NAME in this case.
* So finish that initialization.
*/
datamval = &tmpmval;
/* The below macro finishes the task of GV_BIND_NAME_AND_ROOT_SEARCH
* (e.g. setting gv_cur_region for spanning globals)
*/
GV_BIND_SUBSNAME_IF_GVSPAN(gvnh_reg, gd_targ, gv_currkey, gvnh_reg->gd_reg);
op_gvdata(datamval);
if (MV_FORCE_INT(datamval))
break;
} else
{ /* else gv_target->root would have been initialized by GV_BIND_NAME_AND_ROOT_SEARCH */
if ((0 != gv_target->root) && (0 != gvcst_data()))
break;
}
}
if (found)
break;
/* If previous map corresponding to a spanning global, then do not update gv_currkey as that would
* effectively cause the spanning global to be skipped. If gvkey_len == gvname_len + 1 it is NOT
* a spanning global map entry.
*/
assert(prev_map->gvkey_len >= (prev_map->gvname_len + 1));
if ((prev_map > (gd_map_start + 1)) && (prev_map->gvkey_len == (prev_map->gvname_len + 1)))
{
assert(strlen(prev_map->gvkey.addr) == prev_map->gvname_len);
gv_currkey->end = prev_map->gvname_len + 1;
assert(gv_currkey->end <= (MAX_MIDENT_LEN + 1));
memcpy(gv_currkey->base, prev_map->gvkey.addr, gv_currkey->end);
assert(KEY_DELIMITER == gv_currkey->base[gv_currkey->end - 1]);
gv_currkey->base[gv_currkey->end] = KEY_DELIMITER;
assert(gv_currkey->top > gv_currkey->end); /* ensure we are within allocated bounds */
}
}
/* Reset gv_currkey as we have potentially skipped one or more regions so we no
* longer can expect gv_currkey/gv_cur_region/gv_target to match each other.
*/
gv_currkey->end = 0;
gv_currkey->base[0] = KEY_DELIMITER;
v->mvtype = 0; /* so stp_gcol (if invoked below) can free up space currently occupied (BYPASSOK)
* by this to-be-overwritten mval */
if (found)
{
if (!IS_STP_SPACE_AVAILABLE(gvname.var_name.len + 1))
{
v->str.len = 0; /* so stp_gcol ignores otherwise incompletely setup mval (BYPASSOK) */
INVOKE_STP_GCOL(gvname.var_name.len + 1);
}
v->str.addr = (char *)stringpool.free;
*stringpool.free++ = '^';
memcpy(stringpool.free, gvname.var_name.addr, gvname.var_name.len);
stringpool.free += gvname.var_name.len;
v->str.len = gvname.var_name.len + 1;
assert(v->str.addr < (char *)stringpool.top && v->str.addr >= (char *)stringpool.base);
assert(v->str.addr + v->str.len <= (char *)stringpool.top &&
v->str.addr + v->str.len >= (char *)stringpool.base);
} else
v->str.len = 0;
v->mvtype = MV_STR; /* initialize mvtype now that mval has been otherwise completely set up */
/* No need to restore gv_currkey (to what it was at function entry) as it is already set to NULL */
}
return;
}
void op_gvorder (mval *v)
{
int4 n;
gd_binding *map;
mstr name;
enum db_acc_method acc_meth;
boolean_t found, ok_to_change_currkey;
DCL_THREADGBL_ACCESS;
SETUP_THREADGBL_ACCESS;
acc_meth = gv_cur_region->dyn.addr->acc_meth;
/* Modify gv_currkey such that a gvcst_search of the resulting gv_currkey will find the next available subscript.
* But in case of dba_usr (the custom implementation of $ORDER which is overloaded for DDP but could be more in the
* future) it is better to hand over gv_currkey as it is so the custom implementation can decide what to do with it.
*/
ok_to_change_currkey = (dba_usr != acc_meth);
if (ok_to_change_currkey)
{ /* Modify gv_currkey to reflect the next possible key value in collating order */
if (!TREF(gv_last_subsc_null) || gv_cur_region->std_null_coll)
{
*(&gv_currkey->base[0] + gv_currkey->end - 1) = 1;
*(&gv_currkey->base[0] + gv_currkey->end + 1) = 0;
gv_currkey->end += 1;
} else
{
assert(STR_SUB_PREFIX == gv_currkey->base[gv_currkey->prev]);
assert(KEY_DELIMITER == gv_currkey->base[gv_currkey->end]);
assert(KEY_DELIMITER == gv_currkey->base[gv_currkey->end - 1]);
assert(2 == (gv_currkey->end - gv_currkey->prev));
*(&gv_currkey->base[0] + gv_currkey->prev) = 01;
}
}
if (gv_currkey->prev)
{
if (acc_meth == dba_bg || acc_meth == dba_mm)
{
if (gv_target->root == 0) /* global does not exist */
found = FALSE;
else
found = gvcst_order();
} else if (acc_meth == dba_cm)
found = gvcmx_order();
else
found = gvusr_order();
v->mvtype = 0; /* so stp_gcol (if invoked below) can free up space currently occupied by
* this to-be-overwritten mval */
if (found)
{
gv_altkey->prev = gv_currkey->prev;
if (!(IS_STP_SPACE_AVAILABLE(MAX_KEY_SZ)))
{
if (*(&gv_altkey->base[0] + gv_altkey->prev) != 0xFF)
n = MAX_FORM_NUM_SUBLEN;
else
{
n = gv_altkey->end - gv_altkey->prev;
assert (n > 0);
}
ENSURE_STP_FREE_SPACE(n);
}
v->str.addr = (char *)stringpool.free;
stringpool.free = gvsub2str (&gv_altkey->base[0] + gv_altkey->prev, stringpool.free, FALSE);
v->str.len = INTCAST((char *)stringpool.free - v->str.addr);
assert (v->str.addr < (char *)stringpool.top && v->str.addr >= (char *)stringpool.base);
assert (v->str.addr + v->str.len <= (char *)stringpool.top &&
v->str.addr + v->str.len >= (char *)stringpool.base);
} else
v->str.len = 0;
v->mvtype = MV_STR; /* initialize mvtype now that mval has been otherwise completely set up */
if (ok_to_change_currkey)
{ /* Restore gv_currkey to what it was at function entry time */
if (!TREF(gv_last_subsc_null) || gv_cur_region->std_null_coll)
{
assert(1 == gv_currkey->base[gv_currkey->end - 2]);
assert(KEY_DELIMITER == gv_currkey->base[gv_currkey->end-1]);
assert(KEY_DELIMITER == gv_currkey->base[gv_currkey->end]);
gv_currkey->base[gv_currkey->end - 2] = KEY_DELIMITER;
gv_currkey->end--;
} else
{
assert(01 == gv_currkey->base[gv_currkey->prev]);
gv_currkey->base[gv_currkey->prev] = STR_SUB_PREFIX;
}
}
} else /* the following section is for $O(^gname) */
{
assert (2 < gv_currkey->end);
assert (gv_currkey->end < (MAX_MIDENT_LEN + 3)); /* until names are not in midents */
map = gd_map + 1;
while (map < gd_map_top &&
(memcmp(gv_currkey->base, map->name,
gv_currkey->end == (MAX_MIDENT_LEN + 2) ? MAX_MIDENT_LEN : gv_currkey->end - 1) >= 0))
{
map++;
}
for (; map < gd_map_top; ++map)
{
gv_cur_region = map->reg.addr;
if (!gv_cur_region->open)
gv_init_reg(gv_cur_region);
change_reg();
acc_meth = gv_cur_region->dyn.addr->acc_meth;
for (; ;) /* search region, entries in directory tree could be empty */
{
if (acc_meth == dba_bg || acc_meth == dba_mm)
{
gv_target = cs_addrs->dir_tree;
found = gvcst_order ();
} else if (acc_meth == dba_cm)
found = gvcmx_order ();
else
found = gvusr_order();
if (!found)
break;
assert (1 < gv_altkey->end);
assert (gv_altkey->end < (MAX_MIDENT_LEN + 2)); /* until names are not in midents */
if (memcmp(gv_altkey->base, map->name, gv_altkey->end - 1) > 0)
{
found = FALSE;
break;
}
name.addr = (char *)&gv_altkey->base[0];
name.len = gv_altkey->end - 1;
if (acc_meth == dba_cm)
break;
GV_BIND_NAME_AND_ROOT_SEARCH(gd_header, &name);
if (gv_cur_region != map->reg.addr)
{
found = FALSE;
break;
}
if ((gv_target->root != 0) && (gvcst_data() != 0))
break;
*(&gv_currkey->base[0] + gv_currkey->end - 1) = 1;
*(&gv_currkey->base[0] + gv_currkey->end + 1) = 0;
gv_currkey->end += 1;
}
if (found)
break;
else
{
assert(SIZEOF(map->name) == SIZEOF(mident_fixed));
gv_currkey->end = mid_len((mident_fixed *)map->name);
memcpy(&gv_currkey->base[0], map->name, gv_currkey->end);
gv_currkey->base[ gv_currkey->end - 1 ] -= 1;
gv_currkey->base[ gv_currkey->end ] = 0xFF; /* back off 1 spot from map */
gv_currkey->base[ gv_currkey->end + 1] = 0;
gv_currkey->base[ gv_currkey->end + 2] = 0;
gv_currkey->end += 2;
}
}
/* Reset gv_currkey as we have potentially skipped one or more regions so we no
* longer can expect gv_currkey/gv_cur_region/gv_target to match each other.
*/
gv_currkey->end = 0;
gv_currkey->base[0] = 0;
v->mvtype = 0; /* so stp_gcol (if invoked below) can free up space currently occupied by
* this to-be-overwritten mval */
if (found)
{
if (!IS_STP_SPACE_AVAILABLE(name.len + 1))
{
v->str.len = 0; /* so stp_gcol ignores otherwise incompletely setup mval */
INVOKE_STP_GCOL(name.len + 1);
}
#ifdef mips
/* the following line works around a tandem compiler bug. */
v->str.addr = (char *)0;
#endif
v->str.addr = (char *)stringpool.free;
*stringpool.free++ = '^';
memcpy (stringpool.free, name.addr, name.len);
stringpool.free += name.len;
v->str.len = name.len + 1;
assert (v->str.addr < (char *)stringpool.top && v->str.addr >= (char *)stringpool.base);
assert (v->str.addr + v->str.len <= (char *)stringpool.top &&
v->str.addr + v->str.len >= (char *)stringpool.base);
} else
v->str.len = 0;
v->mvtype = MV_STR; /* initialize mvtype now that mval has been otherwise completely set up */
}
return;
}
