IHqlExpression * HqlCppCaseInfo::buildIndexedMap(BuildCtx & ctx, const CHqlBoundExpr & test)
{
ITypeInfo * compareType = test.queryType()->queryPromotedType();
type_t compareTypeCode = compareType->getTypeCode();
HqlExprArray values;
IHqlExpression * dft = queryActiveTableSelector(); // value doesn't matter as long as it will not occur
__int64 lower = getIntValue(lowerTableBound, 0);
unsigned num = (getIntValue(upperTableBound, 0)-lower)+1;
CHqlBoundExpr indexExpr;
switch (compareTypeCode)
{
case type_int:
indexExpr.set(test);
break;
case type_string:
indexExpr.expr.setown(createValue(no_index, makeCharType(), LINK(test.expr), getZero()));
indexExpr.expr.setown(createValue(no_cast, makeIntType(1, false), LINK(indexExpr.expr)));
break;
default:
throwUnexpectedType(compareType);
}
if (useRangeIndex && (num != 1))
translator.ensureSimpleExpr(ctx, indexExpr);
OwnedHqlExpr mapped;
ITypeInfo * retType = resultType;
//if num == pairs.ordinality() and all results are identical, avoid the table lookup.
if (allResultsMatch && (num == pairs.ordinality()))
{
mapped.set(pairs.item(0).queryChild(1));
}
else
{
values.ensure(num);
unsigned idx;
for (idx = 0; idx < num; idx++)
values.append(*LINK(dft));
ForEachItemIn(idx2, pairs)
{
IHqlExpression & cur = pairs.item(idx2);
IValue * value = cur.queryChild(0)->queryValue();
unsigned replaceIndex;
switch (compareTypeCode)
{
case type_int:
replaceIndex = (unsigned)(value->getIntValue()-lower);
break;
case type_string:
{
StringBuffer temp;
value->getStringValue(temp);
replaceIndex = (unsigned)((unsigned char)temp.charAt(0)-lower);
break;
}
default:
throwUnexpectedType(compareType);
}
IHqlExpression * mapTo = cur.queryChild(1);
if (mapTo->getOperator() != no_constant)
throwUnexpected();
if (replaceIndex >= num)
translator.reportWarning(CategoryIgnored, HQLWRN_CaseCanNeverMatch, "CASE entry %d can never match the test condition", replaceIndex);
else
values.replace(*LINK(mapTo),replaceIndex);
}
//Now replace the placeholders with the default values.
for (idx = 0; idx < num; idx++)
{
if (&values.item(idx) == dft)
values.replace(*defaultValue.getLink(),idx);
}
// use a var string type to get better C++ generated...
ITypeInfo * storeType = getArrayElementType(resultType);
ITypeInfo * listType = makeArrayType(storeType, values.ordinality());
OwnedHqlExpr lvalues = createValue(no_list, listType, values);
CHqlBoundExpr boundTable;
translator.buildExpr(ctx, lvalues, boundTable);
LinkedHqlExpr tableIndex = indexExpr.expr;
if (getIntValue(lowerTableBound, 0))
tableIndex.setown(createValue(no_sub, tableIndex->getType(), LINK(tableIndex), LINK(lowerTableBound)));
IHqlExpression * ret = createValue(no_index, LINK(retType), LINK(boundTable.expr), LINK(tableIndex));
mapped.setown(createTranslatedOwned(ret));
}
