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bcsymbol.go
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bcsymbol.go
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// Copyright 2023 Sneller, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package vm
import (
"fmt"
"github.com/SnellerInc/sneller/ion"
)
// Encodes a symbol ID, which is stored in bytecode.
func encodeSymbolID(id ion.Symbol) uint32 {
if id >= (1<<28)-1 {
panic(fmt.Sprintf("symbol id too large: %d", id))
}
encoded := uint32((id & 0x7F) | 0x80)
id >>= 7
for id != 0 {
encoded = (encoded << 8) | (uint32(id) & 0x7F)
id >>= 7
}
return encoded
}
func decodeSymbolID(value uint32) ion.Symbol {
if (value & 0x80808080) == 0 {
panic(fmt.Sprintf("the provided argument is not an encoded symbol ID: %d", value))
}
decoded := value & 0x7F
value >>= 8
for value != 0 {
decoded = (decoded << 7) | (value & 0x7F)
value >>= 8
}
return ion.Symbol(decoded)
}