117474c477
move binary encoder to its own package Signed-off-by: Edoardo Vacchi <evacchi@users.noreply.github.com>
38 lines
1.2 KiB
Go
38 lines
1.2 KiB
Go
package binaryencoding
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import (
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"bytes"
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"fmt"
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"github.com/tetratelabs/wazero/internal/leb128"
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"github.com/tetratelabs/wazero/internal/wasm"
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)
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func ensureElementKindFuncRef(r *bytes.Reader) error {
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elemKind, err := r.ReadByte()
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if err != nil {
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return fmt.Errorf("read element prefix: %w", err)
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}
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if elemKind != 0x0 { // ElemKind is fixed to 0x0 now: https://www.w3.org/TR/2022/WD-wasm-core-2-20220419/binary/modules.html#element-section
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return fmt.Errorf("element kind must be zero but was 0x%x", elemKind)
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}
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return nil
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}
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// encodeCode returns the wasm.ElementSegment encoded in WebAssembly 1.0 (20191205) Binary Format.
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//
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// https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#element-section%E2%91%A0
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func encodeElement(e *wasm.ElementSegment) (ret []byte) {
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if e.Mode == wasm.ElementModeActive {
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ret = append(ret, leb128.EncodeInt32(int32(e.TableIndex))...)
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ret = append(ret, encodeConstantExpression(e.OffsetExpr)...)
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ret = append(ret, leb128.EncodeUint32(uint32(len(e.Init)))...)
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for _, idx := range e.Init {
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ret = append(ret, leb128.EncodeInt32(int32(*idx))...)
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}
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} else {
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panic("TODO: support encoding for non-active elements in bulk-memory-operations proposal")
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}
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return
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}
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