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package binary
import (
"bytes"
"fmt"
"io"
"unicode/utf8"
"unsafe"
"github.com/tetratelabs/wazero/internal/leb128"
"github.com/tetratelabs/wazero/internal/wasm"
)
func decodeValueTypes(r *bytes.Reader, num uint32) ([]wasm.ValueType, error) {
if num == 0 {
return nil, nil
}
ret := make([]wasm.ValueType, num)
_, err := io.ReadFull(r, ret)
if err != nil {
return nil, err
}
for _, v := range ret {
switch v {
case wasm.ValueTypeI32, wasm.ValueTypeF32, wasm.ValueTypeI64, wasm.ValueTypeF64,
wasm.ValueTypeExternref, wasm.ValueTypeFuncref, wasm.ValueTypeV128:
default:
return nil, fmt.Errorf("invalid value type: %d", v)
}
}
return ret, nil
}
// decodeUTF8 decodes a size prefixed string from the reader, returning it and the count of bytes read.
// contextFormat and contextArgs apply an error format when present
func decodeUTF8(r *bytes.Reader, contextFormat string, contextArgs ...interface{}) (string, uint32, error) {
size, sizeOfSize, err := leb128.DecodeUint32(r)
if err != nil {
return "", 0, fmt.Errorf("failed to read %s size: %w", fmt.Sprintf(contextFormat, contextArgs...), err)
}
if size == 0 {
return "", uint32(sizeOfSize), nil
}
buf := make([]byte, size)
if _, err = io.ReadFull(r, buf); err != nil {
return "", 0, fmt.Errorf("failed to read %s: %w", fmt.Sprintf(contextFormat, contextArgs...), err)
}
if !utf8.Valid(buf) {
return "", 0, fmt.Errorf("%s is not valid UTF-8", fmt.Sprintf(contextFormat, contextArgs...))
}
// TODO: use unsafe.String after flooring Go 1.20.
ret := *(*string)(unsafe.Pointer(&buf))
return ret, size + uint32(sizeOfSize), nil
}
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