120 lines
3.2 KiB
Go
120 lines
3.2 KiB
Go
// Code extracted from vendor/github.com/ethereum/go-ethereum/common/types.go
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package types
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import (
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"encoding/hex"
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"fmt"
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"reflect"
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)
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const (
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// HashLength is the expected length of the hash
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HashLength = 32
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)
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// Hash represents the 32 byte Keccak256 hash of arbitrary data.
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type Hash [HashLength]byte
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var hashT = reflect.TypeOf(Hash{})
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// Encode encodes b as a hex string with 0x prefix.
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func encode(b []byte) string {
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enc := make([]byte, len(b)*2+2)
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copy(enc, "0x")
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hex.Encode(enc[2:], b)
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return string(enc)
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}
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// FromHex returns the bytes represented by the hexadecimal string s.
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// s may be prefixed with "0x".
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func FromHex(s string) []byte {
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if has0xPrefix(s) {
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s = s[2:]
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}
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if len(s)%2 == 1 {
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s = "0" + s
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}
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return Hex2Bytes(s)
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}
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// HexToHash sets byte representation of s to hash.
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// If b is larger than len(h), b will be cropped from the left.
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func HexToHash(s string) Hash { return BytesToHash(FromHex(s)) }
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// Hex converts a hash to a hex string.
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func (h *Hash) Hex() string { return encode(h[:]) }
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// Bytes gets the byte representation of the underlying hash.
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func (h Hash) Bytes() []byte { return h[:] }
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// String implements the stringer interface and is used also by the logger when
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// doing full logging into a file.
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func (h Hash) String() string {
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return h.Hex()
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}
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// SetBytes sets the hash to the value of b.
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// If b is larger than len(h), b will be cropped from the left.
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func (h *Hash) SetBytes(b []byte) {
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if len(b) > len(h) {
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b = b[len(b)-HashLength:]
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}
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copy(h[HashLength-len(b):], b)
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}
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// UnmarshalText parses a hash in hex syntax.
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func (h *Hash) UnmarshalText(input []byte) error {
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return UnmarshalFixedText("Hash", input, h[:])
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}
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// UnmarshalJSON parses a hash in hex syntax.
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func (h *Hash) UnmarshalJSON(input []byte) error {
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return UnmarshalFixedJSON(hashT, input, h[:])
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}
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// MarshalText returns the hex representation of h.
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func (h Hash) MarshalText() ([]byte, error) {
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return HexBytes(h[:]).MarshalText()
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}
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// BytesToHash sets b to hash.
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// If b is larger than len(h), b will be cropped from the left.
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func BytesToHash(b []byte) Hash {
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var h Hash
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h.SetBytes(b)
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return h
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}
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// UnmarshalFixedJSON decodes the input as a string with 0x prefix. The length of out
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// determines the required input length. This function is commonly used to implement the
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// UnmarshalJSON method for fixed-size types.
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func UnmarshalFixedJSON(typ reflect.Type, input, out []byte) error {
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if !isString(input) {
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return errNonString(typ)
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}
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return wrapTypeError(UnmarshalFixedText(typ.String(), input[1:len(input)-1], out), typ)
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}
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// UnmarshalFixedText decodes the input as a string with 0x prefix. The length of out
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// determines the required input length. This function is commonly used to implement the
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// UnmarshalText method for fixed-size types.
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func UnmarshalFixedText(typname string, input, out []byte) error {
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raw, err := checkText(input, true)
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if err != nil {
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return err
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}
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if len(raw)/2 != len(out) {
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return fmt.Errorf("hex string has length %d, want %d for %s", len(raw), len(out)*2, typname)
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}
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// Pre-verify syntax before modifying out.
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for _, b := range raw {
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if decodeNibble(b) == badNibble {
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return ErrSyntax
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}
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}
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_, err = hex.Decode(out, raw)
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return err
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}
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