From f7112cc182ec9ec43ff56d4ff3c84d2518aa30ff Mon Sep 17 00:00:00 2001
From: Felix Lange <fjl@twurst.com>
Date: Mon, 14 Sep 2020 19:23:01 +0200
Subject: [PATCH] rlp: add SplitUint64 (#21563)
This can be useful when working with raw RLP data.
---
rlp/raw.go | 26 ++++++++++++++++++++++++++
rlp/raw_test.go | 45 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 71 insertions(+)
diff --git a/rlp/raw.go b/rlp/raw.go
index 2b3f328f6..c2a8517f6 100644
--- a/rlp/raw.go
+++ b/rlp/raw.go
@@ -57,6 +57,32 @@ func SplitString(b []byte) (content, rest []byte, err error) {
return content, rest, nil
}
+// SplitUint64 decodes an integer at the beginning of b.
+// It also returns the remaining data after the integer in 'rest'.
+func SplitUint64(b []byte) (x uint64, rest []byte, err error) {
+ content, rest, err := SplitString(b)
+ if err != nil {
+ return 0, b, err
+ }
+ switch {
+ case len(content) == 0:
+ return 0, rest, nil
+ case len(content) == 1:
+ if content[0] == 0 {
+ return 0, b, ErrCanonInt
+ }
+ return uint64(content[0]), rest, nil
+ case len(content) > 8:
+ return 0, b, errUintOverflow
+ default:
+ x, err = readSize(content, byte(len(content)))
+ if err != nil {
+ return 0, b, ErrCanonInt
+ }
+ return x, rest, nil
+ }
+}
+
// SplitList splits b into the content of a list and any remaining
// bytes after the list.
func SplitList(b []byte) (content, rest []byte, err error) {
diff --git a/rlp/raw_test.go b/rlp/raw_test.go
index 2aad04210..cdae4ff08 100644
--- a/rlp/raw_test.go
+++ b/rlp/raw_test.go
@@ -71,6 +71,49 @@ func TestSplitTypes(t *testing.T) {
}
}
+func TestSplitUint64(t *testing.T) {
+ tests := []struct {
+ input string
+ val uint64
+ rest string
+ err error
+ }{
+ {"01", 1, "", nil},
+ {"7FFF", 0x7F, "FF", nil},
+ {"80FF", 0, "FF", nil},
+ {"81FAFF", 0xFA, "FF", nil},
+ {"82FAFAFF", 0xFAFA, "FF", nil},
+ {"83FAFAFAFF", 0xFAFAFA, "FF", nil},
+ {"84FAFAFAFAFF", 0xFAFAFAFA, "FF", nil},
+ {"85FAFAFAFAFAFF", 0xFAFAFAFAFA, "FF", nil},
+ {"86FAFAFAFAFAFAFF", 0xFAFAFAFAFAFA, "FF", nil},
+ {"87FAFAFAFAFAFAFAFF", 0xFAFAFAFAFAFAFA, "FF", nil},
+ {"88FAFAFAFAFAFAFAFAFF", 0xFAFAFAFAFAFAFAFA, "FF", nil},
+
+ // errors
+ {"", 0, "", io.ErrUnexpectedEOF},
+ {"00", 0, "00", ErrCanonInt},
+ {"81", 0, "81", ErrValueTooLarge},
+ {"8100", 0, "8100", ErrCanonSize},
+ {"8200FF", 0, "8200FF", ErrCanonInt},
+ {"8103FF", 0, "8103FF", ErrCanonSize},
+ {"89FAFAFAFAFAFAFAFAFAFF", 0, "89FAFAFAFAFAFAFAFAFAFF", errUintOverflow},
+ }
+
+ for i, test := range tests {
+ val, rest, err := SplitUint64(unhex(test.input))
+ if val != test.val {
+ t.Errorf("test %d: val mismatch: got %x, want %x (input %q)", i, val, test.val, test.input)
+ }
+ if !bytes.Equal(rest, unhex(test.rest)) {
+ t.Errorf("test %d: rest mismatch: got %x, want %s (input %q)", i, rest, test.rest, test.input)
+ }
+ if err != test.err {
+ t.Errorf("test %d: error mismatch: got %q, want %q", i, err, test.err)
+ }
+ }
+}
+
func TestSplit(t *testing.T) {
tests := []struct {
input string
@@ -78,7 +121,9 @@ func TestSplit(t *testing.T) {
val, rest string
err error
}{
+ {input: "00FFFF", kind: Byte, val: "00", rest: "FFFF"},
{input: "01FFFF", kind: Byte, val: "01", rest: "FFFF"},
+ {input: "7FFFFF", kind: Byte, val: "7F", rest: "FFFF"},
{input: "80FFFF", kind: String, val: "", rest: "FFFF"},
{input: "C3010203", kind: List, val: "010203"},
--
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