From f7112cc182ec9ec43ff56d4ff3c84d2518aa30ff Mon Sep 17 00:00:00 2001 From: Felix Lange 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 2b3f328f66..c2a8517f62 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 2aad042100..cdae4ff088 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"},