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leb128: make decoding return the number of decoded bytes, in addition to the decoded value (#17912)

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Surman The Dead 2023-04-09 09:32:49 +02:00 committed by GitHub
parent abe0ad886b
commit b772731b98
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2 changed files with 24 additions and 16 deletions
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24
vlib/encoding/leb128/leb128.v
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@ -66,8 +66,8 @@ pub fn encode_u32(value u32) []u8 {
return result return result
} }
// decode_i32 decodes an i32 from the given leb128 encoded array `value` // decode_i32 decodes an i32 and returns the number of bytes used from the given leb128 encoded array `value`
pub fn decode_i32(value []u8) i32 { pub fn decode_i32(value []u8) (i32, int) {
mut result := int(0) mut result := int(0)
mut shift := 0 mut shift := 0
for b in value { for b in value {
@ -80,11 +80,11 @@ pub fn decode_i32(value []u8) i32 {
break break
} }
} }
return result return result, shift / 7
} }
// decode_i64 decodes an i64 from the given leb128 encoded array `value` // decode_i64 decodes an i64 and returns the number of bytes used from the given leb128 encoded array `value`
pub fn decode_i64(value []u8) i64 { pub fn decode_i64(value []u8) (i64, int) {
mut result := u64(0) mut result := u64(0)
mut shift := 0 mut shift := 0
for b in value { for b in value {
@ -97,11 +97,11 @@ pub fn decode_i64(value []u8) i64 {
break break
} }
} }
return i64(result) return i64(result), shift / 7
} }
// decode_u64 decodes an u64 from the given leb128 encoded array `value` // decode_u64 decodes an u64 and returns the number of bytes used from the given leb128 encoded array `value`
pub fn decode_u64(value []u8) u64 { pub fn decode_u64(value []u8) (u64, int) {
mut result := u64(0) mut result := u64(0)
mut shift := 0 mut shift := 0
for b in value { for b in value {
@ -111,11 +111,11 @@ pub fn decode_u64(value []u8) u64 {
} }
shift += 7 shift += 7
} }
return result return result, shift / 7 + 1
} }
// decode_u32 decodes an u32 from the given leb128 encoded array `value` // decode_u32 decodes an u32 and returns the number of bytes used from the given leb128 encoded array `value`
pub fn decode_u32(value []u8) u32 { pub fn decode_u32(value []u8) (u32, int) {
mut result := u32(0) mut result := u32(0)
mut shift := 0 mut shift := 0
for b in value { for b in value {
@ -125,5 +125,5 @@ pub fn decode_u32(value []u8) u32 {
} }
shift += 7 shift += 7
} }
return result return result, shift / 7 + 1
} }

16
vlib/encoding/leb128/leb128_test.v
View File

@ -13,9 +13,13 @@ struct PairI {
fn test_basic() { fn test_basic() {
assert leb128.encode_u64(624485) == [u8(0xe5), 0x8e, 0x26] assert leb128.encode_u64(624485) == [u8(0xe5), 0x8e, 0x26]
assert leb128.decode_u64([u8(0xe5), 0x8e, 0x26]) == 624485 uval, ulen := leb128.decode_u64([u8(0xe5), 0x8e, 0x26])
assert uval == 624485, 'val, _ := leb128.decode_u64([u8(0xe5), 0x8e, 0x26]) == 624486'
assert ulen == 3, '_, len := leb128.decode_u64([u8(0xe5), 0x8e, 0x26]) == 3'
assert leb128.encode_i64(-123456) == [u8(0xc0), 0xbb, 0x78] assert leb128.encode_i64(-123456) == [u8(0xc0), 0xbb, 0x78]
assert leb128.decode_i64([u8(0xc0), 0xbb, 0x78]) == -123456 sval, slen := leb128.decode_i64([u8(0xc0), 0xbb, 0x78])
assert sval == -123456, 'val, _ := leb128.decode_i64([u8(0xc0), 0xbb, 0x78]) == -123456'
assert slen == 3, '_, len := leb128.decode_i64([u8(0xc0), 0xbb, 0x78]) == 3'
} }
fn test_unsigned_data() { fn test_unsigned_data() {
@ -23,7 +27,9 @@ fn test_unsigned_data() {
assert leb128.encode_u64(x.value).hex() == x.encoded, 'leb128.encode_u64( ${x.value} ) == ${x.encoded}' assert leb128.encode_u64(x.value).hex() == x.encoded, 'leb128.encode_u64( ${x.value} ) == ${x.encoded}'
bytes := hex.decode(x.encoded)! bytes := hex.decode(x.encoded)!
// eprintln('>> bytes: ${bytes} | pair: ${x}') // eprintln('>> bytes: ${bytes} | pair: ${x}')
assert leb128.decode_u64(bytes) == x.value, 'leb128.decode_u64( ${x.encoded} ) == ${x.value}' val, len := leb128.decode_u64(bytes)
assert val == x.value, 'val, _ := leb128.decode_u64( ${x.encoded} ) == ${x.value}'
assert len == bytes.len, '_, len := leb128.decode_u64( ${x.encoded} ) = ${bytes.len}'
} }
} }
@ -32,7 +38,9 @@ fn test_signed_data() {
assert leb128.encode_i64(x.value).hex() == x.encoded, 'k: ${x.value} | v: ${x.encoded}' assert leb128.encode_i64(x.value).hex() == x.encoded, 'k: ${x.value} | v: ${x.encoded}'
bytes := hex.decode(x.encoded)! bytes := hex.decode(x.encoded)!
// eprintln('>> bytes: ${bytes} | pair: ${x}') // eprintln('>> bytes: ${bytes} | pair: ${x}')
assert leb128.decode_i64(bytes) == x.value, 'leb128.decode_i64( ${x.encoded} ) == ${x.value}' val, len := leb128.decode_i64(bytes)
assert val == x.value, 'val, _ := leb128.decode_i64( ${x.encoded} ) == ${x.value}'
assert len == bytes.len, '_, len := leb128.decode_i64( ${x.encoded} ) == ${x.value}'
} }
} }