authorgravatar for thatlemon@gmail.comLemonBoy <thatlemon@gmail.com> 2019-05-15 09:41:38+02:00
committergravatar for andrew@ziglang.orgAndrew Kelley <andrew@ziglang.org> 2019-05-15 11:11:16-04:00
log787fd0f1bea262d134f06e5913554b8ca086655f
tree979f546155d5ba67ae85d3c97c508d39e2f62ced
parent057a5d4898f70c6a8169c99375fbb8631e539051

Fix off-by-one error in LEB128 parsing

1 files changed, 30 insertions(+), 2 deletions(-)

std/debug/leb128.zig+30-2
......@@ -46,7 +46,7 @@ pub fn readULEB128Mem(comptime T: type, ptr: *[*]const u8) !T {
4646 result |= operand;
4747
4848 if ((byte & 0x80) == 0) {
49 ptr.* += i;
49 ptr.* += i + 1;
5050 return result;
5151 }
5252
......@@ -114,7 +114,7 @@ pub fn readILEB128Mem(comptime T: type, ptr: *[*]const u8) !T {
114114 if (shift < T.bit_count and (byte & 0x40) != 0) {
115115 result |= @bitCast(UT, @intCast(T, -1)) << @intCast(ShiftT, shift);
116116 }
117 ptr.* += i;
117 ptr.* += i + 1;
118118 return @bitCast(T, result);
119119 }
120120 }
......@@ -148,6 +148,28 @@ fn test_read_uleb128(comptime T: type, encoded: []const u8) !T {
148148 return v1;
149149}
150150
151fn test_read_ileb128_seq(comptime T: type, comptime N: usize, encoded: []const u8) void {
152 var in_stream = std.io.SliceInStream.init(encoded);
153 var in_ptr = encoded.ptr;
154 var i: usize = 0;
155 while (i < N) : (i += 1) {
156 const v1 = readILEB128(T, &in_stream.stream);
157 const v2 = readILEB128Mem(T, &in_ptr);
158 testing.expectEqual(v1, v2);
159 }
160}
161
162fn test_read_uleb128_seq(comptime T: type, comptime N: usize, encoded: []const u8) void {
163 var in_stream = std.io.SliceInStream.init(encoded);
164 var in_ptr = encoded.ptr;
165 var i: usize = 0;
166 while (i < N) : (i += 1) {
167 const v1 = readULEB128(T, &in_stream.stream);
168 const v2 = readULEB128Mem(T, &in_ptr);
169 testing.expectEqual(v1, v2);
170 }
171}
172
151173test "deserialize signed LEB128" {
152174 // Truncated
153175 testing.expectError(error.EndOfStream, test_read_stream_ileb128(i64, "\x80"));
......@@ -188,6 +210,9 @@ test "deserialize signed LEB128" {
188210 testing.expect((try test_read_ileb128(i64, "\xff\x80\x00")) == 0x7f);
189211 testing.expect((try test_read_ileb128(i64, "\x80\x81\x00")) == 0x80);
190212 testing.expect((try test_read_ileb128(i64, "\x80\x81\x80\x00")) == 0x80);
213
214 // Decode sequence of SLEB128 values
215 test_read_ileb128_seq(i64, 4, "\x81\x01\x3f\x80\x7f\x80\x80\x80\x00");
191216}
192217
193218test "deserialize unsigned LEB128" {
......@@ -225,4 +250,7 @@ test "deserialize unsigned LEB128" {
225250 testing.expect((try test_read_uleb128(u64, "\xff\x80\x00")) == 0x7f);
226251 testing.expect((try test_read_uleb128(u64, "\x80\x81\x00")) == 0x80);
227252 testing.expect((try test_read_uleb128(u64, "\x80\x81\x80\x00")) == 0x80);
253
254 // Decode sequence of ULEB128 values
255 test_read_uleb128_seq(u64, 4, "\x81\x01\x3f\x80\x7f\x80\x80\x80\x00");
228256}