srctree

Techatrix parent 88b3c144 9727931f
fix integer overflow in indexOfPosLinear when needle.len > haystack.len

lib/std/mem.zig added: 22, removed: 1, total 21

@@ -1346,6 +1346,7 @@ pub fn lastIndexOfLinear(comptime T: type, haystack: []const T, needle: []const

/// Consider using `indexOfPos` instead of this, which will automatically use a

/// more sophisticated algorithm on larger inputs.

pub fn indexOfPosLinear(comptime T: type, haystack: []const T, start_index: usize, needle: []const T) ?usize {

if (needle.len > haystack.len) return null;

var i: usize = start_index;

const end = haystack.len - needle.len;

while (i <= end) : (i += 1) {

@@ -1354,6 +1355,26 @@ pub fn indexOfPosLinear(comptime T: type, haystack: []const T, start_index: usiz

return null;

}

test indexOfPosLinear {

try testing.expectEqual(0, indexOfPosLinear(u8, "", 0, ""));

try testing.expectEqual(0, indexOfPosLinear(u8, "123", 0, ""));

try testing.expectEqual(null, indexOfPosLinear(u8, "", 0, "1"));

try testing.expectEqual(0, indexOfPosLinear(u8, "1", 0, "1"));

try testing.expectEqual(null, indexOfPosLinear(u8, "2", 0, "1"));

try testing.expectEqual(1, indexOfPosLinear(u8, "21", 0, "1"));

try testing.expectEqual(null, indexOfPosLinear(u8, "222", 0, "1"));

try testing.expectEqual(null, indexOfPosLinear(u8, "", 0, "12"));

try testing.expectEqual(null, indexOfPosLinear(u8, "1", 0, "12"));

try testing.expectEqual(null, indexOfPosLinear(u8, "2", 0, "12"));

try testing.expectEqual(0, indexOfPosLinear(u8, "12", 0, "12"));

try testing.expectEqual(null, indexOfPosLinear(u8, "21", 0, "12"));

try testing.expectEqual(1, indexOfPosLinear(u8, "212", 0, "12"));

try testing.expectEqual(0, indexOfPosLinear(u8, "122", 0, "12"));

try testing.expectEqual(1, indexOfPosLinear(u8, "212112", 0, "12"));

}

fn boyerMooreHorspoolPreprocessReverse(pattern: []const u8, table: *[256]usize) void {

for (table) |*c| {

c.* = pattern.len;