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std.mem.count

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Sobeston
2020-08-24 16:47:44 +01:00
committed by Andrew Kelley
parent 091d693c53
commit 7d0bb0774e
1 changed files with 29 additions and 0 deletions
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29
lib/std/mem.zig
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@@ -893,6 +893,35 @@ test "mem.indexOf" {
testing.expect(lastIndexOfScalar(u8, "boo", 'o').? == 2);
}
/// Returns the number of needles inside the haystack
/// needle.len must be > 0
/// does not count overlapping needles
pub fn count(comptime T: type, haystack: []const T, needle: []const T) usize {
assert(needle.len > 0);
var i: usize = 0;
var found: usize = 0;
while (indexOfPos(T, haystack, i, needle)) |idx| {
i = idx + needle.len;
found += 1;
}
return found;
}
test "mem.count" {
testing.expect(count(u8, "", "h") == 0);
testing.expect(count(u8, "h", "h") == 1);
testing.expect(count(u8, "hh", "h") == 2);
testing.expect(count(u8, "world!", "hello") == 0);
testing.expect(count(u8, "hello world!", "hello") == 1);
testing.expect(count(u8, " abcabc abc", "abc") == 3);
testing.expect(count(u8, "udexdcbvbruhasdrw", "bruh") == 1);
testing.expect(count(u8, "foo bar", "o bar") == 1);
testing.expect(count(u8, "foofoofoo", "foo") == 3);
testing.expect(count(u8, "fffffff", "ff") == 3);
}
/// Reads an integer from memory with size equal to bytes.len.
/// T specifies the return type, which must be large enough to store
/// the result.