ww/lib/bytes/index_test.ww

// Vectors mirror ref/hare/bytes/index.ha (task #5 @test conversion).

package bytes_test;

import bytes;

// ref/hare/bytes/index.ha:112.

@test fn index_byte_cases() void = {
	let a: [4]u8; a[0] = 1u8; a[1] = 3u8; a[2] = 3u8; a[3] = 7u8;
	match (bytes.index(a[0:4], 1u8)) {
	case let i: i32 => { assert(!(i != 0)); };
	case void => abort();
	};
	match (bytes.index(a[0:4], 3u8)) {
	case let i: i32 => { assert(!(i != 1)); };
	case void => abort();
	};
	match (bytes.index(a[0:4], 7u8)) {
	case let i: i32 => { assert(!(i != 3)); };
	case void => abort();
	};
	match (bytes.index(a[0:4], 42u8)) {
	case let i: i32 => abort();
	case void => void;
	};
	let z: [1]u8;
	match (bytes.index(z[0:0], 42u8)) {
	case let i: i32 => abort();
	case void => void;
	};
};

// ref/hare/bytes/index.ha:128-139. Vector strings copied verbatim where
// representable as ASCII byte sequences.

@test fn index_slice_cases() void = {
	let h1: [4]u8; h1[0] = 1u8; h1[1] = 42u8; h1[2] = 24u8; h1[3] = 0u8;
	let n1: [2]u8; n1[0] = 42u8; n1[1] = 24u8;
	match (bytes.index(h1[0:3], n1[0:2])) {
	case let i: i32 => { assert(!(i != 1)); };
	case void => abort();
	};

	let h2: [4]u8; h2[0] = 1u8; h2[1] = 3u8; h2[2] = 3u8; h2[3] = 7u8;
	let n2: [2]u8; n2[0] = 3u8; n2[1] = 3u8;
	match (bytes.index(h2[0:4], n2[0:2])) {
	case let i: i32 => { assert(!(i != 1)); };
	case void => abort();
	};

	// needle longer than haystack — void
	let h3: [3]u8; h3[0] = 1u8; h3[1] = 2u8; h3[2] = 3u8;
	let n3: [4]u8; n3[0] = 1u8; n3[1] = 2u8; n3[2] = 3u8; n3[3] = 4u8;
	match (bytes.index(h3[0:3], n3[0:4])) {
	case let i: i32 => abort();
	case void => void;
	};

	// len(haystack) == len(needle), match — offset 0
	let h4: [2]u8; h4[0] = 42u8; h4[1] = 20u8;
	let n4: [2]u8; n4[0] = 42u8; n4[1] = 20u8;
	match (bytes.index(h4[0:2], n4[0:2])) {
	case let i: i32 => { assert(!(i != 0)); };
	case void => abort();
	};

	// len(haystack) == len(needle), no match — void
	let h5: [4]u8; h5[0] = 1u8; h5[1] = 1u8; h5[2] = 1u8; h5[3] = 2u8;
	let n5: [4]u8; n5[0] = 1u8; n5[1] = 1u8; n5[2] = 1u8; n5[3] = 3u8;
	match (bytes.index(h5[0:4], n5[0:4])) {
	case let i: i32 => abort();
	case void => void;
	};

	// Partial-prefix recovery — needle [1,1,2] aligns at i=1 after the
	// false-start at i=0 ([1,1,1] mismatches at byte 2). Pins the
	// naive scanner's restart discipline.
	let h6: [4]u8; h6[0] = 1u8; h6[1] = 1u8; h6[2] = 1u8; h6[3] = 2u8;
	let n6s: [3]u8; n6s[0] = 1u8; n6s[1] = 1u8; n6s[2] = 2u8;
	match (bytes.index(h6[0:4], n6s[0:3])) {
	case let i: i32 => { assert(!(i != 1)); };
	case void => abort();
	};

	// Same shape, longer haystack with no match anywhere.
	let h7: [5]u8; h7[0] = 1u8; h7[1] = 1u8; h7[2] = 1u8; h7[3] = 3u8; h7[4] = 2u8;
	let n7: [4]u8; n7[0] = 1u8; n7[1] = 1u8; n7[2] = 1u8; n7[3] = 2u8;
	match (bytes.index(h7[0:5], n7[0:4])) {
	case let i: i32 => abort();
	case void => void;
	};

	// empty needle — Hare returns 0 (ref/hare/bytes/index.ha:63).
	let z: [1]u8;
	let zn: [1]u8;
	match (bytes.index(h2[0:4], zn[0:0])) {
	case let i: i32 => { assert(!(i != 0)); };
	case void => abort();
	};
	// empty haystack, non-empty needle — void
	match (bytes.index(z[0:0], n3[0:3])) {
	case let i: i32 => abort();
	case void => void;
	};

	// single-byte slice needle — should semantically equal u8 arm
	let n6: [1]u8; n6[0] = 7u8;
	match (bytes.index(h2[0:4], n6[0:1])) {
	case let i: i32 => { assert(!(i != 3)); };
	case void => abort();
	};

	// Periodic long needles exercise the two-way path's critical-period
	// memory. The first candidate shares a long prefix and must be skipped
	// without missing the later match; the second never matches.
	let hp: [18]u8;
	let np: [7]u8;
	let i: i32 = 0;
	for (i < 18) { hp[i] = 'a'; i += 1; };
	hp[8] = 'b'; hp[17] = 'b';
	i = 0;
	for (i < 6) { np[i] = 'a'; i += 1; };
	np[6] = 'b';
	match (bytes.index(hp[0:18], np[0:7])) {
	case let off: i32 => { assert(!(off != 2)); };
	case void => abort();
	};
	np[6] = 'c';
	match (bytes.index(hp[0:18], np[0:7])) {
	case let off: i32 => abort();
	case void => void;
	};
};

// ref/hare/bytes/index.ha:118.

@test fn rindex_byte_cases() void = {
	let a: [4]u8; a[0] = 1u8; a[1] = 3u8; a[2] = 3u8; a[3] = 7u8;
	match (bytes.rindex(a[0:4], 3u8)) {
	case let i: i32 => { assert(!(i != 2)); };
	case void => abort();
	};
	match (bytes.rindex(a[0:4], 42u8)) {
	case let i: i32 => abort();
	case void => void;
	};
	let z: [1]u8;
	match (bytes.rindex(z[0:0], 42u8)) {
	case let i: i32 => abort();
	case void => void;
	};
};

// ref/hare/bytes/index.ha:123-125. Distinguishes from index when the
// needle appears more than once.

@test fn rindex_slice_cases() void = {
	let a: [4]u8; a[0] = 1u8; a[1] = 1u8; a[2] = 1u8; a[3] = 2u8;
	let n11: [2]u8; n11[0] = 1u8; n11[1] = 1u8;
	match (bytes.rindex(a[0:4], n11[0:2])) {
	case let i: i32 => { assert(!(i != 1)); };
	case void => abort();
	};
	let n12: [2]u8; n12[0] = 1u8; n12[1] = 2u8;
	match (bytes.rindex(a[0:4], n12[0:2])) {
	case let i: i32 => { assert(!(i != 2)); };
	case void => abort();
	};
	// absent
	let n99: [2]u8; n99[0] = 9u8; n99[1] = 9u8;
	match (bytes.rindex(a[0:4], n99[0:2])) {
	case let i: i32 => abort();
	case void => void;
	};
};