authorgravatar for cartersnook04@gmail.comCarter Snook <cartersnook04@gmail.com> 2024-06-14 15:40:54-05:00
committergravatar for cartersnook04@gmail.comCarter Snook <cartersnook04@gmail.com> 2024-06-14 15:40:54-05:00
log56929795a8ce13792322486aa28de50c96865773
tree8a1193a5c63f092c92bc1ff2a00f263e1ec9a02e
parent82a934bb912241809ac8029e1fa5843092a7fdf6

std.unicode: add encode overflow check function and friends

1 files changed, 91 insertions(+), 25 deletions(-)

lib/std/unicode.zig+91-25
......@@ -1405,29 +1405,38 @@ test "ArrayList functions on a re-used list" {
14051405 }
14061406}
14071407
1408/// Converts a UTF-8 string literal into a UTF-16LE string literal.
1409pub fn utf8ToUtf16LeStringLiteral(comptime utf8: []const u8) *const [calcUtf16LeLen(utf8) catch |err| @compileError(err):0]u16 {
1408fn utf8ToUtf16LeStringLiteralImpl(comptime utf8: []const u8, comptime surrogates: Surrogates) *const [calcUtf16LeLenImpl(utf8, surrogates) catch |err| @compileError(err):0]u16 {
14101409 return comptime blk: {
1411 const len: usize = calcUtf16LeLen(utf8) catch unreachable;
1410 const len: usize = calcUtf16LeLenImpl(utf8, surrogates) catch unreachable;
14121411 var utf16le: [len:0]u16 = [_:0]u16{0} ** len;
1413 const utf16le_len = utf8ToUtf16Le(&utf16le, utf8[0..]) catch |err| @compileError(err);
1412 const utf16le_len = utf8ToUtf16LeImpl(&utf16le, utf8[0..], surrogates) catch |err| @compileError(err);
14141413 assert(len == utf16le_len);
14151414 const final = utf16le;
14161415 break :blk &final;
14171416 };
14181417}
14191418
1420const CalcUtf16LeLenError = Utf8DecodeError || error{Utf8InvalidStartByte};
1419/// Converts a UTF-8 string literal into a UTF-16LE string literal.
1420pub fn utf8ToUtf16LeStringLiteral(comptime utf8: []const u8) *const [calcUtf16LeLen(utf8) catch |err| @compileError(err):0]u16 {
1421 return utf8ToUtf16LeStringLiteralImpl(utf8, .cannot_encode_surrogate_half);
1422}
14211423
1422/// Returns length in UTF-16 of UTF-8 slice as length of []u16.
1423/// Length in []u8 is 2*len16.
1424pub fn calcUtf16LeLen(utf8: []const u8) CalcUtf16LeLenError!usize {
1424/// Converts a WTF-8 string literal into a WTF-16LE string literal.
1425pub fn wtf8ToWtf16LeStringLiteral(comptime wtf8: []const u8) *const [calcWtf16LeLen(wtf8) catch |err| @compileError(err):0]u16 {
1426 return utf8ToUtf16LeStringLiteralImpl(wtf8, .can_encode_surrogate_half);
1427}
1428
1429pub fn calcUtf16LeLenImpl(utf8: []const u8, comptime surrogates: Surrogates) !usize {
1430 const utf8DecodeImpl = switch (surrogates) {
1431 .cannot_encode_surrogate_half => utf8Decode,
1432 .can_encode_surrogate_half => wtf8Decode,
1433 };
14251434 var src_i: usize = 0;
14261435 var dest_len: usize = 0;
14271436 while (src_i < utf8.len) {
14281437 const n = try utf8ByteSequenceLength(utf8[src_i]);
14291438 const next_src_i = src_i + n;
1430 const codepoint = try utf8Decode(utf8[src_i..next_src_i]);
1439 const codepoint = try utf8DecodeImpl(utf8[src_i..next_src_i]);
14311440 if (codepoint < 0x10000) {
14321441 dest_len += 1;
14331442 } else {
......@@ -1438,16 +1447,37 @@ pub fn calcUtf16LeLen(utf8: []const u8) CalcUtf16LeLenError!usize {
14381447 return dest_len;
14391448}
14401449
1441fn testCalcUtf16LeLen() !void {
1442 try testing.expectEqual(@as(usize, 1), try calcUtf16LeLen("a"));
1443 try testing.expectEqual(@as(usize, 10), try calcUtf16LeLen("abcdefghij"));
1444 try testing.expectEqual(@as(usize, 10), try calcUtf16LeLen("äåéëþüúíóö"));
1445 try testing.expectEqual(@as(usize, 5), try calcUtf16LeLen("こんにちは"));
1450const CalcUtf16LeLenError = Utf8DecodeError || error{Utf8InvalidStartByte};
1451
1452/// Returns length in UTF-16LE of UTF-8 slice as length of []u16.
1453/// Length in []u8 is 2*len16.
1454pub fn calcUtf16LeLen(utf8: []const u8) CalcUtf16LeLenError!usize {
1455 return calcUtf16LeLenImpl(utf8, .cannot_encode_surrogate_half);
1456}
1457
1458const CalcWtf16LeLenError = Wtf8DecodeError || error{Utf8InvalidStartByte};
1459
1460/// Returns length in WTF-16LE of WTF-8 slice as length of []u16.
1461/// Length in []u8 is 2*len16.
1462pub fn calcWtf16LeLen(wtf8: []const u8) CalcWtf16LeLenError!usize {
1463 return calcUtf16LeLenImpl(wtf8, .can_encode_surrogate_half);
14461464}
14471465
1448test "calculate utf16 string length of given utf8 string in u16" {
1449 try testCalcUtf16LeLen();
1450 try comptime testCalcUtf16LeLen();
1466fn testCalcUtf16LeLenImpl(calcUtf16LeLenImpl_: anytype) !void {
1467 try testing.expectEqual(@as(usize, 1), try calcUtf16LeLenImpl_("a"));
1468 try testing.expectEqual(@as(usize, 10), try calcUtf16LeLenImpl_("abcdefghij"));
1469 try testing.expectEqual(@as(usize, 10), try calcUtf16LeLenImpl_("äåéëþüúíóö"));
1470 try testing.expectEqual(@as(usize, 5), try calcUtf16LeLenImpl_("こんにちは"));
1471}
1472
1473test calcUtf16LeLen {
1474 try testCalcUtf16LeLenImpl(calcUtf16LeLen);
1475 try comptime testCalcUtf16LeLenImpl(calcUtf16LeLen);
1476}
1477
1478test calcWtf16LeLen {
1479 try testCalcUtf16LeLenImpl(calcWtf16LeLen);
1480 try comptime testCalcUtf16LeLenImpl(calcWtf16LeLen);
14511481}
14521482
14531483/// Print the given `utf16le` string, encoded as UTF-8 bytes.
......@@ -1487,8 +1517,10 @@ pub fn fmtUtf16Le(utf16le: []const u16) std.fmt.Formatter(formatUtf16Le) {
14871517test fmtUtf16Le {
14881518 const expectFmt = testing.expectFmt;
14891519 try expectFmt("", "{}", .{fmtUtf16Le(utf8ToUtf16LeStringLiteral(""))});
1520 try expectFmt("", "{}", .{fmtUtf16Le(wtf8ToWtf16LeStringLiteral(""))});
14901521 try expectFmt("foo", "{}", .{fmtUtf16Le(utf8ToUtf16LeStringLiteral("foo"))});
1491 try expectFmt("𐐷", "{}", .{fmtUtf16Le(utf8ToUtf16LeStringLiteral("𐐷"))});
1522 try expectFmt("foo", "{}", .{fmtUtf16Le(wtf8ToWtf16LeStringLiteral("foo"))});
1523 try expectFmt("𐐷", "{}", .{fmtUtf16Le(wtf8ToWtf16LeStringLiteral("𐐷"))});
14921524 try expectFmt("퟿", "{}", .{fmtUtf16Le(&[_]u16{mem.readInt(u16, "\xff\xd7", native_endian)})});
14931525 try expectFmt("�", "{}", .{fmtUtf16Le(&[_]u16{mem.readInt(u16, "\x00\xd8", native_endian)})});
14941526 try expectFmt("�", "{}", .{fmtUtf16Le(&[_]u16{mem.readInt(u16, "\xff\xdb", native_endian)})});
......@@ -1497,12 +1529,12 @@ test fmtUtf16Le {
14971529 try expectFmt("", "{}", .{fmtUtf16Le(&[_]u16{mem.readInt(u16, "\x00\xe0", native_endian)})});
14981530}
14991531
1500test utf8ToUtf16LeStringLiteral {
1532fn testUtf8ToUtf16LeStringLiteral(utf8ToUtf16LeStringLiteral_: anytype) !void {
15011533 {
15021534 const bytes = [_:0]u16{
15031535 mem.nativeToLittle(u16, 0x41),
15041536 };
1505 const utf16 = utf8ToUtf16LeStringLiteral("A");
1537 const utf16 = utf8ToUtf16LeStringLiteral_("A");
15061538 try testing.expectEqualSlices(u16, &bytes, utf16);
15071539 try testing.expect(utf16[1] == 0);
15081540 }
......@@ -1511,7 +1543,7 @@ test utf8ToUtf16LeStringLiteral {
15111543 mem.nativeToLittle(u16, 0xD801),
15121544 mem.nativeToLittle(u16, 0xDC37),
15131545 };
1514 const utf16 = utf8ToUtf16LeStringLiteral("𐐷");
1546 const utf16 = utf8ToUtf16LeStringLiteral_("𐐷");
15151547 try testing.expectEqualSlices(u16, &bytes, utf16);
15161548 try testing.expect(utf16[2] == 0);
15171549 }
......@@ -1519,7 +1551,7 @@ test utf8ToUtf16LeStringLiteral {
15191551 const bytes = [_:0]u16{
15201552 mem.nativeToLittle(u16, 0x02FF),
15211553 };
1522 const utf16 = utf8ToUtf16LeStringLiteral("\u{02FF}");
1554 const utf16 = utf8ToUtf16LeStringLiteral_("\u{02FF}");
15231555 try testing.expectEqualSlices(u16, &bytes, utf16);
15241556 try testing.expect(utf16[1] == 0);
15251557 }
......@@ -1527,7 +1559,7 @@ test utf8ToUtf16LeStringLiteral {
15271559 const bytes = [_:0]u16{
15281560 mem.nativeToLittle(u16, 0x7FF),
15291561 };
1530 const utf16 = utf8ToUtf16LeStringLiteral("\u{7FF}");
1562 const utf16 = utf8ToUtf16LeStringLiteral_("\u{7FF}");
15311563 try testing.expectEqualSlices(u16, &bytes, utf16);
15321564 try testing.expect(utf16[1] == 0);
15331565 }
......@@ -1535,7 +1567,7 @@ test utf8ToUtf16LeStringLiteral {
15351567 const bytes = [_:0]u16{
15361568 mem.nativeToLittle(u16, 0x801),
15371569 };
1538 const utf16 = utf8ToUtf16LeStringLiteral("\u{801}");
1570 const utf16 = utf8ToUtf16LeStringLiteral_("\u{801}");
15391571 try testing.expectEqualSlices(u16, &bytes, utf16);
15401572 try testing.expect(utf16[1] == 0);
15411573 }
......@@ -1544,12 +1576,20 @@ test utf8ToUtf16LeStringLiteral {
15441576 mem.nativeToLittle(u16, 0xDBFF),
15451577 mem.nativeToLittle(u16, 0xDFFF),
15461578 };
1547 const utf16 = utf8ToUtf16LeStringLiteral("\u{10FFFF}");
1579 const utf16 = utf8ToUtf16LeStringLiteral_("\u{10FFFF}");
15481580 try testing.expectEqualSlices(u16, &bytes, utf16);
15491581 try testing.expect(utf16[2] == 0);
15501582 }
15511583}
15521584
1585test utf8ToUtf16LeStringLiteral {
1586 try testUtf8ToUtf16LeStringLiteral(utf8ToUtf16LeStringLiteral);
1587}
1588
1589test wtf8ToWtf16LeStringLiteral {
1590 try testUtf8ToUtf16LeStringLiteral(wtf8ToWtf16LeStringLiteral);
1591}
1592
15531593fn testUtf8CountCodepoints() !void {
15541594 try testing.expectEqual(@as(usize, 10), try utf8CountCodepoints("abcdefghij"));
15551595 try testing.expectEqual(@as(usize, 10), try utf8CountCodepoints("äåéëþüúíóö"));
......@@ -1795,6 +1835,30 @@ pub fn wtf8ToWtf16Le(wtf16le: []u16, wtf8: []const u8) error{InvalidWtf8}!usize
17951835 return utf8ToUtf16LeImpl(wtf16le, wtf8, .can_encode_surrogate_half);
17961836}
17971837
1838fn checkUtf8ToUtf16LeOverflowImpl(utf8: []const u8, utf16le: []const u16, comptime surrogates: Surrogates) !bool {
1839 // Each u8 in UTF-8/WTF-8 correlates to at most one u16 in UTF-16LE/WTF-16LE.
1840 if (utf16le.len >= utf8.len) return false;
1841 const utf16_len = calcUtf16LeLenImpl(utf8, surrogates) catch {
1842 return switch (surrogates) {
1843 .cannot_encode_surrogate_half => error.InvalidUtf8,
1844 .can_encode_surrogate_half => error.InvalidWtf8,
1845 };
1846 };
1847 return utf16_len > utf16le.len;
1848}
1849
1850/// Checks if calling `utf8ToUtf16Le` would overflow. Might fail if utf8 is not
1851/// valid UTF-8.
1852pub fn checkUtf8ToUtf16LeOverflow(utf8: []const u8, utf16le: []const u16) error{InvalidUtf8}!bool {
1853 return checkUtf8ToUtf16LeOverflowImpl(utf8, utf16le, .cannot_encode_surrogate_half);
1854}
1855
1856/// Checks if calling `utf8ToUtf16Le` would overflow. Might fail if wtf8 is not
1857/// valid WTF-8.
1858pub fn checkWtf8ToWtf16LeOverflow(wtf8: []const u8, wtf16le: []const u16) error{InvalidWtf8}!bool {
1859 return checkUtf8ToUtf16LeOverflowImpl(wtf8, wtf16le, .can_encode_surrogate_half);
1860}
1861
17981862/// Surrogate codepoints (U+D800 to U+DFFF) are replaced by the Unicode replacement
17991863/// character (U+FFFD).
18001864/// All surrogate codepoints and the replacement character are encoded as three
......@@ -2000,6 +2064,8 @@ fn testRoundtripWtf8(wtf8: []const u8) !void {
20002064 {
20012065 var wtf16_buf: [32]u16 = undefined;
20022066 const wtf16_len = try wtf8ToWtf16Le(&wtf16_buf, wtf8);
2067 try testing.expectEqual(wtf16_len, calcWtf16LeLen(wtf8));
2068 try testing.expectEqual(false, checkWtf8ToWtf16LeOverflow(wtf8, &wtf16_buf));
20032069 const wtf16 = wtf16_buf[0..wtf16_len];
20042070
20052071 var roundtripped_buf: [32]u8 = undefined;