1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543
//! C-style wide string slices.
//!
//! This module contains the [`UCStr`] string slices and related types.
use crate::{
error::{ContainsNul, MissingNulTerminator, NulError},
iter::{CharsLossy, Utf16CharIndices, Utf16CharIndicesLossy, Utf16Chars, Utf32Chars},
UChar, UStr, WideChar,
};
#[cfg(feature = "alloc")]
use alloc::{
borrow::ToOwned,
boxed::Box,
string::{FromUtf16Error, String},
};
use core::{fmt::Write, ops::Range, slice};
/// C-style wide string reference for [`UCString`][crate::UCString].
///
/// [`UCStr`] is aware of nul values. Unless unchecked conversions are used, all [`UCStr`]
/// strings end with a nul-terminator in the underlying buffer and contain no internal nul values.
/// The strings may still contain invalid or ill-formed UTF-16 or UTF-32 data. These strings are
/// intended to be used with FFI functions such as Windows API that may require nul-terminated
/// strings.
///
/// [`UCStr`] can be converted to and from many other string types, including
/// [`UString`][crate::UString], [`OsString`][std::ffi::OsString], and [`String`], making proper
/// Unicode FFI safe and easy.
///
/// Please prefer using the type aliases [`U16CStr`], [`U32CStr`], or [`WideCStr`] to using
/// [`UCStr`] directly.
#[derive(PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct UCStr<C> {
inner: [C],
}
impl<C: UChar> UCStr<C> {
/// Coerces a value into a [`UCStr`].
#[inline]
pub fn new<S: AsRef<UCStr<C>> + ?Sized>(s: &S) -> &Self {
s.as_ref()
}
/// Constructs a [`UCStr`] from a nul-terminated string pointer.
///
/// This will scan for nul values beginning with `p`. The first nul value will be used as the
/// nul terminator for the string, similar to how libc string functions such as `strlen` work.
///
/// # Safety
///
/// This function is unsafe as there is no guarantee that the given pointer is valid or has a
/// nul terminator, and the function could scan past the underlying buffer.
///
/// In addition, the data must meet the safety conditions of [std::slice::from_raw_parts].
/// In particular, the returned string reference *must not be mutated* for the duration of
/// lifetime `'a`, except inside an [`UnsafeCell`][std::cell::UnsafeCell].
///
/// # Panics
///
/// This function panics if `p` is null.
///
/// # Caveat
///
/// The lifetime for the returned string is inferred from its usage. To prevent accidental
/// misuse, it's suggested to tie the lifetime to whichever source lifetime is safe in the
/// context, such as by providing a helper function taking the lifetime of a host value for the
/// string, or by explicit annotation.
pub unsafe fn from_ptr_str<'a>(p: *const C) -> &'a Self {
assert!(!p.is_null());
let mut i = 0;
while *p.add(i) != UChar::NUL {
i += 1;
}
Self::from_ptr_unchecked(p, i)
}
/// Constructs a mutable [`UCStr`] from a mutable nul-terminated string pointer.
///
/// This will scan for nul values beginning with `p`. The first nul value will be used as the
/// nul terminator for the string, similar to how libc string functions such as `strlen` work.
///
/// # Safety
///
/// This function is unsafe as there is no guarantee that the given pointer is valid or has a
/// nul terminator, and the function could scan past the underlying buffer.
///
/// In addition, the data must meet the safety conditions of [std::slice::from_raw_parts_mut].
///
/// # Panics
///
/// This function panics if `p` is null.
///
/// # Caveat
///
/// The lifetime for the returned string is inferred from its usage. To prevent accidental
/// misuse, it's suggested to tie the lifetime to whichever source lifetime is safe in the
/// context, such as by providing a helper function taking the lifetime of a host value for the
/// string, or by explicit annotation.
pub unsafe fn from_ptr_str_mut<'a>(p: *mut C) -> &'a mut Self {
assert!(!p.is_null());
let mut i = 0;
while *p.add(i) != UChar::NUL {
i += 1;
}
Self::from_ptr_unchecked_mut(p, i)
}
/// Constructs a [`UCStr`] from a pointer and a length.
///
/// The `len` argument is the number of elements, **not** the number of bytes, and does
/// **not** include the nul terminator of the string. Thus, a `len` of 0 is valid and means
/// that `p` is a pointer directly to the nul terminator of the string.
///
/// # Errors
///
/// This will scan the pointer string for an interior nul value and error if one is found
/// before the nul terminator at `len` offset. To avoid scanning for interior nuls,
/// [`from_ptr_unchecked`][Self::from_ptr_unchecked] may be used instead.
///
/// An error is returned if the value at `len` offset is not a nul terminator.
///
/// # Safety
///
/// This function is unsafe as there is no guarantee that the given pointer is valid for `len +
/// 1` elements.
///
/// In addition, the data must meet the safety conditions of [std::slice::from_raw_parts].
/// In particular, the returned string reference *must not be mutated* for the duration of
/// lifetime `'a`, except inside an [`UnsafeCell`][std::cell::UnsafeCell].
///
/// # Panics
///
/// This function panics if `p` is null.
///
/// # Caveat
///
/// The lifetime for the returned string is inferred from its usage. To prevent accidental
/// misuse, it's suggested to tie the lifetime to whichever source lifetime is safe in the
/// context, such as by providing a helper function taking the lifetime of a host value for the
/// string, or by explicit annotation.
pub unsafe fn from_ptr<'a>(p: *const C, len: usize) -> Result<&'a Self, NulError<C>> {
assert!(!p.is_null());
if *p.add(len) != UChar::NUL {
return Err(MissingNulTerminator::new().into());
}
for i in 0..len {
if *p.add(i) == UChar::NUL {
return Err(ContainsNul::empty(i).into());
}
}
Ok(Self::from_ptr_unchecked(p, len))
}
/// Constructs a mutable [`UCStr`] from a mutable pointer and a length.
///
/// The `len` argument is the number of elements, **not** the number of bytes, and does
/// **not** include the nul terminator of the string. Thus, a `len` of 0 is valid and means
/// that `p` is a pointer directly to the nul terminator of the string.
///
/// # Errors
///
/// This will scan the pointer string for an interior nul value and error if one is found
/// before the nul terminator at `len` offset. To avoid scanning for interior nuls,
/// [`from_ptr_unchecked_mut`][Self::from_ptr_unchecked_mut] may be used instead.
///
/// An error is returned if the value at `len` offset is not a nul terminator.
///
/// # Safety
///
/// This function is unsafe as there is no guarantee that the given pointer is valid for `len +
/// 1` elements.
///
/// In addition, the data must meet the safety conditions of [std::slice::from_raw_parts_mut].
///
/// # Panics
///
/// This function panics if `p` is null.
///
/// # Caveat
///
/// The lifetime for the returned string is inferred from its usage. To prevent accidental
/// misuse, it's suggested to tie the lifetime to whichever source lifetime is safe in the
/// context, such as by providing a helper function taking the lifetime of a host value for the
/// string, or by explicit annotation.
pub unsafe fn from_ptr_mut<'a>(p: *mut C, len: usize) -> Result<&'a mut Self, NulError<C>> {
assert!(!p.is_null());
if *p.add(len) != UChar::NUL {
return Err(MissingNulTerminator::new().into());
}
for i in 0..len {
if *p.add(i) == UChar::NUL {
return Err(ContainsNul::empty(i).into());
}
}
Ok(Self::from_ptr_unchecked_mut(p, len))
}
/// Constructs a [`UCStr`] from a pointer and a length, truncating at the first nul terminator.
///
/// The `len` argument is the number of elements, **not** the number of bytes. This will scan
/// for nul values beginning with `p` until offset `len`. The first nul value will be used as
/// the nul terminator for the string, ignoring any remaining values left before `len`.
///
/// # Errors
///
/// If no nul terminator is found after `len` + 1 elements, an error is returned.
///
/// # Safety
///
/// This function is unsafe as there is no guarantee that the given pointer is valid or has a
/// nul terminator, and the function could scan past the underlying buffer.
///
/// In addition, the data must meet the safety conditions of [std::slice::from_raw_parts].
/// In particular, the returned string reference *must not be mutated* for the duration of
/// lifetime `'a`, except inside an [`UnsafeCell`][std::cell::UnsafeCell].
///
/// # Panics
///
/// This function panics if `p` is null.
///
/// # Caveat
///
/// The lifetime for the returned string is inferred from its usage. To prevent accidental
/// misuse, it's suggested to tie the lifetime to whichever source lifetime is safe in the
/// context, such as by providing a helper function taking the lifetime of a host value for the
/// string, or by explicit annotation.
pub unsafe fn from_ptr_truncate<'a>(
p: *const C,
len: usize,
) -> Result<&'a Self, MissingNulTerminator> {
assert!(!p.is_null());
for i in 0..=len {
if *p.add(i) == UChar::NUL {
return Ok(Self::from_ptr_unchecked(p, i));
}
}
Err(MissingNulTerminator::new())
}
/// Constructs a mutable [`UCStr`] from a mutable pointer and a length, truncating at the first
/// nul terminator.
///
/// The `len` argument is the number of elements, **not** the number of bytes. This will scan
/// for nul values beginning with `p` until offset `len`. The first nul value will be used as
/// the nul terminator for the string, ignoring any remaining values left before `len`.
///
/// # Errors
///
/// If no nul terminator is found after `len` + 1 elements, an error is returned.
///
/// # Safety
///
/// This function is unsafe as there is no guarantee that the given pointer is valid or has a
/// nul terminator, and the function could scan past the underlying buffer.
///
/// In addition, the data must meet the safety conditions of [std::slice::from_raw_parts_mut].
///
/// # Panics
///
/// This function panics if `p` is null.
///
/// # Caveat
///
/// The lifetime for the returned string is inferred from its usage. To prevent accidental
/// misuse, it's suggested to tie the lifetime to whichever source lifetime is safe in the
/// context, such as by providing a helper function taking the lifetime of a host value for the
/// string, or by explicit annotation.
pub unsafe fn from_ptr_truncate_mut<'a>(
p: *mut C,
len: usize,
) -> Result<&'a mut Self, MissingNulTerminator> {
assert!(!p.is_null());
for i in 0..=len {
if *p.add(i) == UChar::NUL {
return Ok(Self::from_ptr_unchecked_mut(p, i));
}
}
Err(MissingNulTerminator::new())
}
/// Constructs a [`UCStr`] from a pointer and a length without checking for any nul values.
///
/// The `len` argument is the number of elements, **not** the number of bytes, and does
/// **not** include the nul terminator of the string. Thus, a `len` of 0 is valid and means
/// that `p` is a pointer directly to the nul terminator of the string.
///
/// # Safety
///
/// This function is unsafe as there is no guarantee that the given pointer is valid for `len +
/// 1` elements, nor that it has a terminating nul value.
///
/// In addition, the data must meet the safety conditions of [std::slice::from_raw_parts].
/// In particular, the returned string reference *must not be mutated* for the duration of
/// lifetime `'a`, except inside an [`UnsafeCell`][std::cell::UnsafeCell].
///
/// The interior values of the pointer are not scanned for nul. Any interior nul values or
/// a missing nul terminator at pointer offset `len` + 1 will result in an invalid [`UCStr`].
///
/// # Panics
///
/// This function panics if `p` is null.
///
/// # Caveat
///
/// The lifetime for the returned string is inferred from its usage. To prevent accidental
/// misuse, it's suggested to tie the lifetime to whichever source lifetime is safe in the
/// context, such as by providing a helper function taking the lifetime of a host value for the
/// string, or by explicit annotation.
pub unsafe fn from_ptr_unchecked<'a>(p: *const C, len: usize) -> &'a Self {
assert!(!p.is_null());
let ptr: *const [C] = slice::from_raw_parts(p, len + 1);
&*(ptr as *const Self)
}
/// Constructs a mutable [`UCStr`] from a mutable pointer and a length without checking for any
/// nul values.
///
/// The `len` argument is the number of elements, **not** the number of bytes, and does
/// **not** include the nul terminator of the string. Thus, a `len` of 0 is valid and means
/// that `p` is a pointer directly to the nul terminator of the string.
///
/// # Safety
///
/// This function is unsafe as there is no guarantee that the given pointer is valid for `len +
/// 1` elements, nor that is has a terminating nul value.
///
/// In addition, the data must meet the safety conditions of [std::slice::from_raw_parts_mut].
///
/// The interior values of the pointer are not scanned for nul. Any interior nul values or
/// a missing nul terminator at pointer offset `len` + 1 will result in an invalid [`UCStr`].
///
/// # Panics
///
/// This function panics if `p` is null.
///
/// # Caveat
///
/// The lifetime for the returned string is inferred from its usage. To prevent accidental
/// misuse, it's suggested to tie the lifetime to whichever source lifetime is safe in the
/// context, such as by providing a helper function taking the lifetime of a host value for the
/// string, or by explicit annotation.
pub unsafe fn from_ptr_unchecked_mut<'a>(p: *mut C, len: usize) -> &'a mut Self {
assert!(!p.is_null());
let ptr: *mut [C] = slice::from_raw_parts_mut(p, len + 1);
&mut *(ptr as *mut Self)
}
/// Constructs a [`UCStr`] from a slice of values with a terminating nul, checking for invalid
/// interior nul values.
///
/// The slice must have at least one item, the nul terminator, even for an empty string.
///
/// # Errors
///
/// If there are nul values in the slice except for the last value, an error is returned.
///
/// An error is also returned if the last value of the slice is not a nul terminator.
pub fn from_slice(slice: &[C]) -> Result<&Self, NulError<C>> {
if slice.last() != Some(&UChar::NUL) {
return Err(MissingNulTerminator::new().into());
}
match slice[..slice.len() - 1]
.iter()
.position(|x| *x == UChar::NUL)
{
None => Ok(unsafe { Self::from_slice_unchecked(slice) }),
Some(i) => Err(ContainsNul::empty(i).into()),
}
}
/// Constructs a mutable [`UCStr`] from a mutable slice of values with a terminating nul,
/// checking for invalid interior nul values.
///
/// The slice must have at least one item, the nul terminator, even for an empty string.
///
/// # Errors
///
/// If there are nul values in the slice except for the last value, an error is returned.
///
/// An error is also returned if the last value of the slice is not a nul terminator.
pub fn from_slice_mut(slice: &mut [C]) -> Result<&mut Self, NulError<C>> {
if slice.last() != Some(&UChar::NUL) {
return Err(MissingNulTerminator::new().into());
}
match slice[..slice.len() - 1]
.iter()
.position(|x| *x == UChar::NUL)
{
None => Ok(unsafe { Self::from_slice_unchecked_mut(slice) }),
Some(i) => Err(ContainsNul::empty(i).into()),
}
}
/// Constructs a [`UCStr`] from a slice of values, truncating at the first nul terminator.
///
/// The slice will be scanned for nul values. When a nul value is found, it is treated as the
/// terminator for the string, and the [`UCStr`] slice will be truncated to that nul.
///
/// # Errors
///
/// If there are no nul values in the slice, an error is returned.
pub fn from_slice_truncate(slice: &[C]) -> Result<&Self, MissingNulTerminator> {
match slice.iter().position(|x| *x == UChar::NUL) {
None => Err(MissingNulTerminator::new()),
Some(i) => Ok(unsafe { Self::from_slice_unchecked(&slice[..i + 1]) }),
}
}
/// Constructs a mutable [`UCStr`] from a mutable slice of values, truncating at the first nul
/// terminator.
///
/// The slice will be scanned for nul values. When a nul value is found, it is treated as the
/// terminator for the string, and the [`UCStr`] slice will be truncated to that nul.
///
/// # Errors
///
/// If there are no nul values in the slice, an error is returned.
pub fn from_slice_truncate_mut(slice: &mut [C]) -> Result<&mut Self, MissingNulTerminator> {
match slice.iter().position(|x| *x == UChar::NUL) {
None => Err(MissingNulTerminator::new()),
Some(i) => Ok(unsafe { Self::from_slice_unchecked_mut(&mut slice[..i + 1]) }),
}
}
/// Constructs a [`UCStr`] from a slice of values without checking for a terminating or interior
/// nul values.
///
/// # Safety
///
/// This function is unsafe because it can lead to invalid [`UCStr`] values when the slice
/// is missing a terminating nul value or there are non-terminating interior nul values
/// in the slice. In particular, an empty slice will result in an invalid [`UCStr`].
pub unsafe fn from_slice_unchecked(slice: &[C]) -> &Self {
let ptr: *const [C] = slice;
&*(ptr as *const Self)
}
/// Constructs a mutable [`UCStr`] from a mutable slice of values without checking for a
/// terminating or interior nul values.
///
/// # Safety
///
/// This function is unsafe because it can lead to invalid [`UCStr`] values when the slice
/// is missing a terminating nul value or there are non-terminating interior nul values
/// in the slice. In particular, an empty slice will result in an invalid [`UCStr`].
pub unsafe fn from_slice_unchecked_mut(slice: &mut [C]) -> &mut Self {
let ptr: *mut [C] = slice;
&mut *(ptr as *mut Self)
}
/// Copies the string reference to a new owned [`UCString`][crate::UCString].
#[inline]
#[cfg(feature = "alloc")]
#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
pub fn to_ucstring(&self) -> crate::UCString<C> {
unsafe { crate::UCString::from_vec_unchecked(self.inner.to_owned()) }
}
/// Copies the string reference to a new owned [`UString`][crate::UString].
///
/// The resulting [`UString`][crate::UString] will **not** have a nul terminator
///
/// # Examples
///
/// ```rust
/// use widestring::U16CString;
/// let wcstr = U16CString::from_str("MyString").unwrap();
/// // Convert U16CString to a U16String
/// let wstr = wcstr.to_ustring();
///
/// // U16CString will have a terminating nul
/// let wcvec = wcstr.into_vec_with_nul();
/// assert_eq!(wcvec[wcvec.len()-1], 0);
/// // The resulting U16String will not have the terminating nul
/// let wvec = wstr.into_vec();
/// assert_ne!(wvec[wvec.len()-1], 0);
/// ```
///
/// ```rust
/// use widestring::U32CString;
/// let wcstr = U32CString::from_str("MyString").unwrap();
/// // Convert U32CString to a U32String
/// let wstr = wcstr.to_ustring();
///
/// // U32CString will have a terminating nul
/// let wcvec = wcstr.into_vec_with_nul();
/// assert_eq!(wcvec[wcvec.len()-1], 0);
/// // The resulting U32String will not have the terminating nul
/// let wvec = wstr.into_vec();
/// assert_ne!(wvec[wvec.len()-1], 0);
/// ```
#[inline]
#[cfg(feature = "alloc")]
#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
pub fn to_ustring(&self) -> crate::UString<C> {
crate::UString::from_vec(self.as_slice())
}
/// Converts to a slice of the underlying code units.
///
/// The slice will **not** include the nul terminator.
#[inline]
pub fn as_slice(&self) -> &[C] {
&self.inner[..self.len()]
}
/// Converts to a mutable slice of the underlying code units.
///
/// The slice will **not** include the nul terminator.
///
/// # Safety
///
/// This method is unsafe because you can violate the invariants of this type when mutating the
/// slice (i.e. by adding interior nul values).
#[inline]
pub unsafe fn as_mut_slice(&mut self) -> &mut [C] {
let len = self.len();
&mut self.inner[..len]
}
/// Converts to a slice of the underlying code units, including the nul terminator.
#[inline]
pub fn as_slice_with_nul(&self) -> &[C] {
&self.inner
}
/// Returns a raw pointer to the string.
///
/// The caller must ensure that the string outlives the pointer this function returns, or else
/// it will end up pointing to garbage.
///
/// The caller must also ensure that the memory the pointer (non-transitively) points to is
/// never written to (except inside an `UnsafeCell`) using this pointer or any pointer derived
/// from it. If you need to mutate the contents of the string, use
/// [`as_mut_ptr`][Self::as_mut_ptr].
///
/// Modifying the container referenced by this string may cause its buffer to be reallocated,
/// which would also make any pointers to it invalid.
#[inline]
pub fn as_ptr(&self) -> *const C {
self.inner.as_ptr()
}
/// Returns a mutable raw pointer to the string.
///
/// The caller must ensure that the string outlives the pointer this function returns, or else
/// it will end up pointing to garbage.
///
/// Modifying the container referenced by this string may cause its buffer to be reallocated,
/// which would also make any pointers to it invalid.
///
/// # Safety
///
/// This method is unsafe because you can violate the invariants of this type when mutating the
/// memory the pointer points to (i.e. by adding interior nul values).
#[inline]
pub unsafe fn as_mut_ptr(&mut self) -> *mut C {
self.inner.as_mut_ptr()
}
/// Returns the two raw pointers spanning the string slice.
///
/// The returned range is half-open, which means that the end pointer points one past the last
/// element of the slice. This way, an empty slice is represented by two equal pointers, and the
/// difference between the two pointers represents the size of the slice.
///
/// See [`as_ptr`][Self::as_ptr] for warnings on using these pointers. The end pointer requires
/// extra caution, as it does not point to a valid element in the slice.
///
/// This function is useful for interacting with foreign interfaces which use two pointers to
/// refer to a range of elements in memory, as is common in C++.
#[inline]
pub fn as_ptr_range(&self) -> Range<*const C> {
self.inner.as_ptr_range()
}
/// Returns the two unsafe mutable pointers spanning the string slice.
///
/// The returned range is half-open, which means that the end pointer points one past the last
/// element of the slice. This way, an empty slice is represented by two equal pointers, and the
/// difference between the two pointers represents the size of the slice.
///
/// See [`as_mut_ptr`][Self::as_mut_ptr] for warnings on using these pointers. The end pointer requires
/// extra caution, as it does not point to a valid element in the slice.
///
/// This function is useful for interacting with foreign interfaces which use two pointers to
/// refer to a range of elements in memory, as is common in C++.
#[inline]
pub fn as_mut_ptr_range(&mut self) -> Range<*mut C> {
self.inner.as_mut_ptr_range()
}
/// Returns the length of the string as number of elements (**not** number of bytes)
/// **not** including nul terminator.
#[inline]
pub fn len(&self) -> usize {
self.inner.len() - 1
}
/// Returns whether this string contains no data (i.e. is only the nul terminator).
#[inline]
pub fn is_empty(&self) -> bool {
self.len() == 0
}
/// Converts a [`Box<UCStr>`] into a [`UCString`][crate::UCString] without copying or
/// allocating.
///
/// # Examples
///
/// ```
/// use widestring::U16CString;
///
/// let v = vec![102u16, 111u16, 111u16]; // "foo"
/// let c_string = U16CString::from_vec(v.clone()).unwrap();
/// let boxed = c_string.into_boxed_ucstr();
/// assert_eq!(boxed.into_ucstring(), U16CString::from_vec(v).unwrap());
/// ```
///
/// ```
/// use widestring::U32CString;
///
/// let v = vec![102u32, 111u32, 111u32]; // "foo"
/// let c_string = U32CString::from_vec(v.clone()).unwrap();
/// let boxed = c_string.into_boxed_ucstr();
/// assert_eq!(boxed.into_ucstring(), U32CString::from_vec(v).unwrap());
/// ```
#[cfg(feature = "alloc")]
#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
pub fn into_ucstring(self: Box<Self>) -> crate::UCString<C> {
let raw = Box::into_raw(self) as *mut [C];
crate::UCString {
inner: unsafe { Box::from_raw(raw) },
}
}
/// Returns a [`UStr`] reference to this string reference.
///
/// The [`UStr`] reference will not include the nul-terminator.
#[inline]
pub fn as_ustr(&self) -> &UStr<C> {
UStr::from_slice(self.as_slice())
}
/// Returns a [`UStr`] reference to this string reference.
///
/// The [`UStr`] reference will include the nul-terminator.
#[inline]
pub fn as_ustr_with_nul(&self) -> &UStr<C> {
UStr::from_slice(self.as_slice())
}
/// Returns a mutable [`UStr`] reference to this string reference.
///
/// The [`UStr`] reference will not include the nul-terminator.
///
/// # Safety
///
/// This method is unsafe because you can violate the invariants of this type when mutating the
/// string (i.e. by adding interior nul values).
#[inline]
pub unsafe fn as_mut_ustr(&mut self) -> &mut UStr<C> {
UStr::from_slice_mut(self.as_mut_slice())
}
#[doc(hidden)]
#[deprecated = "use `from_ptr_unchecked` instead"]
pub unsafe fn from_ptr_with_nul<'a>(p: *const C, len: usize) -> &'a Self {
Self::from_ptr_unchecked(p, len)
}
#[allow(deprecated)]
#[doc(hidden)]
#[deprecated = "use `from_slice_truncate` instead"]
pub fn from_slice_with_nul(slice: &[C]) -> Result<&Self, crate::MissingNulError> {
Self::from_slice_truncate(slice)
}
#[doc(hidden)]
#[deprecated = "use `from_slice_unchecked` instead"]
pub unsafe fn from_slice_with_nul_unchecked(slice: &[C]) -> &Self {
Self::from_slice_unchecked(slice)
}
#[cfg(feature = "alloc")]
pub(crate) fn from_inner(slice: &[C]) -> &UCStr<C> {
let ptr: *const [C] = slice;
unsafe { &*(ptr as *const UCStr<C>) }
}
#[cfg(feature = "alloc")]
pub(crate) fn from_inner_mut(slice: &mut [C]) -> &mut UCStr<C> {
let ptr: *mut [C] = slice;
unsafe { &mut *(ptr as *mut UCStr<C>) }
}
/// Returns an object that implements [`Display`][std::fmt::Display] for printing strings that
/// may contain non-Unicode data.
///
/// A [`UCStr`] might contain ill-formed UTF encoding. This struct implements the
/// [`Display`][std::fmt::Display] trait in a way that decoding the string is lossy but no heap
/// allocations are performed, such as by [`to_string_lossy`][UCStr::to_string_lossy].
///
/// By default, invalid Unicode data is replaced with
/// [`U+FFFD REPLACEMENT CHARACTER`][std::char::REPLACEMENT_CHARACTER] (�). If you wish to simply
/// skip any invalid Uncode data and forego the replacement, you may use the
/// [alternate formatting][std::fmt#sign0] with `{:#}`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// use widestring::U16CStr;
///
/// // 𝄞mus<invalid>ic<invalid>
/// let s = U16CStr::from_slice(&[
/// 0xD834, 0xDD1E, 0x006d, 0x0075, 0x0073, 0xDD1E, 0x0069, 0x0063, 0xD834, 0x0000,
/// ]).unwrap();
///
/// assert_eq!(format!("{}", s.display()),
/// "𝄞mus�ic�"
/// );
/// ```
///
/// Using alternate formatting style to skip invalid values entirely:
///
/// ```
/// use widestring::U16CStr;
///
/// // 𝄞mus<invalid>ic<invalid>
/// let s = U16CStr::from_slice(&[
/// 0xD834, 0xDD1E, 0x006d, 0x0075, 0x0073, 0xDD1E, 0x0069, 0x0063, 0xD834, 0x0000,
/// ]).unwrap();
///
/// assert_eq!(format!("{:#}", s.display()),
/// "𝄞music"
/// );
/// ```
#[inline]
pub fn display(&self) -> Display<'_, C> {
Display { str: self }
}
}
impl UCStr<u16> {
/// Decodes a string reference to an owned [`OsString`][std::ffi::OsString].
///
/// This makes a string copy of the [`U16CStr`]. Since [`U16CStr`] makes no guarantees that it
/// is valid UTF-16, there is no guarantee that the resulting [`OsString`][std::ffi::OsString]
/// will be valid data. The [`OsString`][std::ffi::OsString] will **not** have a nul
/// terminator.
///
/// Note that the encoding of [`OsString`][std::ffi::OsString] is platform-dependent, so on
/// some platforms this may make an encoding conversions, while on other platforms (such as
/// windows) no changes to the string will be made.
///
/// # Examples
///
/// ```rust
/// use widestring::U16CString;
/// use std::ffi::OsString;
/// let s = "MyString";
/// // Create a wide string from the string
/// let wstr = U16CString::from_str(s).unwrap();
/// // Create an OsString from the wide string
/// let osstr = wstr.to_os_string();
///
/// assert_eq!(osstr, OsString::from(s));
/// ```
#[inline]
#[cfg(feature = "std")]
#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
pub fn to_os_string(&self) -> std::ffi::OsString {
crate::platform::os_from_wide(self.as_slice())
}
/// Decodes the string reference to a [`String`] if it contains valid UTF-16 data.
///
/// # Errors
///
/// Returns an error if the string contains any invalid UTF-16 data.
///
/// # Examples
///
/// ```rust
/// use widestring::U16CString;
/// let s = "MyString";
/// // Create a wide string from the string
/// let wstr = U16CString::from_str(s).unwrap();
/// // Create a regular string from the wide string
/// let s2 = wstr.to_string().unwrap();
///
/// assert_eq!(s2, s);
/// ```
#[inline]
#[cfg(feature = "alloc")]
#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
pub fn to_string(&self) -> Result<String, FromUtf16Error> {
String::from_utf16(self.as_slice())
}
/// Decodes the string reference to a [`String`] even if it is invalid UTF-16 data.
///
/// Any non-Unicode sequences are replaced with `U+FFFD REPLACEMENT CHARACTER`.
///
/// # Examples
///
/// ```rust
/// use widestring::U16CString;
/// let s = "MyString";
/// // Create a wide string from the string
/// let wstr = U16CString::from_str(s).unwrap();
/// // Create a regular string from the wide string
/// let s2 = wstr.to_string_lossy();
///
/// assert_eq!(s2, s);
/// ```
#[inline]
#[cfg(feature = "alloc")]
#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
pub fn to_string_lossy(&self) -> String {
String::from_utf16_lossy(self.as_slice())
}
/// Returns an iterator over the [`char`][prim@char]s of a string slice.
///
/// As this string slice may consist of invalid UTF-16, the iterator returned by this method
/// is an iterator over `Result<char, DecodeUtf16Error>` instead of [`char`][prim@char]s
/// directly. If you would like a lossy iterator over [`chars`][prim@char]s directly, instead
/// use [`chars_lossy`][Self::chars_lossy].
///
/// It's important to remember that [`char`][prim@char] represents a Unicode Scalar Value, and
/// may not match your idea of what a 'character' is. Iteration over grapheme clusters may be
/// what you actually want. That functionality is not provided by by this crate.
#[inline]
pub fn chars(&self) -> Utf16Chars<'_> {
Utf16Chars::from_ucstr(self)
}
/// Returns a lossy iterator over the [`char`][prim@char]s of a string slice.
///
/// As this string slice may consist of invalid UTF-16, the iterator returned by this method
/// will replace unpaired surrogates with
/// [`U+FFFD REPLACEMENT CHARACTER`][std::char::REPLACEMENT_CHARACTER] (�). This is a lossy
/// version of [`chars`][Self::chars].
///
/// It's important to remember that [`char`][prim@char] represents a Unicode Scalar Value, and
/// may not match your idea of what a 'character' is. Iteration over grapheme clusters may be
/// what you actually want. That functionality is not provided by by this crate.
#[inline]
pub fn chars_lossy(&self) -> CharsLossy<'_> {
CharsLossy::from_u16cstr(self)
}
/// Returns an iterator over the chars of a string slice, and their positions.
///
/// As this string slice may consist of invalid UTF-16, the iterator returned by this method
/// is an iterator over `Result<char, DecodeUtf16Error>` as well as their positions, instead of
/// [`char`][prim@char]s directly. If you would like a lossy indices iterator over
/// [`chars`][prim@char]s directly, instead use
/// [`char_indices_lossy`][Self::char_indices_lossy].
///
/// The iterator yields tuples. The position is first, the [`char`][prim@char] is second.
#[inline]
pub fn char_indices(&self) -> Utf16CharIndices<'_> {
Utf16CharIndices::from_ucstr(self)
}
/// Returns a lossy iterator over the chars of a string slice, and their positions.
///
/// As this string slice may consist of invalid UTF-16, the iterator returned by this method
/// will replace unpaired surrogates with
/// [`U+FFFD REPLACEMENT CHARACTER`][std::char::REPLACEMENT_CHARACTER] (�), as well as the
/// positions of all characters. This is a lossy version of
/// [`char_indices`][Self::char_indices].
///
/// The iterator yields tuples. The position is first, the [`char`][prim@char] is second.
#[inline]
pub fn char_indices_lossy(&self) -> Utf16CharIndicesLossy<'_> {
Utf16CharIndicesLossy::from_ucstr(self)
}
}
impl UCStr<u32> {
/// Constructs a string reference from a [`char`] nul-terminated string pointer.
///
/// This will scan for nul values beginning with `p`. The first nul value will be used as the
/// nul terminator for the string, similar to how libc string functions such as `strlen` work.
///
/// # Safety
///
/// This function is unsafe as there is no guarantee that the given pointer is valid or has a
/// nul terminator, and the function could scan past the underlying buffer.
///
/// In addition, the data must meet the safety conditions of [std::slice::from_raw_parts].
/// In particular, the returned string reference *must not be mutated* for the duration of
/// lifetime `'a`, except inside an [`UnsafeCell`][std::cell::UnsafeCell].
///
/// # Panics
///
/// This function panics if `p` is null.
///
/// # Caveat
///
/// The lifetime for the returned string is inferred from its usage. To prevent accidental
/// misuse, it's suggested to tie the lifetime to whichever source lifetime is safe in the
/// context, such as by providing a helper function taking the lifetime of a host value for the
/// string, or by explicit annotation.
#[inline]
pub unsafe fn from_char_ptr_str<'a>(p: *const char) -> &'a Self {
Self::from_ptr_str(p as *const u32)
}
/// Constructs a mutable string reference from a mutable [`char`] nul-terminated string pointer.
///
/// This will scan for nul values beginning with `p`. The first nul value will be used as the
/// nul terminator for the string, similar to how libc string functions such as `strlen` work.
///
/// # Safety
///
/// This function is unsafe as there is no guarantee that the given pointer is valid or has a
/// nul terminator, and the function could scan past the underlying buffer.
///
/// In addition, the data must meet the safety conditions of [std::slice::from_raw_parts_mut].
///
/// # Panics
///
/// This function panics if `p` is null.
///
/// # Caveat
///
/// The lifetime for the returned string is inferred from its usage. To prevent accidental
/// misuse, it's suggested to tie the lifetime to whichever source lifetime is safe in the
/// context, such as by providing a helper function taking the lifetime of a host value for the
/// string, or by explicit annotation.
#[inline]
pub unsafe fn from_char_ptr_str_mut<'a>(p: *mut char) -> &'a mut Self {
Self::from_ptr_str_mut(p as *mut u32)
}
/// Constructs a string reference from a [`char`] pointer and a length.
///
/// The `len` argument is the number of elements, **not** the number of bytes, and does
/// **not** include the nul terminator of the string. Thus, a `len` of 0 is valid and means
/// that `p` is a pointer directly to the nul terminator of the string.
///
/// # Errors
///
/// This will scan the pointer string for an interior nul value and error if one is found
/// before the nul terminator at `len` offset. To avoid scanning for interior nuls,
/// [`from_ptr_unchecked`][Self::from_ptr_unchecked] may be used instead.
///
/// An error is returned if the value at `len` offset is not a nul terminator.
///
/// # Safety
///
/// This function is unsafe as there is no guarantee that the given pointer is valid for `len +
/// 1` elements.
///
/// In addition, the data must meet the safety conditions of [std::slice::from_raw_parts].
/// In particular, the returned string reference *must not be mutated* for the duration of
/// lifetime `'a`, except inside an [`UnsafeCell`][std::cell::UnsafeCell].
///
/// # Panics
///
/// This function panics if `p` is null.
///
/// # Caveat
///
/// The lifetime for the returned string is inferred from its usage. To prevent accidental
/// misuse, it's suggested to tie the lifetime to whichever source lifetime is safe in the
/// context, such as by providing a helper function taking the lifetime of a host value for the
/// string, or by explicit annotation.
pub unsafe fn from_char_ptr<'a>(p: *const char, len: usize) -> Result<&'a Self, NulError<u32>> {
Self::from_ptr(p as *const u32, len)
}
/// Constructs a mutable string reference from a mutable [`char`] pointer and a length.
///
/// The `len` argument is the number of elements, **not** the number of bytes, and does
/// **not** include the nul terminator of the string. Thus, a `len` of 0 is valid and means
/// that `p` is a pointer directly to the nul terminator of the string.
///
/// # Errors
///
/// This will scan the pointer string for an interior nul value and error if one is found
/// before the nul terminator at `len` offset. To avoid scanning for interior nuls,
/// [`from_ptr_unchecked_mut`][Self::from_ptr_unchecked_mut] may be used instead.
///
/// An error is returned if the value at `len` offset is not a nul terminator.
///
/// # Safety
///
/// This function is unsafe as there is no guarantee that the given pointer is valid for `len +
/// 1` elements.
///
/// In addition, the data must meet the safety conditions of [std::slice::from_raw_parts_mut].
///
/// # Panics
///
/// This function panics if `p` is null.
///
/// # Caveat
///
/// The lifetime for the returned string is inferred from its usage. To prevent accidental
/// misuse, it's suggested to tie the lifetime to whichever source lifetime is safe in the
/// context, such as by providing a helper function taking the lifetime of a host value for the
/// string, or by explicit annotation.
pub unsafe fn from_char_ptr_mut<'a>(
p: *mut char,
len: usize,
) -> Result<&'a mut Self, NulError<u32>> {
Self::from_ptr_mut(p as *mut u32, len)
}
/// Constructs a string reference from a [`char`] pointer and a length, truncating at the first
/// nul terminator.
///
/// The `len` argument is the number of elements, **not** the number of bytes. This will scan
/// for nul values beginning with `p` until offset `len`. The first nul value will be used as
/// the nul terminator for the string, ignoring any remaining values left before `len`.
///
/// # Errors
///
/// If no nul terminator is found after `len` + 1 elements, an error is returned.
///
/// # Safety
///
/// This function is unsafe as there is no guarantee that the given pointer is valid or has a
/// nul terminator, and the function could scan past the underlying buffer.
///
/// In addition, the data must meet the safety conditions of [std::slice::from_raw_parts].
/// In particular, the returned string reference *must not be mutated* for the duration of
/// lifetime `'a`, except inside an [`UnsafeCell`][std::cell::UnsafeCell].
///
/// # Panics
///
/// This function panics if `p` is null.
///
/// # Caveat
///
/// The lifetime for the returned string is inferred from its usage. To prevent accidental
/// misuse, it's suggested to tie the lifetime to whichever source lifetime is safe in the
/// context, such as by providing a helper function taking the lifetime of a host value for the
/// string, or by explicit annotation.
pub unsafe fn from_char_ptr_truncate<'a>(
p: *const char,
len: usize,
) -> Result<&'a Self, MissingNulTerminator> {
Self::from_ptr_truncate(p as *const u32, len)
}
/// Constructs a mutable string reference from a mutable [`char`] pointer and a length,
/// truncating at the first nul terminator.
///
/// The `len` argument is the number of elements, **not** the number of bytes. This will scan
/// for nul values beginning with `p` until offset `len`. The first nul value will be used as
/// the nul terminator for the string, ignoring any remaining values left before `len`.
///
/// # Errors
///
/// If no nul terminator is found after `len` + 1 elements, an error is returned.
///
/// # Safety
///
/// This function is unsafe as there is no guarantee that the given pointer is valid or has a
/// nul terminator, and the function could scan past the underlying buffer.
///
/// In addition, the data must meet the safety conditions of [std::slice::from_raw_parts_mut].
///
/// # Panics
///
/// This function panics if `p` is null.
///
/// # Caveat
///
/// The lifetime for the returned string is inferred from its usage. To prevent accidental
/// misuse, it's suggested to tie the lifetime to whichever source lifetime is safe in the
/// context, such as by providing a helper function taking the lifetime of a host value for the
/// string, or by explicit annotation.
pub unsafe fn from_char_ptr_truncate_mut<'a>(
p: *mut char,
len: usize,
) -> Result<&'a mut Self, MissingNulTerminator> {
Self::from_ptr_truncate_mut(p as *mut u32, len)
}
/// Constructs a string reference from a [`char`] pointer and a length without checking for any
/// nul values.
///
/// The `len` argument is the number of elements, **not** the number of bytes, and does
/// **not** include the nul terminator of the string. Thus, a `len` of 0 is valid and means
/// that `p` is a pointer directly to the nul terminator of the string.
///
/// # Safety
///
/// This function is unsafe as there is no guarantee that the given pointer is valid for `len +
/// 1` elements, nor that is has a terminating nul value.
///
/// In addition, the data must meet the safety conditions of [std::slice::from_raw_parts].
/// In particular, the returned string reference *must not be mutated* for the duration of
/// lifetime `'a`, except inside an [`UnsafeCell`][std::cell::UnsafeCell].
///
/// The interior values of the pointer are not scanned for nul. Any interior nul values or
/// a missing nul terminator at pointer offset `len` + 1 will result in an invalid [`UCStr`].
///
/// # Panics
///
/// This function panics if `p` is null.
///
/// # Caveat
///
/// The lifetime for the returned string is inferred from its usage. To prevent accidental
/// misuse, it's suggested to tie the lifetime to whichever source lifetime is safe in the
/// context, such as by providing a helper function taking the lifetime of a host value for the
/// string, or by explicit annotation.
#[inline]
pub unsafe fn from_char_ptr_unchecked<'a>(p: *const char, len: usize) -> &'a Self {
Self::from_ptr_unchecked(p as *const u32, len)
}
/// Constructs a mutable string reference from a mutable [`char`] pointer and a length without
/// checking for any nul values.
///
/// The `len` argument is the number of elements, **not** the number of bytes, and does
/// **not** include the nul terminator of the string. Thus, a `len` of 0 is valid and means
/// that `p` is a pointer directly to the nul terminator of the string.
///
/// # Safety
///
/// This function is unsafe as there is no guarantee that the given pointer is valid for `len +
/// 1` elements, nor that is has a terminating nul value.
///
/// In addition, the data must meet the safety conditions of [std::slice::from_raw_parts_mut].
///
/// The interior values of the pointer are not scanned for nul. Any interior nul values or
/// a missing nul terminator at pointer offset `len` + 1 will result in an invalid [`UCStr`].
///
/// # Panics
///
/// This function panics if `p` is null.
///
/// # Caveat
///
/// The lifetime for the returned string is inferred from its usage. To prevent accidental
/// misuse, it's suggested to tie the lifetime to whichever source lifetime is safe in the
/// context, such as by providing a helper function taking the lifetime of a host value for the
/// string, or by explicit annotation.
#[inline]
pub unsafe fn from_char_ptr_unchecked_mut<'a>(p: *mut char, len: usize) -> &'a mut Self {
Self::from_ptr_unchecked_mut(p as *mut u32, len)
}
/// Constructs a string reference from a [`char`] slice with a terminating nul, checking for
/// invalid interior nul values.
///
/// The slice must have at least one item, the nul terminator, even for an empty string.
///
/// # Errors
///
/// If there are nul values in the slice except for the last value, an error is returned.
///
/// An error is also returned if the last value of the slice is not a nul terminator.
pub fn from_char_slice(slice: &[char]) -> Result<&Self, NulError<u32>> {
let ptr: *const [char] = slice;
Self::from_slice(unsafe { &*(ptr as *const [u32]) })
}
/// Constructs a mutable string reference from a mutable [`char`] slice with a terminating nul,
/// checking for invalid interior nul values.
///
/// The slice must have at least one item, the nul terminator, even for an empty string.
///
/// # Errors
///
/// If there are nul values in the slice except for the last value, an error is returned.
///
/// An error is also returned if the last value of the slice is not a nul terminator.
pub fn from_char_slice_mut(slice: &mut [char]) -> Result<&mut Self, NulError<u32>> {
let ptr: *mut [char] = slice;
Self::from_slice_mut(unsafe { &mut *(ptr as *mut [u32]) })
}
/// Constructs a string reference from a slice of [`char`] values, truncating at the first nul
/// terminator.
///
/// The slice will be scanned for nul values. When a nul value is found, it is treated as the
/// terminator for the string, and the [`UCStr`] slice will be truncated to that nul.
///
/// # Errors
///
/// If there are no nul values in the slice, an error is returned.
#[inline]
pub fn from_char_slice_truncate(slice: &[char]) -> Result<&Self, MissingNulTerminator> {
let ptr: *const [char] = slice;
Self::from_slice_truncate(unsafe { &*(ptr as *const [u32]) })
}
/// Constructs a mutable string reference from a mutable slice of [`char`] values, truncating at
/// the first nul terminator.
///
/// The slice will be scanned for nul values. When a nul value is found, it is treated as the
/// terminator for the string, and the [`UCStr`] slice will be truncated to that nul.
///
/// # Errors
///
/// If there are no nul values in the slice, an error is returned.
#[inline]
pub fn from_char_slice_truncate_mut(
slice: &mut [char],
) -> Result<&mut Self, MissingNulTerminator> {
let ptr: *mut [char] = slice;
Self::from_slice_truncate_mut(unsafe { &mut *(ptr as *mut [u32]) })
}
/// Constructs a string reference from a [`char`] slice without checking for a terminating or
/// interior nul values.
///
/// # Safety
///
/// This function is unsafe because it can lead to invalid [`UCStr`] values when the slice
/// is missing a terminating nul value or there are non-terminating interior nul values
/// in the slice. In particular, an empty slice will result in an invalid [`UCStr`].
#[inline]
pub unsafe fn from_char_slice_unchecked(slice: &[char]) -> &Self {
let ptr: *const [char] = slice;
Self::from_slice_unchecked(&*(ptr as *const [u32]))
}
/// Constructs a mutable string reference from a mutable [`char`] slice without checking for a
/// terminating or interior nul values.
///
/// # Safety
///
/// This function is unsafe because it can lead to invalid [`UCStr`] values when the slice
/// is missing a terminating nul value or there are non-terminating interior nul values
/// in the slice. In particular, an empty slice will result in an invalid [`UCStr`].
#[inline]
pub unsafe fn from_char_slice_unchecked_mut(slice: &mut [char]) -> &mut Self {
let ptr: *mut [char] = slice;
Self::from_slice_unchecked_mut(&mut *(ptr as *mut [u32]))
}
/// Decodes a string reference to an owned [`OsString`][std::ffi::OsString].
///
/// This makes a string copy of this reference. Since [`UCStr<u32>`] makes no guarantees that it
/// is valid UTF-32, there is no guarantee that the resulting [`OsString`][std::ffi::OsString]
/// will be valid data. The [`OsString`][std::ffi::OsString] will **not** have a nul
/// terminator.
///
/// Note that the encoding of [`OsString`][std::ffi::OsString] is platform-dependent, so on
/// some platforms this may make an encoding conversions, while on other platforms no changes to
/// the string will be made.
///
/// # Examples
///
/// ```rust
/// use widestring::U32CString;
/// use std::ffi::OsString;
/// let s = "MyString";
/// // Create a wide string from the string
/// let wstr = U32CString::from_str(s).unwrap();
/// // Create an OsString from the wide string
/// let osstr = wstr.to_os_string();
///
/// assert_eq!(osstr, OsString::from(s));
/// ```
#[inline]
#[cfg(feature = "std")]
#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
pub fn to_os_string(&self) -> std::ffi::OsString {
self.as_ustr().to_os_string()
}
/// Decodes the string reference to a [`String`] if it contains valid UTF-32 data.
///
/// # Errors
///
/// Returns an error if the string contains any invalid UTF-32 data.
///
/// # Examples
///
/// ```rust
/// use widestring::U32CString;
/// let s = "MyString";
/// // Create a wide string from the string
/// let wstr = U32CString::from_str(s).unwrap();
/// // Create a regular string from the wide string
/// let s2 = wstr.to_string().unwrap();
///
/// assert_eq!(s2, s);
/// ```
#[inline]
#[cfg(feature = "alloc")]
#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
pub fn to_string(&self) -> Result<String, crate::error::FromUtf32Error> {
self.as_ustr().to_string()
}
/// Decodes the string reference to a [`String`] even if it is invalid UTF-32 data.
///
/// Any non-Unicode sequences are replaced with `U+FFFD REPLACEMENT CHARACTER`.
///
/// # Examples
///
/// ```rust
/// use widestring::U32CString;
/// let s = "MyString";
/// // Create a wide string from the string
/// let wstr = U32CString::from_str(s).unwrap();
/// // Create a regular string from the wide string
/// let s2 = wstr.to_string_lossy();
///
/// assert_eq!(s2, s);
/// ```
#[inline]
#[cfg(feature = "alloc")]
#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
pub fn to_string_lossy(&self) -> String {
self.as_ustr().to_string_lossy()
}
#[doc(hidden)]
#[deprecated = "use `from_char_ptr_unchecked` instead"]
pub unsafe fn from_char_ptr_with_nul<'a>(p: *const char, len: usize) -> &'a Self {
Self::from_char_ptr_unchecked(p, len)
}
#[allow(deprecated)]
#[doc(hidden)]
#[deprecated = "use `from_char_slice_truncate` instead"]
pub fn from_char_slice_with_nul(slice: &[char]) -> Result<&Self, crate::MissingNulError> {
Self::from_char_slice_truncate(slice)
}
#[doc(hidden)]
#[deprecated = "use `from_char_slice_unchecked` instead"]
pub unsafe fn from_char_slice_with_nul_unchecked(slice: &[char]) -> &Self {
Self::from_char_slice_unchecked(slice)
}
/// Returns an iterator over the [`char`][prim@char]s of a string slice.
///
/// As this string slice may consist of invalid UTF-32, the iterator returned by this method
/// is an iterator over `Result<char, DecodeUtf32Error>` instead of [`char`][prim@char]s
/// directly. If you would like a lossy iterator over [`chars`][prim@char]s directly, instead
/// use [`chars_lossy`][Self::chars_lossy].
///
/// It's important to remember that [`char`][prim@char] represents a Unicode Scalar Value, and
/// may not match your idea of what a 'character' is. Iteration over grapheme clusters may be
/// what you actually want. That functionality is not provided by by this crate.
#[inline]
pub fn chars(&self) -> Utf32Chars<'_> {
Utf32Chars::from_ucstr(self)
}
/// Returns a lossy iterator over the [`char`][prim@char]s of a string slice.
///
/// As this string slice may consist of invalid UTF-32, the iterator returned by this method
/// will replace surrogate values or invalid code points with
/// [`U+FFFD REPLACEMENT CHARACTER`][std::char::REPLACEMENT_CHARACTER] (�). This is a lossy
/// version of [`chars`][Self::chars].
///
/// It's important to remember that [`char`][prim@char] represents a Unicode Scalar Value, and
/// may not match your idea of what a 'character' is. Iteration over grapheme clusters may be
/// what you actually want. That functionality is not provided by by this crate.
#[inline]
pub fn chars_lossy(&self) -> CharsLossy<'_> {
CharsLossy::from_u32cstr(self)
}
}
impl<C: UChar> AsMut<UCStr<C>> for UCStr<C> {
#[inline]
fn as_mut(&mut self) -> &mut UCStr<C> {
self
}
}
impl<C: UChar> AsRef<UCStr<C>> for UCStr<C> {
#[inline]
fn as_ref(&self) -> &Self {
self
}
}
impl<C: UChar> AsRef<[C]> for UCStr<C> {
#[inline]
fn as_ref(&self) -> &[C] {
self.as_slice()
}
}
impl<C: UChar> AsRef<UStr<C>> for UCStr<C> {
#[inline]
fn as_ref(&self) -> &UStr<C> {
self.as_ustr()
}
}
impl core::fmt::Debug for U16CStr {
#[inline]
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
crate::debug_fmt_u16(self.as_slice_with_nul(), f)
}
}
impl core::fmt::Debug for U32CStr {
#[inline]
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
crate::debug_fmt_u32(self.as_slice_with_nul(), f)
}
}
impl<'a> Default for &'a UCStr<u16> {
#[inline]
fn default() -> Self {
const SLICE: &[u16] = &[UChar::NUL];
unsafe { UCStr::from_slice_unchecked(SLICE) }
}
}
impl<'a> Default for &'a UCStr<u32> {
#[inline]
fn default() -> Self {
const SLICE: &[u32] = &[UChar::NUL];
unsafe { UCStr::from_slice_unchecked(SLICE) }
}
}
#[cfg(feature = "alloc")]
impl<C: UChar> Default for Box<UCStr<C>> {
#[inline]
fn default() -> Box<UCStr<C>> {
let boxed: Box<[C]> = Box::from([UChar::NUL]);
unsafe { Box::from_raw(Box::into_raw(boxed) as *mut UCStr<C>) }
}
}
#[cfg(feature = "alloc")]
impl<'a, C: UChar> From<&'a UCStr<C>> for Box<UCStr<C>> {
#[inline]
fn from(s: &'a UCStr<C>) -> Box<UCStr<C>> {
let boxed: Box<[C]> = Box::from(s.as_slice_with_nul());
unsafe { Box::from_raw(Box::into_raw(boxed) as *mut UCStr<C>) }
}
}
impl<C: UChar> PartialEq<crate::UStr<C>> for UCStr<C> {
#[inline]
fn eq(&self, other: &crate::UStr<C>) -> bool {
self.as_slice() == other.as_slice()
}
}
impl<C: UChar> PartialOrd<crate::UStr<C>> for UCStr<C> {
#[inline]
fn partial_cmp(&self, other: &crate::UStr<C>) -> Option<core::cmp::Ordering> {
self.as_ustr().partial_cmp(other)
}
}
/// C-style string reference for [`U16CString`][crate::U16CString].
///
/// [`U16CStr`] is aware of nul values. Unless unchecked conversions are used, all [`U16CStr`]
/// strings end with a nul-terminator in the underlying buffer and contain no internal nul values.
/// The strings may still contain invalid or ill-formed UTF-16 data. These strings are intended to
/// be used with FFI functions such as Windows API that may require nul-terminated strings.
///
/// [`U16CStr`] can be converted to and from many other string types, including
/// [`U16String`][crate::U16String], [`OsString`][std::ffi::OsString], and [`String`], making proper
/// Unicode FFI safe and easy.
pub type U16CStr = UCStr<u16>;
/// C-style string reference for [`U32CString`][crate::U32CString].
///
/// [`U32CStr`] is aware of nul values. Unless unchecked conversions are used, all [`U32CStr`]
/// strings end with a nul-terminator in the underlying buffer and contain no internal nul values.
/// The strings may still contain invalid or ill-formed UTF-32 data. These strings are intended to
/// be used with FFI functions such as Windows API that may require nul-terminated strings.
///
/// [`U32CStr`] can be converted to and from many other string types, including
/// [`U32String`][crate::U32String], [`OsString`][std::ffi::OsString], and [`String`], making proper
/// Unicode FFI safe and easy.
pub type U32CStr = UCStr<u32>;
/// Alias for [`U16CStr`] or [`U32CStr`] depending on platform. Intended to match typical C
/// `wchar_t` size on platform.
pub type WideCStr = UCStr<WideChar>;
/// Helper struct for printing [`UCStr`] values with [`format!`] and `{}`.
///
/// A [`UCStr`] might contain ill-formed UTF encoding. This struct implements the
/// [`Display`][std::fmt::Display] trait in a way that decoding the string is lossy but no heap
/// allocations are performed, such as by [`to_string_lossy`][UCStr::to_string_lossy]. It is created
/// by the [`display`][UCStr::display] method on [`UCStr`].
///
/// By default, invalid Unicode data is replaced with
/// [`U+FFFD REPLACEMENT CHARACTER`][std::char::REPLACEMENT_CHARACTER] (�). If you wish to simply
/// skip any invalid Uncode data and forego the replacement, you may use the
/// [alternate formatting][std::fmt#sign0] with `{:#}`.
pub struct Display<'a, C: UChar> {
str: &'a UCStr<C>,
}
impl<'a> core::fmt::Debug for Display<'a, u16> {
#[inline]
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
core::fmt::Debug::fmt(&self.str, f)
}
}
impl<'a> core::fmt::Debug for Display<'a, u32> {
#[inline]
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
core::fmt::Debug::fmt(&self.str, f)
}
}
impl<'a> core::fmt::Display for Display<'a, u16> {
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
for c in crate::decode_utf16_lossy(self.str.as_slice().iter().copied()) {
// Allow alternate {:#} format which skips replacment chars entirely
if c != core::char::REPLACEMENT_CHARACTER || !f.alternate() {
f.write_char(c)?;
}
}
Ok(())
}
}
impl<'a> core::fmt::Display for Display<'a, u32> {
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
for c in crate::decode_utf32_lossy(self.str.as_slice().iter().copied()) {
// Allow alternate {:#} format which skips replacment chars entirely
if c != core::char::REPLACEMENT_CHARACTER || !f.alternate() {
f.write_char(c)?;
}
}
Ok(())
}
}