]> wimlib.net Git - wimlib/blobdiff - src/encoding.c
encoding.c: Upgrade upcase table and rewrite decompression code
[wimlib] / src / encoding.c
index e0f4e2d06666521b367b39e928f485fda7d6c3bd..8910ea4d0bc38a965e8b94d10dbc993bb1e88260 100644 (file)
@@ -1,38 +1,51 @@
 /*
- * encoding.c:  Convert "multibyte" strings (the locale-default encoding---
- * generally, UTF-8 or something like ISO-8859-1) to UTF-16LE strings, and vice
- * versa.
+ * encoding.c
  */
 
 /*
  * Copyright (C) 2012, 2013 Eric Biggers
  *
- * This file is part of wimlib, a library for working with WIM files.
+ * This file is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation; either version 3 of the License, or (at your option) any
+ * later version.
  *
- * wimlib is free software; you can redistribute it and/or modify it under the
- * terms of the GNU General Public License as published by the Free
- * Software Foundation; either version 3 of the License, or (at your option)
- * any later version.
- *
- * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
- * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
- * A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * This file is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
  * details.
  *
- * You should have received a copy of the GNU General Public License
- * along with wimlib; if not, see http://www.gnu.org/licenses/.
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this file; if not, see http://www.gnu.org/licenses/.
  */
 
-#include "config.h"
-#include "wimlib_internal.h"
-#include <pthread.h>
-#include "list.h"
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif
 
+#include <errno.h>
 #include <iconv.h>
-#include <stdlib.h>
+#include <pthread.h>
+#include <string.h>
 
-bool wimlib_mbs_is_utf8 = false;
+#include "wimlib.h"
+#include "wimlib/alloca.h"
+#include "wimlib/assert.h"
+#include "wimlib/encoding.h"
+#include "wimlib/endianness.h"
+#include "wimlib/error.h"
+#include "wimlib/list.h"
+#include "wimlib/util.h"
 
+
+bool wimlib_mbs_is_utf8 = !TCHAR_IS_UTF16LE;
+
+/* List of iconv_t conversion descriptors for a specific character conversion.
+ * The idea is that it is not thread-safe to have just one conversion
+ * descriptor, but it also is inefficient to open a new conversion descriptor to
+ * convert every string.  Both these problems can be solved by maintaining a
+ * list of conversion descriptors; then, a thread can use an existing conversion
+ * descriptor if available. */
 struct iconv_list_head {
        const char *from_encoding;
        const char *to_encoding;
@@ -50,8 +63,6 @@ struct iconv_node {
 struct iconv_list_head name = {                                \
        .from_encoding = from,                          \
        .to_encoding = to,                              \
-       .list = LIST_HEAD_INIT(name.list),              \
-       .mutex = PTHREAD_MUTEX_INITIALIZER,             \
 }
 
 static iconv_t *
@@ -94,7 +105,7 @@ put_iconv(iconv_t *cd)
        int errno_save = errno;
        struct iconv_node *i = container_of(cd, struct iconv_node, cd);
        struct iconv_list_head *head = i->head;
-       
+
        pthread_mutex_lock(&head->mutex);
        list_add(&i->list, &head->list);
        pthread_mutex_unlock(&head->mutex);
@@ -103,13 +114,16 @@ put_iconv(iconv_t *cd)
 
 #define DEFINE_CHAR_CONVERSION_FUNCTIONS(varname1, longname1, chartype1,\
                                         varname2, longname2, chartype2,\
+                                        earlyreturn_on_utf8_locale,    \
+                                        earlyreturn_expr,              \
                                         worst_case_len_expr,           \
                                         err_return,                    \
-                                        err_msg)                       \
+                                        err_msg,                       \
+                                        modifier)                      \
 static ICONV_LIST(iconv_##varname1##_to_##varname2,                    \
                  longname1, longname2);                                \
                                                                        \
-int                                                                    \
+modifier int                                                           \
 varname1##_to_##varname2##_nbytes(const chartype1 *in, size_t in_nbytes,\
                                  size_t *out_nbytes_ret)               \
 {                                                                      \
@@ -117,12 +131,25 @@ varname1##_to_##varname2##_nbytes(const chartype1 *in, size_t in_nbytes,\
        if (cd == NULL)                                                 \
                return WIMLIB_ERR_ICONV_NOT_AVAILABLE;                  \
                                                                        \
+       chartype2 *buf;                                                 \
+       size_t bufsize;                                                 \
+       bool buf_onheap;                                                \
+       bufsize = (worst_case_len_expr) * sizeof(chartype2);            \
        /* Worst case length */                                         \
-       chartype2 buf[worst_case_len_expr];                             \
+       if (bufsize <= STACK_MAX) {                                     \
+               buf = alloca(bufsize);                                  \
+               buf_onheap = false;                                     \
+       } else {                                                        \
+               buf = MALLOC(bufsize);                                  \
+               if (!buf)                                               \
+                       return WIMLIB_ERR_NOMEM;                        \
+               buf_onheap = true;                                      \
+       }                                                               \
+                                                                       \
        char *inbuf = (char*)in;                                        \
        size_t inbytesleft = in_nbytes;                                 \
        char *outbuf = (char*)buf;                                      \
-       size_t outbytesleft = sizeof(buf);                              \
+       size_t outbytesleft = bufsize;                                  \
        size_t len;                                                     \
        int ret;                                                        \
                                                                        \
@@ -131,14 +158,16 @@ varname1##_to_##varname2##_nbytes(const chartype1 *in, size_t in_nbytes,\
                err_msg;                                                \
                ret = err_return;                                       \
        } else {                                                        \
-               *out_nbytes_ret = sizeof(buf) - outbytesleft;           \
+               *out_nbytes_ret = bufsize - outbytesleft;               \
                ret = 0;                                                \
        }                                                               \
        put_iconv(cd);                                                  \
+       if (buf_onheap)                                                 \
+               FREE(buf);                                              \
        return ret;                                                     \
 }                                                                      \
                                                                        \
-int                                                                    \
+modifier int                                                           \
 varname1##_to_##varname2##_buf(const chartype1 *in, size_t in_nbytes,  \
                               chartype2 *out)                          \
 {                                                                      \
@@ -166,7 +195,7 @@ varname1##_to_##varname2##_buf(const chartype1 *in, size_t in_nbytes,       \
        return ret;                                                     \
 }                                                                      \
                                                                        \
-int                                                                    \
+modifier int                                                           \
 varname1##_to_##varname2(const chartype1 *in, size_t in_nbytes,                \
                         chartype2 **out_ret,                           \
                         size_t *out_nbytes_ret)                        \
@@ -175,6 +204,19 @@ varname1##_to_##varname2(const chartype1 *in, size_t in_nbytes,            \
        chartype2 *out;                                                 \
        size_t out_nbytes;                                              \
                                                                        \
+       if (earlyreturn_on_utf8_locale && wimlib_mbs_is_utf8) {         \
+               earlyreturn_expr;                                       \
+               /* Out same as in */                                    \
+               out = MALLOC(in_nbytes + sizeof(chartype2));            \
+               if (!out)                                               \
+                       return WIMLIB_ERR_NOMEM;                        \
+               memcpy(out, in, in_nbytes);                             \
+               out[in_nbytes / sizeof(chartype2)] = 0;                 \
+               *out_ret = out;                                         \
+               *out_nbytes_ret = in_nbytes;                            \
+               return 0;                                               \
+       }                                                               \
+                                                                       \
        ret = varname1##_to_##varname2##_nbytes(in, in_nbytes,          \
                                                &out_nbytes);           \
        if (ret)                                                        \
@@ -186,9 +228,7 @@ varname1##_to_##varname2(const chartype1 *in, size_t in_nbytes,             \
                                                                        \
        ret = varname1##_to_##varname2##_buf(in, in_nbytes, out);       \
        if (ret) {                                                      \
-               int errno_save = errno;                                 \
                FREE(out);                                              \
-               errno = errno_save;                                     \
        } else {                                                        \
                *out_ret = out;                                         \
                *out_nbytes_ret = out_nbytes;                           \
@@ -196,27 +236,132 @@ varname1##_to_##varname2(const chartype1 *in, size_t in_nbytes,          \
        return ret;                                                     \
 }
 
+#if !TCHAR_IS_UTF16LE
+
+/* UNIX */
+
+DEFINE_CHAR_CONVERSION_FUNCTIONS(utf8, "UTF-8", tchar,
+                                utf16le, "UTF-16LE", utf16lechar,
+                                false,
+                                ,
+                                in_nbytes * 2,
+                                WIMLIB_ERR_INVALID_UTF8_STRING,
+                                ERROR_WITH_ERRNO("Failed to convert UTF-8 string "
+                                                 "to UTF-16LE string!"),
+                                static)
+
 DEFINE_CHAR_CONVERSION_FUNCTIONS(utf16le, "UTF-16LE", utf16lechar,
-                                mbs, "", mbchar,
-                                in_nbytes / 2 * MB_CUR_MAX,
-                                WIMLIB_ERR_UNICODE_STRING_NOT_REPRESENTABLE,
-                                ERROR_WITH_ERRNO("Failed to convert UTF-16LE "
-                                                 "string %U to multibyte string", in))
+                                utf8, "UTF-8", tchar,
+                                false,
+                                ,
+                                in_nbytes * 2,
+                                WIMLIB_ERR_INVALID_UTF16_STRING,
+                                ERROR_WITH_ERRNO("Failed to convert UTF-16LE string "
+                                                 "to UTF-8 string!"),
+                                static)
 
-DEFINE_CHAR_CONVERSION_FUNCTIONS(mbs, "", mbchar,
+DEFINE_CHAR_CONVERSION_FUNCTIONS(tstr, "", tchar,
                                 utf16le, "UTF-16LE", utf16lechar,
+                                true,
+                                return utf8_to_utf16le(in, in_nbytes, out_ret, out_nbytes_ret),
                                 in_nbytes * 2,
                                 WIMLIB_ERR_INVALID_MULTIBYTE_STRING,
                                 ERROR_WITH_ERRNO("Failed to convert multibyte "
-                                                 "string %s to UTF-16LE string", in))
+                                                 "string \"%"TS"\" to UTF-16LE string!", in);
+                                ERROR("If the data you provided was UTF-8, please make sure "
+                                      "the character encoding\n"
+                                      "        of your current locale is UTF-8."),
+                                )
 
-DEFINE_CHAR_CONVERSION_FUNCTIONS(utf8, "UTF-8", utf8char,
-                                mbs, "", mbchar,
-                                in_nbytes,
+DEFINE_CHAR_CONVERSION_FUNCTIONS(utf16le, "UTF-16LE", utf16lechar,
+                                tstr, "", tchar,
+                                true,
+                                return utf16le_to_utf8(in, in_nbytes, out_ret, out_nbytes_ret),
+                                in_nbytes * 2,
+                                WIMLIB_ERR_UNICODE_STRING_NOT_REPRESENTABLE,
+                                ERROR("Failed to convert UTF-16LE string to "
+                                      "multibyte string!");
+                                ERROR("This may be because the UTF-16LE string "
+                                      "could not be represented\n"
+                                      "        in your locale's character encoding."),
+                                )
+#endif
+
+/* tchar to UTF-8 and back */
+#if TCHAR_IS_UTF16LE
+
+/* Windows */
+DEFINE_CHAR_CONVERSION_FUNCTIONS(tstr, "UTF-16LE", tchar,
+                                utf8, "UTF-8", char,
+                                false,
+                                ,
+                                in_nbytes * 2,
+                                WIMLIB_ERR_INVALID_UTF16_STRING,
+                                ERROR_WITH_ERRNO("Failed to convert UTF-16LE "
+                                                 "string \"%"TS"\" to UTF-8 string!", in),
+                                )
+
+DEFINE_CHAR_CONVERSION_FUNCTIONS(utf8, "UTF-8", char,
+                                tstr, "UTF-16LE", tchar,
+                                false,
+                                ,
+                                in_nbytes * 2,
                                 WIMLIB_ERR_INVALID_UTF8_STRING,
-                                ERROR_WITH_ERRNO("Failed to convert UTF-8 "
-                                                 "string %U to multibyte string", in))
+                                ERROR_WITH_ERRNO("Failed to convert UTF-8 string "
+                                                 "to UTF-16LE string!"),
+                                )
+#else
+
+/* UNIX */
 
+DEFINE_CHAR_CONVERSION_FUNCTIONS(tstr, "", tchar,
+                                utf8, "UTF-8", char,
+                                true,
+                                ,
+                                in_nbytes * 4,
+                                WIMLIB_ERR_INVALID_MULTIBYTE_STRING,
+                                ERROR_WITH_ERRNO("Failed to convert multibyte "
+                                                 "string \"%"TS"\" to UTF-8 string!", in);
+                                ERROR("If the data you provided was UTF-8, please make sure "
+                                      "the character\n"
+                                      "        encoding of your current locale is UTF-8."),
+                                )
+
+DEFINE_CHAR_CONVERSION_FUNCTIONS(utf8, "UTF-8", char,
+                                tstr, "", tchar,
+                                true,
+                                ,
+                                in_nbytes * 4,
+                                WIMLIB_ERR_UNICODE_STRING_NOT_REPRESENTABLE,
+                                ERROR("Failed to convert UTF-8 string to "
+                                      "multibyte string!");
+                                ERROR("This may be because the UTF-8 data "
+                                      "could not be represented\n"
+                                      "        in your locale's character encoding."),
+                                )
+#endif
+
+int
+tstr_to_utf8_simple(const tchar *tstr, char **out)
+{
+       size_t out_nbytes;
+       return tstr_to_utf8(tstr, tstrlen(tstr) * sizeof(tchar),
+                           out, &out_nbytes);
+}
+
+int
+utf8_to_tstr_simple(const char *utf8str, tchar **out)
+{
+       size_t out_nbytes;
+       return utf8_to_tstr(utf8str, strlen(utf8str), out, &out_nbytes);
+}
+
+static void
+iconv_init(struct iconv_list_head *head)
+{
+       pthread_mutex_init(&head->mutex, NULL);
+       INIT_LIST_HEAD(&head->list);
+}
 
 static void
 iconv_cleanup(struct iconv_list_head *head)
@@ -224,7 +369,7 @@ iconv_cleanup(struct iconv_list_head *head)
        pthread_mutex_destroy(&head->mutex);
        while (!list_empty(&head->list)) {
                struct iconv_node *i;
-               
+
                i = container_of(head->list.next, struct iconv_node, list);
                list_del(&i->list);
                iconv_close(i->cd);
@@ -233,21 +378,234 @@ iconv_cleanup(struct iconv_list_head *head)
 }
 
 void
-iconv_global_cleanup()
+iconv_global_init(void)
+{
+       iconv_init(&iconv_utf8_to_tstr);
+       iconv_init(&iconv_tstr_to_utf8);
+#if !TCHAR_IS_UTF16LE
+       iconv_init(&iconv_utf16le_to_tstr);
+       iconv_init(&iconv_tstr_to_utf16le);
+       iconv_init(&iconv_utf16le_to_utf8);
+       iconv_init(&iconv_utf8_to_utf16le);
+#endif
+}
+
+void
+iconv_global_cleanup(void)
+{
+       iconv_cleanup(&iconv_utf8_to_tstr);
+       iconv_cleanup(&iconv_tstr_to_utf8);
+#if !TCHAR_IS_UTF16LE
+       iconv_cleanup(&iconv_utf16le_to_tstr);
+       iconv_cleanup(&iconv_tstr_to_utf16le);
+       iconv_cleanup(&iconv_utf16le_to_utf8);
+       iconv_cleanup(&iconv_utf8_to_utf16le);
+#endif
+}
+
+/* A table that maps from UCS-2 characters to their upper case equivalents.
+ * Index and array values are both CPU endian.
+ * Note: this is only an *approximation* of real UTF-16 case folding.
+ */
+static u16 upcase[65536];
+
+void
+init_upcase(void)
+{
+       /* This is the table used in NTFS volumes formatted by Windows 10.
+        * It was compressed by tools/compress_upcase_table.c.  */
+       static const u16 upcase_compressed[] = {
+               0x0000, 0x0000, 0x0060, 0x0000, 0x0000, 0xffe0, 0x0019, 0x0061,
+               0x0061, 0x0000, 0x001b, 0x005d, 0x0008, 0x0060, 0x0000, 0x0079,
+               0x0000, 0x0000, 0x0000, 0xffff, 0x002f, 0x0100, 0x0002, 0x0000,
+               0x0007, 0x012b, 0x0011, 0x0121, 0x002f, 0x0103, 0x0006, 0x0101,
+               0x0000, 0x00c3, 0x0006, 0x0131, 0x0007, 0x012e, 0x0004, 0x0000,
+               0x0003, 0x012f, 0x0000, 0x0061, 0x0004, 0x0130, 0x0000, 0x00a3,
+               0x0003, 0x0000, 0x0000, 0x0082, 0x000b, 0x0131, 0x0006, 0x0189,
+               0x0008, 0x012f, 0x0007, 0x012e, 0x0000, 0x0038, 0x0006, 0x0000,
+               0x0000, 0xfffe, 0x0007, 0x01c4, 0x000f, 0x0101, 0x0000, 0xffb1,
+               0x0015, 0x011e, 0x0004, 0x01cc, 0x002a, 0x0149, 0x0014, 0x0149,
+               0x0007, 0x0000, 0x0009, 0x018c, 0x000b, 0x0138, 0x0000, 0x2a1f,
+               0x0000, 0x2a1c, 0x0000, 0x0000, 0x0000, 0xff2e, 0x0000, 0xff32,
+               0x0000, 0x0000, 0x0000, 0xff33, 0x0000, 0xff33, 0x0000, 0x0000,
+               0x0000, 0xff36, 0x0000, 0x0000, 0x0000, 0xff35, 0x0004, 0x0000,
+               0x0002, 0x0257, 0x0000, 0x0000, 0x0000, 0xff31, 0x0004, 0x0000,
+               0x0000, 0xff2f, 0x0000, 0xff2d, 0x0000, 0x0000, 0x0000, 0x29f7,
+               0x0003, 0x0000, 0x0002, 0x0269, 0x0000, 0x29fd, 0x0000, 0xff2b,
+               0x0002, 0x0000, 0x0000, 0xff2a, 0x0007, 0x0000, 0x0000, 0x29e7,
+               0x0002, 0x0000, 0x0000, 0xff26, 0x0005, 0x027e, 0x0003, 0x027e,
+               0x0000, 0xffbb, 0x0000, 0xff27, 0x0000, 0xff27, 0x0000, 0xffb9,
+               0x0005, 0x0000, 0x0000, 0xff25, 0x0065, 0x007b, 0x0079, 0x0293,
+               0x0008, 0x012d, 0x0003, 0x019c, 0x0002, 0x037b, 0x002e, 0x0000,
+               0x0000, 0xffda, 0x0000, 0xffdb, 0x0002, 0x03ad, 0x0012, 0x0060,
+               0x000a, 0x0060, 0x0000, 0xffc0, 0x0000, 0xffc1, 0x0000, 0xffc1,
+               0x0008, 0x0000, 0x0000, 0xfff8, 0x001a, 0x0118, 0x0000, 0x0007,
+               0x0008, 0x018d, 0x0009, 0x0233, 0x0046, 0x0035, 0x0006, 0x0061,
+               0x0000, 0xffb0, 0x000f, 0x0450, 0x0025, 0x010e, 0x000a, 0x036b,
+               0x0032, 0x048b, 0x000e, 0x0100, 0x0000, 0xfff1, 0x0037, 0x048a,
+               0x0026, 0x0465, 0x0034, 0x0000, 0x0000, 0xffd0, 0x0025, 0x0561,
+               0x00de, 0x0293, 0x1714, 0x0587, 0x0000, 0x8a04, 0x0003, 0x0000,
+               0x0000, 0x0ee6, 0x0087, 0x02ee, 0x0092, 0x1e01, 0x0069, 0x1df7,
+               0x0000, 0x0008, 0x0007, 0x1f00, 0x0008, 0x0000, 0x000e, 0x1f02,
+               0x0008, 0x1f0e, 0x0010, 0x1f06, 0x001a, 0x1f06, 0x0002, 0x1f0f,
+               0x0007, 0x1f50, 0x0017, 0x1f19, 0x0000, 0x004a, 0x0000, 0x004a,
+               0x0000, 0x0056, 0x0003, 0x1f72, 0x0000, 0x0064, 0x0000, 0x0064,
+               0x0000, 0x0080, 0x0000, 0x0080, 0x0000, 0x0070, 0x0000, 0x0070,
+               0x0000, 0x007e, 0x0000, 0x007e, 0x0028, 0x1f1e, 0x000c, 0x1f06,
+               0x0000, 0x0000, 0x0000, 0x0009, 0x000f, 0x0000, 0x000d, 0x1fb3,
+               0x000d, 0x1f44, 0x0008, 0x1fcd, 0x0006, 0x03f2, 0x0015, 0x1fbb,
+               0x014e, 0x0587, 0x0000, 0xffe4, 0x0021, 0x0000, 0x0000, 0xfff0,
+               0x000f, 0x2170, 0x000a, 0x0238, 0x0346, 0x0587, 0x0000, 0xffe6,
+               0x0019, 0x24d0, 0x0746, 0x0587, 0x0026, 0x0561, 0x000b, 0x057e,
+               0x0004, 0x012f, 0x0000, 0xd5d5, 0x0000, 0xd5d8, 0x000c, 0x022e,
+               0x000e, 0x03f8, 0x006e, 0x1e33, 0x0011, 0x0000, 0x0000, 0xe3a0,
+               0x0025, 0x2d00, 0x17f2, 0x0587, 0x6129, 0x2d26, 0x002e, 0x0201,
+               0x002a, 0x1def, 0x0098, 0xa5b7, 0x0040, 0x1dff, 0x000e, 0x0368,
+               0x000d, 0x022b, 0x034c, 0x2184, 0x5469, 0x2d26, 0x007f, 0x0061,
+               0x0040, 0x0000,
+       };
+
+       /* Simple LZ decoder  */
+       const u16 *in_next = upcase_compressed;
+       for (u32 i = 0; i < ARRAY_LEN(upcase); ) {
+               u16 length = *in_next++;
+               u16 src_pos = *in_next++;
+               if (length == 0) {
+                       /* Literal */
+                       upcase[i++] = src_pos;
+               } else {
+                       /* Match */
+                       do {
+                               upcase[i++] = upcase[src_pos++];
+                       } while (--length);
+               }
+       }
+
+       /* Delta filter  */
+       for (u32 i = 0; i < ARRAY_LEN(upcase); i++)
+               upcase[i] += i;
+
+#if 0
+       /* Sanity checks  */
+       wimlib_assert(upcase['a'] == 'A');
+       wimlib_assert(upcase['A'] == 'A');
+       wimlib_assert(upcase['z'] == 'Z');
+       wimlib_assert(upcase['Z'] == 'Z');
+       wimlib_assert(upcase['1'] == '1');
+       wimlib_assert(upcase[0x00e9] == 0x00c9); /* Latin letter e, with acute accent  */
+       wimlib_assert(upcase[0x00c9] == 0x00c9);
+       wimlib_assert(upcase[0x03c1] == 0x03a1); /* Greek letter rho  */
+       wimlib_assert(upcase[0x03a1] == 0x03a1);
+       wimlib_assert(upcase[0x0436] == 0x0416); /* Cyrillic letter zhe  */
+       wimlib_assert(upcase[0x0416] == 0x0416);
+       wimlib_assert(upcase[0x0567] == 0x0537); /* Armenian letter eh  */
+       wimlib_assert(upcase[0x0537] == 0x0537);
+       wimlib_assert(upcase[0x24d0] == 0x24b6); /* Circled Latin letter A
+                                                   (is that a real character???)  */
+       wimlib_assert(upcase[0x24b6] == 0x24b6);
+       wimlib_assert(upcase[0x2603] == 0x2603); /* Note to self: Upper case
+                                                   snowman symbol does not
+                                                   exist.  */
+#endif
+}
+
+/* Compare UTF-16LE strings case-sensitively (%ignore_case == false) or
+ * case-insensitively (%ignore_case == true).
+ *
+ * This is implemented using the default upper-case table used by NTFS.  It does
+ * not handle all possible cases allowed by UTF-16LE.  For example, different
+ * normalizations of the same sequence of "characters" are not considered equal.
+ * It hopefully does the right thing most of the time though.  */
+int
+cmp_utf16le_strings(const utf16lechar *s1, size_t n1,
+                   const utf16lechar *s2, size_t n2,
+                   bool ignore_case)
 {
-       iconv_cleanup(&iconv_utf16le_to_mbs);
-       iconv_cleanup(&iconv_mbs_to_utf16le);
-       iconv_cleanup(&iconv_utf8_to_mbs);
+       size_t n = min(n1, n2);
+
+       if (ignore_case) {
+               for (size_t i = 0; i < n; i++) {
+                       u16 c1 = upcase[le16_to_cpu(s1[i])];
+                       u16 c2 = upcase[le16_to_cpu(s2[i])];
+                       if (c1 != c2)
+                               return (c1 < c2) ? -1 : 1;
+               }
+       } else {
+               for (size_t i = 0; i < n; i++) {
+                       u16 c1 = le16_to_cpu(s1[i]);
+                       u16 c2 = le16_to_cpu(s2[i]);
+                       if (c1 != c2)
+                               return (c1 < c2) ? -1 : 1;
+               }
+       }
+       if (n1 == n2)
+               return 0;
+       return (n1 < n2) ? -1 : 1;
 }
 
+/* Like cmp_utf16le_strings(), but assumes the strings are null terminated.  */
+int
+cmp_utf16le_strings_z(const utf16lechar *s1, const utf16lechar *s2,
+                     bool ignore_case)
+{
+       if (ignore_case) {
+               for (;;) {
+                       u16 c1 = upcase[le16_to_cpu(*s1)];
+                       u16 c2 = upcase[le16_to_cpu(*s2)];
+                       if (c1 != c2)
+                               return (c1 < c2) ? -1 : 1;
+                       if (c1 == 0)
+                               return 0;
+                       s1++, s2++;
+               }
+       } else {
+               while (*s1 && *s1 == *s2)
+                       s1++, s2++;
+               if (*s1 == *s2)
+                       return 0;
+               return (le16_to_cpu(*s1) < le16_to_cpu(*s2)) ? -1 : 1;
+       }
+}
+
+/* Duplicate a UTF-16LE string.  The input string might not be null terminated
+ * and might be misaligned, but the returned string is guaranteed to be null
+ * terminated and properly aligned.  */
+utf16lechar *
+utf16le_dupz(const void *ustr, size_t usize)
+{
+       utf16lechar *dup = MALLOC(usize + sizeof(utf16lechar));
+       if (dup) {
+               memcpy(dup, ustr, usize);
+               dup[usize / sizeof(utf16lechar)] = 0;
+       }
+       return dup;
+}
 
+/* Duplicate a null-terminated UTF-16LE string.  */
+utf16lechar *
+utf16le_dup(const utf16lechar *ustr)
+{
+       const utf16lechar *p = ustr;
+       while (*p++)
+               ;
+       return memdup(ustr, (const u8 *)p - (const u8 *)ustr);
+}
+
+/* Return the length, in bytes, of a UTF-null terminated UTF-16 string,
+ * excluding the null terminator.  */
+size_t
+utf16le_len_bytes(const utf16lechar *s)
+{
+       const utf16lechar *p = s;
+       while (*p)
+               p++;
+       return (p - s) * sizeof(utf16lechar);
+}
 
-bool
-utf8_str_contains_nonascii_chars(const utf8char *utf8_str)
+/* Return the length, in UTF-16 coding units, of a UTF-null terminated UTF-16
+ * string, excluding the null terminator.  */
+size_t
+utf16le_len_chars(const utf16lechar *s)
 {
-       do {
-               if ((unsigned char)*utf8_str > 127)
-                       return false;
-       } while (*++utf8_str);
-       return true;
+       return utf16le_len_bytes(s) / sizeof(utf16lechar);
 }