]> wimlib.net Git - wimlib/blobdiff - src/encoding.c
Implement setting of Windows-specific XML information
[wimlib] / src / encoding.c
index 752ab847bed3cfeb6d8f7a7ae8341ebc9c47e7d8..4fd8712b62a94725f41117ede8a6b8b3961b3518 100644 (file)
@@ -5,27 +5,31 @@
 /*
  * 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/.
  */
 
 #ifdef HAVE_CONFIG_H
 #  include "config.h"
 #endif
 
+#include <errno.h>
+#include <iconv.h>
+#include <pthread.h>
+#include <string.h>
+
 #include "wimlib.h"
+#include "wimlib/alloca.h"
 #include "wimlib/assert.h"
 #include "wimlib/encoding.h"
 #include "wimlib/endianness.h"
 #include "wimlib/list.h"
 #include "wimlib/util.h"
 
-#include <errno.h>
-#include <iconv.h>
-#include <pthread.h>
-#include <stdlib.h>
-#include <string.h>
 
 bool wimlib_mbs_is_utf8 = !TCHAR_IS_UTF16LE;
 
@@ -64,8 +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 *
@@ -115,11 +112,6 @@ put_iconv(iconv_t *cd)
        errno = errno_save;
 }
 
-/* Prevent printing an error message if a character conversion error occurs
- * while printing an error message.  (This variable is not per-thread but it
- * doesn't matter too much since it's just the error messages.) */
-static bool error_message_being_printed = false;
-
 #define DEFINE_CHAR_CONVERSION_FUNCTIONS(varname1, longname1, chartype1,\
                                         varname2, longname2, chartype2,\
                                         earlyreturn_on_utf8_locale,    \
@@ -139,28 +131,39 @@ 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;                                                        \
                                                                        \
        len = iconv(*cd, &inbuf, &inbytesleft, &outbuf, &outbytesleft); \
        if (len == (size_t)-1) {                                        \
-               if (!error_message_being_printed) {                     \
-                       error_message_being_printed = true;             \
-                       err_msg;                                        \
-                       error_message_being_printed = false;            \
-               }                                                       \
+               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;                                                     \
 }                                                                      \
                                                                        \
@@ -182,11 +185,7 @@ varname1##_to_##varname2##_buf(const chartype1 *in, size_t in_nbytes,      \
                                                                        \
        len = iconv(*cd, &inbuf, &inbytesleft, &outbuf, &outbytesleft); \
        if (len == (size_t)-1) {                                        \
-               if (!error_message_being_printed) {                     \
-                       error_message_being_printed = true;             \
-                       err_msg;                                        \
-                       error_message_being_printed = false;            \
-               }                                                       \
+               err_msg;                                                \
                ret = err_return;                                       \
        } else {                                                        \
                out[(LARGE_NUMBER-outbytesleft)/sizeof(chartype2)] = 0; \
@@ -357,6 +356,13 @@ utf8_to_tstr_simple(const char *utf8str, tchar **out)
        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)
 {
@@ -371,6 +377,19 @@ iconv_cleanup(struct iconv_list_head *head)
        }
 }
 
+void
+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)
 {
@@ -388,98 +407,83 @@ iconv_global_cleanup(void)
  * Index and array values are both CPU endian.
  * Note: this is only an *approximation* of real UTF-16 case folding.
  */
-static u16 upcase[65536];
+u16 upcase[65536];
 
-/*
- * Initialize the 'upcase' table.
- *
- * Code modified from NTFS-3g, original copyright notices below:
- *
- * Copyright (c) 2000-2004 Anton Altaparmakov
- * Copyright (c) 2002-2009 Szabolcs Szakacsits
- * Copyright (c) 2008-2011 Jean-Pierre Andre
- * Copyright (c) 2008      Bernhard Kaindl
- *
- * License GPLv2 or later.  (Or may actually be LGPL since it's in libntfs-3g.)
- *
- * The expanded table itself is the same as that used by Windows Vista for
- * NTFS case insensitivity.
- */
 void
 init_upcase(void)
 {
-       /*
-        *      This is the table as defined by Vista
-        */
-       /*
-        * "Start" is inclusive and "End" is exclusive, every value has the
-        * value of "Add" added to it.
-        */
-       static const u16 uc_run_table[][3] = { /* Start, End, Add */
-       {0x0061, 0x007b,   -32}, {0x00e0, 0x00f7,  -32}, {0x00f8, 0x00ff, -32},
-       {0x0256, 0x0258,  -205}, {0x028a, 0x028c, -217}, {0x037b, 0x037e, 130},
-       {0x03ac, 0x03ad,   -38}, {0x03ad, 0x03b0,  -37}, {0x03b1, 0x03c2, -32},
-       {0x03c2, 0x03c3,   -31}, {0x03c3, 0x03cc,  -32}, {0x03cc, 0x03cd, -64},
-       {0x03cd, 0x03cf,   -63}, {0x0430, 0x0450,  -32}, {0x0450, 0x0460, -80},
-       {0x0561, 0x0587,   -48}, {0x1f00, 0x1f08,    8}, {0x1f10, 0x1f16,   8},
-       {0x1f20, 0x1f28,     8}, {0x1f30, 0x1f38,    8}, {0x1f40, 0x1f46,   8},
-       {0x1f51, 0x1f52,     8}, {0x1f53, 0x1f54,    8}, {0x1f55, 0x1f56,   8},
-       {0x1f57, 0x1f58,     8}, {0x1f60, 0x1f68,    8}, {0x1f70, 0x1f72,  74},
-       {0x1f72, 0x1f76,    86}, {0x1f76, 0x1f78,  100}, {0x1f78, 0x1f7a, 128},
-       {0x1f7a, 0x1f7c,   112}, {0x1f7c, 0x1f7e,  126}, {0x1f80, 0x1f88,   8},
-       {0x1f90, 0x1f98,     8}, {0x1fa0, 0x1fa8,    8}, {0x1fb0, 0x1fb2,   8},
-       {0x1fb3, 0x1fb4,     9}, {0x1fcc, 0x1fcd,   -9}, {0x1fd0, 0x1fd2,   8},
-       {0x1fe0, 0x1fe2,     8}, {0x1fe5, 0x1fe6,    7}, {0x1ffc, 0x1ffd,  -9},
-       {0x2170, 0x2180,   -16}, {0x24d0, 0x24ea,  -26}, {0x2c30, 0x2c5f, -48},
-       {0x2d00, 0x2d26, -7264}, {0xff41, 0xff5b,  -32},
-       };
-       /*
-        * "Start" is exclusive and "End" is inclusive, every second value is
-        * decremented by one.
-        */
-       static const u16 uc_dup_table[][2] = { /* Start, End */
-       {0x0100, 0x012f}, {0x0132, 0x0137}, {0x0139, 0x0149}, {0x014a, 0x0178},
-       {0x0179, 0x017e}, {0x01a0, 0x01a6}, {0x01b3, 0x01b7}, {0x01cd, 0x01dd},
-       {0x01de, 0x01ef}, {0x01f4, 0x01f5}, {0x01f8, 0x01f9}, {0x01fa, 0x0220},
-       {0x0222, 0x0234}, {0x023b, 0x023c}, {0x0241, 0x0242}, {0x0246, 0x024f},
-       {0x03d8, 0x03ef}, {0x03f7, 0x03f8}, {0x03fa, 0x03fb}, {0x0460, 0x0481},
-       {0x048a, 0x04bf}, {0x04c1, 0x04c4}, {0x04c5, 0x04c8}, {0x04c9, 0x04ce},
-       {0x04ec, 0x04ed}, {0x04d0, 0x04eb}, {0x04ee, 0x04f5}, {0x04f6, 0x0513},
-       {0x1e00, 0x1e95}, {0x1ea0, 0x1ef9}, {0x2183, 0x2184}, {0x2c60, 0x2c61},
-       {0x2c67, 0x2c6c}, {0x2c75, 0x2c76}, {0x2c80, 0x2ce3},
-       };
-       /*
-        * Set the Unicode character at offset "Offset" to "Value".  Note,
-        * "Value" is host endian.
-        */
-       static const u16 uc_byte_table[][2] = { /* Offset, Value */
-       {0x00ff, 0x0178}, {0x0180, 0x0243}, {0x0183, 0x0182}, {0x0185, 0x0184},
-       {0x0188, 0x0187}, {0x018c, 0x018b}, {0x0192, 0x0191}, {0x0195, 0x01f6},
-       {0x0199, 0x0198}, {0x019a, 0x023d}, {0x019e, 0x0220}, {0x01a8, 0x01a7},
-       {0x01ad, 0x01ac}, {0x01b0, 0x01af}, {0x01b9, 0x01b8}, {0x01bd, 0x01bc},
-       {0x01bf, 0x01f7}, {0x01c6, 0x01c4}, {0x01c9, 0x01c7}, {0x01cc, 0x01ca},
-       {0x01dd, 0x018e}, {0x01f3, 0x01f1}, {0x023a, 0x2c65}, {0x023e, 0x2c66},
-       {0x0253, 0x0181}, {0x0254, 0x0186}, {0x0259, 0x018f}, {0x025b, 0x0190},
-       {0x0260, 0x0193}, {0x0263, 0x0194}, {0x0268, 0x0197}, {0x0269, 0x0196},
-       {0x026b, 0x2c62}, {0x026f, 0x019c}, {0x0272, 0x019d}, {0x0275, 0x019f},
-       {0x027d, 0x2c64}, {0x0280, 0x01a6}, {0x0283, 0x01a9}, {0x0288, 0x01ae},
-       {0x0289, 0x0244}, {0x028c, 0x0245}, {0x0292, 0x01b7}, {0x03f2, 0x03f9},
-       {0x04cf, 0x04c0}, {0x1d7d, 0x2c63}, {0x214e, 0x2132},
+       /* 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,
        };
 
-       for (u32 i = 0; i < 65536; i++)
-               upcase[i] = i;
-
-       for (u32 r = 0; r < ARRAY_LEN(uc_run_table); r++)
-               for (u32 i = uc_run_table[r][0]; i < uc_run_table[r][1]; i++)
-                       upcase[i] = i + uc_run_table[r][2];
-
-       for (u32 r = 0; r < ARRAY_LEN(uc_dup_table); r++)
-               for (u32 i = uc_dup_table[r][0]; i < uc_dup_table[r][1]; i += 2)
-                       upcase[i + 1] = i;
+       /* 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);
+               }
+       }
 
-       for (u32 r = 0; r < ARRAY_LEN(uc_byte_table); r++)
-               upcase[uc_byte_table[r][0]] = uc_byte_table[r][1];
+       /* Delta filter  */
+       for (u32 i = 0; i < ARRAY_LEN(upcase); i++)
+               upcase[i] += i;
 
 #if 0
        /* Sanity checks  */
@@ -539,40 +543,69 @@ cmp_utf16le_strings(const utf16lechar *s1, size_t n1,
        return (n1 < n2) ? -1 : 1;
 }
 
-/* Duplicates a string of system-dependent encoding into a UTF-16LE string and
- * returns the string and its length, in bytes, in the pointer arguments.  Frees
- * any existing string at the return location before overwriting it. */
+/* Like cmp_utf16le_strings(), but assumes the strings are null terminated.  */
 int
-get_utf16le_string(const tchar *name, utf16lechar **name_utf16le_ret,
-                  u16 *name_utf16le_nbytes_ret)
+cmp_utf16le_strings_z(const utf16lechar *s1, const utf16lechar *s2,
+                     bool ignore_case)
 {
-       utf16lechar *name_utf16le;
-       size_t name_utf16le_nbytes;
-       int ret;
-#if TCHAR_IS_UTF16LE
-       name_utf16le_nbytes = tstrlen(name) * sizeof(utf16lechar);
-       name_utf16le = MALLOC(name_utf16le_nbytes + sizeof(utf16lechar));
-       if (name_utf16le == NULL)
-               return WIMLIB_ERR_NOMEM;
-       memcpy(name_utf16le, name, name_utf16le_nbytes + sizeof(utf16lechar));
-       ret = 0;
-#else
-
-       ret = tstr_to_utf16le(name, tstrlen(name), &name_utf16le,
-                             &name_utf16le_nbytes);
-       if (ret == 0) {
-               if (name_utf16le_nbytes > 0xffff) {
-                       FREE(name_utf16le);
-                       ERROR("Multibyte string \"%"TS"\" is too long!", name);
-                       ret = WIMLIB_ERR_INVALID_UTF8_STRING;
+       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;
        }
-#endif
-       if (ret == 0) {
-               FREE(*name_utf16le_ret);
-               *name_utf16le_ret = name_utf16le;
-               *name_utf16le_nbytes_ret = name_utf16le_nbytes;
+}
+
+/* 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 ret;
+       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);
+}
+
+/* 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)
+{
+       return utf16le_len_bytes(s) / sizeof(utf16lechar);
+}