libarchive/archive_string.c - third_party/libarchive - Git at Google

 /*-
  * Copyright (c) 2003-2007 Tim Kientzle
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "archive_platform.h"
 __FBSDID("$FreeBSD: src/lib/libarchive/archive_string.c,v 1.17 2008/12/06 05:56:43 kientzle Exp $");

 /*
  * Basic resizable string support, to simplify manipulating arbitrary-sized
  * strings while minimizing heap activity.
  */

 #ifdef HAVE_STDLIB_H
 #include <stdlib.h>
 #endif
 #ifdef HAVE_STRING_H
 #include <string.h>
 #endif
 #ifdef HAVE_WCHAR_H
 #include <wchar.h>
 #endif
 #if defined(_WIN32) && !defined(__CYGWIN__)
 #include <windows.h>
 #endif

 #include "archive_private.h"
 #include "archive_string.h"

 struct archive_string *
 __archive_string_append(struct archive_string *as, const char *p, size_t s)
 {
 	if (__archive_string_ensure(as, as->length + s + 1) == NULL)
 		__archive_errx(1, "Out of memory");
 	memcpy(as->s + as->length, p, s);
 	as->s[as->length + s] = 0;
 	as->length += s;
 	return (as);
 }

 void
 __archive_string_copy(struct archive_string *dest, struct archive_string *src)
 {
 	if (src->length == 0)
 		dest->length = 0;
 	else {
 		if (__archive_string_ensure(dest, src->length + 1) == NULL)
 			__archive_errx(1, "Out of memory");
 		memcpy(dest->s, src->s, src->length);
 		dest->length = src->length;
 		dest->s[dest->length] = 0;
 	}
 }

 void
 __archive_string_concat(struct archive_string *dest, struct archive_string *src)
 {
 	if (src->length > 0) {
 		if (__archive_string_ensure(dest, dest->length + src->length + 1) == NULL)
 			__archive_errx(1, "Out of memory");
 		memcpy(dest->s + dest->length, src->s, src->length);
 		dest->length += src->length;
 		dest->s[dest->length] = 0;
 	}
 }

 void
 __archive_string_free(struct archive_string *as)
 {
 	as->length = 0;
 	as->buffer_length = 0;
 	if (as->s != NULL) {
 		free(as->s);
 		as->s = NULL;
 	}
 }

 /* Returns NULL on any allocation failure. */
 struct archive_string *
 __archive_string_ensure(struct archive_string *as, size_t s)
 {
 	/* If buffer is already big enough, don't reallocate. */
 	if (as->s && (s <= as->buffer_length))
 		return (as);

 	/*
 	 * Growing the buffer at least exponentially ensures that
 	 * append operations are always linear in the number of
 	 * characters appended.  Using a smaller growth rate for
 	 * larger buffers reduces memory waste somewhat at the cost of
 	 * a larger constant factor.
 	 */
 	if (as->buffer_length < 32)
 		/* Start with a minimum 32-character buffer. */
 		as->buffer_length = 32;
 	else if (as->buffer_length < 8192)
 		/* Buffers under 8k are doubled for speed. */
 		as->buffer_length += as->buffer_length;
 	else {
 		/* Buffers 8k and over grow by at least 25% each time. */
 		size_t old_length = as->buffer_length;
 		as->buffer_length += as->buffer_length / 4;
 		/* Be safe: If size wraps, release buffer and return NULL. */
 		if (as->buffer_length < old_length) {
 			free(as->s);
 			as->s = NULL;
 			return (NULL);
 		}
 	}
 	/*
 	 * The computation above is a lower limit to how much we'll
 	 * grow the buffer.  In any case, we have to grow it enough to
 	 * hold the request.
 	 */
 	if (as->buffer_length < s)
 		as->buffer_length = s;
 	/* Now we can reallocate the buffer. */
 	as->s = (char *)realloc(as->s, as->buffer_length);
 	if (as->s == NULL)
 		return (NULL);
 	return (as);
 }

 struct archive_string *
 __archive_strncat(struct archive_string *as, const void *_p, size_t n)
 {
 	size_t s;
 	const char *p, *pp;

 	p = (const char *)_p;

 	/* Like strlen(p), except won't examine positions beyond p[n]. */
 	s = 0;
 	pp = p;
 	while (*pp && s < n) {
 		pp++;
 		s++;
 	}
 	return (__archive_string_append(as, p, s));
 }

 struct archive_string *
 __archive_strappend_char(struct archive_string *as, char c)
 {
 	return (__archive_string_append(as, &c, 1));
 }

 /*
  * Translates a wide character string into UTF-8 and appends
  * to the archive_string.  Note: returns NULL if conversion fails,
  * but still leaves a best-effort conversion in the argument as.
  */
 struct archive_string *
 __archive_strappend_w_utf8(struct archive_string *as, const wchar_t *w)
 {
 	char *p;
 	unsigned wc;
 	char buff[256];
 	struct archive_string *return_val = as;

 	/*
 	 * Convert one wide char at a time into 'buff', whenever that
 	 * fills, append it to the string.
 	 */
 	p = buff;
 	while (*w != L'\0') {
 		/* Flush the buffer when we have <=16 bytes free. */
 		/* (No encoding has a single character >16 bytes.) */
 		if ((size_t)(p - buff) >= (size_t)(sizeof(buff) - 16)) {
 			*p = '\0';
 			archive_strcat(as, buff);
 			p = buff;
 		}
 		wc = *w++;
 		/* If this is a surrogate pair, assemble the full code point.*/
 		/* Note: wc must not be wchar_t here, because the full code
 		 * point can be more than 16 bits! */
 		if (wc >= 0xD800 && wc <= 0xDBff
 		    && *w >= 0xDC00 && *w <= 0xDFFF) {
 			wc -= 0xD800;
 			wc *= 0x400;
 			wc += (*w - 0xDC00);
 			wc += 0x10000;
 			++w;
 		}
 		/* Translate code point to UTF8 */
 		if (wc <= 0x7f) {
 			*p++ = (char)wc;
 		} else if (wc <= 0x7ff) {
 			*p++ = 0xc0 | ((wc >> 6) & 0x1f);
 			*p++ = 0x80 | (wc & 0x3f);
 		} else if (wc <= 0xffff) {
 			*p++ = 0xe0 | ((wc >> 12) & 0x0f);
 			*p++ = 0x80 | ((wc >> 6) & 0x3f);
 			*p++ = 0x80 | (wc & 0x3f);
 		} else if (wc <= 0x1fffff) {
 			*p++ = 0xf0 | ((wc >> 18) & 0x07);
 			*p++ = 0x80 | ((wc >> 12) & 0x3f);
 			*p++ = 0x80 | ((wc >> 6) & 0x3f);
 			*p++ = 0x80 | (wc & 0x3f);
 		} else {
 			/* Unicode has no codes larger than 0x1fffff. */
 			/* TODO: use \uXXXX escape here instead of ? */
 			*p++ = '?';
 			return_val = NULL;
 		}
 	}
 	*p = '\0';
 	archive_strcat(as, buff);
 	return (return_val);
 }

 static int
 utf8_to_unicode(int *pwc, const char *s, size_t n)
 {
         int ch;

         /*
 	 * Decode 1-4 bytes depending on the value of the first byte.
 	 */
         ch = (unsigned char)*s;
 	if (ch == 0) {
 		return (0); /* Standard:  return 0 for end-of-string. */
 	}
 	if ((ch & 0x80) == 0) {
                 *pwc = ch & 0x7f;
 		return (1);
         }
 	if ((ch & 0xe0) == 0xc0) {
 		if (n < 2)
 			return (-1);
 		if ((s[1] & 0xc0) != 0x80) return (-1);
                 *pwc = ((ch & 0x1f) << 6) | (s[1] & 0x3f);
 		return (2);
         }
 	if ((ch & 0xf0) == 0xe0) {
 		if (n < 3)
 			return (-1);
 		if ((s[1] & 0xc0) != 0x80) return (-1);
 		if ((s[2] & 0xc0) != 0x80) return (-1);
                 *pwc = ((ch & 0x0f) << 12)
 		    | ((s[1] & 0x3f) << 6)
 		    | (s[2] & 0x3f);
 		return (3);
         }
 	if ((ch & 0xf8) == 0xf0) {
 		if (n < 4)
 			return (-1);
 		if ((s[1] & 0xc0) != 0x80) return (-1);
 		if ((s[2] & 0xc0) != 0x80) return (-1);
 		if ((s[3] & 0xc0) != 0x80) return (-1);
                 *pwc = ((ch & 0x07) << 18)
 		    | ((s[1] & 0x3f) << 12)
 		    | ((s[2] & 0x3f) << 6)
 		    | (s[3] & 0x3f);
 		return (4);
         }
 	/* Invalid first byte. */
 	return (-1);
 }

 /*
  * Return a wide-character Unicode string by converting this archive_string
  * from UTF-8.  We assume that systems with 16-bit wchar_t always use
  * UTF16 and systems with 32-bit wchar_t can accept UCS4.
  */
 wchar_t *
 __archive_string_utf8_w(struct archive_string *as)
 {
 	wchar_t *ws, *dest;
 	int wc, wc2;/* Must be large enough for a 21-bit Unicode code point. */
 	const char *src;
 	int n;
 	int err;

 	ws = (wchar_t *)malloc((as->length + 1) * sizeof(wchar_t));
 	if (ws == NULL)
 		__archive_errx(1, "Out of memory");
 	err = 0;
 	dest = ws;
 	src = as->s;
 	while (*src != '\0') {
 		n = utf8_to_unicode(&wc, src, 8);
 		if (n == 0)
 			break;
 		if (n < 0) {
 			free(ws);
 			return (NULL);
 		}
 		src += n;
 		if (wc >= 0xDC00 && wc <= 0xDBFF) {
 			/* This is a leading surrogate; some idiot
 			 * has translated UTF16 to UTF8 without combining
 			 * surrogates; rebuild the full code point before
 			 * continuing. */
 			n = utf8_to_unicode(&wc2, src, 8);
 			if (n < 0) {
 				free(ws);
 				return (NULL);
 			}
 			if (n == 0) /* Ignore the leading surrogate */
 				break;
 			if (wc2 < 0xDC00 || wc2 > 0xDFFF) {
 				/* If the second character isn't a
 				 * trailing surrogate, then someone
 				 * has really screwed up and this is
 				 * invalid. */
 				free(ws);
 				return (NULL);
 			} else {
 				src += n;
 				wc -= 0xD800;
 				wc *= 0x400;
 				wc += wc2 - 0xDC00;
 				wc += 0x10000;
 			}
 		}
 		if ((sizeof(wchar_t) < 4) && (wc > 0xffff)) {
 			/* We have a code point that won't fit into a
 			 * wchar_t; convert it to a surrogate pair. */
 			wc -= 0x10000;
 			*dest++ = ((wc >> 10) & 0x3ff) + 0xD800;
 			*dest++ = (wc & 0x3ff) + 0xDC00;
 		} else
 			*dest++ = wc;
 	}
 	*dest++ = L'\0';
 	return (ws);
 }

 #if defined(_WIN32) && !defined(__CYGWIN__)

 /*
  * Translates a wide character string into current locale character set
  * and appends to the archive_string.  Note: returns NULL if conversion
  * fails.
  *
  * Win32 builds use WideCharToMultiByte from the Windows API.
  * (Maybe Cygwin should too?  WideCharToMultiByte will know a
  * lot more about local character encodings than the wcrtomb()
  * wrapper is going to know.)
  */
 struct archive_string *
 __archive_strappend_w_mbs(struct archive_string *as, const wchar_t *w)
 {
 	char *p;
 	int l, wl;
 	BOOL useDefaultChar = FALSE;

 	wl = (int)wcslen(w);
 	l = wl * 4 + 4;
 	p = malloc(l);
 	if (p == NULL)
 		__archive_errx(1, "Out of memory");
 	/* To check a useDefaultChar is to simulate error handling of
 	 * the my_wcstombs() which is running on non Windows system with
 	 * wctomb().
 	 * And to set NULL for last argument is necessary when a codepage
 	 * is not CP_ACP(current locale).
 	 */
 	l = WideCharToMultiByte(CP_ACP, 0, w, wl, p, l, NULL, &useDefaultChar);
 	if (l == 0) {
 		free(p);
 		return (NULL);
 	}
 	__archive_string_append(as, p, l);
 	free(p);
 	return (as);
 }

 #else

 /*
  * Translates a wide character string into current locale character set
  * and appends to the archive_string.  Note: returns NULL if conversion
  * fails.
  *
  * Non-Windows uses ISO C wcrtomb() or wctomb() to perform the conversion
  * one character at a time.  If a non-Windows platform doesn't have
  * either of these, fall back to the built-in UTF8 conversion.
  */
 struct archive_string *
 __archive_strappend_w_mbs(struct archive_string *as, const wchar_t *w)
 {
 #if !defined(HAVE_WCTOMB) && !defined(HAVE_WCRTOMB)
 	/* If there's no built-in locale support, fall back to UTF8 always. */
 	return __archive_strappend_w_utf8(as, w);
 #else
 	/* We cannot use the standard wcstombs() here because it
 	 * cannot tell us how big the output buffer should be.  So
 	 * I've built a loop around wcrtomb() or wctomb() that
 	 * converts a character at a time and resizes the string as
 	 * needed.  We prefer wcrtomb() when it's available because
 	 * it's thread-safe. */
 	int n;
 	char *p;
 	char buff[256];
 #if HAVE_WCRTOMB
 	mbstate_t shift_state;

 	memset(&shift_state, 0, sizeof(shift_state));
 #else
 	/* Clear the shift state before starting. */
 	wctomb(NULL, L'\0');
 #endif

 	/*
 	 * Convert one wide char at a time into 'buff', whenever that
 	 * fills, append it to the string.
 	 */
 	p = buff;
 	while (*w != L'\0') {
 		/* Flush the buffer when we have <=16 bytes free. */
 		/* (No encoding has a single character >16 bytes.) */
 		if ((size_t)(p - buff) >= (size_t)(sizeof(buff) - MB_CUR_MAX)) {
 			*p = '\0';
 			archive_strcat(as, buff);
 			p = buff;
 		}
 #if HAVE_WCRTOMB
 		n = wcrtomb(p, *w++, &shift_state);
 #else
 		n = wctomb(p, *w++);
 #endif
 		if (n == -1)
 			return (NULL);
 		p += n;
 	}
 	*p = '\0';
 	archive_strcat(as, buff);
 	return (as);
 #endif
 }

 #endif /* _WIN32 && ! __CYGWIN__ */
	/*-
	* Copyright (c) 2003-2007 Tim Kientzle
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	* IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "archive_platform.h"
	__FBSDID("$FreeBSD: src/lib/libarchive/archive_string.c,v 1.17 2008/12/06 05:56:43 kientzle Exp $");

	/*
	* Basic resizable string support, to simplify manipulating arbitrary-sized
	* strings while minimizing heap activity.
	*/

	#ifdef HAVE_STDLIB_H
	#include <stdlib.h>
	#endif
	#ifdef HAVE_STRING_H
	#include <string.h>
	#endif
	#ifdef HAVE_WCHAR_H
	#include <wchar.h>
	#endif
	#if defined(_WIN32) && !defined(__CYGWIN__)
	#include <windows.h>
	#endif

	#include "archive_private.h"
	#include "archive_string.h"

	struct archive_string *
	__archive_string_append(struct archive_string as, const char p, size_t s)
	{
	if (__archive_string_ensure(as, as->length + s + 1) == NULL)
	__archive_errx(1, "Out of memory");
	memcpy(as->s + as->length, p, s);
	as->s[as->length + s] = 0;
	as->length += s;
	return (as);
	}

	void
	__archive_string_copy(struct archive_string dest, struct archive_string src)
	{
	if (src->length == 0)
	dest->length = 0;
	else {
	if (__archive_string_ensure(dest, src->length + 1) == NULL)
	__archive_errx(1, "Out of memory");
	memcpy(dest->s, src->s, src->length);
	dest->length = src->length;
	dest->s[dest->length] = 0;
	}
	}

	void
	__archive_string_concat(struct archive_string dest, struct archive_string src)
	{
	if (src->length > 0) {
	if (__archive_string_ensure(dest, dest->length + src->length + 1) == NULL)
	__archive_errx(1, "Out of memory");
	memcpy(dest->s + dest->length, src->s, src->length);
	dest->length += src->length;
	dest->s[dest->length] = 0;
	}
	}

	void
	__archive_string_free(struct archive_string *as)
	{
	as->length = 0;
	as->buffer_length = 0;
	if (as->s != NULL) {
	free(as->s);
	as->s = NULL;
	}
	}

	/* Returns NULL on any allocation failure. */
	struct archive_string *
	__archive_string_ensure(struct archive_string *as, size_t s)
	{
	/* If buffer is already big enough, don't reallocate. */
	if (as->s && (s <= as->buffer_length))
	return (as);

	/*
	* Growing the buffer at least exponentially ensures that
	* append operations are always linear in the number of
	* characters appended. Using a smaller growth rate for
	* larger buffers reduces memory waste somewhat at the cost of
	* a larger constant factor.
	*/
	if (as->buffer_length < 32)
	/* Start with a minimum 32-character buffer. */
	as->buffer_length = 32;
	else if (as->buffer_length < 8192)
	/* Buffers under 8k are doubled for speed. */
	as->buffer_length += as->buffer_length;
	else {
	/* Buffers 8k and over grow by at least 25% each time. */
	size_t old_length = as->buffer_length;
	as->buffer_length += as->buffer_length / 4;
	/* Be safe: If size wraps, release buffer and return NULL. */
	if (as->buffer_length < old_length) {
	free(as->s);
	as->s = NULL;
	return (NULL);
	}
	}
	/*
	* The computation above is a lower limit to how much we'll
	* grow the buffer. In any case, we have to grow it enough to
	* hold the request.
	*/
	if (as->buffer_length < s)
	as->buffer_length = s;
	/* Now we can reallocate the buffer. */
	as->s = (char *)realloc(as->s, as->buffer_length);
	if (as->s == NULL)
	return (NULL);
	return (as);
	}

	struct archive_string *
	__archive_strncat(struct archive_string as, const void _p, size_t n)
	{
	size_t s;
	const char p, pp;

	p = (const char *)_p;

	/* Like strlen(p), except won't examine positions beyond p[n]. */
	s = 0;
	pp = p;
	while (*pp && s < n) {
	pp++;
	s++;
	}
	return (__archive_string_append(as, p, s));
	}

	struct archive_string *
	__archive_strappend_char(struct archive_string *as, char c)
	{
	return (__archive_string_append(as, &c, 1));
	}

	/*
	* Translates a wide character string into UTF-8 and appends
	* to the archive_string. Note: returns NULL if conversion fails,
	* but still leaves a best-effort conversion in the argument as.
	*/
	struct archive_string *
	__archive_strappend_w_utf8(struct archive_string as, const wchar_t w)
	{
	char *p;
	unsigned wc;
	char buff[256];
	struct archive_string *return_val = as;

	/*
	* Convert one wide char at a time into 'buff', whenever that
	* fills, append it to the string.
	*/
	p = buff;
	while (*w != L'\0') {
	/* Flush the buffer when we have <=16 bytes free. */
	/* (No encoding has a single character >16 bytes.) */
	if ((size_t)(p - buff) >= (size_t)(sizeof(buff) - 16)) {
	*p = '\0';
	archive_strcat(as, buff);
	p = buff;
	}
	wc = *w++;
	/* If this is a surrogate pair, assemble the full code point.*/
	/* Note: wc must not be wchar_t here, because the full code
	* point can be more than 16 bits! */
	if (wc >= 0xD800 && wc <= 0xDBff
	&& w >= 0xDC00 && w <= 0xDFFF) {
	wc -= 0xD800;
	wc *= 0x400;
	wc += (*w - 0xDC00);
	wc += 0x10000;
	++w;
	}
	/* Translate code point to UTF8 */
	if (wc <= 0x7f) {
	*p++ = (char)wc;
	} else if (wc <= 0x7ff) {
	*p++ = 0xc0 \| ((wc >> 6) & 0x1f);
	*p++ = 0x80 \| (wc & 0x3f);
	} else if (wc <= 0xffff) {
	*p++ = 0xe0 \| ((wc >> 12) & 0x0f);
	*p++ = 0x80 \| ((wc >> 6) & 0x3f);
	*p++ = 0x80 \| (wc & 0x3f);
	} else if (wc <= 0x1fffff) {
	*p++ = 0xf0 \| ((wc >> 18) & 0x07);
	*p++ = 0x80 \| ((wc >> 12) & 0x3f);
	*p++ = 0x80 \| ((wc >> 6) & 0x3f);
	*p++ = 0x80 \| (wc & 0x3f);
	} else {
	/* Unicode has no codes larger than 0x1fffff. */
	/* TODO: use \uXXXX escape here instead of ? */
	*p++ = '?';
	return_val = NULL;
	}
	}
	*p = '\0';
	archive_strcat(as, buff);
	return (return_val);
	}

	static int
	utf8_to_unicode(int pwc, const char s, size_t n)
	{
	int ch;

	/*
	* Decode 1-4 bytes depending on the value of the first byte.
	*/
	ch = (unsigned char)*s;
	if (ch == 0) {
	return (0); /* Standard: return 0 for end-of-string. */
	}
	if ((ch & 0x80) == 0) {
	*pwc = ch & 0x7f;
	return (1);
	}
	if ((ch & 0xe0) == 0xc0) {
	if (n < 2)
	return (-1);
	if ((s[1] & 0xc0) != 0x80) return (-1);
	*pwc = ((ch & 0x1f) << 6) \| (s[1] & 0x3f);
	return (2);
	}
	if ((ch & 0xf0) == 0xe0) {
	if (n < 3)
	return (-1);
	if ((s[1] & 0xc0) != 0x80) return (-1);
	if ((s[2] & 0xc0) != 0x80) return (-1);
	*pwc = ((ch & 0x0f) << 12)
	\| ((s[1] & 0x3f) << 6)
	\| (s[2] & 0x3f);
	return (3);
	}
	if ((ch & 0xf8) == 0xf0) {
	if (n < 4)
	return (-1);
	if ((s[1] & 0xc0) != 0x80) return (-1);
	if ((s[2] & 0xc0) != 0x80) return (-1);
	if ((s[3] & 0xc0) != 0x80) return (-1);
	*pwc = ((ch & 0x07) << 18)
	\| ((s[1] & 0x3f) << 12)
	\| ((s[2] & 0x3f) << 6)
	\| (s[3] & 0x3f);
	return (4);
	}
	/* Invalid first byte. */
	return (-1);
	}

	/*
	* Return a wide-character Unicode string by converting this archive_string
	* from UTF-8. We assume that systems with 16-bit wchar_t always use
	* UTF16 and systems with 32-bit wchar_t can accept UCS4.
	*/
	wchar_t *
	__archive_string_utf8_w(struct archive_string *as)
	{
	wchar_t ws, dest;
	int wc, wc2;/* Must be large enough for a 21-bit Unicode code point. */
	const char *src;
	int n;
	int err;

	ws = (wchar_t )malloc((as->length + 1) sizeof(wchar_t));
	if (ws == NULL)
	__archive_errx(1, "Out of memory");
	err = 0;
	dest = ws;
	src = as->s;
	while (*src != '\0') {
	n = utf8_to_unicode(&wc, src, 8);
	if (n == 0)
	break;
	if (n < 0) {
	free(ws);
	return (NULL);
	}
	src += n;
	if (wc >= 0xDC00 && wc <= 0xDBFF) {
	/* This is a leading surrogate; some idiot
	* has translated UTF16 to UTF8 without combining
	* surrogates; rebuild the full code point before
	* continuing. */
	n = utf8_to_unicode(&wc2, src, 8);
	if (n < 0) {
	free(ws);
	return (NULL);
	}
	if (n == 0) /* Ignore the leading surrogate */
	break;
	if (wc2 < 0xDC00 \|\| wc2 > 0xDFFF) {
	/* If the second character isn't a
	* trailing surrogate, then someone
	* has really screwed up and this is
	* invalid. */
	free(ws);
	return (NULL);
	} else {
	src += n;
	wc -= 0xD800;
	wc *= 0x400;
	wc += wc2 - 0xDC00;
	wc += 0x10000;
	}
	}
	if ((sizeof(wchar_t) < 4) && (wc > 0xffff)) {
	/* We have a code point that won't fit into a
	* wchar_t; convert it to a surrogate pair. */
	wc -= 0x10000;
	*dest++ = ((wc >> 10) & 0x3ff) + 0xD800;
	*dest++ = (wc & 0x3ff) + 0xDC00;
	} else
	*dest++ = wc;
	}
	*dest++ = L'\0';
	return (ws);
	}

	#if defined(_WIN32) && !defined(__CYGWIN__)

	/*
	* Translates a wide character string into current locale character set
	* and appends to the archive_string. Note: returns NULL if conversion
	* fails.
	*
	* Win32 builds use WideCharToMultiByte from the Windows API.
	* (Maybe Cygwin should too? WideCharToMultiByte will know a
	* lot more about local character encodings than the wcrtomb()
	* wrapper is going to know.)
	*/
	struct archive_string *
	__archive_strappend_w_mbs(struct archive_string as, const wchar_t w)
	{
	char *p;
	int l, wl;
	BOOL useDefaultChar = FALSE;

	wl = (int)wcslen(w);
	l = wl * 4 + 4;
	p = malloc(l);
	if (p == NULL)
	__archive_errx(1, "Out of memory");
	/* To check a useDefaultChar is to simulate error handling of
	* the my_wcstombs() which is running on non Windows system with
	* wctomb().
	* And to set NULL for last argument is necessary when a codepage
	* is not CP_ACP(current locale).
	*/
	l = WideCharToMultiByte(CP_ACP, 0, w, wl, p, l, NULL, &useDefaultChar);
	if (l == 0) {
	free(p);
	return (NULL);
	}
	__archive_string_append(as, p, l);
	free(p);
	return (as);
	}

	#else

	/*
	* Translates a wide character string into current locale character set
	* and appends to the archive_string. Note: returns NULL if conversion
	* fails.
	*
	* Non-Windows uses ISO C wcrtomb() or wctomb() to perform the conversion
	* one character at a time. If a non-Windows platform doesn't have
	* either of these, fall back to the built-in UTF8 conversion.
	*/
	struct archive_string *
	__archive_strappend_w_mbs(struct archive_string as, const wchar_t w)
	{
	#if !defined(HAVE_WCTOMB) && !defined(HAVE_WCRTOMB)
	/* If there's no built-in locale support, fall back to UTF8 always. */
	return __archive_strappend_w_utf8(as, w);
	#else
	/* We cannot use the standard wcstombs() here because it
	* cannot tell us how big the output buffer should be. So
	* I've built a loop around wcrtomb() or wctomb() that
	* converts a character at a time and resizes the string as
	* needed. We prefer wcrtomb() when it's available because
	* it's thread-safe. */
	int n;
	char *p;
	char buff[256];
	#if HAVE_WCRTOMB
	mbstate_t shift_state;

	memset(&shift_state, 0, sizeof(shift_state));
	#else
	/* Clear the shift state before starting. */
	wctomb(NULL, L'\0');
	#endif

	/*
	* Convert one wide char at a time into 'buff', whenever that
	* fills, append it to the string.
	*/
	p = buff;
	while (*w != L'\0') {
	/* Flush the buffer when we have <=16 bytes free. */
	/* (No encoding has a single character >16 bytes.) */
	if ((size_t)(p - buff) >= (size_t)(sizeof(buff) - MB_CUR_MAX)) {
	*p = '\0';
	archive_strcat(as, buff);
	p = buff;
	}
	#if HAVE_WCRTOMB
	n = wcrtomb(p, *w++, &shift_state);
	#else
	n = wctomb(p, *w++);
	#endif
	if (n == -1)
	return (NULL);
	p += n;
	}
	*p = '\0';
	archive_strcat(as, buff);
	return (as);
	#endif
	}

	#endif /* _WIN32 && ! __CYGWIN__ */