text: #ifndef lint
  static char *rcsid = "$Id: race.c,v 1.1 2003/06/04 00:26:07 marka Exp $";
  #endif
  
  /*
   * Copyright (c) 2000,2001,2002 Japan Network Information Center.
   * All rights reserved.
   *  
   * By using this file, you agree to the terms and conditions set forth bellow.
   * 
   * 			LICENSE TERMS AND CONDITIONS 
   * 
   * The following License Terms and Conditions apply, unless a different
   * license is obtained from Japan Network Information Center ("JPNIC"),
   * a Japanese association, Kokusai-Kougyou-Kanda Bldg 6F, 2-3-4 Uchi-Kanda,
   * Chiyoda-ku, Tokyo 101-0047, Japan.
   * 
   * 1. Use, Modification and Redistribution (including distribution of any
   *    modified or derived work) in source and/or binary forms is permitted
   *    under this License Terms and Conditions.
   * 
   * 2. Redistribution of source code must retain the copyright notices as they
   *    appear in each source code file, this License Terms and Conditions.
   * 
   * 3. Redistribution in binary form must reproduce the Copyright Notice,
   *    this License Terms and Conditions, in the documentation and/or other
   *    materials provided with the distribution.  For the purposes of binary
   *    distribution the "Copyright Notice" refers to the following language:
   *    "Copyright (c) 2000-2002 Japan Network Information Center.  All rights reserved."
   * 
   * 4. The name of JPNIC may not be used to endorse or promote products
   *    derived from this Software without specific prior written approval of
   *    JPNIC.
   * 
   * 5. Disclaimer/Limitation of Liability: THIS SOFTWARE IS PROVIDED BY JPNIC
   *    "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 JPNIC 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 DAMAGES.
   */
  
  #include <config.h>
  
  #include <stddef.h>
  #include <stdlib.h>
  #include <string.h>
  
  #include <idn/result.h>
  #include <idn/assert.h>
  #include <idn/logmacro.h>
  #include <idn/converter.h>
  #include <idn/ucs4.h>
  #include <idn/debug.h>
  #include <idn/race.h>
  #include <idn/util.h>
  
  #ifndef IDN_RACE_PREFIX
  #define IDN_RACE_PREFIX		"bq--"
  #endif
  #define RACE_2OCTET_MODE	0xd8
  #define RACE_ESCAPE		0xff
  #define RACE_ESCAPE_2ND		0x99
  
  #define RACE_BUF_SIZE		128		/* more than enough */
  
  /*
   * Unicode surrogate pair.
   */
  #define IS_SURROGATE_HIGH(v)	(0xd800 <= (v) && (v) <= 0xdbff)
  #define IS_SURROGATE_LOW(v)	(0xdc00 <= (v) && (v) <= 0xdfff)
  #define SURROGATE_HIGH(v)	(SURROGATE_H_OFF + (((v) - 0x10000) >> 10))
  #define SURROGATE_LOW(v)	(SURROGATE_L_OFF + ((v) & 0x3ff))
  #define SURROGATE_BASE		0x10000
  #define SURROGATE_H_OFF		0xd800
  #define SURROGATE_L_OFF		0xdc00
  #define COMBINE_SURROGATE(h, l) \
  	(SURROGATE_BASE + (((h)-SURROGATE_H_OFF)<<10) + ((l)-SURROGATE_L_OFF))
  
  /*
   * Compression type.
   */
  enum {
  	compress_one,	/* all characters are in a single row */
  	compress_two,	/* row 0 and another row */
  	compress_none	/* nope */
  };
  
  static idn_result_t	race_decode_decompress(const char *from,
  					       unsigned short *buf,
  					       size_t buflen);
  static idn_result_t	race_compress_encode(const unsigned short *p,
  					     int compress_mode,
  					     char *to, size_t tolen);
  static int		get_compress_mode(unsigned short *p);
  
  idn_result_t
  idn__race_decode(idn_converter_t ctx, void *privdata, 
  		 const char *from, unsigned long *to, size_t tolen) {
  	unsigned short *buf = NULL;
  	size_t prefixlen = strlen(IDN_RACE_PREFIX);
  	size_t fromlen;
  	size_t buflen;
  	idn_result_t r;
  
  	assert(ctx != NULL);
  
  	TRACE(("idn__race_decode(from=\"%s\", tolen=%d)\n",
  	       idn__debug_xstring(from, 50), (int)tolen));
  
  	if (!idn__util_asciihaveaceprefix(from, IDN_RACE_PREFIX)) {
  		if (*from == '\0') {
  			r = idn_ucs4_utf8toucs4(from, to, tolen);
  			goto ret;
  		}
  		r = idn_invalid_encoding;
  		goto ret;
  	}
  	from += prefixlen;
  	fromlen = strlen(from);
  
  	/*
  	 * Allocate sufficient buffer.
  	 */
  	buflen = fromlen + 1;
  	buf = malloc(sizeof(*buf) * buflen);
  	if (buf == NULL) {
  		r = idn_nomemory;
  		goto ret;
  	}
  
  	/*
  	 * Decode base32 and decompress.
  	 */
  	r = race_decode_decompress(from, buf, buflen);
  	if (r != idn_success)
  		goto ret;
  
  	/*
  	 * Now 'buf' points the decompressed string, which must contain
  	 * UTF-16 characters.
  	 */
  
  	/*
  	 * Convert to UCS4.
  	 */
  	r = idn_ucs4_utf16toucs4(buf, to, tolen);
  	if (r != idn_success)
  		goto ret;
  
  ret:
  	free(buf);
  	if (r == idn_success) {
  		TRACE(("idn__race_decode(): succcess (to=\"%s\")\n",
  		       idn__debug_ucs4xstring(to, 50)));
  	} else {
  		TRACE(("idn__race_decode(): %s\n", idn_result_tostring(r)));
  	}
  	return (r);
  }
  
  static idn_result_t
  race_decode_decompress(const char *from, unsigned short *buf, size_t buflen)
  {
  	unsigned short *p = buf;
  	unsigned int bitbuf = 0;
  	int bitlen = 0;
  	int i, j;
  	size_t len;
  
  	while (*from != '\0') {
  		int c = *from++;
  		int x;
  
  		if ('a' <= c && c <= 'z')
  			x = c - 'a';
  		else if ('A' <= c && c <= 'Z')
  			x = c - 'A';
  		else if ('2' <= c && c <= '7')
  			x = c - '2' + 26;
  		else
  			return (idn_invalid_encoding);
  
  		bitbuf = (bitbuf << 5) + x;
  		bitlen += 5;
  		if (bitlen >= 8) {
  			*p++ = (bitbuf >> (bitlen - 8)) & 0xff;
  			bitlen -= 8;
  		}
  	}
  	len = p - buf;
  
  	/*
  	 * Now 'buf' holds the decoded string.
  	 */
  
  	/*
  	 * Decompress.
  	 */
  	if (buf[0] == RACE_2OCTET_MODE) {
  		if ((len - 1) % 2 != 0)
  			return (idn_invalid_encoding);
  		for (i = 1, j = 0; i < len; i += 2, j++)
  			buf[j] = (buf[i] << 8) + buf[i + 1];
  		len = j;
  	} else {
  		unsigned short c = buf[0] << 8;	/* higher octet */
  
  		for (i = 1, j = 0; i < len; j++) {
  			if (buf[i] == RACE_ESCAPE) {
  				if (i + 1 >= len)
  					return (idn_invalid_encoding);
  				else if (buf[i + 1] == RACE_ESCAPE_2ND)
  					buf[j] = c | 0xff;
  				else
  					buf[j] = buf[i + 1];
  				i += 2;
  
  			} else if (buf[i] == 0x99 && c == 0x00) {
  				/*
  				 * The RACE specification says this is error.
  				 */
  				return (idn_invalid_encoding);
  				 
  			} else {
  				buf[j] = c | buf[i++];
  			}
  		}
  		len = j;
  	}
  	buf[len] = '\0';
  
  	return (idn_success);
  }
  
  idn_result_t
  idn__race_encode(idn_converter_t ctx, void *privdata, 
  		 const unsigned long *from, char *to, size_t tolen) {
  	char *to_org = to;
  	unsigned short *p, *buf = NULL;
  	size_t prefixlen = strlen(IDN_RACE_PREFIX);
  	size_t buflen;
  	size_t fromlen;
  	idn_result_t r;
  	int compress_mode;
  
  	assert(ctx != NULL);
  
  	TRACE(("idn__race_encode(from=\"%s\", tolen=%d)\n",
  	       idn__debug_ucs4xstring(from, 50), (int)tolen));
  
  	if (*from == '\0') {
  		r = idn_ucs4_ucs4toutf8(from, to, tolen);
  		goto ret;
  	} else if (idn__util_ucs4haveaceprefix(from, IDN_RACE_PREFIX)) {
  		r = idn_prohibited;
  		goto ret;
  	}
  
  	if (tolen < prefixlen) {
  		r  = idn_buffer_overflow;
  		goto ret;
  	}
  	memcpy(to, IDN_RACE_PREFIX, prefixlen);
  	to += prefixlen;
  	tolen -= prefixlen;
  
  	fromlen = idn_ucs4_strlen(from);
  	buflen = fromlen * 2 + 2;
  
  	/*
  	 * Convert to UTF-16.
  	 * Preserve space for a character at the top of the buffer.
  	 */
  	for (;;) {
  		unsigned short *new_buf;
  
  		new_buf = realloc(buf, sizeof(*buf) * buflen);
  		if (new_buf == NULL) {
  			r = idn_nomemory;
  			goto ret;
  		}
  		buf = new_buf;
  
  		r = idn_ucs4_ucs4toutf16(from, buf + 1, buflen - 1);
  		if (r == idn_success)
  			break;
  		else if (r != idn_buffer_overflow)
  			goto ret;
  
  		buflen = fromlen * 2 + 2;
  	}
  	p = buf + 1;
  
  	/*
  	 * Now 'p' contains UTF-16 encoded string.
  	 */
  
  	/*
  	 * Check U+0099. 
  	 * RACE doesn't permit U+0099 in an input string.
  	 */
  	for (p = buf + 1; *p != '\0'; p++) {
  		if (*p == 0x0099) {
  			r = idn_invalid_encoding;
  			goto ret;
  		}
  	}
  
  	/*
  	 * Compress, encode in base-32 and output.
  	 */
  	compress_mode = get_compress_mode(buf + 1);
  	r = race_compress_encode(buf, compress_mode, to, tolen);
  
  ret:
  	free(buf);
  	if (r == idn_success) {
  		TRACE(("idn__race_encode(): succcess (to=\"%s\")\n",
  		       idn__debug_xstring(to_org, 50)));
  	} else {
  		TRACE(("idn__race_encode(): %s\n", idn_result_tostring(r)));
  	}
  	return (r);
  }
  
  static idn_result_t
  race_compress_encode(const unsigned short *p, int compress_mode,
  		     char *to, size_t tolen)
  {
  	unsigned long bitbuf = *p++;	/* bit stream buffer */
  	int bitlen = 8;			/* # of bits in 'bitbuf' */
  
  	while (*p != '\0' || bitlen > 0) {
  		unsigned int c = *p;
  
  		if (c == '\0') {
  			/* End of data.  Flush. */
  			bitbuf <<= (5 - bitlen);
  			bitlen = 5;
  		} else if (compress_mode == compress_none) {
  			/* Push 16 bit data. */
  			bitbuf = (bitbuf << 16) | c;
  			bitlen += 16;
  			p++;
  		} else {/* compress_mode == compress_one/compress_two */
  			/* Push 8 or 16 bit data. */
  			if (compress_mode == compress_two &&
  			    (c & 0xff00) == 0) {
  				/* Upper octet is zero (and not U1). */
  				bitbuf = (bitbuf << 16) | 0xff00 | c;
  				bitlen += 16;
  			} else if ((c & 0xff) == 0xff) {
  				/* Lower octet is 0xff. */
  				bitbuf = (bitbuf << 16) |
  					(RACE_ESCAPE << 8) | RACE_ESCAPE_2ND;
  				bitlen += 16;
  			} else {
  				/* Just output lower octet. */
  				bitbuf = (bitbuf << 8) | (c & 0xff);
  				bitlen += 8;
  			}
  			p++;
  		}
  
  		/*
  		 * Output bits in 'bitbuf' in 5-bit unit.
  		 */
  		while (bitlen >= 5) {
  			int x;
  
  			/* Get top 5 bits. */
  			x = (bitbuf >> (bitlen - 5)) & 0x1f;
  			bitlen -= 5;
  
  			/* Encode. */
  			if (x < 26)
  				x += 'a';
  			else
  				x = (x - 26) + '2';
  
  			if (tolen < 1)
  				return (idn_buffer_overflow);
  
  			*to++ = x;
  			tolen--;
  		}
  	}
  
  	if (tolen <= 0)
  		return (idn_buffer_overflow);
  
  	*to = '\0';
  	return (idn_success);
  }
  
  static int
  get_compress_mode(unsigned short *p) {
  	int zero = 0;
  	unsigned int upper = 0;
  	unsigned short *modepos = p - 1;
  
  	while (*p != '\0') {
  		unsigned int hi = *p++ & 0xff00;
  
  		if (hi == 0) {
  			zero++;
  		} else if (hi == upper) {
  			;
  		} else if (upper == 0) {
  			upper = hi;
  		} else {
  			*modepos = RACE_2OCTET_MODE;
  			return (compress_none);
  		}
  	}
  	*modepos = upper >> 8;
  	if (upper > 0 && zero > 0)
  		return (compress_two);
  	else
  		return (compress_one);
  }
  