text: /* crypto/asn1/a_bitstr.c */
  /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   * All rights reserved.
   *
   * This package is an SSL implementation written
   * by Eric Young (eay@cryptsoft.com).
   * The implementation was written so as to conform with Netscapes SSL.
   * 
   * This library is free for commercial and non-commercial use as long as
   * the following conditions are aheared to.  The following conditions
   * apply to all code found in this distribution, be it the RC4, RSA,
   * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
   * included with this distribution is covered by the same copyright terms
   * except that the holder is Tim Hudson (tjh@cryptsoft.com).
   * 
   * Copyright remains Eric Young's, and as such any Copyright notices in
   * the code are not to be removed.
   * If this package is used in a product, Eric Young should be given attribution
   * as the author of the parts of the library used.
   * This can be in the form of a textual message at program startup or
   * in documentation (online or textual) provided with the package.
   * 
   * 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 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.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *    "This product includes cryptographic software written by
   *     Eric Young (eay@cryptsoft.com)"
   *    The word 'cryptographic' can be left out if the rouines from the library
   *    being used are not cryptographic related :-).
   * 4. If you include any Windows specific code (or a derivative thereof) from 
   *    the apps directory (application code) you must include an acknowledgement:
   *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
   * 
   * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``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 OR CONTRIBUTORS 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.
   * 
   * The licence and distribution terms for any publically available version or
   * derivative of this code cannot be changed.  i.e. this code cannot simply be
   * copied and put under another distribution licence
   * [including the GNU Public Licence.]
   */
  
  #include <stdio.h>
  #include "cryptlib.h"
  #include <openssl/asn1.h>
  
  ASN1_BIT_STRING *ASN1_BIT_STRING_new(void)
  { return M_ASN1_BIT_STRING_new(); }
  
  void ASN1_BIT_STRING_free(ASN1_BIT_STRING *x)
  { M_ASN1_BIT_STRING_free(x); }
  
  int ASN1_BIT_STRING_set(ASN1_BIT_STRING *x, unsigned char *d, int len)
  { return M_ASN1_BIT_STRING_set(x, d, len); }
  
  int i2d_ASN1_BIT_STRING(ASN1_BIT_STRING *a, unsigned char **pp)
  {
  	int len, ret;
  	len = i2c_ASN1_BIT_STRING(a, NULL);	
  	ret=ASN1_object_size(0,len,V_ASN1_BIT_STRING);
  	if(pp) {
  		ASN1_put_object(pp,0,len,V_ASN1_BIT_STRING,V_ASN1_UNIVERSAL);
  		i2c_ASN1_BIT_STRING(a, pp);	
  	}
  	return ret;
  }
  
  int i2c_ASN1_BIT_STRING(ASN1_BIT_STRING *a, unsigned char **pp)
  	{
  	int ret,j,bits,len;
  	unsigned char *p,*d;
  
  	if (a == NULL) return(0);
  
  	len=a->length;
  	ret=1+len;
  	if (pp == NULL) return(ret);
  
  	if (len > 0)
  		{
  		if (a->flags & ASN1_STRING_FLAG_BITS_LEFT)
  			{
  			bits=(int)a->flags&0x07;
  			}
  		else
  			{
  			for ( ; len > 0; len--)
  				{
  				if (a->data[len-1]) break;
  				}
  			j=a->data[len-1];
  			if      (j & 0x01) bits=0;
  			else if (j & 0x02) bits=1;
  			else if (j & 0x04) bits=2;
  			else if (j & 0x08) bits=3;
  			else if (j & 0x10) bits=4;
  			else if (j & 0x20) bits=5;
  			else if (j & 0x40) bits=6;
  			else if (j & 0x80) bits=7;
  			else bits=0; /* should not happen */
  			}
  		}
  	else
  		bits=0;
  	p= *pp;
  
  	*(p++)=(unsigned char)bits;
  	d=a->data;
  	memcpy(p,d,len);
  	p+=len;
  	if (len > 0) p[-1]&=(0xff<<bits);
  	*pp=p;
  	return(ret);
  	}
  
  
  /* Convert DER encoded ASN1 BIT_STRING to ASN1_BIT_STRING structure */
  ASN1_BIT_STRING *d2i_ASN1_BIT_STRING(ASN1_BIT_STRING **a, unsigned char **pp,
  	     long length)
  {
  	unsigned char *p;
  	long len;
  	int i;
  	int inf,tag,xclass;
  	ASN1_BIT_STRING *ret;
  
  	p= *pp;
  	inf=ASN1_get_object(&p,&len,&tag,&xclass,length);
  	if (inf & 0x80)
  		{
  		i=ASN1_R_BAD_OBJECT_HEADER;
  		goto err;
  		}
  
  	if (tag != V_ASN1_BIT_STRING)
  		{
  		i=ASN1_R_EXPECTING_A_BIT_STRING;
  		goto err;
  		}
  	if (len < 1) { i=ASN1_R_STRING_TOO_SHORT; goto err; }
  	ret = c2i_ASN1_BIT_STRING(a, &p, len);
  	if(ret) *pp = p;
  	return ret;
  err:
  	ASN1err(ASN1_F_D2I_ASN1_BIT_STRING,i);
  	return(NULL);
  
  }
  
  ASN1_BIT_STRING *c2i_ASN1_BIT_STRING(ASN1_BIT_STRING **a, unsigned char **pp,
  	     long len)
  	{
  	ASN1_BIT_STRING *ret=NULL;
  	unsigned char *p,*s;
  	int i;
  
  	if ((a == NULL) || ((*a) == NULL))
  		{
  		if ((ret=M_ASN1_BIT_STRING_new()) == NULL) return(NULL);
  		}
  	else
  		ret=(*a);
  
  	p= *pp;
  	i= *(p++);
  	/* We do this to preserve the settings.  If we modify
  	 * the settings, via the _set_bit function, we will recalculate
  	 * on output */
  	ret->flags&= ~(ASN1_STRING_FLAG_BITS_LEFT|0x07); /* clear */
  	ret->flags|=(ASN1_STRING_FLAG_BITS_LEFT|(i&0x07)); /* set */
  
  	if (len-- > 1) /* using one because of the bits left byte */
  		{
  		s=(unsigned char *)OPENSSL_malloc((int)len);
  		if (s == NULL)
  			{
  			i=ERR_R_MALLOC_FAILURE;
  			goto err;
  			}
  		memcpy(s,p,(int)len);
  		s[len-1]&=(0xff<<i);
  		p+=len;
  		}
  	else
  		s=NULL;
  
  	ret->length=(int)len;
  	if (ret->data != NULL) OPENSSL_free(ret->data);
  	ret->data=s;
  	ret->type=V_ASN1_BIT_STRING;
  	if (a != NULL) (*a)=ret;
  	*pp=p;
  	return(ret);
  err:
  	ASN1err(ASN1_F_D2I_ASN1_BIT_STRING,i);
  	if ((ret != NULL) && ((a == NULL) || (*a != ret)))
  		M_ASN1_BIT_STRING_free(ret);
  	return(NULL);
  	}
  
  /* These next 2 functions from Goetz Babin-Ebell <babinebell@trustcenter.de>
   */
  int ASN1_BIT_STRING_set_bit(ASN1_BIT_STRING *a, int n, int value)
  	{
  	int w,v,iv;
  	unsigned char *c;
  
  	w=n/8;
  	v=1<<(7-(n&0x07));
  	iv= ~v;
  	if (!value) v=0;
  
  	a->flags&= ~(ASN1_STRING_FLAG_BITS_LEFT|0x07); /* clear, set on write */
  
  	if (a == NULL) return(0);
  	if ((a->length < (w+1)) || (a->data == NULL))
  		{
  		if (!value) return(1); /* Don't need to set */
  		if (a->data == NULL)
  			c=(unsigned char *)OPENSSL_malloc(w+1);
  		else
  			c=(unsigned char *)OPENSSL_realloc(a->data,w+1);
  		if (c == NULL) return(0);
  		if (w+1-a->length > 0) memset(c+a->length, 0, w+1-a->length);
  		a->data=c;
  		a->length=w+1;
  	}
  	a->data[w]=((a->data[w])&iv)|v;
  	while ((a->length > 0) && (a->data[a->length-1] == 0))
  		a->length--;
  	return(1);
  	}
  
  int ASN1_BIT_STRING_get_bit(ASN1_BIT_STRING *a, int n)
  	{
  	int w,v;
  
  	w=n/8;
  	v=1<<(7-(n&0x07));
  	if ((a == NULL) || (a->length < (w+1)) || (a->data == NULL))
  		return(0);
  	return((a->data[w]&v) != 0);
  	}
  
  