/*
 * This source file is part of the bstring string library.  This code was
 * written by Paul Hsieh in 2002-2008, and is covered by the BSD open source
 * license and the GPL. Refer to the accompanying documentation for details
 * on usage and license.
 */

/*
 * bstrlib.c
 *
 * This file is the core module for implementing the bstring functions.
 */

#include <ctype.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <atalk/bstrlib.h>

/* Optionally include a mechanism for debugging memory */

#if defined(MEMORY_DEBUG) || defined(BSTRLIB_MEMORY_DEBUG)
#include "memdbg.h"
#endif

#ifndef bstr__alloc
#define bstr__alloc(x) malloc (x)
#endif

#ifndef bstr__free
#define bstr__free(p) free (p)
#endif

#ifndef bstr__realloc
#define bstr__realloc(p,x) realloc ((p), (x))
#endif

#ifndef bstr__memcpy
#define bstr__memcpy(d,s,l) memcpy ((d), (s), (l))
#endif

#ifndef bstr__memmove
#define bstr__memmove(d,s,l) memmove ((d), (s), (l))
#endif

#ifndef bstr__memset
#define bstr__memset(d,c,l) memset ((d), (c), (l))
#endif

#ifndef bstr__memcmp
#define bstr__memcmp(d,c,l) memcmp ((d), (c), (l))
#endif

#ifndef bstr__memchr
#define bstr__memchr(s,c,l) memchr ((s), (c), (l))
#endif

/* Just a length safe wrapper for memmove. */

#define bBlockCopy(D,S,L) { if ((L) > 0) bstr__memmove ((D),(S),(L)); }

/* Compute the snapped size for a given requested size.  By snapping to powers
   of 2 like this, repeated reallocations are avoided. */
static int snapUpSize (int i) {
	if (i < 8) {
		i = 8;
	} else {
		unsigned int j;
		j = (unsigned int) i;

		j |= (j >>  1);
		j |= (j >>  2);
		j |= (j >>  4);
		j |= (j >>  8);		/* Ok, since int >= 16 bits */
#if (UINT_MAX != 0xffff)
		j |= (j >> 16);		/* For 32 bit int systems */
#if (UINT_MAX > 0xffffffffUL)
		j |= (j >> 32);		/* For 64 bit int systems */
#endif
#endif
		/* Least power of two greater than i */
		j++;
		if ((int) j >= i) i = (int) j;
	}
	return i;
}

/*  int balloc (bstring b, int len)
 *
 *  Increase the size of the memory backing the bstring b to at least len.
 */
int balloc (bstring b, int olen) {
	int len;
	if (b == NULL || b->data == NULL || b->slen < 0 || b->mlen <= 0 ||
	    b->mlen < b->slen || olen <= 0) {
		return BSTR_ERR;
	}

	if (olen >= b->mlen) {
		unsigned char * x;

		if ((len = snapUpSize (olen)) <= b->mlen) return BSTR_OK;

		/* Assume probability of a non-moving realloc is 0.125 */
		if (7 * b->mlen < 8 * b->slen) {

			/* If slen is close to mlen in size then use realloc to reduce
			   the memory defragmentation */

			reallocStrategy:;

			x = (unsigned char *) bstr__realloc (b->data, (size_t) len);
			if (x == NULL) {

				/* Since we failed, try allocating the tighest possible
				   allocation */

				if (NULL == (x = (unsigned char *) bstr__realloc (b->data, (size_t) (len = olen)))) {
					return BSTR_ERR;
				}
			}
		} else {

			/* If slen is not close to mlen then avoid the penalty of copying
			   the extra bytes that are allocated, but not considered part of
			   the string */

			if (NULL == (x = (unsigned char *) bstr__alloc ((size_t) len))) {

				/* Perhaps there is no available memory for the two
				   allocations to be in memory at once */

				goto reallocStrategy;

			} else {
				if (b->slen) bstr__memcpy ((char *) x, (char *) b->data, (size_t) b->slen);
				bstr__free (b->data);
			}
		}
		b->data = x;
		b->mlen = len;
		b->data[b->slen] = (unsigned char) '\0';
	}

	return BSTR_OK;
}

/*  int ballocmin (bstring b, int len)
 *
 *  Set the size of the memory backing the bstring b to len or b->slen+1,
 *  whichever is larger.  Note that repeated use of this function can degrade
 *  performance.
 */
int ballocmin (bstring b, int len) {
	unsigned char * s;

	if (b == NULL || b->data == NULL || (b->slen+1) < 0 || b->mlen <= 0 ||
	    b->mlen < b->slen || len <= 0) {
		return BSTR_ERR;
	}

	if (len < b->slen + 1) len = b->slen + 1;

	if (len != b->mlen) {
		s = (unsigned char *) bstr__realloc (b->data, (size_t) len);
		if (NULL == s) return BSTR_ERR;
		s[b->slen] = (unsigned char) '\0';
		b->data = s;
		b->mlen = len;
	}

	return BSTR_OK;
}

/*  bstring bfromcstr (const char * str)
 *
 *  Create a bstring which contains the contents of the '\0' terminated char *
 *  buffer str.
 */
bstring bfromcstr (const char * str) {
bstring b;
int i;
size_t j;

	if (str == NULL) return NULL;
	j = (strlen) (str);
	i = snapUpSize ((int) (j + (2 - (j != 0))));
	if (i <= (int) j) return NULL;

	b = (bstring) bstr__alloc (sizeof (struct tagbstring));
	if (NULL == b) return NULL;
	b->slen = (int) j;
	if (NULL == (b->data = (unsigned char *) bstr__alloc (b->mlen = i))) {
		bstr__free (b);
		return NULL;
	}

	bstr__memcpy (b->data, str, j+1);
	return b;
}

/*  bstring bfromcstralloc (int mlen, const char * str)
 *
 *  Create a bstring which contains the contents of the '\0' terminated char *
 *  buffer str.  The memory buffer backing the string is at least len
 *  characters in length.
 */
bstring bfromcstralloc (int mlen, const char * str) {
bstring b;
int i;
size_t j;

	if (str == NULL) return NULL;
	j = (strlen) (str);
	i = snapUpSize ((int) (j + (2 - (j != 0))));
	if (i <= (int) j) return NULL;

	b = (bstring) bstr__alloc (sizeof (struct tagbstring));
	if (b == NULL) return NULL;
	b->slen = (int) j;
	if (i < mlen) i = mlen;

	if (NULL == (b->data = (unsigned char *) bstr__alloc (b->mlen = i))) {
		bstr__free (b);
		return NULL;
	}

	bstr__memcpy (b->data, str, j+1);
	return b;
}

/*  bstring blk2bstr (const void * blk, int len)
 *
 *  Create a bstring which contains the content of the block blk of length
 *  len.
 */
bstring blk2bstr (const void * blk, int len) {
bstring b;
int i;

	if (blk == NULL || len < 0) return NULL;
	b = (bstring) bstr__alloc (sizeof (struct tagbstring));
	if (b == NULL) return NULL;
	b->slen = len;

	i = len + (2 - (len != 0));
	i = snapUpSize (i);

	b->mlen = i;

	b->data = (unsigned char *) bstr__alloc ((size_t) b->mlen);
	if (b->data == NULL) {
		bstr__free (b);
		return NULL;
	}

	if (len > 0) bstr__memcpy (b->data, blk, (size_t) len);
	b->data[len] = (unsigned char) '\0';

	return b;
}

/*  char * bstr2cstr (const_bstring s, char z)
 *
 *  Create a '\0' terminated char * buffer which is equal to the contents of
 *  the bstring s, except that any contained '\0' characters are converted
 *  to the character in z. This returned value should be freed with a
 *  bcstrfree () call, by the calling application.
 */
char * bstr2cstr (const_bstring b, char z) {
int i, l;
char * r;

	if (b == NULL || b->slen < 0 || b->data == NULL) return NULL;
	l = b->slen;
	r = (char *) bstr__alloc ((size_t) (l + 1));
	if (r == NULL) return r;

	for (i=0; i < l; i ++) {
		r[i] = (char) ((b->data[i] == '\0') ? z : (char) (b->data[i]));
	}

	r[l] = (unsigned char) '\0';

	return r;
}

/*  int bcstrfree (char * s)
 *
 *  Frees a C-string generated by bstr2cstr ().  This is normally unnecessary
 *  since it just wraps a call to bstr__free (), however, if bstr__alloc ()
 *  and bstr__free () have been redefined as a macros within the bstrlib
 *  module (via defining them in memdbg.h after defining
 *  BSTRLIB_MEMORY_DEBUG) with some difference in behaviour from the std
 *  library functions, then this allows a correct way of freeing the memory
 *  that allows higher level code to be independent from these macro
 *  redefinitions.
 */
int bcstrfree (char * s) {
	if (s) {
		bstr__free (s);
		return BSTR_OK;
	}
	return BSTR_ERR;
}

/*  int bconcat (bstring b0, const_bstring b1)
 *
 *  Concatenate the bstring b1 to the bstring b0.
 */
int bconcat (bstring b0, const_bstring b1) {
int len, d;
bstring aux = (bstring) b1;

	if (b0 == NULL || b1 == NULL || b0->data == NULL || b1->data == NULL) return BSTR_ERR;

	d = b0->slen;
	len = b1->slen;
	if ((d | (b0->mlen - d) | len | (d + len)) < 0) return BSTR_ERR;

	if (b0->mlen <= d + len + 1) {
		ptrdiff_t pd = b1->data - b0->data;
		if (0 <= pd && pd < b0->mlen) {
			if (NULL == (aux = bstrcpy (b1))) return BSTR_ERR;
		}
		if (balloc (b0, d + len + 1) != BSTR_OK) {
			if (aux != b1) bdestroy (aux);
			return BSTR_ERR;
		}
	}

	bBlockCopy (&b0->data[d], &aux->data[0], (size_t) len);
	b0->data[d + len] = (unsigned char) '\0';
	b0->slen = d + len;
	if (aux != b1) bdestroy (aux);
	return BSTR_OK;
}

/*  int bconchar (bstring b, char c)
/ *
 *  Concatenate the single character c to the bstring b.
 */
int bconchar (bstring b, char c) {
int d;

	if (b == NULL) return BSTR_ERR;
	d = b->slen;
	if ((d | (b->mlen - d)) < 0 || balloc (b, d + 2) != BSTR_OK) return BSTR_ERR;
	b->data[d] = (unsigned char) c;
	b->data[d + 1] = (unsigned char) '\0';
	b->slen++;
	return BSTR_OK;
}

/*  int bcatcstr (bstring b, const char * s)
 *
 *  Concatenate a char * string to a bstring.
 */
int bcatcstr (bstring b, const char * s) {
char * d;
int i, l;

	if (b == NULL || b->data == NULL || b->slen < 0 || b->mlen < b->slen
	 || b->mlen <= 0 || s == NULL) return BSTR_ERR;

	/* Optimistically concatenate directly */
	l = b->mlen - b->slen;
	d = (char *) &b->data[b->slen];
	for (i=0; i < l; i++) {
		if ((*d++ = *s++) == '\0') {
			b->slen += i;
			return BSTR_OK;
		}
	}
	b->slen += i;

	/* Need to explicitely resize and concatenate tail */
	return bcatblk (b, (const void *) s, (int) strlen (s));
}

/*  int bcatblk (bstring b, const void * s, int len)
 *
 *  Concatenate a fixed length buffer to a bstring.
 */
int bcatblk (bstring b, const void * s, int len) {
int nl;

	if (b == NULL || b->data == NULL || b->slen < 0 || b->mlen < b->slen
	 || b->mlen <= 0 || s == NULL || len < 0) return BSTR_ERR;

	if (0 > (nl = b->slen + len)) return BSTR_ERR; /* Overflow? */
	if (b->mlen <= nl && 0 > balloc (b, nl + 1)) return BSTR_ERR;

	bBlockCopy (&b->data[b->slen], s, (size_t) len);
	b->slen = nl;
	b->data[nl] = (unsigned char) '\0';
	return BSTR_OK;
}

/*  bstring bstrcpy (const_bstring b)
 *
 *  Create a copy of the bstring b.
 */
bstring bstrcpy (const_bstring b) {
bstring b0;
int i,j;

	/* Attempted to copy an invalid string? */
	if (b == NULL || b->slen < 0 || b->data == NULL) return NULL;

	b0 = (bstring) bstr__alloc (sizeof (struct tagbstring));
	if (b0 == NULL) {
		/* Unable to allocate memory for string header */
		return NULL;
	}

	i = b->slen;
	j = snapUpSize (i + 1);

	b0->data = (unsigned char *) bstr__alloc (j);
	if (b0->data == NULL) {
		j = i + 1;
		b0->data = (unsigned char *) bstr__alloc (j);
		if (b0->data == NULL) {
			/* Unable to allocate memory for string data */
			bstr__free (b0);
			return NULL;
		}
	}

	b0->mlen = j;
	b0->slen = i;

	if (i) bstr__memcpy ((char *) b0->data, (char *) b->data, i);
	b0->data[b0->slen] = (unsigned char) '\0';

	return b0;
}

/*  int bassign (bstring a, const_bstring b)
 *
 *  Overwrite the string a with the contents of string b.
 */
int bassign (bstring a, const_bstring b) {
	if (b == NULL || b->data == NULL || b->slen < 0)
		return BSTR_ERR;
	if (b->slen != 0) {
		if (balloc (a, b->slen) != BSTR_OK) return BSTR_ERR;
		bstr__memmove (a->data, b->data, b->slen);
	} else {
		if (a == NULL || a->data == NULL || a->mlen < a->slen ||
		    a->slen < 0 || a->mlen == 0)
			return BSTR_ERR;
	}
	a->data[b->slen] = (unsigned char) '\0';
	a->slen = b->slen;
	return BSTR_OK;
}

/*  int bassignmidstr (bstring a, const_bstring b, int left, int len)
 *
 *  Overwrite the string a with the middle of contents of string b
 *  starting from position left and running for a length len.  left and
 *  len are clamped to the ends of b as with the function bmidstr.
 */
int bassignmidstr (bstring a, const_bstring b, int left, int len) {
	if (b == NULL || b->data == NULL || b->slen < 0)
		return BSTR_ERR;

	if (left < 0) {
		len += left;
		left = 0;
	}

	if (len > b->slen - left) len = b->slen - left;

	if (a == NULL || a->data == NULL || a->mlen < a->slen ||
	    a->slen < 0 || a->mlen == 0)
		return BSTR_ERR;

	if (len > 0) {
		if (balloc (a, len) != BSTR_OK) return BSTR_ERR;
		bstr__memmove (a->data, b->data + left, len);
		a->slen = len;
	} else {
		a->slen = 0;
	}
	a->data[a->slen] = (unsigned char) '\0';
	return BSTR_OK;
}

/*  int bassigncstr (bstring a, const char * str)
 *
 *  Overwrite the string a with the contents of char * string str.  Note that
 *  the bstring a must be a well defined and writable bstring.  If an error
 *  occurs BSTR_ERR is returned however a may be partially overwritten.
 */
int bassigncstr (bstring a, const char * str) {
int i;
size_t len;
	if (a == NULL || a->data == NULL || a->mlen < a->slen ||
	    a->slen < 0 || a->mlen == 0 || NULL == str)
		return BSTR_ERR;

	for (i=0; i < a->mlen; i++) {
		if ('\0' == (a->data[i] = str[i])) {
			a->slen = i;
			return BSTR_OK;
		}
	}

	a->slen = i;
	len = strlen (str + i);
	if (len > INT_MAX || i + len + 1 > INT_MAX ||
	    0 > balloc (a, (int) (i + len + 1))) return BSTR_ERR;
	bBlockCopy (a->data + i, str + i, (size_t) len + 1);
	a->slen += (int) len;
	return BSTR_OK;
}

/*  int bassignblk (bstring a, const void * s, int len)
 *
 *  Overwrite the string a with the contents of the block (s, len).  Note that
 *  the bstring a must be a well defined and writable bstring.  If an error
 *  occurs BSTR_ERR is returned and a is not overwritten.
 */
int bassignblk (bstring a, const void * s, int len) {
	if (a == NULL || a->data == NULL || a->mlen < a->slen ||
	    a->slen < 0 || a->mlen == 0 || NULL == s || len + 1 < 1)
		return BSTR_ERR;
	if (len + 1 > a->mlen && 0 > balloc (a, len + 1)) return BSTR_ERR;
	bBlockCopy (a->data, s, (size_t) len);
	a->data[len] = (unsigned char) '\0';
	a->slen = len;
	return BSTR_OK;
}

/*  int btrunc (bstring b, int n)
 *
 *  Truncate the bstring to at most n characters.
 */
int btrunc (bstring b, int n) {
	if (n < 0 || b == NULL || b->data == NULL || b->mlen < b->slen ||
	    b->slen < 0 || b->mlen <= 0) return BSTR_ERR;
	if (b->slen > n) {
		b->slen = n;
		b->data[n] = (unsigned char) '\0';
	}
	return BSTR_OK;
}

#define   upcase(c) (toupper ((unsigned char) c))
#define downcase(c) (tolower ((unsigned char) c))
#define   wspace(c) (isspace ((unsigned char) c))

/*  int btoupper (bstring b)
 *
 *  Convert contents of bstring to upper case.
 */
int btoupper (bstring b) {
int i, len;
	if (b == NULL || b->data == NULL || b->mlen < b->slen ||
	    b->slen < 0 || b->mlen <= 0) return BSTR_ERR;
	for (i=0, len = b->slen; i < len; i++) {
		b->data[i] = (unsigned char) upcase (b->data[i]);
	}
	return BSTR_OK;
}

/*  int btolower (bstring b)
 *
 *  Convert contents of bstring to lower case.
 */
int btolower (bstring b) {
int i, len;
	if (b == NULL || b->data == NULL || b->mlen < b->slen ||
	    b->slen < 0 || b->mlen <= 0) return BSTR_ERR;
	for (i=0, len = b->slen; i < len; i++) {
		b->data[i] = (unsigned char) downcase (b->data[i]);
	}
	return BSTR_OK;
}

/*  int bstricmp (const_bstring b0, const_bstring b1)
 *
 *  Compare two strings without differentiating between case.  The return
 *  value is the difference of the values of the characters where the two
 *  strings first differ after lower case transformation, otherwise 0 is
 *  returned indicating that the strings are equal.  If the lengths are
 *  different, then a difference from 0 is given, but if the first extra
 *  character is '\0', then it is taken to be the value UCHAR_MAX+1.
 */
int bstricmp (const_bstring b0, const_bstring b1) {
int i, v, n;

	if (bdata (b0) == NULL || b0->slen < 0 ||
	    bdata (b1) == NULL || b1->slen < 0) return SHRT_MIN;
	if ((n = b0->slen) > b1->slen) n = b1->slen;
	else if (b0->slen == b1->slen && b0->data == b1->data) return BSTR_OK;

	for (i = 0; i < n; i ++) {
		v  = (char) downcase (b0->data[i])
		   - (char) downcase (b1->data[i]);
		if (0 != v) return v;
	}

	if (b0->slen > n) {
		v = (char) downcase (b0->data[n]);
		if (v) return v;
		return UCHAR_MAX + 1;
	}
	if (b1->slen > n) {
		v = - (char) downcase (b1->data[n]);
		if (v) return v;
		return - (int) (UCHAR_MAX + 1);
	}
	return BSTR_OK;
}

/*  int bstrnicmp (const_bstring b0, const_bstring b1, int n)
 *
 *  Compare two strings without differentiating between case for at most n
 *  characters.  If the position where the two strings first differ is
 *  before the nth position, the return value is the difference of the values
 *  of the characters, otherwise 0 is returned.  If the lengths are different
 *  and less than n characters, then a difference from 0 is given, but if the
 *  first extra character is '\0', then it is taken to be the value
 *  UCHAR_MAX+1.
 */
int bstrnicmp (const_bstring b0, const_bstring b1, int n) {
int i, v, m;

	if (bdata (b0) == NULL || b0->slen < 0 ||
	    bdata (b1) == NULL || b1->slen < 0 || n < 0) return SHRT_MIN;
	m = n;
	if (m > b0->slen) m = b0->slen;
	if (m > b1->slen) m = b1->slen;

	if (b0->data != b1->data) {
		for (i = 0; i < m; i ++) {
			v  = (char) downcase (b0->data[i]);
			v -= (char) downcase (b1->data[i]);
			if (v != 0) return b0->data[i] - b1->data[i];
		}
	}

	if (n == m || b0->slen == b1->slen) return BSTR_OK;

	if (b0->slen > m) {
		v = (char) downcase (b0->data[m]);
		if (v) return v;
		return UCHAR_MAX + 1;
	}

	v = - (char) downcase (b1->data[m]);
	if (v) return v;
	return - (int) (UCHAR_MAX + 1);
}

/*  int biseqcaseless (const_bstring b0, const_bstring b1)
 *
 *  Compare two strings for equality without differentiating between case.
 *  If the strings differ other than in case, 0 is returned, if the strings
 *  are the same, 1 is returned, if there is an error, -1 is returned.  If
 *  the length of the strings are different, this function is O(1).  '\0'
 *  termination characters are not treated in any special way.
 */
int biseqcaseless (const_bstring b0, const_bstring b1) {
int i, n;

	if (bdata (b0) == NULL || b0->slen < 0 ||
	    bdata (b1) == NULL || b1->slen < 0) return BSTR_ERR;
	if (b0->slen != b1->slen) return BSTR_OK;
	if (b0->data == b1->data || b0->slen == 0) return 1;
	for (i=0, n=b0->slen; i < n; i++) {
		if (b0->data[i] != b1->data[i]) {
			unsigned char c = (unsigned char) downcase (b0->data[i]);
			if (c != (unsigned char) downcase (b1->data[i])) return 0;
		}
	}
	return 1;
}

/*  int bisstemeqcaselessblk (const_bstring b0, const void * blk, int len)
 *
 *  Compare beginning of string b0 with a block of memory of length len
 *  without differentiating between case for equality.  If the beginning of b0
 *  differs from the memory block other than in case (or if b0 is too short),
 *  0 is returned, if the strings are the same, 1 is returned, if there is an
 *  error, -1 is returned.  '\0' characters are not treated in any special
 *  way.
 */
int bisstemeqcaselessblk (const_bstring b0, const void * blk, int len) {
int i;

	if (bdata (b0) == NULL || b0->slen < 0 || NULL == blk || len < 0)
		return BSTR_ERR;
	if (b0->slen < len) return BSTR_OK;
	if (b0->data == (const unsigned char *) blk || len == 0) return 1;

	for (i = 0; i < len; i ++) {
		if (b0->data[i] != ((const unsigned char *) blk)[i]) {
			if (downcase (b0->data[i]) !=
			    downcase (((const unsigned char *) blk)[i])) return 0;
		}
	}
	return 1;
}

/*
 * int bltrimws (bstring b)
 *
 * Delete whitespace contiguous from the left end of the string.
 */
int bltrimws (bstring b) {
int i, len;

	if (b == NULL || b->data == NULL || b->mlen < b->slen ||
	    b->slen < 0 || b->mlen <= 0) return BSTR_ERR;

	for (len = b->slen, i = 0; i < len; i++) {
		if (!wspace (b->data[i])) {
			return bdelete (b, 0, i);
		}
	}

	b->data[0] = (unsigned char) '\0';
	b->slen = 0;
	return BSTR_OK;
}

/*
 * int brtrimws (bstring b)
 *
 * Delete whitespace contiguous from the right end of the string.
 */
int brtrimws (bstring b) {
int i;

	if (b == NULL || b->data == NULL || b->mlen < b->slen ||
	    b->slen < 0 || b->mlen <= 0) return BSTR_ERR;

	for (i = b->slen - 1; i >= 0; i--) {
		if (!wspace (b->data[i])) {
			if (b->mlen > i) b->data[i+1] = (unsigned char) '\0';
			b->slen = i + 1;
			return BSTR_OK;
		}
	}

	b->data[0] = (unsigned char) '\0';
	b->slen = 0;
	return BSTR_OK;
}

/*
 * int btrimws (bstring b)
 *
 * Delete whitespace contiguous from both ends of the string.
 */
int btrimws (bstring b) {
int i, j;

	if (b == NULL || b->data == NULL || b->mlen < b->slen ||
	    b->slen < 0 || b->mlen <= 0) return BSTR_ERR;

	for (i = b->slen - 1; i >= 0; i--) {
		if (!wspace (b->data[i])) {
			if (b->mlen > i) b->data[i+1] = (unsigned char) '\0';
			b->slen = i + 1;
			for (j = 0; wspace (b->data[j]); j++) {}
			return bdelete (b, 0, j);
		}
	}

	b->data[0] = (unsigned char) '\0';
	b->slen = 0;
	return BSTR_OK;
}

/*  int biseq (const_bstring b0, const_bstring b1)
 *
 *  Compare the string b0 and b1.  If the strings differ, 0 is returned, if
 *  the strings are the same, 1 is returned, if there is an error, -1 is
 *  returned.  If the length of the strings are different, this function is
 *  O(1).  '\0' termination characters are not treated in any special way.
 */
int biseq (const_bstring b0, const_bstring b1) {
	if (b0 == NULL || b1 == NULL || b0->data == NULL || b1->data == NULL ||
		b0->slen < 0 || b1->slen < 0) return BSTR_ERR;
	if (b0->slen != b1->slen) return BSTR_OK;
	if (b0->data == b1->data || b0->slen == 0) return 1;
	return !bstr__memcmp (b0->data, b1->data, b0->slen);
}

/*  int bisstemeqblk (const_bstring b0, const void * blk, int len)
 *
 *  Compare beginning of string b0 with a block of memory of length len for
 *  equality.  If the beginning of b0 differs from the memory block (or if b0
 *  is too short), 0 is returned, if the strings are the same, 1 is returned,
 *  if there is an error, -1 is returned.  '\0' characters are not treated in
 *  any special way.
 */
int bisstemeqblk (const_bstring b0, const void * blk, int len) {
int i;

	if (bdata (b0) == NULL || b0->slen < 0 || NULL == blk || len < 0)
		return BSTR_ERR;
	if (b0->slen < len) return BSTR_OK;
	if (b0->data == (const unsigned char *) blk || len == 0) return 1;

	for (i = 0; i < len; i ++) {
		if (b0->data[i] != ((const unsigned char *) blk)[i]) return BSTR_OK;
	}
	return 1;
}

/*  int biseqcstr (const_bstring b, const char *s)
 *
 *  Compare the bstring b and char * string s.  The C string s must be '\0'
 *  terminated at exactly the length of the bstring b, and the contents
 *  between the two must be identical with the bstring b with no '\0'
 *  characters for the two contents to be considered equal.  This is
 *  equivalent to the condition that their current contents will be always be
 *  equal when comparing them in the same format after converting one or the
 *  other.  If the strings are equal 1 is returned, if they are unequal 0 is
 *  returned and if there is a detectable error BSTR_ERR is returned.
 */
int biseqcstr (const_bstring b, const char * s) {
int i;
	if (b == NULL || s == NULL || b->data == NULL || b->slen < 0) return BSTR_ERR;
	for (i=0; i < b->slen; i++) {
		if (s[i] == '\0' || b->data[i] != (unsigned char) s[i]) return BSTR_OK;
	}
	return s[i] == '\0';
}

/*  int biseqcstrcaseless (const_bstring b, const char *s)
 *
 *  Compare the bstring b and char * string s.  The C string s must be '\0'
 *  terminated at exactly the length of the bstring b, and the contents
 *  between the two must be identical except for case with the bstring b with
 *  no '\0' characters for the two contents to be considered equal.  This is
 *  equivalent to the condition that their current contents will be always be
 *  equal ignoring case when comparing them in the same format after
 *  converting one or the other.  If the strings are equal, except for case,
 *  1 is returned, if they are unequal regardless of case 0 is returned and
 *  if there is a detectable error BSTR_ERR is returned.
 */
int biseqcstrcaseless (const_bstring b, const char * s) {
int i;
	if (b == NULL || s == NULL || b->data == NULL || b->slen < 0) return BSTR_ERR;
	for (i=0; i < b->slen; i++) {
		if (s[i] == '\0' ||
		    (b->data[i] != (unsigned char) s[i] &&
		     downcase (b->data[i]) != (unsigned char) downcase (s[i])))
			return BSTR_OK;
	}
	return s[i] == '\0';
}

/*  int bstrcmp (const_bstring b0, const_bstring b1)
 *
 *  Compare the string b0 and b1.  If there is an error, SHRT_MIN is returned,
 *  otherwise a value less than or greater than zero, indicating that the
 *  string pointed to by b0 is lexicographically less than or greater than
 *  the string pointed to by b1 is returned.  If the the string lengths are
 *  unequal but the characters up until the length of the shorter are equal
 *  then a value less than, or greater than zero, indicating that the string
 *  pointed to by b0 is shorter or longer than the string pointed to by b1 is
 *  returned.  0 is returned if and only if the two strings are the same.  If
 *  the length of the strings are different, this function is O(n).  Like its
 *  standard C library counter part strcmp, the comparison does not proceed
 *  past any '\0' termination characters encountered.
 */
int bstrcmp (const_bstring b0, const_bstring b1) {
int i, v, n;

	if (b0 == NULL || b1 == NULL || b0->data == NULL || b1->data == NULL ||
		b0->slen < 0 || b1->slen < 0) return SHRT_MIN;
	n = b0->slen; if (n > b1->slen) n = b1->slen;
	if (b0->slen == b1->slen && (b0->data == b1->data || b0->slen == 0))
		return BSTR_OK;

	for (i = 0; i < n; i ++) {
		v = ((char) b0->data[i]) - ((char) b1->data[i]);
		if (v != 0) return v;
		if (b0->data[i] == (unsigned char) '\0') return BSTR_OK;
	}

	if (b0->slen > n) return 1;
	if (b1->slen > n) return -1;
	return BSTR_OK;
}

/*  int bstrncmp (const_bstring b0, const_bstring b1, int n)
 *
 *  Compare the string b0 and b1 for at most n characters.  If there is an
 *  error, SHRT_MIN is returned, otherwise a value is returned as if b0 and
 *  b1 were first truncated to at most n characters then bstrcmp was called
 *  with these new strings are paremeters.  If the length of the strings are
 *  different, this function is O(n).  Like its standard C library counter
 *  part strcmp, the comparison does not proceed past any '\0' termination
 *  characters encountered.
 */
int bstrncmp (const_bstring b0, const_bstring b1, int n) {
int i, v, m;

	if (b0 == NULL || b1 == NULL || b0->data == NULL || b1->data == NULL ||
		b0->slen < 0 || b1->slen < 0) return SHRT_MIN;
	m = n;
	if (m > b0->slen) m = b0->slen;
	if (m > b1->slen) m = b1->slen;

	if (b0->data != b1->data) {
		for (i = 0; i < m; i ++) {
			v = ((char) b0->data[i]) - ((char) b1->data[i]);
			if (v != 0) return v;
			if (b0->data[i] == (unsigned char) '\0') return BSTR_OK;
		}
	}

	if (n == m || b0->slen == b1->slen) return BSTR_OK;

	if (b0->slen > m) return 1;
	return -1;
}

/*  bstring bmidstr (const_bstring b, int left, int len)
 *
 *  Create a bstring which is the substring of b starting from position left
 *  and running for a length len (clamped by the end of the bstring b.)  If
 *  b is detectably invalid, then NULL is returned.  The section described
 *  by (left, len) is clamped to the boundaries of b.
 */
bstring bmidstr (const_bstring b, int left, int len) {

	if (b == NULL || b->slen < 0 || b->data == NULL) return NULL;

	if (left < 0) {
		len += left;
		left = 0;
	}

	if (len > b->slen - left) len = b->slen - left;

	if (len <= 0) return bfromcstr ("");
	return blk2bstr (b->data + left, len);
}

/*  int bdelete (bstring b, int pos, int len)
 *
 *  Removes characters from pos to pos+len-1 inclusive and shifts the tail of
 *  the bstring starting from pos+len to pos.  len must be positive for this
 *  call to have any effect.  The section of the string described by (pos,
 *  len) is clamped to boundaries of the bstring b.
 */
int bdelete (bstring b, int pos, int len) {
	/* Clamp to left side of bstring */
	if (pos < 0) {
		len += pos;
		pos = 0;
	}

	if (len < 0 || b == NULL || b->data == NULL || b->slen < 0 ||
	    b->mlen < b->slen || b->mlen <= 0)
		return BSTR_ERR;
	if (len > 0 && pos < b->slen) {
		if (pos + len >= b->slen) {
			b->slen = pos;
		} else {
			bBlockCopy ((char *) (b->data + pos),
			            (char *) (b->data + pos + len),
			            b->slen - (pos+len));
			b->slen -= len;
		}
		b->data[b->slen] = (unsigned char) '\0';
	}
	return BSTR_OK;
}

/*  int bdestroy (bstring b)
 *
 *  Free up the bstring.  Note that if b is detectably invalid or not writable
 *  then no action is performed and BSTR_ERR is returned.  Like a freed memory
 *  allocation, dereferences, writes or any other action on b after it has
 *  been bdestroyed is undefined.
 */
int bdestroy (bstring b) {
	if (b == NULL || b->slen < 0 || b->mlen <= 0 || b->mlen < b->slen ||
	    b->data == NULL)
		return BSTR_ERR;

	bstr__free (b->data);

	/* In case there is any stale usage, there is one more chance to
	   notice this error. */

	b->slen = -1;
	b->mlen = -__LINE__;
	b->data = NULL;

	bstr__free (b);
	return BSTR_OK;
}

/*  int binstr (const_bstring b1, int pos, const_bstring b2)
 *
 *  Search for the bstring b2 in b1 starting from position pos, and searching
 *  forward.  If it is found then return with the first position where it is
 *  found, otherwise return BSTR_ERR.  Note that this is just a brute force
 *  string searcher that does not attempt clever things like the Boyer-Moore
 *  search algorithm.  Because of this there are many degenerate cases where
 *  this can take much longer than it needs to.
 */
int binstr (const_bstring b1, int pos, const_bstring b2) {
int j, ii, ll, lf;
unsigned char * d0;
unsigned char c0;
register unsigned char * d1;
register unsigned char c1;
register int i;

	if (b1 == NULL || b1->data == NULL || b1->slen < 0 ||
	    b2 == NULL || b2->data == NULL || b2->slen < 0) return BSTR_ERR;
	if (b1->slen == pos) return (b2->slen == 0)?pos:BSTR_ERR;
	if (b1->slen < pos || pos < 0) return BSTR_ERR;
	if (b2->slen == 0) return pos;

	/* No space to find such a string? */
	if ((lf = b1->slen - b2->slen + 1) <= pos) return BSTR_ERR;

	/* An obvious alias case */
	if (b1->data == b2->data && pos == 0) return 0;

	i = pos;

	d0 = b2->data;
	d1 = b1->data;
	ll = b2->slen;

	/* Peel off the b2->slen == 1 case */
	c0 = d0[0];
	if (1 == ll) {
		for (;i < lf; i++) if (c0 == d1[i]) return i;
		return BSTR_ERR;
	}

	c1 = c0;
	j = 0;
	lf = b1->slen - 1;

	ii = -1;
	if (i < lf) do {
		/* Unrolled current character test */
		if (c1 != d1[i]) {
			if (c1 != d1[1+i]) {
				i += 2;
				continue;
			}
			i++;
		}

		/* Take note if this is the start of a potential match */
		if (0 == j) ii = i;

		/* Shift the test character down by one */
		j++;
		i++;

		/* If this isn't past the last character continue */
		if (j < ll) {
			c1 = d0[j];
			continue;
		}

		N0:;

		/* If no characters mismatched, then we matched */
		if (i == ii+j) return ii;

		/* Shift back to the beginning */
		i -= j;
		j  = 0;
		c1 = c0;
	} while (i < lf);

	/* Deal with last case if unrolling caused a misalignment */
	if (i == lf && ll == j+1 && c1 == d1[i]) goto N0;

	return BSTR_ERR;
}

/*  int binstrr (const_bstring b1, int pos, const_bstring b2)
 *
 *  Search for the bstring b2 in b1 starting from position pos, and searching
 *  backward.  If it is found then return with the first position where it is
 *  found, otherwise return BSTR_ERR.  Note that this is just a brute force
 *  string searcher that does not attempt clever things like the Boyer-Moore
 *  search algorithm.  Because of this there are many degenerate cases where
 *  this can take much longer than it needs to.
 */
int binstrr (const_bstring b1, int pos, const_bstring b2) {
int j, i, l;
unsigned char * d0, * d1;

	if (b1 == NULL || b1->data == NULL || b1->slen < 0 ||
	    b2 == NULL || b2->data == NULL || b2->slen < 0) return BSTR_ERR;
	if (b1->slen == pos && b2->slen == 0) return pos;
	if (b1->slen < pos || pos < 0) return BSTR_ERR;
	if (b2->slen == 0) return pos;

	/* Obvious alias case */
	if (b1->data == b2->data && pos == 0 && b2->slen <= b1->slen) return 0;

	i = pos;
	if ((l = b1->slen - b2->slen) < 0) return BSTR_ERR;

	/* If no space to find such a string then snap back */
	if (l + 1 <= i) i = l;
	j = 0;

	d0 = b2->data;
	d1 = b1->data;
	l  = b2->slen;

	for (;;) {
		if (d0[j] == d1[i + j]) {
			j ++;
			if (j >= l) return i;
		} else {
			i --;
			if (i < 0) break;
			j=0;
		}
	}

	return BSTR_ERR;
}

/*  int binstrcaseless (const_bstring b1, int pos, const_bstring b2)
 *
 *  Search for the bstring b2 in b1 starting from position pos, and searching
 *  forward but without regard to case.  If it is found then return with the
 *  first position where it is found, otherwise return BSTR_ERR.  Note that
 *  this is just a brute force string searcher that does not attempt clever
 *  things like the Boyer-Moore search algorithm.  Because of this there are
 *  many degenerate cases where this can take much longer than it needs to.
 */
int binstrcaseless (const_bstring b1, int pos, const_bstring b2) {
int j, i, l, ll;
unsigned char * d0, * d1;

	if (b1 == NULL || b1->data == NULL || b1->slen < 0 ||
	    b2 == NULL || b2->data == NULL || b2->slen < 0) return BSTR_ERR;
	if (b1->slen == pos) return (b2->slen == 0)?pos:BSTR_ERR;
	if (b1->slen < pos || pos < 0) return BSTR_ERR;
	if (b2->slen == 0) return pos;

	l = b1->slen - b2->slen + 1;

	/* No space to find such a string? */
	if (l <= pos) return BSTR_ERR;

	/* An obvious alias case */
	if (b1->data == b2->data && pos == 0) return BSTR_OK;

	i = pos;
	j = 0;

	d0 = b2->data;
	d1 = b1->data;
	ll = b2->slen;

	for (;;) {
		if (d0[j] == d1[i + j] || downcase (d0[j]) == downcase (d1[i + j])) {
			j ++;
			if (j >= ll) return i;
		} else {
			i ++;
			if (i >= l) break;
			j=0;
		}
	}

	return BSTR_ERR;
}

/*  int binstrrcaseless (const_bstring b1, int pos, const_bstring b2)
 *
 *  Search for the bstring b2 in b1 starting from position pos, and searching
 *  backward but without regard to case.  If it is found then return with the
 *  first position where it is found, otherwise return BSTR_ERR.  Note that
 *  this is just a brute force string searcher that does not attempt clever
 *  things like the Boyer-Moore search algorithm.  Because of this there are
 *  many degenerate cases where this can take much longer than it needs to.
 */
int binstrrcaseless (const_bstring b1, int pos, const_bstring b2) {
int j, i, l;
unsigned char * d0, * d1;

	if (b1 == NULL || b1->data == NULL || b1->slen < 0 ||
	    b2 == NULL || b2->data == NULL || b2->slen < 0) return BSTR_ERR;
	if (b1->slen == pos && b2->slen == 0) return pos;
	if (b1->slen < pos || pos < 0) return BSTR_ERR;
	if (b2->slen == 0) return pos;

	/* Obvious alias case */
	if (b1->data == b2->data && pos == 0 && b2->slen <= b1->slen) return BSTR_OK;

	i = pos;
	if ((l = b1->slen - b2->slen) < 0) return BSTR_ERR;

	/* If no space to find such a string then snap back */
	if (l + 1 <= i) i = l;
	j = 0;

	d0 = b2->data;
	d1 = b1->data;
	l  = b2->slen;

	for (;;) {
		if (d0[j] == d1[i + j] || downcase (d0[j]) == downcase (d1[i + j])) {
			j ++;
			if (j >= l) return i;
		} else {
			i --;
			if (i < 0) break;
			j=0;
		}
	}

	return BSTR_ERR;
}


/*  int bstrchrp (const_bstring b, int c, int pos)
 *
 *  Search for the character c in b forwards from the position pos
 *  (inclusive).
 */
int bstrchrp (const_bstring b, int c, int pos) {
unsigned char * p;

	if (b == NULL || b->data == NULL || b->slen <= pos || pos < 0) return BSTR_ERR;
	p = (unsigned char *) bstr__memchr ((b->data + pos), (unsigned char) c, (b->slen - pos));
	if (p) return (int) (p - b->data);
	return BSTR_ERR;
}

/*  int bstrrchrp (const_bstring b, int c, int pos)
 *
 *  Search for the character c in b backwards from the position pos in string
 *  (inclusive).
 */
int bstrrchrp (const_bstring b, int c, int pos) {
int i;

	if (b == NULL || b->data == NULL || b->slen <= pos || pos < 0) return BSTR_ERR;
	for (i=pos; i >= 0; i--) {
		if (b->data[i] == (unsigned char) c) return i;
	}
	return BSTR_ERR;
}

#if !defined (BSTRLIB_AGGRESSIVE_MEMORY_FOR_SPEED_TRADEOFF)
#define LONG_LOG_BITS_QTY (3)
#define LONG_BITS_QTY (1 << LONG_LOG_BITS_QTY)
#define LONG_TYPE unsigned char

#define CFCLEN ((1 << CHAR_BIT) / LONG_BITS_QTY)
struct charField { LONG_TYPE content[CFCLEN]; };
#define testInCharField(cf,c) ((cf)->content[(c) >> LONG_LOG_BITS_QTY] & (((long)1) << ((c) & (LONG_BITS_QTY-1))))
#define setInCharField(cf,idx) { \
	unsigned int c = (unsigned int) (idx); \
	(cf)->content[c >> LONG_LOG_BITS_QTY] |= (LONG_TYPE) (1ul << (c & (LONG_BITS_QTY-1))); \
}

#else

#define CFCLEN (1 << CHAR_BIT)
struct charField { unsigned char content[CFCLEN]; };
#define testInCharField(cf,c) ((cf)->content[(unsigned char) (c)])
#define setInCharField(cf,idx) (cf)->content[(unsigned int) (idx)] = ~0

#endif

/* Convert a bstring to charField */
static int buildCharField (struct charField * cf, const_bstring b) {
int i;
	if (b == NULL || b->data == NULL || b->slen <= 0) return BSTR_ERR;
	memset ((void *) cf->content, 0, sizeof (struct charField));
	for (i=0; i < b->slen; i++) {
		setInCharField (cf, b->data[i]);
	}
	return BSTR_OK;
}

static void invertCharField (struct charField * cf) {
int i;
	for (i=0; i < CFCLEN; i++) cf->content[i] = ~cf->content[i];
}

/* Inner engine for binchr */
static int binchrCF (const unsigned char * data, int len, int pos, const struct charField * cf) {
int i;
	for (i=pos; i < len; i++) {
		unsigned char c = (unsigned char) data[i];
		if (testInCharField (cf, c)) return i;
	}
	return BSTR_ERR;
}

/*  int binchr (const_bstring b0, int pos, const_bstring b1);
 *
 *  Search for the first position in b0 starting from pos or after, in which
 *  one of the characters in b1 is found and return it.  If such a position
 *  does not exist in b0, then BSTR_ERR is returned.
 */
int binchr (const_bstring b0, int pos, const_bstring b1) {
struct charField chrs;
	if (pos < 0 || b0 == NULL || b0->data == NULL ||
	    b0->slen <= pos) return BSTR_ERR;
	if (1 == b1->slen) return bstrchrp (b0, b1->data[0], pos);
	if (0 > buildCharField (&chrs, b1)) return BSTR_ERR;
	return binchrCF (b0->data, b0->slen, pos, &chrs);
}

/* Inner engine for binchrr */
static int binchrrCF (const unsigned char * data, int pos, const struct charField * cf) {
int i;
	for (i=pos; i >= 0; i--) {
		unsigned int c = (unsigned int) data[i];
		if (testInCharField (cf, c)) return i;
	}
	return BSTR_ERR;
}

/*  int binchrr (const_bstring b0, int pos, const_bstring b1);
 *
 *  Search for the last position in b0 no greater than pos, in which one of
 *  the characters in b1 is found and return it.  If such a position does not
 *  exist in b0, then BSTR_ERR is returned.
 */
int binchrr (const_bstring b0, int pos, const_bstring b1) {
struct charField chrs;
	if (pos < 0 || b0 == NULL || b0->data == NULL || b1 == NULL ||
	    b0->slen < pos) return BSTR_ERR;
	if (pos == b0->slen) pos--;
	if (1 == b1->slen) return bstrrchrp (b0, b1->data[0], pos);
	if (0 > buildCharField (&chrs, b1)) return BSTR_ERR;
	return binchrrCF (b0->data, pos, &chrs);
}

/*  int bninchr (const_bstring b0, int pos, const_bstring b1);
 *
 *  Search for the first position in b0 starting from pos or after, in which
 *  none of the characters in b1 is found and return it.  If such a position
 *  does not exist in b0, then BSTR_ERR is returned.
 */
int bninchr (const_bstring b0, int pos, const_bstring b1) {
struct charField chrs;
	if (pos < 0 || b0 == NULL || b0->data == NULL ||
	    b0->slen <= pos) return BSTR_ERR;
	if (buildCharField (&chrs, b1) < 0) return BSTR_ERR;
	invertCharField (&chrs);
	return binchrCF (b0->data, b0->slen, pos, &chrs);
}

/*  int bninchrr (const_bstring b0, int pos, const_bstring b1);
 *
 *  Search for the last position in b0 no greater than pos, in which none of
 *  the characters in b1 is found and return it.  If such a position does not
 *  exist in b0, then BSTR_ERR is returned.
 */
int bninchrr (const_bstring b0, int pos, const_bstring b1) {
struct charField chrs;
	if (pos < 0 || b0 == NULL || b0->data == NULL ||
	    b0->slen < pos) return BSTR_ERR;
	if (pos == b0->slen) pos--;
	if (buildCharField (&chrs, b1) < 0) return BSTR_ERR;
	invertCharField (&chrs);
	return binchrrCF (b0->data, pos, &chrs);
}

/*  int bsetstr (bstring b0, int pos, bstring b1, unsigned char fill)
 *
 *  Overwrite the string b0 starting at position pos with the string b1. If
 *  the position pos is past the end of b0, then the character "fill" is
 *  appended as necessary to make up the gap between the end of b0 and pos.
 *  If b1 is NULL, it behaves as if it were a 0-length string.
 */
int bsetstr (bstring b0, int pos, const_bstring b1, unsigned char fill) {
int d, newlen;
ptrdiff_t pd;
bstring aux = (bstring) b1;

	if (pos < 0 || b0 == NULL || b0->slen < 0 || NULL == b0->data ||
	    b0->mlen < b0->slen || b0->mlen <= 0) return BSTR_ERR;
	if (b1 != NULL && (b1->slen < 0 || b1->data == NULL)) return BSTR_ERR;

	d = pos;

	/* Aliasing case */
	if (NULL != aux) {
		if ((pd = (ptrdiff_t) (b1->data - b0->data)) >= 0 && pd < (ptrdiff_t) b0->mlen) {
			if (NULL == (aux = bstrcpy (b1))) return BSTR_ERR;
		}
		d += aux->slen;
	}

	/* Increase memory size if necessary */
	if (balloc (b0, d + 1) != BSTR_OK) {
		if (aux != b1) bdestroy (aux);
		return BSTR_ERR;
	}

	newlen = b0->slen;

	/* Fill in "fill" character as necessary */
	if (pos > newlen) {
		bstr__memset (b0->data + b0->slen, (int) fill, (size_t) (pos - b0->slen));
		newlen = pos;
	}

	/* Copy b1 to position pos in b0. */
	if (aux != NULL) {
		bBlockCopy ((char *) (b0->data + pos), (char *) aux->data, aux->slen);
		if (aux != b1) bdestroy (aux);
	}

	/* Indicate the potentially increased size of b0 */
	if (d > newlen) newlen = d;

	b0->slen = newlen;
	b0->data[newlen] = (unsigned char) '\0';

	return BSTR_OK;
}

/*  int binsert (bstring b1, int pos, bstring b2, unsigned char fill)
 *
 *  Inserts the string b2 into b1 at position pos.  If the position pos is
 *  past the end of b1, then the character "fill" is appended as necessary to
 *  make up the gap between the end of b1 and pos.  Unlike bsetstr, binsert
 *  does not allow b2 to be NULL.
 */
int binsert (bstring b1, int pos, const_bstring b2, unsigned char fill) {
int d, l;
ptrdiff_t pd;
bstring aux = (bstring) b2;

	if (pos < 0 || b1 == NULL || b2 == NULL || b1->slen < 0 ||
	    b2->slen < 0 || b1->mlen < b1->slen || b1->mlen <= 0) return BSTR_ERR;

	/* Aliasing case */
	if ((pd = (ptrdiff_t) (b2->data - b1->data)) >= 0 && pd < (ptrdiff_t) b1->mlen) {
		if (NULL == (aux = bstrcpy (b2))) return BSTR_ERR;
	}

	/* Compute the two possible end pointers */
	d = b1->slen + aux->slen;
	l = pos + aux->slen;
	if ((d|l) < 0) return BSTR_ERR;

	if (l > d) {
		/* Inserting past the end of the string */
		if (balloc (b1, l + 1) != BSTR_OK) {
			if (aux != b2) bdestroy (aux);
			return BSTR_ERR;
		}
		bstr__memset (b1->data + b1->slen, (int) fill, (size_t) (pos - b1->slen));
		b1->slen = l;
	} else {
		/* Inserting in the middle of the string */
		if (balloc (b1, d + 1) != BSTR_OK) {
			if (aux != b2) bdestroy (aux);
			return BSTR_ERR;
		}
		bBlockCopy (b1->data + l, b1->data + pos, d - l);
		b1->slen = d;
	}
	bBlockCopy (b1->data + pos, aux->data, aux->slen);
	b1->data[b1->slen] = (unsigned char) '\0';
	if (aux != b2) bdestroy (aux);
	return BSTR_OK;
}

/*  int breplace (bstring b1, int pos, int len, bstring b2,
 *                unsigned char fill)
 *
 *  Replace a section of a string from pos for a length len with the string b2.
 *  fill is used is pos > b1->slen.
 */
int breplace (bstring b1, int pos, int len, const_bstring b2,
			  unsigned char fill) {
int pl, ret;
ptrdiff_t pd;
bstring aux = (bstring) b2;

	if (pos < 0 || len < 0 || (pl = pos + len) < 0 || b1 == NULL ||
	    b2 == NULL || b1->data == NULL || b2->data == NULL ||
	    b1->slen < 0 || b2->slen < 0 || b1->mlen < b1->slen ||
	    b1->mlen <= 0) return BSTR_ERR;

	/* Straddles the end? */
	if (pl >= b1->slen) {
		if ((ret = bsetstr (b1, pos, b2, fill)) < 0) return ret;
		if (pos + b2->slen < b1->slen) {
			b1->slen = pos + b2->slen;
			b1->data[b1->slen] = (unsigned char) '\0';
		}
		return ret;
	}

	/* Aliasing case */
	if ((pd = (ptrdiff_t) (b2->data - b1->data)) >= 0 && pd < (ptrdiff_t) b1->slen) {
		if (NULL == (aux = bstrcpy (b2))) return BSTR_ERR;
	}

	if (aux->slen > len) {
		if (balloc (b1, b1->slen + aux->slen - len) != BSTR_OK) {
			if (aux != b2) bdestroy (aux);
			return BSTR_ERR;
		}
	}

	if (aux->slen != len) bstr__memmove (b1->data + pos + aux->slen, b1->data + pos + len, b1->slen - (pos + len));
	bstr__memcpy (b1->data + pos, aux->data, aux->slen);
	b1->slen += aux->slen - len;
	b1->data[b1->slen] = (unsigned char) '\0';
	if (aux != b2) bdestroy (aux);
	return BSTR_OK;
}

/*  int bfindreplace (bstring b, const_bstring find, const_bstring repl,
 *                    int pos)
 *
 *  Replace all occurrences of a find string with a replace string after a
 *  given point in a bstring.
 */

typedef int (*instr_fnptr) (const_bstring s1, int pos, const_bstring s2);

static int findreplaceengine (bstring b, const_bstring find, const_bstring repl, int pos, instr_fnptr instr) {
int i, ret, slen, mlen, delta, acc;
int * d;
int static_d[32];
ptrdiff_t pd;
bstring auxf = (bstring) find;
bstring auxr = (bstring) repl;

	if (b == NULL || b->data == NULL || find == NULL ||
	    find->data == NULL || repl == NULL || repl->data == NULL ||
	    pos < 0 || find->slen <= 0 || b->mlen < 0 || b->slen > b->mlen ||
	    b->mlen <= 0 || b->slen < 0 || repl->slen < 0) return BSTR_ERR;
	if (pos > b->slen - find->slen) return BSTR_OK;

	/* Alias with find string */
	pd = (ptrdiff_t) (find->data - b->data);
	if ((ptrdiff_t) (pos - find->slen) < pd && pd < (ptrdiff_t) b->slen) {
		if (NULL == (auxf = bstrcpy (find))) return BSTR_ERR;
	}

	/* Alias with repl string */
	pd = (ptrdiff_t) (repl->data - b->data);
	if ((ptrdiff_t) (pos - repl->slen) < pd && pd < (ptrdiff_t) b->slen) {
		if (NULL == (auxr = bstrcpy (repl))) {
			if (auxf != find) bdestroy (auxf);
			return BSTR_ERR;
		}
	}

	delta = auxf->slen - auxr->slen;

	/* in-place replacement since find and replace strings are of equal
	   length */
	if (delta == 0) {
		while ((pos = instr (b, pos, auxf)) >= 0) {
			bstr__memcpy (b->data + pos, auxr->data, auxr->slen);
			pos += auxf->slen;
		}
		if (auxf != find) bdestroy (auxf);
		if (auxr != repl) bdestroy (auxr);
		return BSTR_OK;
	}

	/* shrinking replacement since auxf->slen > auxr->slen */
	if (delta > 0) {
		acc = 0;

		while ((i = instr (b, pos, auxf)) >= 0) {
			if (acc && i > pos)
				bstr__memmove (b->data + pos - acc, b->data + pos, i - pos);
			if (auxr->slen)
				bstr__memcpy (b->data + i - acc, auxr->data, auxr->slen);
			acc += delta;
			pos = i + auxf->slen;
		}

		if (acc) {
			i = b->slen;
			if (i > pos)
				bstr__memmove (b->data + pos - acc, b->data + pos, i - pos);
			b->slen -= acc;
			b->data[b->slen] = (unsigned char) '\0';
		}

		if (auxf != find) bdestroy (auxf);
		if (auxr != repl) bdestroy (auxr);
		return BSTR_OK;
	}

	/* expanding replacement since find->slen < repl->slen.  Its a lot
	   more complicated. */

	mlen = 32;
	d = (int *) static_d; /* Avoid malloc for trivial cases */
	acc = slen = 0;

	while ((pos = instr (b, pos, auxf)) >= 0) {
		if (slen + 1 >= mlen) {
			int sl;
			int * t;
			mlen += mlen;
			sl = sizeof (int *) * mlen;
			if (static_d == d) d = NULL;
			if (sl < mlen || NULL == (t = (int *) bstr__realloc (d, sl))) {
				ret = BSTR_ERR;
				goto done;
			}
			if (NULL == d) bstr__memcpy (t, static_d, sizeof (static_d));
			d = t;
		}
		d[slen] = pos;
		slen++;
		acc -= delta;
		pos += auxf->slen;
		if (pos < 0 || acc < 0) {
			ret = BSTR_ERR;
			goto done;
		}
	}
	d[slen] = b->slen;

	if (BSTR_OK == (ret = balloc (b, b->slen + acc + 1))) {
		b->slen += acc;
		for (i = slen-1; i >= 0; i--) {
			int s, l;
			s = d[i] + auxf->slen;
			l = d[i+1] - s;
			if (l) {
				bstr__memmove (b->data + s + acc, b->data + s, l);
			}
			if (auxr->slen) {
				bstr__memmove (b->data + s + acc - auxr->slen,
				         auxr->data, auxr->slen);
			}
			acc += delta;		
		}
		b->data[b->slen] = (unsigned char) '\0';
	}

	done:;
	if (static_d == d) d = NULL;
	bstr__free (d);
	if (auxf != find) bdestroy (auxf);
	if (auxr != repl) bdestroy (auxr);
	return ret;
}

/*  int bfindreplace (bstring b, const_bstring find, const_bstring repl,
 *                    int pos)
 *
 *  Replace all occurrences of a find string with a replace string after a
 *  given point in a bstring.
 */
int bfindreplace (bstring b, const_bstring find, const_bstring repl, int pos) {
	return findreplaceengine (b, find, repl, pos, binstr);
}

/*  int bfindreplacecaseless (bstring b, const_bstring find, const_bstring repl,
 *                    int pos)
 *
 *  Replace all occurrences of a find string, ignoring case, with a replace
 *  string after a given point in a bstring.
 */
int bfindreplacecaseless (bstring b, const_bstring find, const_bstring repl, int pos) {
	return findreplaceengine (b, find, repl, pos, binstrcaseless);
}

/*  int binsertch (bstring b, int pos, int len, unsigned char fill)
 *
 *  Inserts the character fill repeatedly into b at position pos for a
 *  length len.  If the position pos is past the end of b, then the
 *  character "fill" is appended as necessary to make up the gap between the
 *  end of b and the position pos + len.
 */
int binsertch (bstring b, int pos, int len, unsigned char fill) {
int d, l, i;

	if (pos < 0 || b == NULL || b->slen < 0 || b->mlen < b->slen ||
	    b->mlen <= 0 || len < 0) return BSTR_ERR;

	/* Compute the two possible end pointers */
	d = b->slen + len;
	l = pos + len;
	if ((d|l) < 0) return BSTR_ERR;

	if (l > d) {
		/* Inserting past the end of the string */
		if (balloc (b, l + 1) != BSTR_OK) return BSTR_ERR;
		pos = b->slen;
		b->slen = l;
	} else {
		/* Inserting in the middle of the string */
		if (balloc (b, d + 1) != BSTR_OK) return BSTR_ERR;
		for (i = d - 1; i >= l; i--) {
			b->data[i] = b->data[i - len];
		}
		b->slen = d;
	}

	for (i=pos; i < l; i++) b->data[i] = fill;
	b->data[b->slen] = (unsigned char) '\0';
	return BSTR_OK;
}

/*  int bpattern (bstring b, int len)
 *
 *  Replicate the bstring, b in place, end to end repeatedly until it
 *  surpasses len characters, then chop the result to exactly len characters.
 *  This function operates in-place.  The function will return with BSTR_ERR
 *  if b is NULL or of length 0, otherwise BSTR_OK is returned.
 */
int bpattern (bstring b, int len) {
int i, d;

	d = blength (b);
	if (d <= 0 || len < 0 || balloc (b, len + 1) != BSTR_OK) return BSTR_ERR;
	if (len > 0) {
		if (d == 1) return bsetstr (b, len, NULL, b->data[0]);
		for (i = d; i < len; i++) b->data[i] = b->data[i - d];
	}
	b->data[len] = (unsigned char) '\0';
	b->slen = len;
	return BSTR_OK;
}

#define BS_BUFF_SZ (1024)

/*  int breada (bstring b, bNread readPtr, void * parm)
 *
 *  Use a finite buffer fread-like function readPtr to concatenate to the
 *  bstring b the entire contents of file-like source data in a roughly
 *  efficient way.
 */
int breada (bstring b, bNread readPtr, void * parm) {
int i, l, n;

	if (b == NULL || b->mlen <= 0 || b->slen < 0 || b->mlen < b->slen ||
	    b->mlen <= 0 || readPtr == NULL) return BSTR_ERR;

	i = b->slen;
	for (n=i+16; ; n += ((n < BS_BUFF_SZ) ? n : BS_BUFF_SZ)) {
		if (BSTR_OK != balloc (b, n + 1)) return BSTR_ERR;
		l = (int) readPtr ((void *) (b->data + i), 1, n - i, parm);
		i += l;
		b->slen = i;
		if (i < n) break;
	}

	b->data[i] = (unsigned char) '\0';
	return BSTR_OK;
}

/*  bstring bread (bNread readPtr, void * parm)
 *
 *  Use a finite buffer fread-like function readPtr to create a bstring
 *  filled with the entire contents of file-like source data in a roughly
 *  efficient way.
 */
bstring bread (bNread readPtr, void * parm) {
bstring buff;

	if (0 > breada (buff = bfromcstr (""), readPtr, parm)) {
		bdestroy (buff);
		return NULL;
	}
	return buff;
}

/*  int bassigngets (bstring b, bNgetc getcPtr, void * parm, char terminator)
 *
 *  Use an fgetc-like single character stream reading function (getcPtr) to
 *  obtain a sequence of characters which are concatenated to the end of the
 *  bstring b.  The stream read is terminated by the passed in terminator
 *  parameter.
 *
 *  If getcPtr returns with a negative number, or the terminator character
 *  (which is appended) is read, then the stream reading is halted and the
 *  function returns with a partial result in b.  If there is an empty partial
 *  result, 1 is returned.  If no characters are read, or there is some other
 *  detectable error, BSTR_ERR is returned.
 */
int bassigngets (bstring b, bNgetc getcPtr, void * parm, char terminator) {
int c, d, e;

	if (b == NULL || b->mlen <= 0 || b->slen < 0 || b->mlen < b->slen ||
	    b->mlen <= 0 || getcPtr == NULL) return BSTR_ERR;
	d = 0;
	e = b->mlen - 2;

	while ((c = getcPtr (parm)) >= 0) {
		if (d > e) {
			b->slen = d;
			if (balloc (b, d + 2) != BSTR_OK) return BSTR_ERR;
			e = b->mlen - 2;
		}
		b->data[d] = (unsigned char) c;
		d++;
		if (c == terminator) break;
	}

	b->data[d] = (unsigned char) '\0';
	b->slen = d;

	return d == 0 && c < 0;
}

/*  int bgetsa (bstring b, bNgetc getcPtr, void * parm, char terminator)
 *
 *  Use an fgetc-like single character stream reading function (getcPtr) to
 *  obtain a sequence of characters which are concatenated to the end of the
 *  bstring b.  The stream read is terminated by the passed in terminator
 *  parameter.
 *
 *  If getcPtr returns with a negative number, or the terminator character
 *  (which is appended) is read, then the stream reading is halted and the
 *  function returns with a partial result concatentated to b.  If there is
 *  an empty partial result, 1 is returned.  If no characters are read, or
 *  there is some other detectable error, BSTR_ERR is returned.
 */
int bgetsa (bstring b, bNgetc getcPtr, void * parm, char terminator) {
int c, d, e;

	if (b == NULL || b->mlen <= 0 || b->slen < 0 || b->mlen < b->slen ||
	    b->mlen <= 0 || getcPtr == NULL) return BSTR_ERR;
	d = b->slen;
	e = b->mlen - 2;

	while ((c = getcPtr (parm)) >= 0) {
		if (d > e) {
			b->slen = d;
			if (balloc (b, d + 2) != BSTR_OK) return BSTR_ERR;
			e = b->mlen - 2;
		}
		b->data[d] = (unsigned char) c;
		d++;
		if (c == terminator) break;
	}

	b->data[d] = (unsigned char) '\0';
	b->slen = d;

	return d == 0 && c < 0;
}

/*  bstring bgetstream (bNgetc getcPtr, void * parm, char terminator)
 *
 *  Use an fgetc-like single character stream reading function (getcPtr) to
 *  obtain a sequence of characters which are concatenated into a bstring.
 *  The stream read is terminated by the passed in terminator function.
 *
 *  If getcPtr returns with a negative number, or the terminator character
 *  (which is appended) is read, then the stream reading is halted and the
 *  result obtained thus far is returned.  If no characters are read, or
 *  there is some other detectable error, NULL is returned.
 */
bstring bgetstream (bNgetc getcPtr, void * parm, char terminator) {
bstring buff;

	if (0 > bgetsa (buff = bfromcstr (""), getcPtr, parm, terminator) || 0 >= buff->slen) {
		bdestroy (buff);
		buff = NULL;
	}
	return buff;
}

struct bStream {
	bstring buff;		/* Buffer for over-reads */
	void * parm;		/* The stream handle for core stream */
	bNread readFnPtr;	/* fread compatible fnptr for core stream */
	int isEOF;		/* track file's EOF state */
	int maxBuffSz;
};

/*  struct bStream * bsopen (bNread readPtr, void * parm)
 *
 *  Wrap a given open stream (described by a fread compatible function
 *  pointer and stream handle) into an open bStream suitable for the bstring
 *  library streaming functions.
 */
struct bStream * bsopen (bNread readPtr, void * parm) {
struct bStream * s;

	if (readPtr == NULL) return NULL;
	s = (struct bStream *) bstr__alloc (sizeof (struct bStream));
	if (s == NULL) return NULL;
	s->parm = parm;
	s->buff = bfromcstr ("");
	s->readFnPtr = readPtr;
	s->maxBuffSz = BS_BUFF_SZ;
	s->isEOF = 0;
	return s;
}

/*  int bsbufflength (struct bStream * s, int sz)
 *
 *  Set the length of the buffer used by the bStream.  If sz is zero, the
 *  length is not set.  This function returns with the previous length.
 */
int bsbufflength (struct bStream * s, int sz) {
int oldSz;
	if (s == NULL || sz < 0) return BSTR_ERR;
	oldSz = s->maxBuffSz;
	if (sz > 0) s->maxBuffSz = sz;
	return oldSz;
}

int bseof (const struct bStream * s) {
	if (s == NULL || s->readFnPtr == NULL) return BSTR_ERR;
	return s->isEOF && (s->buff->slen == 0);
}

/*  void * bsclose (struct bStream * s)
 *
 *  Close the bStream, and return the handle to the stream that was originally
 *  used to open the given stream.
 */
void * bsclose (struct bStream * s) {
void * parm;
	if (s == NULL) return NULL;
	s->readFnPtr = NULL;
	if (s->buff) bdestroy (s->buff);
	s->buff = NULL;
	parm = s->parm;
	s->parm = NULL;
	s->isEOF = 1;
	bstr__free (s);
	return parm;
}

/*  int bsreadlna (bstring r, struct bStream * s, char terminator)
 *
 *  Read a bstring terminated by the terminator character or the end of the
 *  stream from the bStream (s) and return it into the parameter r.  This
 *  function may read additional characters from the core stream that are not
 *  returned, but will be retained for subsequent read operations.
 */
int bsreadlna (bstring r, struct bStream * s, char terminator) {
int i, l, ret, rlo;
char * b;
struct tagbstring x;

	if (s == NULL || s->buff == NULL || r == NULL || r->mlen <= 0 ||
	    r->slen < 0 || r->mlen < r->slen) return BSTR_ERR;
	l = s->buff->slen;
	if (BSTR_OK != balloc (s->buff, s->maxBuffSz + 1)) return BSTR_ERR;
	b = (char *) s->buff->data;
	x.data = (unsigned char *) b;

	/* First check if the current buffer holds the terminator */
	b[l] = terminator; /* Set sentinel */
	for (i=0; b[i] != terminator; i++) ;
	if (i < l) {
		x.slen = i + 1;
		ret = bconcat (r, &x);
		s->buff->slen = l;
		if (BSTR_OK == ret) bdelete (s->buff, 0, i + 1);
		return BSTR_OK;
	}

	rlo = r->slen;

	/* If not then just concatenate the entire buffer to the output */
	x.slen = l;
	if (BSTR_OK != bconcat (r, &x)) return BSTR_ERR;

	/* Perform direct in-place reads into the destination to allow for
	   the minimum of data-copies */
	for (;;) {
		if (BSTR_OK != balloc (r, r->slen + s->maxBuffSz + 1)) return BSTR_ERR;
		b = (char *) (r->data + r->slen);
		l = (int) s->readFnPtr (b, 1, s->maxBuffSz, s->parm);
		if (l <= 0) {
			r->data[r->slen] = (unsigned char) '\0';
			s->buff->slen = 0;
			s->isEOF = 1;
			/* If nothing was read return with an error message */
			return BSTR_ERR & -(r->slen == rlo);
		}
		b[l] = terminator; /* Set sentinel */
		for (i=0; b[i] != terminator; i++) ;
		if (i < l) break;
		r->slen += l;
	}

	/* Terminator found, push over-read back to buffer */
	i++;
	r->slen += i;
	s->buff->slen = l - i;
	bstr__memcpy (s->buff->data, b + i, l - i);
	r->data[r->slen] = (unsigned char) '\0';
	return BSTR_OK;
}

/*  int bsreadlnsa (bstring r, struct bStream * s, bstring term)
 *
 *  Read a bstring terminated by any character in the term string or the end
 *  of the stream from the bStream (s) and return it into the parameter r.
 *  This function may read additional characters from the core stream that
 *  are not returned, but will be retained for subsequent read operations.
 */
int bsreadlnsa (bstring r, struct bStream * s, const_bstring term) {
int i, l, ret, rlo;
unsigned char * b;
struct tagbstring x;
struct charField cf;

	if (s == NULL || s->buff == NULL || r == NULL || term == NULL ||
	    term->data == NULL || r->mlen <= 0 || r->slen < 0 ||
	    r->mlen < r->slen) return BSTR_ERR;
	if (term->slen == 1) return bsreadlna (r, s, term->data[0]);
	if (term->slen < 1 || buildCharField (&cf, term)) return BSTR_ERR;

	l = s->buff->slen;
	if (BSTR_OK != balloc (s->buff, s->maxBuffSz + 1)) return BSTR_ERR;
	b = (unsigned char *) s->buff->data;
	x.data = b;

	/* First check if the current buffer holds the terminator */
	b[l] = term->data[0]; /* Set sentinel */
	for (i=0; !testInCharField (&cf, b[i]); i++) ;
	if (i < l) {
		x.slen = i + 1;
		ret = bconcat (r, &x);
		s->buff->slen = l;
		if (BSTR_OK == ret) bdelete (s->buff, 0, i + 1);
		return BSTR_OK;
	}

	rlo = r->slen;

	/* If not then just concatenate the entire buffer to the output */
	x.slen = l;
	if (BSTR_OK != bconcat (r, &x)) return BSTR_ERR;

	/* Perform direct in-place reads into the destination to allow for
	   the minimum of data-copies */
	for (;;) {
		if (BSTR_OK != balloc (r, r->slen + s->maxBuffSz + 1)) return BSTR_ERR;
		b = (unsigned char *) (r->data + r->slen);
		l = (int) s->readFnPtr (b, 1, s->maxBuffSz, s->parm);
		if (l <= 0) {
			r->data[r->slen] = (unsigned char) '\0';
			s->buff->slen = 0;
			s->isEOF = 1;
			/* If nothing was read return with an error message */
			return BSTR_ERR & -(r->slen == rlo);
		}

		b[l] = term->data[0]; /* Set sentinel */
		for (i=0; !testInCharField (&cf, b[i]); i++) ;
		if (i < l) break;
		r->slen += l;
	}

	/* Terminator found, push over-read back to buffer */
	i++;
	r->slen += i;
	s->buff->slen = l - i;
	bstr__memcpy (s->buff->data, b + i, l - i);
	r->data[r->slen] = (unsigned char) '\0';
	return BSTR_OK;
}

/*  int bsreada (bstring r, struct bStream * s, int n)
 *
 *  Read a bstring of length n (or, if it is fewer, as many bytes as is
 *  remaining) from the bStream.  This function may read additional
 *  characters from the core stream that are not returned, but will be
 *  retained for subsequent read operations.  This function will not read
 *  additional characters from the core stream beyond virtual stream pointer.
 */
int bsreada (bstring r, struct bStream * s, int n) {
int l, ret, orslen;
char * b;
struct tagbstring x;

	if (s == NULL || s->buff == NULL || r == NULL || r->mlen <= 0
	 || r->slen < 0 || r->mlen < r->slen || n <= 0) return BSTR_ERR;

	n += r->slen;
	if (n <= 0) return BSTR_ERR;

	l = s->buff->slen;

	orslen = r->slen;

	if (0 == l) {
		if (s->isEOF) return BSTR_ERR;
		if (r->mlen > n) {
			l = (int) s->readFnPtr (r->data + r->slen, 1, n - r->slen, s->parm);
			if (0 >= l || l > n - r->slen) {
				s->isEOF = 1;
				return BSTR_ERR;
			}
			r->slen += l;
			r->data[r->slen] = (unsigned char) '\0';
			return 0;
		}
	}

	if (BSTR_OK != balloc (s->buff, s->maxBuffSz + 1)) return BSTR_ERR;
	b = (char *) s->buff->data;
	x.data = (unsigned char *) b;

	do {
		if (l + r->slen >= n) {
			x.slen = n - r->slen;
			ret = bconcat (r, &x);
			s->buff->slen = l;
			if (BSTR_OK == ret) bdelete (s->buff, 0, x.slen);
			return BSTR_ERR & -(r->slen == orslen);
		}

		x.slen = l;
		if (BSTR_OK != bconcat (r, &x)) break;

		l = n - r->slen;
		if (l > s->maxBuffSz) l = s->maxBuffSz;

		l = (int) s->readFnPtr (b, 1, l, s->parm);

	} while (l > 0);
	if (l < 0) l = 0;
	if (l == 0) s->isEOF = 1;
	s->buff->slen = l;
	return BSTR_ERR & -(r->slen == orslen);
}

/*  int bsreadln (bstring r, struct bStream * s, char terminator)
 *
 *  Read a bstring terminated by the terminator character or the end of the
 *  stream from the bStream (s) and return it into the parameter r.  This
 *  function may read additional characters from the core stream that are not
 *  returned, but will be retained for subsequent read operations.
 */
int bsreadln (bstring r, struct bStream * s, char terminator) {
	if (s == NULL || s->buff == NULL || r == NULL || r->mlen <= 0)
		return BSTR_ERR;
	if (BSTR_OK != balloc (s->buff, s->maxBuffSz + 1)) return BSTR_ERR;
	r->slen = 0;
	return bsreadlna (r, s, terminator);
}

/*  int bsreadlns (bstring r, struct bStream * s, bstring term)
 *
 *  Read a bstring terminated by any character in the term string or the end
 *  of the stream from the bStream (s) and return it into the parameter r.
 *  This function may read additional characters from the core stream that
 *  are not returned, but will be retained for subsequent read operations.
 */
int bsreadlns (bstring r, struct bStream * s, const_bstring term) {
	if (s == NULL || s->buff == NULL || r == NULL || term == NULL
	 || term->data == NULL || r->mlen <= 0) return BSTR_ERR;
	if (term->slen == 1) return bsreadln (r, s, term->data[0]);
	if (term->slen < 1) return BSTR_ERR;
	if (BSTR_OK != balloc (s->buff, s->maxBuffSz + 1)) return BSTR_ERR;
	r->slen = 0;
	return bsreadlnsa (r, s, term);
}

/*  int bsread (bstring r, struct bStream * s, int n)
 *
 *  Read a bstring of length n (or, if it is fewer, as many bytes as is
 *  remaining) from the bStream.  This function may read additional
 *  characters from the core stream that are not returned, but will be
 *  retained for subsequent read operations.  This function will not read
 *  additional characters from the core stream beyond virtual stream pointer.
 */
int bsread (bstring r, struct bStream * s, int n) {
	if (s == NULL || s->buff == NULL || r == NULL || r->mlen <= 0
	 || n <= 0) return BSTR_ERR;
	if (BSTR_OK != balloc (s->buff, s->maxBuffSz + 1)) return BSTR_ERR;
	r->slen = 0;
	return bsreada (r, s, n);
}

/*  int bsunread (struct bStream * s, const_bstring b)
 *
 *  Insert a bstring into the bStream at the current position.  These
 *  characters will be read prior to those that actually come from the core
 *  stream.
 */
int bsunread (struct bStream * s, const_bstring b) {
	if (s == NULL || s->buff == NULL) return BSTR_ERR;
	return binsert (s->buff, 0, b, (unsigned char) '?');
}

/*  int bspeek (bstring r, const struct bStream * s)
 *
 *  Return the currently buffered characters from the bStream that will be
 *  read prior to reads from the core stream.
 */
int bspeek (bstring r, const struct bStream * s) {
	if (s == NULL || s->buff == NULL) return BSTR_ERR;
	return bassign (r, s->buff);
}

/*  bstring bjoin (const struct bstrList * bl, const_bstring sep);
 *
 *  Join the entries of a bstrList into one bstring by sequentially
 *  concatenating them with the sep string in between.  If there is an error
 *  NULL is returned, otherwise a bstring with the correct result is returned.
 */
bstring bjoin (const struct bstrList * bl, const_bstring sep) {
bstring b;
int i, c, v;

	if (bl == NULL || bl->qty < 0) return NULL;
	if (sep != NULL && (sep->slen < 0 || sep->data == NULL)) return NULL;

	for (i = 0, c = 1; i < bl->qty; i++) {
		v = bl->entry[i]->slen;
		if (v < 0) return NULL;	/* Invalid input */
		c += v;
		if (c < 0) return NULL;	/* Wrap around ?? */
	}

	if (sep != NULL) c += (bl->qty - 1) * sep->slen;

	b = (bstring) bstr__alloc (sizeof (struct tagbstring));
	if (NULL == b) return NULL; /* Out of memory */
	b->data = (unsigned char *) bstr__alloc (c);
	if (b->data == NULL) {
		bstr__free (b);
		return NULL;
	}

	b->mlen = c;
	b->slen = c-1;

	for (i = 0, c = 0; i < bl->qty; i++) {
		if (i > 0 && sep != NULL) {
			bstr__memcpy (b->data + c, sep->data, sep->slen);
			c += sep->slen;
		}
		v = bl->entry[i]->slen;
		bstr__memcpy (b->data + c, bl->entry[i]->data, v);
		c += v;
	}
	b->data[c] = (unsigned char) '\0';
	return b;
}

#define BSSSC_BUFF_LEN (256)

/*  int bssplitscb (struct bStream * s, const_bstring splitStr,
 *	int (* cb) (void * parm, int ofs, const_bstring entry), void * parm)
 *
 *  Iterate the set of disjoint sequential substrings read from a stream
 *  divided by any of the characters in splitStr.  An empty splitStr causes
 *  the whole stream to be iterated once.
 *
 *  Note: At the point of calling the cb function, the bStream pointer is
 *  pointed exactly at the position right after having read the split
 *  character.  The cb function can act on the stream by causing the bStream
 *  pointer to move, and bssplitscb will continue by starting the next split
 *  at the position of the pointer after the return from cb.
 *
 *  However, if the cb causes the bStream s to be destroyed then the cb must
 *  return with a negative value, otherwise bssplitscb will continue in an
 *  undefined manner.
 */
int bssplitscb (struct bStream * s, const_bstring splitStr,
	int (* cb) (void * parm, int ofs, const_bstring entry), void * parm) {
struct charField chrs;
bstring buff;
int i, p, ret;

	if (cb == NULL || s == NULL || s->readFnPtr == NULL
	 || splitStr == NULL || splitStr->slen < 0) return BSTR_ERR;

	if (NULL == (buff = bfromcstr (""))) return BSTR_ERR;

	if (splitStr->slen == 0) {
		while (bsreada (buff, s, BSSSC_BUFF_LEN) >= 0) ;
		if ((ret = cb (parm, 0, buff)) > 0)
			ret = 0;
	} else {
		buildCharField (&chrs, splitStr);
		ret = p = i = 0;
		for (;;) {
			if (i >= buff->slen) {
				bsreada (buff, s, BSSSC_BUFF_LEN);
				if (i >= buff->slen) {
					if (0 < (ret = cb (parm, p, buff))) ret = 0;
					break;
				}
			}
			if (testInCharField (&chrs, buff->data[i])) {
				struct tagbstring t;
				unsigned char c;

				blk2tbstr (t, buff->data + i + 1, buff->slen - (i + 1));
				if ((ret = bsunread (s, &t)) < 0) break;
				buff->slen = i;
				c = buff->data[i];
				buff->data[i] = (unsigned char) '\0';
				if ((ret = cb (parm, p, buff)) < 0) break;
				buff->data[i] = c;
				buff->slen = 0;
				p += i + 1;
				i = -1;
			}
			i++;
		}
	}

	bdestroy (buff);
	return ret;
}

/*  int bssplitstrcb (struct bStream * s, const_bstring splitStr,
 *	int (* cb) (void * parm, int ofs, const_bstring entry), void * parm)
 *
 *  Iterate the set of disjoint sequential substrings read from a stream
 *  divided by the entire substring splitStr.  An empty splitStr causes
 *  each character of the stream to be iterated.
 *
 *  Note: At the point of calling the cb function, the bStream pointer is
 *  pointed exactly at the position right after having read the split
 *  character.  The cb function can act on the stream by causing the bStream
 *  pointer to move, and bssplitscb will continue by starting the next split
 *  at the position of the pointer after the return from cb.
 *
 *  However, if the cb causes the bStream s to be destroyed then the cb must
 *  return with a negative value, otherwise bssplitscb will continue in an
 *  undefined manner.
 */
int bssplitstrcb (struct bStream * s, const_bstring splitStr,
	int (* cb) (void * parm, int ofs, const_bstring entry), void * parm) {
bstring buff;
int i, p, ret;

	if (cb == NULL || s == NULL || s->readFnPtr == NULL
	 || splitStr == NULL || splitStr->slen < 0) return BSTR_ERR;

	if (splitStr->slen == 1) return bssplitscb (s, splitStr, cb, parm);

	if (NULL == (buff = bfromcstr (""))) return BSTR_ERR;

	if (splitStr->slen == 0) {
		for (i=0; bsreada (buff, s, BSSSC_BUFF_LEN) >= 0; i++) {
			if ((ret = cb (parm, 0, buff)) < 0) {
				bdestroy (buff);
				return ret;
			}
			buff->slen = 0;
		}
		return BSTR_OK;
	} else {
		ret = p = i = 0;
		for (i=p=0;;) {
			if ((ret = binstr (buff, 0, splitStr)) >= 0) {
				struct tagbstring t;
				blk2tbstr (t, buff->data, ret);
				i = ret + splitStr->slen;
				if ((ret = cb (parm, p, &t)) < 0) break;
				p += i;
				bdelete (buff, 0, i);
			} else {
				bsreada (buff, s, BSSSC_BUFF_LEN);
				if (bseof (s)) {
					if ((ret = cb (parm, p, buff)) > 0) ret = 0;
					break;
				}
			}
		}
	}

	bdestroy (buff);
	return ret;
}

/*  int bstrListCreate (void)
 *
 *  Create a bstrList.
 */
struct bstrList * bstrListCreate (void) {
struct bstrList * sl = (struct bstrList *) bstr__alloc (sizeof (struct bstrList));
	if (sl) {
		sl->entry = (bstring *) bstr__alloc (1*sizeof (bstring));
		if (!sl->entry) {
			bstr__free (sl);
			sl = NULL;
		} else {
			sl->qty = 0;
			sl->mlen = 1;
		}
	}
	return sl;
}

/*  int bstrListDestroy (struct bstrList * sl)
 *
 *  Destroy a bstrList that has been created by bsplit, bsplits or bstrListCreate.
 */
int bstrListDestroy (struct bstrList * sl) {
int i;
	if (sl == NULL || sl->qty < 0) return BSTR_ERR;
	for (i=0; i < sl->qty; i++) {
		if (sl->entry[i]) {
			bdestroy (sl->entry[i]);
			sl->entry[i] = NULL;
		}
	}
	sl->qty  = -1;
	sl->mlen = -1;
	bstr__free (sl->entry);
	sl->entry = NULL;
	bstr__free (sl);
	return BSTR_OK;
}

/*  int bstrListAlloc (struct bstrList * sl, int msz)
 *
 *  Ensure that there is memory for at least msz number of entries for the
 *  list.
 */
int bstrListAlloc (struct bstrList * sl, int msz) {
bstring * l;
int smsz;
size_t nsz;
	if (!sl || msz <= 0 || !sl->entry || sl->qty < 0 || sl->mlen <= 0 || sl->qty > sl->mlen) return BSTR_ERR;
	if (sl->mlen >= msz) return BSTR_OK;
	smsz = snapUpSize (msz);
	nsz = ((size_t) smsz) * sizeof (bstring);
	if (nsz < (size_t) smsz) return BSTR_ERR;
	l = (bstring *) bstr__realloc (sl->entry, nsz);
	if (!l) {
		smsz = msz;
		nsz = ((size_t) smsz) * sizeof (bstring);
		l = (bstring *) bstr__realloc (sl->entry, nsz);
		if (!l) return BSTR_ERR;
	}
	sl->mlen = smsz;
	sl->entry = l;
	return BSTR_OK;
}

/*  int bstrListAllocMin (struct bstrList * sl, int msz)
 *
 *  Try to allocate the minimum amount of memory for the list to include at
 *  least msz entries or sl->qty whichever is greater.
 */
int bstrListAllocMin (struct bstrList * sl, int msz) {
bstring * l;
size_t nsz;
	if (!sl || msz <= 0 || !sl->entry || sl->qty < 0 || sl->mlen <= 0 || sl->qty > sl->mlen) return BSTR_ERR;
	if (msz < sl->qty) msz = sl->qty;
	if (sl->mlen == msz) return BSTR_OK;
	nsz = ((size_t) msz) * sizeof (bstring);
	if (nsz < (size_t) msz) return BSTR_ERR;
	l = (bstring *) bstr__realloc (sl->entry, nsz);
	if (!l) return BSTR_ERR;
	sl->mlen = msz;
	sl->entry = l;
	return BSTR_OK;
}

/*  int bsplitcb (const_bstring str, unsigned char splitChar, int pos,
 *	int (* cb) (void * parm, int ofs, int len), void * parm)
 *
 *  Iterate the set of disjoint sequential substrings over str divided by the
 *  character in splitChar.
 *
 *  Note: Non-destructive modification of str from within the cb function
 *  while performing this split is not undefined.  bsplitcb behaves in
 *  sequential lock step with calls to cb.  I.e., after returning from a cb
 *  that return a non-negative integer, bsplitcb continues from the position
 *  1 character after the last detected split character and it will halt
 *  immediately if the length of str falls below this point.  However, if the
 *  cb function destroys str, then it *must* return with a negative value,
 *  otherwise bsplitcb will continue in an undefined manner.
 */
int bsplitcb (const_bstring str, unsigned char splitChar, int pos,
	int (* cb) (void * parm, int ofs, int len), void * parm) {
int i, p, ret;

	if (cb == NULL || str == NULL || pos < 0 || pos > str->slen)
		return BSTR_ERR;

	p = pos;
	do {
		for (i=p; i < str->slen; i++) {
			if (str->data[i] == splitChar) break;
		}
		if ((ret = cb (parm, p, i - p)) < 0) return ret;
		p = i + 1;
	} while (p <= str->slen);
	return BSTR_OK;
}

/*  int bsplitscb (const_bstring str, const_bstring splitStr, int pos,
 *	int (* cb) (void * parm, int ofs, int len), void * parm)
 *
 *  Iterate the set of disjoint sequential substrings over str divided by any
 *  of the characters in splitStr.  An empty splitStr causes the whole str to
 *  be iterated once.
 *
 *  Note: Non-destructive modification of str from within the cb function
 *  while performing this split is not undefined.  bsplitscb behaves in
 *  sequential lock step with calls to cb.  I.e., after returning from a cb
 *  that return a non-negative integer, bsplitscb continues from the position
 *  1 character after the last detected split character and it will halt
 *  immediately if the length of str falls below this point.  However, if the
 *  cb function destroys str, then it *must* return with a negative value,
 *  otherwise bsplitscb will continue in an undefined manner.
 */
int bsplitscb (const_bstring str, const_bstring splitStr, int pos,
	int (* cb) (void * parm, int ofs, int len), void * parm) {
struct charField chrs;
int i, p, ret;

	if (cb == NULL || str == NULL || pos < 0 || pos > str->slen
	 || splitStr == NULL || splitStr->slen < 0) return BSTR_ERR;
	if (splitStr->slen == 0) {
		if ((ret = cb (parm, 0, str->slen)) > 0) ret = 0;
		return ret;
	}

	if (splitStr->slen == 1)
		return bsplitcb (str, splitStr->data[0], pos, cb, parm);

	buildCharField (&chrs, splitStr);

	p = pos;
	do {
		for (i=p; i < str->slen; i++) {
			if (testInCharField (&chrs, str->data[i])) break;
		}
		if ((ret = cb (parm, p, i - p)) < 0) return ret;
		p = i + 1;
	} while (p <= str->slen);
	return BSTR_OK;
}

/*  int bsplitstrcb (const_bstring str, const_bstring splitStr, int pos,
 *	int (* cb) (void * parm, int ofs, int len), void * parm)
 *
 *  Iterate the set of disjoint sequential substrings over str divided by the
 *  substring splitStr.  An empty splitStr causes the whole str to be
 *  iterated once.
 *
 *  Note: Non-destructive modification of str from within the cb function
 *  while performing this split is not undefined.  bsplitstrcb behaves in
 *  sequential lock step with calls to cb.  I.e., after returning from a cb
 *  that return a non-negative integer, bsplitscb continues from the position
 *  1 character after the last detected split character and it will halt
 *  immediately if the length of str falls below this point.  However, if the
 *  cb function destroys str, then it *must* return with a negative value,
 *  otherwise bsplitscb will continue in an undefined manner.
 */
int bsplitstrcb (const_bstring str, const_bstring splitStr, int pos,
	int (* cb) (void * parm, int ofs, int len), void * parm) {
int i, p, ret;

	if (cb == NULL || str == NULL || pos < 0 || pos > str->slen
	 || splitStr == NULL || splitStr->slen < 0) return BSTR_ERR;

	if (0 == splitStr->slen) {
		for (i=pos; i < str->slen; i++) {
			if ((ret = cb (parm, i, 1)) < 0) return ret;
		}
		return BSTR_OK;
	}

	if (splitStr->slen == 1)
		return bsplitcb (str, splitStr->data[0], pos, cb, parm);

	for (i=p=pos; i <= str->slen - splitStr->slen; i++) {
		if (0 == bstr__memcmp (splitStr->data, str->data + i, splitStr->slen)) {
			if ((ret = cb (parm, p, i - p)) < 0) return ret;
			i += splitStr->slen;
			p = i;
		}
	}
	if ((ret = cb (parm, p, str->slen - p)) < 0) return ret;
	return BSTR_OK;
}

struct genBstrList {
	bstring b;
	struct bstrList * bl;
};

static int bscb (void * parm, int ofs, int len) {
struct genBstrList * g = (struct genBstrList *) parm;
	if (g->bl->qty >= g->bl->mlen) {
		int mlen = g->bl->mlen * 2;
		bstring * tbl;

		while (g->bl->qty >= mlen) {
			if (mlen < g->bl->mlen) return BSTR_ERR;
			mlen += mlen;
		}

		tbl = (bstring *) bstr__realloc (g->bl->entry, sizeof (bstring) * mlen);
		if (tbl == NULL) return BSTR_ERR;

		g->bl->entry = tbl;
		g->bl->mlen = mlen;
	}

	g->bl->entry[g->bl->qty] = bmidstr (g->b, ofs, len);
	g->bl->qty++;
	return BSTR_OK;
}

/*  struct bstrList * bsplit (const_bstring str, unsigned char splitChar)
 *
 *  Create an array of sequential substrings from str divided by the character
 *  splitChar.
 */
struct bstrList * bsplit (const_bstring str, unsigned char splitChar) {
struct genBstrList g;

	if (str == NULL || str->data == NULL || str->slen < 0) return NULL;

	g.bl = (struct bstrList *) bstr__alloc (sizeof (struct bstrList));
	if (g.bl == NULL) return NULL;
	g.bl->mlen = 4;
	g.bl->entry = (bstring *) bstr__alloc (g.bl->mlen * sizeof (bstring));
	if (NULL == g.bl->entry) {
		bstr__free (g.bl);
		return NULL;
	}

	g.b = (bstring) str;
	g.bl->qty = 0;
	if (bsplitcb (str, splitChar, 0, bscb, &g) < 0) {
		bstrListDestroy (g.bl);
		return NULL;
	}
	return g.bl;
}

/*  struct bstrList * bsplitstr (const_bstring str, const_bstring splitStr)
 *
 *  Create an array of sequential substrings from str divided by the entire
 *  substring splitStr.
 */
struct bstrList * bsplitstr (const_bstring str, const_bstring splitStr) {
struct genBstrList g;

	if (str == NULL || str->data == NULL || str->slen < 0) return NULL;

	g.bl = (struct bstrList *) bstr__alloc (sizeof (struct bstrList));
	if (g.bl == NULL) return NULL;
	g.bl->mlen = 4;
	g.bl->entry = (bstring *) bstr__alloc (g.bl->mlen * sizeof (bstring));
	if (NULL == g.bl->entry) {
		bstr__free (g.bl);
		return NULL;
	}

	g.b = (bstring) str;
	g.bl->qty = 0;
	if (bsplitstrcb (str, splitStr, 0, bscb, &g) < 0) {
		bstrListDestroy (g.bl);
		return NULL;
	}
	return g.bl;
}

/*  struct bstrList * bsplits (const_bstring str, bstring splitStr)
 *
 *  Create an array of sequential substrings from str divided by any of the
 *  characters in splitStr.  An empty splitStr causes a single entry bstrList
 *  containing a copy of str to be returned.
 */
struct bstrList * bsplits (const_bstring str, const_bstring splitStr) {
struct genBstrList g;

	if (     str == NULL ||      str->slen < 0 ||      str->data == NULL ||
	    splitStr == NULL || splitStr->slen < 0 || splitStr->data == NULL)
		return NULL;

	g.bl = (struct bstrList *) bstr__alloc (sizeof (struct bstrList));
	if (g.bl == NULL) return NULL;
	g.bl->mlen = 4;
	g.bl->entry = (bstring *) bstr__alloc (g.bl->mlen * sizeof (bstring));
	if (NULL == g.bl->entry) {
		bstr__free (g.bl);
		return NULL;
	}
	g.b = (bstring) str;
	g.bl->qty = 0;

	if (bsplitscb (str, splitStr, 0, bscb, &g) < 0) {
		bstrListDestroy (g.bl);
		return NULL;
	}
	return g.bl;
}

#if defined (__TURBOC__) && !defined (__BORLANDC__)
# ifndef BSTRLIB_NOVSNP
#  define BSTRLIB_NOVSNP
# endif
#endif

/* Give WATCOM C/C++, MSVC some latitude for their non-support of vsnprintf */
#if defined(__WATCOMC__) || defined(_MSC_VER)
#define exvsnprintf(r,b,n,f,a) {r = _vsnprintf (b,n,f,a);}
#else
#ifdef BSTRLIB_NOVSNP
/* This is just a hack.  If you are using a system without a vsnprintf, it is
   not recommended that bformat be used at all. */
#define exvsnprintf(r,b,n,f,a) {vsprintf (b,f,a); r = -1;}
#define START_VSNBUFF (256)
#else

#define exvsnprintf(r,b,n,f,a) {r = vsnprintf (b,n,f,a);}
#endif
#endif

#if !defined (BSTRLIB_NOVSNP)

#ifndef START_VSNBUFF
#define START_VSNBUFF (16)
#endif

/*  int bformata (bstring b, const char * fmt, ...)
 *
 *  After the first parameter, it takes the same parameters as printf (), but
 *  rather than outputting results to stdio, it appends the results to
 *  a bstring which contains what would have been output. Note that if there
 *  is an early generation of a '\0' character, the bstring will be truncated
 *  to this end point.
 */
int bformata (bstring b, const char * fmt, ...) {
va_list arglist;
bstring buff;
int n, r;

	if (b == NULL || fmt == NULL || b->data == NULL || b->mlen <= 0
	 || b->slen < 0 || b->slen > b->mlen) return BSTR_ERR;

	/* Since the length is not determinable beforehand, a search is
	   performed using the truncating "vsnprintf" call (to avoid buffer
	   overflows) on increasing potential sizes for the output result. */

	if ((n = (int) (2*strlen (fmt))) < START_VSNBUFF) n = START_VSNBUFF;
	if (NULL == (buff = bfromcstralloc (n + 2, ""))) {
		n = 1;
		if (NULL == (buff = bfromcstralloc (n + 2, ""))) return BSTR_ERR;
	}

	for (;;) {
		va_start (arglist, fmt);
		exvsnprintf (r, (char *) buff->data, n + 1, fmt, arglist);
		va_end (arglist);

		buff->data[n] = (unsigned char) '\0';
		buff->slen = (int) (strlen) ((char *) buff->data);

		if (buff->slen < n) break;

		if (r > n) n = r; else n += n;

		if (BSTR_OK != balloc (buff, n + 2)) {
			bdestroy (buff);
			return BSTR_ERR;
		}
	}

	r = bconcat (b, buff);
	bdestroy (buff);
	return r;
}

/*  int bassignformat (bstring b, const char * fmt, ...)
 *
 *  After the first parameter, it takes the same parameters as printf (), but
 *  rather than outputting results to stdio, it outputs the results to
 *  the bstring parameter b. Note that if there is an early generation of a
 *  '\0' character, the bstring will be truncated to this end point.
 */
int bassignformat (bstring b, const char * fmt, ...) {
va_list arglist;
bstring buff;
int n, r;

	if (b == NULL || fmt == NULL || b->data == NULL || b->mlen <= 0
	 || b->slen < 0 || b->slen > b->mlen) return BSTR_ERR;

	/* Since the length is not determinable beforehand, a search is
	   performed using the truncating "vsnprintf" call (to avoid buffer
	   overflows) on increasing potential sizes for the output result. */

	if ((n = (int) (2*strlen (fmt))) < START_VSNBUFF) n = START_VSNBUFF;
	if (NULL == (buff = bfromcstralloc (n + 2, ""))) {
		n = 1;
		if (NULL == (buff = bfromcstralloc (n + 2, ""))) return BSTR_ERR;
	}

	for (;;) {
		va_start (arglist, fmt);
		exvsnprintf (r, (char *) buff->data, n + 1, fmt, arglist);
		va_end (arglist);

		buff->data[n] = (unsigned char) '\0';
		buff->slen = (int) (strlen) ((char *) buff->data);

		if (buff->slen < n) break;

		if (r > n) n = r; else n += n;

		if (BSTR_OK != balloc (buff, n + 2)) {
			bdestroy (buff);
			return BSTR_ERR;
		}
	}

	r = bassign (b, buff);
	bdestroy (buff);
	return r;
}

/*  bstring bformat (const char * fmt, ...)
 *
 *  Takes the same parameters as printf (), but rather than outputting results
 *  to stdio, it forms a bstring which contains what would have been output.
 *  Note that if there is an early generation of a '\0' character, the
 *  bstring will be truncated to this end point.
 */
bstring bformat (const char * fmt, ...) {
va_list arglist;
bstring buff;
int n, r;

	if (fmt == NULL) return NULL;

	/* Since the length is not determinable beforehand, a search is
	   performed using the truncating "vsnprintf" call (to avoid buffer
	   overflows) on increasing potential sizes for the output result. */

	if ((n = (int) (2*strlen (fmt))) < START_VSNBUFF) n = START_VSNBUFF;
	if (NULL == (buff = bfromcstralloc (n + 2, ""))) {
		n = 1;
		if (NULL == (buff = bfromcstralloc (n + 2, ""))) return NULL;
	}

	for (;;) {
		va_start (arglist, fmt);
		exvsnprintf (r, (char *) buff->data, n + 1, fmt, arglist);
		va_end (arglist);

		buff->data[n] = (unsigned char) '\0';
		buff->slen = (int) (strlen) ((char *) buff->data);

		if (buff->slen < n) break;

		if (r > n) n = r; else n += n;

		if (BSTR_OK != balloc (buff, n + 2)) {
			bdestroy (buff);
			return NULL;
		}
	}

	return buff;
}

/*  int bvcformata (bstring b, int count, const char * fmt, va_list arglist)
 *
 *  The bvcformata function formats data under control of the format control
 *  string fmt and attempts to append the result to b.  The fmt parameter is
 *  the same as that of the printf function.  The variable argument list is
 *  replaced with arglist, which has been initialized by the va_start macro.
 *  The size of the output is upper bounded by count.  If the required output
 *  exceeds count, the string b is not augmented with any contents and a value
 *  below BSTR_ERR is returned.  If a value below -count is returned then it
 *  is recommended that the negative of this value be used as an update to the
 *  count in a subsequent pass.  On other errors, such as running out of
 *  memory, parameter errors or numeric wrap around BSTR_ERR is returned.
 *  BSTR_OK is returned when the output is successfully generated and
 *  appended to b.
 *
 *  Note: There is no sanity checking of arglist, and this function is
 *  destructive of the contents of b from the b->slen point onward.  If there
 *  is an early generation of a '\0' character, the bstring will be truncated
 *  to this end point.
 */
int bvcformata (bstring b, int count, const char * fmt, va_list arg) {
int n, r, l;

	if (b == NULL || fmt == NULL || count <= 0 || b->data == NULL
	 || b->mlen <= 0 || b->slen < 0 || b->slen > b->mlen) return BSTR_ERR;

	if (count > (n = b->slen + count) + 2) return BSTR_ERR;
	if (BSTR_OK != balloc (b, n + 2)) return BSTR_ERR;

	exvsnprintf (r, (char *) b->data + b->slen, count + 2, fmt, arg);

	/* Did the operation complete successfully within bounds? */

	if (n >= (l = b->slen + (int) (strlen) ((const char *) b->data + b->slen))) {
		b->slen = l;
		return BSTR_OK;
	}

	/* Abort, since the buffer was not large enough.  The return value
	   tries to help set what the retry length should be. */

	b->data[b->slen] = '\0';
	if (r > count+1) l = r; else {
		l = count+count;
		if (count > l) l = INT_MAX;
	}
	n = -l;
	if (n > BSTR_ERR-1) n = BSTR_ERR-1;
	return n;
}

#endif
