lyx_mirror/src/support/lyxstring.C

/**
 * \file lyxstring.C
 * This file is part of LyX, the document processor.
 * Licence details can be found in the file COPYING.
 *
 * \author Lars Gullik Bjønnes
 *
 * Full author contact details are available in file CREDITS
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "lyxstring.h"
#include <cstdlib>
#include <cctype>
#include <algorithm>

#include "LAssert.h"

#include "debug.h"

using std::min;
using std::istream;
using std::ostream;

// This class is supposed to be functionaly equivalent to a
// standard conformant string. This mean among others that we
// are useing the same requirements. Before you change anything
// in this file consult me and/or the standard to discover the
// right behavior.

// Asserts with a STD! are required by the standard.
// Asserts with a OURS! are added by me.
// Some asserts could still be missing and some of the existing
// ones might be wrong or not needed.

// Reference count has been checked, empty_rep removed and
// introduced again in a similar guise. Where is empty_rep _really_
// needed?

// We are missing a couple of imporant things from the standard:
// reverse iterators and methods taking InputIterators as paramters.
// Also the methods returning iterators is returning the wrong value.

// All the different find functions need a good look over.
// I have so far not tested them extensively and would be
// happy if others took the time to have a peek.

// Space allocation of string.
// I have tried to do this very simple without using any special tricks.
// Earlier we used a fixed value to enlarge the string with this would
// cause a lot of reallocations with large strings (especially if
// push_back was used) and wasting space for very small strings.
// I have now changed the allocation to use a doubling of reserved
// space until it is large enough. So far tests show a small speed
// increase and a noticable memory saving.

// Lgb.


///////////////////////////////////////
// The internal string representation
///////////////////////////////////////

struct lyxstring::Srep {
	/// size
	size_t sz;
	/// Reference count
	size_t ref;
	/// The total amount of data reserved for this representaion
	size_t res;
	/// Data. At least 1 char for trailing null.
	lyxstring::value_type * s;

	///
	Srep(lyxstring::size_type nsz, const lyxstring::value_type * p);
	///
	Srep(lyxstring::size_type nsz, lyxstring::value_type ch);
	///
	~Srep() { delete[] s; }
	///
	Srep * get_own_copy() {
		if (ref == 1) return this;
		--ref;
		return new Srep(sz, s);
	}

	///
	void assign(lyxstring::size_type nsz, const lyxstring::value_type * p);
	///
	void assign(lyxstring::size_type nsz, lyxstring::value_type ch);
	///
	void append(lyxstring::size_type asz, const lyxstring::value_type * p);
	///
	void push_back(lyxstring::value_type c);
	///
	void insert(lyxstring::size_type pos,
		    const lyxstring::value_type * p,
		    lyxstring::size_type n);
	///
	void resize(lyxstring::size_type n, lyxstring::value_type c);
	///
	void reserve(lyxstring::size_type res_arg);
	///
	void replace(lyxstring::size_type i, lyxstring::size_type n,
		     lyxstring::value_type const * p, lyxstring::size_type n2);
private:
	Srep(const Srep &);
	Srep & operator=(const Srep &);
};


lyxstring::Srep::Srep(lyxstring::size_type nsz, const value_type * p)
{
	// can be called with p == 0 by
	// lyxstring::assign(const value_type *, size_type)

	sz = nsz;
	ref = 1;
	res = sz ? sz : 1;
	s = new value_type[res + 1]; // add space for terminator
	if (p && sz) {
		// if sz = 0 nothing gets copied and we have an error
		memcpy(s, p, sz);
	} else {
		// possibly allows for large but empty string
		sz = 0;  // this line should be redundant
		s[0] = '\0';
	}
}


lyxstring::Srep::Srep(lyxstring::size_type nsz, value_type ch)
{
	sz = nsz;
	ref = 1;
	res = sz ? sz : 1;
	s = new value_type[res + 1]; // add space for terminator
	memset(s, ch, sz);
	if (!ch) {
		// if ch == '\0' strlen(lyxstring.c_str()) == 0 so sz = 0
		// allows for large but empty string
		sz = 0;
	}
}


void lyxstring::Srep::assign(lyxstring::size_type nsz, const value_type * p)
{
	// can be called with p == 0
	// by lyxstring::assign(const value_type *, size_type)

	if (res < nsz) {
		delete[] s;
		sz = nsz;
		res = sz ? sz : 1;
		s = new value_type[res + 1]; // add space for terminator
	} else {
		sz = nsz;
	}
	if (p && sz) {
		// if sz = 0 nothing gets copied and we have an error
		memcpy(s, p, sz);
	} else {
		// stops segfaults
		sz = 0;  // this line should be redundant
		s[0] = '\0';
	}
}


void lyxstring::Srep::assign(lyxstring::size_type nsz, value_type ch)
{
	sz = nsz;
	if (res < nsz) {
		delete[] s;
		res = sz ? sz : 1;
		s = new value_type[res + 1]; // add space for terminator
	}
	memset(s, ch, sz);
	if (!ch) {
		// if ch == '\0' strlen(lyxstring.c_str()) == 0 so sz = 0
		// allows for a large empty string
		sz = 0;
	}
}


void lyxstring::Srep::append(lyxstring::size_type asz, const value_type * p)
{
	register unsigned int const len = sz + asz;
	if (res < len) {
		do {
			res *= 2;
		} while (res < len);
		value_type * tmp = new value_type[res + 1];
		memcpy(tmp, s, sz);
		memcpy(tmp + sz, p, asz);
		sz += asz;
		delete[] s;
		s = tmp;
	} else {
		memcpy(s + sz, p, asz);
		sz += asz;
	}
}


void lyxstring::Srep::push_back(value_type c)
{
	s[sz] = c; // it is always room to put a value_type at the end
	++sz;
	if (res < sz) {
		do {
			res *= 2;
		} while (res < sz);
		value_type * tmp = new value_type[res + 1];
		memcpy(tmp, s, sz);
		delete[] s;
		s = tmp;
	}
}


void lyxstring::Srep::insert(lyxstring::size_type pos, const value_type * p,
			     lyxstring::size_type n)
{
	if (res < n + sz) {
		do {
			res *= 2;
		} while (res < n + sz);
		value_type * tmp = new value_type[res + 1];
		memcpy(tmp, s, pos);
		memcpy(tmp + pos, p, n);
		memcpy(tmp + pos + n, &s[pos], sz - pos);
		sz += n;
		delete[] s;
		s = tmp;
	} else {
		memmove(s + pos + n, &s[pos], sz - pos);
		memcpy(s + pos, p, n);
		sz += n;
	}
}


void lyxstring::Srep::resize(size_type n, value_type c)
{
	// This resets sz to res_arg
	res = min(n, npos - 2); // We keep no xtra when we resize
	value_type * tmp = new value_type[res + 1];
	memcpy(tmp, s, min(sz, res));
	if (res > sz)
		memset(tmp + sz, c, res - sz);
	delete[] s;
	sz = res;
	s = tmp;
}


void lyxstring::Srep::reserve(lyxstring::size_type res_arg)
{
	// This keeps the old sz, but
	// increases res with res_arg
	res += res_arg;
	value_type * tmp = new value_type[res + 1];
	memcpy(tmp, s, sz);
	delete[] s;
	s = tmp;
}


void lyxstring::Srep::replace(lyxstring::size_type i, lyxstring::size_type n,
			      value_type const * p, size_type n2)
{
// can be called with p= 0 and n2= 0
	n = min(sz - i, n);
	sz -= n;
	if (res >= n2 + sz) {
		memmove(s + i + n2, &s[i + n], sz - i);
		memcpy(s + i, p, n2);
		sz += n2;
	} else {
		do {
			res *= 2;
		} while (res < n2 + sz);
		value_type * tmp = new value_type[res + 1];
		memcpy(tmp, s, i);
		memcpy(tmp + i, p, n2);
		memcpy(tmp + i + n2, &s[i + n], sz - i);
		delete[] s;
		s = tmp;
		sz += n2;
	}
}


///////////////////////////////////////
// The lyxstring Invariant tester
///////////////////////////////////////

// There are no know bugs in lyxstring now, and it have been
// tested for a long time. so we disable the invariant checker. (Lgb)
#undef ENABLE_ASSERTIONS
#ifdef ENABLE_ASSERTIONS

/** Testing of the lyxstring invariant
 * By creating an object that tests the lyxstring invariant during its
 * construction *and* its deconstruction we greatly simplify our code.
 * Calling TestlyxstringInvariant() upon entry to an lyxstring method
 * will test the invariant upon entry to the code.  If the Asserts fail
 * then we know from the stack trace that the corruption occurred *before*
 * entry to this method.  We can also be sure it didn't happen in any of
 * the tested lyxstring methods.  It is therefore likely to be due to some
 * other external force.
 * Several lyxstring methods have multiple exit points which would otherwise
 * require us to insert a separate test before each return.  But since we
 * created an object its destructor will be called upon exit (any exit!).
 * We thus get testing at both start and end of a method with one line of
 * code at the head of a method.  More importantly,  we get good testing
 * everytime we run the code.
 * NOTE:  just because we test the invariant doesn't mean we can forget
 * about testing pre and post conditions specific to any given method.
 * This test simply proves that the lyxstring/Srep is in a valid state it
 * does *not* prove that the method did what it was supposed to.
 */
class lyxstringInvariant {
public:
	lyxstringInvariant(lyxstring const *);
	~lyxstringInvariant();
private:
	void helper() const;
	lyxstring const * object;
};


// To test if this scheme works "as advertised" uncomment the printf's in
// the constructor and destructor below and then uncomment the printf and the
// call to TestlyxstringInvariant() in lyxstring::operator=(char const *).
// The correct output when LyX has been recompiled and run is:
//     lyxstringInvariant constructor
//     lyxstring::operator=(char const *)
//     lyxstringInvariant constructor
//     lyxstringInvariant destructor completed
//     lyxstringInvariant destructor completed
// NOTE: The easiest way to catch this snippet of the output is to wait for
//       the splash screen to disappear and then open and close Help->Credits
//
lyxstringInvariant::lyxstringInvariant(lyxstring const * ls) : object(ls)
{
	// printf("lyxstringInvariant constructor\n");
	helper();
}


lyxstringInvariant::~lyxstringInvariant()
{
	helper();
	// printf("lyxstringInvariant destructor completed\n");
}


void lyxstringInvariant::helper() const
{
	// Some of these tests might look pointless but they are
	// all part of the invariant and if we want to make sure
	// we have a bullet proof implementation then we need to
	// test every last little thing we *know* should be true.
	// I may have missed a test or two, so feel free to fill
	// in the gaps.  ARRae.
	using lyx::Assert;
	Assert(object);
	Assert(object->rep);
	Assert(object->rep->s);    // s is never 0
	Assert(object->rep->res);  // res cannot be 0
	Assert(object->rep->sz <= object->rep->res);
	Assert(object->rep->ref >= 1);  // its in use so it must be referenced
	Assert(object->rep->ref < 1UL << (8UL * sizeof(object->rep->ref) - 1));
	// if it does ever == then we should be generating a new copy
	// and starting again.  (Is char always 8-bits?)
}
#define TestlyxstringInvariant(s) lyxstringInvariant lyxstring_invariant(s);
#else
#define TestlyxstringInvariant(s)
#endif /* ENABLE_ASSERTIONS */


///////////////////////////////////////
// Constructors and Deconstructors.
///////////////////////////////////////

lyxstring::size_type const lyxstring::npos =
static_cast<lyxstring::size_type>(-1);


lyxstring::lyxstring()
{
	static Srep empty_rep(0, "");
	++empty_rep.ref;
	rep = &empty_rep;
}


lyxstring::lyxstring(lyxstring const & x, size_type pos, size_type n)
{
	lyx::Assert(pos <= x.rep->sz); // STD!
	if (pos == 0 && n >= x.length()) { // this is the default
		x.rep->ref++;
		rep = x.rep;
	} else {
		rep = new Srep(min(n, x.rep->sz - pos), &(x.rep->s[pos]));
	}
}


lyxstring::lyxstring(value_type const * s, size_type n)
{
	lyx::Assert(s && n < npos); // STD!
	static Srep empty_rep(0, "");
	if (n) { // n > 0
		rep = new Srep(n, s);
	} else {
		++empty_rep.ref;
		rep = &empty_rep;
	}
}


lyxstring::lyxstring(value_type const * s)
{
	lyx::Assert(s); // STD!
	static Srep empty_rep(0, "");
	if (*s) { // s is not empty string
		rep = new Srep(strlen(s), s);
	} else {
		++empty_rep.ref;
		rep = &empty_rep;
	}
}


lyxstring::lyxstring(size_type n, value_type c)
{
	lyx::Assert(n < npos); // STD!
	rep = new Srep(n, c);
}


lyxstring::lyxstring(const_iterator first, const_iterator last)
{
	rep = new Srep(last - first, first);
}


lyxstring::~lyxstring()
{
	if (--rep->ref == 0) delete rep;
}

///////////////////////
// Iterators
///////////////////////

lyxstring::iterator lyxstring::begin()
{
	rep = rep->get_own_copy();
	return rep->s;
}


lyxstring::const_iterator lyxstring::begin() const
{
	return rep->s;
}


lyxstring::iterator lyxstring::end()
{
	rep = rep->get_own_copy();
	return rep->s + rep->sz;
}


lyxstring::const_iterator lyxstring::end() const
{
	return rep->s + rep->sz;
}

#if 0
reverse_iterator lyxstring::rbegin()
{
	return reverse_iterator( end() );
}


const_reverse_iterator lyxstring::rbegin() const
{
	return const_reverse_iterator( end() );
}


reverse_iterator lyxstring::rend()
{
	return reverse_iterator( begin() );
}


const_reverse_iterator lyxstring::rend() const
{
	return const_reverse_iterator( begin() );
}
#endif


///////////////////////
// Size and Capacity
///////////////////////

lyxstring::size_type lyxstring::size() const
{
	return rep->sz;
}


void lyxstring::resize(size_type n, value_type c)
{
	lyx::Assert(n <= npos); // STD!
	TestlyxstringInvariant(this);

	// This resets sz to res_arg
	rep = rep->get_own_copy();
	rep->resize(n, c);
}


lyxstring::size_type lyxstring::capacity() const
{
	return rep->res;
}


void lyxstring::reserve(size_type res_arg)
{
	TestlyxstringInvariant(this);

	rep = rep->get_own_copy();
	rep->reserve(res_arg);
}


////////////////
// Assignment
////////////////

lyxstring & lyxstring::operator=(lyxstring const & x)
{
	TestlyxstringInvariant(this);

	return assign(x);
}


lyxstring & lyxstring::operator=(value_type const * s)
{
	lyx::Assert(s); // OURS!
	TestlyxstringInvariant(this);
//	printf("lyxstring::operator= (value_type const *)\n");

	return assign(s);
}


lyxstring & lyxstring::operator=(value_type c)
{
	TestlyxstringInvariant(this);

	value_type s[1];
	s[0] = c;
	if (rep->ref == 1) // recycle rep
		rep->assign(1, s);
	else {
		rep->ref--;
		rep = new Srep(1, s);
	}
	return *this;
}


lyxstring & lyxstring::assign(lyxstring const & x)
{
	TestlyxstringInvariant(this);

	x.rep->ref++; // protect against ``st = st''
	if (--rep->ref == 0) delete rep;
	rep = x.rep; // share representation
	return *this;
}


lyxstring & lyxstring::assign(lyxstring const & x, size_type pos, size_type n)
{
	lyx::Assert(pos <= x.rep->sz); // STD!
	TestlyxstringInvariant(this);

	return assign(x.substr(pos, n));
}


lyxstring & lyxstring::assign(value_type const * s, size_type n)
{
	lyx::Assert(s && n < npos); // STD!
	TestlyxstringInvariant(this);

	if (rep->ref == 1) // recycle rep
		rep->assign(n, s);
	else {
		--rep->ref;
		rep = new Srep(n, s);
	}
	return *this;
}


lyxstring & lyxstring::assign(value_type const * s)
{
	lyx::Assert(s); // OURS!
	TestlyxstringInvariant(this);

	return assign(s, strlen(s));
}


lyxstring & lyxstring::assign(size_type n, value_type ch)
{
	TestlyxstringInvariant(this);

	rep = rep->get_own_copy();
	rep->assign(n, ch);
	return *this;
}


lyxstring & lyxstring::assign(const_iterator first, const_iterator last)
{
	TestlyxstringInvariant(this);

	rep = rep->get_own_copy();
	rep->assign(last - first, first);
	return *this;
}


////////////////////
// Element Access
////////////////////

lyxstring::const_reference lyxstring::operator[](size_type pos) const
{
#if 0
	// This is actually what the standard requires,
	lyx::Assert(pos <= rep->sz); // OURS!
	static char const helper = '\0';
	return pos == rep->sz ? helper : rep->s[pos];
#else
	// but we use this one since it is stricter
	// and more according to the real intent of std::string.
	lyx::Assert(pos < rep->sz); // OURS!
	return rep->s[pos];
#endif
}


lyxstring::reference lyxstring::operator[](size_type pos)
{
	lyx::Assert(pos < rep->sz); // OURS!
	TestlyxstringInvariant(this);

	rep = rep->get_own_copy();
	return rep->s[pos];
}


lyxstring::const_reference lyxstring::at(size_type n) const
{
	lyx::Assert(n < rep->sz); // STD!
	return rep->s[n];
}


lyxstring::reference lyxstring::at(size_type n)
{
	lyx::Assert(n < rep->sz); // STD!
	TestlyxstringInvariant(this);

	rep = rep->get_own_copy();
	return rep->s[n];
}


/////////////
// Insert
/////////////

lyxstring & lyxstring::operator+=(lyxstring const & x)
{
	TestlyxstringInvariant(this);

	return append(x);
}


lyxstring & lyxstring::operator+=(value_type const * x)
{
	lyx::Assert(x); // OURS!
	TestlyxstringInvariant(this);

	return append(x);
}


lyxstring & lyxstring::operator+=(value_type c)
{
	TestlyxstringInvariant(this);

	push_back(c);
	return *this;
}


void lyxstring::push_back(value_type c)
{
	TestlyxstringInvariant(this);

	rep = rep->get_own_copy();
	rep->push_back(c);
}


lyxstring & lyxstring::append(lyxstring const & x)
{
	TestlyxstringInvariant(this);

	if (x.empty()) return *this;
	rep = rep->get_own_copy();
	rep->append(x.length(), x.rep->s);
	return *this;
}


lyxstring & lyxstring::append(lyxstring const & x, size_type pos, size_type n)
{
	lyx::Assert(pos <= x.rep->sz); // STD!
	TestlyxstringInvariant(this);

	return append(x.substr(pos, n));
}


lyxstring & lyxstring::append(value_type const * p, size_type n)
{
	lyx::Assert(p); // OURS!
	TestlyxstringInvariant(this);

	if (!*p || !n) return *this;
	rep = rep->get_own_copy();
	rep->append(n, p);
	return *this;
}


lyxstring & lyxstring::append(value_type const * p)
{
	lyx::Assert(p); // OURS!
	return append(p, strlen(p));
}


lyxstring & lyxstring::append(size_type n, value_type c)
{
	TestlyxstringInvariant(this);

	value_type * tmp = new value_type[n];
	memset(tmp, c, n);
	rep = rep->get_own_copy();
	rep->append(n, tmp);
	delete[] tmp;
	return *this;
}


lyxstring & lyxstring::append(iterator first, iterator last)
{
	TestlyxstringInvariant(this);

	rep = rep->get_own_copy();
	rep->append(last - first, first);
	return *this;
}

// insert characters before (*this)[pos]

lyxstring & lyxstring::insert(size_type pos, lyxstring const & x)
{
	TestlyxstringInvariant(this);

	return insert(pos, x, 0, x.rep->sz);
}


lyxstring & lyxstring::insert(size_type pos, lyxstring const & x,
			      size_type pos2, size_type n)
{
	lyx::Assert(pos <= rep->sz && pos2 <= x.rep->sz); // STD!
	TestlyxstringInvariant(this);

	rep = rep->get_own_copy();
	rep->insert(pos, &(x.rep->s[pos2]), min(n, x.rep->sz));
	return *this;
}


lyxstring & lyxstring::insert(size_type pos, value_type const * p, size_type n)
{
	lyx::Assert(p); // OURS!
	TestlyxstringInvariant(this);

	if (*p && n) {
		// insert nothing and you change nothing
		rep = rep->get_own_copy();
		rep->insert(pos, p, n);
	}
	return *this;
}


lyxstring & lyxstring::insert(size_type pos, value_type const * p)
{
	lyx::Assert(p); // OURS!
	return insert(pos, p, strlen(p));
}


lyxstring & lyxstring::insert(size_type pos, size_type n, value_type c)
{
	TestlyxstringInvariant(this);

	rep = rep->get_own_copy();
	value_type * tmp = new value_type[n];
	memset(tmp, c, n);
	rep->insert(pos, tmp, n);
	delete[] tmp;
	return *this;
}


lyxstring::iterator lyxstring::insert(iterator p, value_type c)
{
	TestlyxstringInvariant(this);

	// what iterator is this supposed to return??
	size_type tmp = p - begin();
	insert(p - begin(), 1, c);
	return begin() + tmp + 1; // ??
}


void lyxstring::insert(iterator p, size_type n , value_type c)
{
	TestlyxstringInvariant(this);

	insert(p - begin(), n , c);
}


void lyxstring::insert(iterator p, iterator first, iterator last)
{
	TestlyxstringInvariant(this);

	insert(p - begin(), first, last - first);
}


////////////////
// Find
////////////////

	 // All the below find functions should be verified,
	 // it is very likely that I have mixed up or interpreted
	 // some of the parameters wrong, also some of the funcs can surely
	 // be written more effectively.

lyxstring::size_type lyxstring::find(lyxstring const & a, size_type i) const
{
	if (!rep->sz || i >= rep->sz) return npos;

	TestlyxstringInvariant(this);

	size_type n = a.length();
	if (!n) return npos;
	for (size_type t = i; rep->sz - t >= n; ++t) {
		// search until (*this)[i] == a[0]
		if (rep->s[t] == a[0]) {
			// check if the rest of the value_types match
			bool equal = true;
			for (size_type j = 1; j < n; ++j) {
				if (rep->s[t + j] != a[j]) {
					equal = false;
					break;
				}
			}
			if (equal) return t;
		}
	}
	return npos;
}


lyxstring::size_type lyxstring::find(value_type const * ptr, size_type i,
				     size_type n) const
{
	lyx::Assert(ptr); // OURS!
	if (!rep->sz || !*ptr || i >= rep->sz) return npos;

	TestlyxstringInvariant(this);

	// What is "n" here? is it the number of value_types to use in ptr
	// or does "i" and "n" togeter form a substring to search
	// for ptr in? For now I will assume that "n" tells the length
	// of ptr. (Lgb)
	n = min(n, strlen(ptr));
	if (!n) return npos;
	for (size_type t = i; rep->sz - t >= n; ++t) {
		// search until (*this)[i] == a[0]
		if (rep->s[t] == ptr[0]) {
			// check if the rest of the value_types match
			bool equal = true;
			for (size_type j = 1; j < n; ++j) {
				if (rep->s[t + j] != ptr[j]) {
					equal = false;
					break;
				}
			}
			if (equal) return t;
		}
	}
	return npos;
}


lyxstring::size_type lyxstring::find(value_type const * s, size_type i) const
{
	lyx::Assert(s); // OURS!
	if (!rep->sz || i >= rep->sz) return npos;

	TestlyxstringInvariant(this);

	if (!s || !*s) return npos;
	return find(s, i, strlen(s));
}


lyxstring::size_type lyxstring::find(value_type c, size_type i) const
{
	if (!rep->sz || i >= rep->sz) return npos;

	TestlyxstringInvariant(this);

	for (size_type t = 0; t + i < rep->sz; ++t) {
		if (rep->s[t + i] == c) return t + i;
	}
	return npos;
}


lyxstring::size_type lyxstring::rfind(lyxstring const & a, size_type i) const
{
	TestlyxstringInvariant(this);

	size_type n = a.length();
	if (!n || rep->sz < n)
		return npos;

	size_type t = min(rep->sz - n, i);
	do {
		if (rep->s[t] == a[0]) {
			// check if the rest of the value_types match
			bool equal = true;
			for (size_type j = 1; j < n; ++j) {
				if (rep->s[t + j] != a[j]) {
					equal = false;
					break;
				}
			}
			if (equal) return t;
		}
	} while (t-- > 0);
	return npos;
}


lyxstring::size_type lyxstring::rfind(value_type const * ptr, size_type i,
				      size_type n) const
{
	lyx::Assert(ptr); // OURS!
	TestlyxstringInvariant(this);

	n = min(n, strlen(ptr));
	if (!n || rep->sz < n)
		return npos;

	size_type t = min(rep->sz - n, i);
	do {
		if (rep->s[t] == ptr[0]) {
			// check if the rest of the value_types match
			bool equal = true;
			for (size_type j = 1; j < n; ++j) {
				if (rep->s[t + j] != ptr[j]) {
					equal = false;
					break;
				}
			}
			if (equal) return t;
		}
	} while (t-- > 0);
	return npos;
}


lyxstring::size_type lyxstring::rfind(value_type const * ptr,
				      size_type i) const
{
	lyx::Assert(ptr); // OURS!

	if (!ptr || !*ptr) return npos;
	return rfind(ptr, i, strlen(ptr));
}


lyxstring::size_type lyxstring::rfind(value_type c, size_type i) const
{
	TestlyxstringInvariant(this);

	size_type const sz = rep->sz;
	if (sz < 1) return npos;
	size_type ii = min(sz - 1, i);
	do {
		if (rep->s[ii] == c) return ii;
	} while (ii-- > 0);
	return npos;
}


lyxstring::size_type lyxstring::find_first_of(lyxstring const & a,
					      size_type i) const
{
	lyx::Assert(i <= rep->sz); // OURS!
	TestlyxstringInvariant(this);

	for (size_type t = i; t < rep->sz; ++t) {
		if (a.find(rep->s[t]) != npos) return t;
	}
	return npos;
}


lyxstring::size_type lyxstring::find_first_of(value_type const * ptr,
					      size_type i,
					      size_type n) const
{
	lyx::Assert(ptr && i <= rep->sz); // OURS!
	TestlyxstringInvariant(this);
	if (!n) return npos;

	for (size_type t = i; t < rep->sz; ++t) {
		if (memchr(ptr, rep->s[t], n) != 0) return t;
	}
	return npos;
}


lyxstring::size_type lyxstring::find_first_of(value_type const * ptr,
					      size_type i) const
{
	lyx::Assert(ptr && i <= rep->sz); // OURS!
	TestlyxstringInvariant(this);

	for (size_type t = i; t < rep->sz; ++t) {
		if (strchr(ptr, rep->s[t]) != 0) return t;
	}
	return npos;
}


lyxstring::size_type lyxstring::find_first_of(value_type c, size_type i) const
{
	lyx::Assert(i <= rep->sz); // OURS!
	TestlyxstringInvariant(this);

	for (size_type t = i; t < rep->sz; ++t) {
		if (rep->s[t] == c) return t;
	}
	return npos;
}


lyxstring::size_type lyxstring::find_last_of(lyxstring const & a,
					     size_type i) const
{
	TestlyxstringInvariant(this);

	size_type ii = min(rep->sz - 1, i);
	for (int t = ii; t >= 0; --t) {
		if (a.find(rep->s[t]) != npos) return t;
	}
	return npos;
}


lyxstring::size_type lyxstring::find_last_of(value_type const * ptr,
					     size_type i,
					     size_type n) const
{
	lyx::Assert(ptr); // OURS!
	TestlyxstringInvariant(this);
	if (!n) return npos;

	size_type ii = min(rep->sz - 1, i);
	for (int t = ii; t >= 0; --t) {
		if (memchr(ptr, rep->s[t], n) != 0) return t;
	}
	return npos;
}


lyxstring::size_type lyxstring::find_last_of(value_type const * ptr,
					     size_type i) const
{
	lyx::Assert(ptr); // OURS!
	TestlyxstringInvariant(this);

	size_type ii = min(rep->sz - 1, i);
	for (int t = ii; t >= 0; --t) {
		if (strchr(ptr, rep->s[t]) != 0) return t;
	}
	return npos;
}


lyxstring::size_type lyxstring::find_last_of(value_type c, size_type i) const
{
	TestlyxstringInvariant(this);

	if (!rep->sz) return npos;
	size_type ii = min(rep->sz - 1, i);
	for (int t = ii; t >= 0; --t) {
		if (rep->s[t] == c) return t;
	}
	return npos;
}


lyxstring::size_type lyxstring::find_first_not_of(lyxstring const & a,
						  size_type i) const
{
	TestlyxstringInvariant(this);

	if (!rep->sz) return npos;
	lyx::Assert(i <= rep->sz);
	for (size_type t = i; t < rep->sz; ++t) {
		if (a.find(rep->s[t]) == npos) return t;
	}
	return npos;
}


lyxstring::size_type lyxstring::find_first_not_of(value_type const * ptr,
						  size_type i,
						  size_type n) const
{
	lyx::Assert(ptr && i <= rep->sz); // OURS!
	TestlyxstringInvariant(this);

	if (!n) return (i < rep->sz) ? i : npos;
	for (size_type t = i; t < rep->sz; ++t) {
		if (memchr(ptr, rep->s[t], n) == 0) return t;
	}
	return npos;
}


lyxstring::size_type lyxstring::find_first_not_of(value_type const * ptr,
						  size_type i) const
{
	lyx::Assert(ptr && i <= rep->sz); // OURS!
	TestlyxstringInvariant(this);

	for (size_type t = i; t < rep->sz; ++t) {
		if (strchr(ptr, rep->s[t]) == 0) return t;
	}
	return npos;
}


lyxstring::size_type lyxstring::find_first_not_of(value_type c,
						  size_type i) const
{
	if (!rep->sz) return npos;
	lyx::Assert(i <= rep->sz); // OURS!
	TestlyxstringInvariant(this);

	for (size_type t = i; t < rep->sz; ++t) {
		if (rep->s[t] != c) return t;
	}
	return npos;
}


lyxstring::size_type lyxstring::find_last_not_of(lyxstring const & a,
						 size_type i) const
{
	TestlyxstringInvariant(this);

	size_type ii = min(rep->sz - 1, i);
	for (int t = ii; t >= 0; --t) {
		if (a.find(rep->s[t]) == npos) return t;
	}
	return npos;
}


lyxstring::size_type lyxstring::find_last_not_of(value_type const * ptr,
						 size_type i,
						 size_type n) const
{
	lyx::Assert(ptr); // OURS!
	TestlyxstringInvariant(this);

	if (!n) return npos;
	size_type ii = min(rep->sz - 1, i);

	for (int t = ii; t >= 0; --t) {
		if (memchr(ptr, rep->s[t], n) == 0) return t;
	}
	return npos;
}


lyxstring::size_type lyxstring::find_last_not_of(value_type const * ptr,
						 size_type i) const
{
	lyx::Assert(ptr); // OURS!
	TestlyxstringInvariant(this);

	size_type ii = min(rep->sz - 1, i);
	for (int t = ii; t >= 0; --t) {
		if (strchr(ptr, rep->s[t]) == 0) return t;
	}
	return npos;
}


lyxstring::size_type lyxstring::find_last_not_of(value_type c,
						 size_type i) const
{
	TestlyxstringInvariant(this);

	size_type ii = min(rep->sz - 1, i);
	for (int t = ii; t >= 0; --t) {
		if (rep->s[t] != c) return t;
	}
	return npos;
}


/////////////////
// Replace
/////////////////

lyxstring & lyxstring::replace(size_type i, size_type n, lyxstring const & x)
{
	lyx::Assert(i <= rep->sz); // OURS!
	TestlyxstringInvariant(this);

	return replace(i, n, x, 0, x.rep->sz);
}


lyxstring & lyxstring::replace(size_type i, size_type n, lyxstring const & x,
			       size_type i2, size_type n2)
{
	lyx::Assert(i <= rep->sz && i2 <= x.rep->sz); // STD!
	TestlyxstringInvariant(this);

	rep = rep->get_own_copy();
	rep->replace(i, min(n, rep->sz), &(x.rep->s[i2]), min(n2, x.rep->sz));
	return *this;
}


lyxstring & lyxstring::replace(size_type i, size_type n,
			       value_type const * p, size_type n2)
{
	lyx::Assert(p && i <= rep->sz); // OURS!
	TestlyxstringInvariant(this);

	rep = rep->get_own_copy();
	rep->replace(i, min(n, rep->sz), p, min(n2, strlen(p)));
	return *this;
}


lyxstring & lyxstring::replace(size_type i, size_type n, value_type const * p)
{
	lyx::Assert(p && i <= rep->sz); // OURS!
	TestlyxstringInvariant(this);

	return replace(i, min(n, rep->sz), p, (!p) ? 0 : strlen(p));
}


lyxstring & lyxstring::replace(size_type i, size_type n,
			       size_type n2, value_type c)
{
	lyx::Assert(i <= rep->sz);  // OURS!
	TestlyxstringInvariant(this);

	rep = rep->get_own_copy();
	value_type * tmp = new value_type[n2];
	memset(tmp, c, n2);
	rep->replace(i, min(n, rep->sz), tmp, n2);
	delete[] tmp;
	return *this;
}


/// FY! FY! FY! go away !
lyxstring & lyxstring::replace(size_type i, size_type n, value_type c)
{
	return replace(i, n, 1, c);
}


lyxstring & lyxstring::replace(iterator i, iterator i2, const lyxstring & str)
{
	TestlyxstringInvariant(this);

	return replace(i - begin(), i2 - i, str);
}


lyxstring & lyxstring::replace(iterator i, iterator i2,
			       value_type const * p, size_type n)
{
	lyx::Assert(p); // OURS!
	TestlyxstringInvariant(this);

	return replace(i - begin(), i2 - i, p, n);
}


lyxstring & lyxstring::replace(iterator i, iterator i2, value_type const * p)
{
	lyx::Assert(p); // OURS!
	TestlyxstringInvariant(this);

	return replace(i - begin(), i2 - i, p);
}


lyxstring & lyxstring::replace(iterator i, iterator i2,
			       size_type n , value_type c)
{
	TestlyxstringInvariant(this);

	return replace(i - begin(), i2 - i, n, c);
}


lyxstring & lyxstring::replace(iterator i, iterator i2,
			       iterator j, iterator j2)
{
	TestlyxstringInvariant(this);

	return replace(i - begin(), i2 - i, j, j2 - j);
}


void lyxstring::swap(lyxstring & str)
{
	if (rep == str.rep) return;
	Srep * tmp = str.rep;
	str.rep = rep;
	rep = tmp;
}


lyxstring & lyxstring::erase(size_type i, size_type n)
{
	lyx::Assert(i <= rep->sz); // STD!
	TestlyxstringInvariant(this);

	rep = rep->get_own_copy();
	if (i == 0 && n >= rep->sz) {
		rep->sz = 0;
	} else {
		n = min(n, rep->sz - i);
		memmove(&(rep->s[i]), &(rep->s[i + n]), rep->sz - i - n);
		rep->sz -= n;
	}
	return *this;
}


lyxstring::iterator lyxstring::erase(iterator i)
{
	TestlyxstringInvariant(this);

	// what iterator is this supposed to return?
	// the iterator after the one erased
	erase(i - begin(), 1);
	return begin(); // BUG
}


lyxstring::iterator lyxstring::erase(iterator first, iterator last)
{
	TestlyxstringInvariant(this);

	erase(first - begin(), last - first);
	return begin(); // BUG
}


/////////////////////////////////////
// Conversion to C-style Strings
/////////////////////////////////////

lyxstring::value_type const * lyxstring::c_str() const
{
	rep->s[length()] = '\0';
	return rep->s;
}


lyxstring::value_type const * lyxstring::data() const
{
	return rep->s;
}


lyxstring::size_type lyxstring::copy(value_type * buf, size_type len,
				     size_type pos) const
{
	lyx::Assert(buf); // OURS!
	lyx::Assert(pos <= rep->sz); // STD!
	TestlyxstringInvariant(this);

	register int nn = min(len, length() - pos);
	memcpy(buf, &(rep->s[pos]), nn);
	return nn;
}


////////////////////
// Comparisons
////////////////////

// Compare funcs should be verified.

int lyxstring::internal_compare(size_type pos, size_type n,
				value_type const * s,
				size_type slen, size_type n2) const
{
	if ((rep->sz == 0 || n == 0) && (!*s || n2 == 0)) return 0;
	if (!*s) return 1;
	// since n > n2, min(n, n2) == 0, c == 0 (stops segfault also)

	// remember that n can very well be a lot larger than rep->sz
	// so we have to ensure that n is no larger than rep->sz
	n = min(n, rep->sz);
	n2 = min(n2, slen);
	if (n == n2)
		return memcmp(&(rep->s[pos]), s, n);
	int c = memcmp(&(rep->s[pos]), s, min(n, n2));
	if (c)
		return c;
	if (n < n2)
		return -1;
	return 1;
}


int lyxstring::compare(lyxstring const & str) const
{
	TestlyxstringInvariant(this);
	return internal_compare(0, rep->sz, str.rep->s,
				str.rep->sz, str.rep->sz);
}


int lyxstring::compare(value_type const * s) const
{
	lyx::Assert(s); //OURS!
	TestlyxstringInvariant(this);
	int n = (!s) ? 0 : strlen(s);
	return internal_compare(0, rep->sz, s, n, n);
}


int lyxstring::compare(size_type pos, size_type n,
		       lyxstring const & str) const
{
	lyx::Assert(pos <= rep->sz); // OURS!
	TestlyxstringInvariant(this);
	return internal_compare(pos, n, str.rep->s, str.rep->sz, str.rep->sz);
}


int lyxstring::compare(size_type pos, size_type n, lyxstring const & str,
		       size_type pos2, size_type n2) const
{
	lyx::Assert(pos <= rep->sz); // OURS!
	lyx::Assert(pos2 <= str.rep->sz); // OURS!
	TestlyxstringInvariant(this);
	return internal_compare(pos, n,
				str.rep->s + pos2,
				str.rep->sz - pos2, n2);
}


int lyxstring::compare(size_type pos, size_type n, value_type const * s,
		       size_type n2) const
{
	lyx::Assert(s && pos <= rep->sz); // OURS!
	TestlyxstringInvariant(this);
	return internal_compare(pos, n, s, (!s) ? 0 : strlen(s), n2);
}


/////////////////
// Substrings
/////////////////

// i = index, n = length
lyxstring lyxstring::substr(size_type i, size_type n) const
{
	lyx::Assert(i <= rep->sz); // STD!
	TestlyxstringInvariant(this);

	return lyxstring(*this, i, n);
}


/////////////////////////////////////////////
// String operators, non member functions
/////////////////////////////////////////////

bool operator==(lyxstring const & a, lyxstring const & b)
{
	return a.compare(b) == 0;
}


bool operator==(lyxstring::value_type const * a, lyxstring const & b)
{
	lyx::Assert(a); // OURS!
	return b.compare(a) == 0;
}


bool operator==(lyxstring const & a, lyxstring::value_type const * b)
{
	lyx::Assert(b); // OURS!
	return a.compare(b) == 0;
}


bool operator!=(lyxstring const & a, lyxstring const & b)
{
	return a.compare(b) != 0;
}


bool operator!=(lyxstring::value_type const * a, lyxstring const & b)
{
	lyx::Assert(a); // OURS!
	return b.compare(a) != 0;
}


bool operator!=(lyxstring const & a, lyxstring::value_type const * b)
{
	lyx::Assert(b); // OURS!
	return a.compare(b) != 0;
}


bool operator>(lyxstring const & a, lyxstring const & b)
{
	return a.compare(b) > 0;
}


bool operator>(lyxstring::value_type const * a, lyxstring const & b)
{
	lyx::Assert(a); // OURS!
	return b.compare(a) < 0; // since we reverse the parameters
}


bool operator>(lyxstring const & a, lyxstring::value_type const * b)
{
	lyx::Assert(b); // OURS!
	return a.compare(b) > 0;
}


bool operator<(lyxstring const & a, lyxstring const & b)
{
	return a.compare(b) < 0;
}


bool operator<(lyxstring::value_type const * a, lyxstring const & b)
{
	lyx::Assert(a); // OURS!
	return b.compare(a) > 0; // since we reverse the parameters
}


bool operator<(lyxstring const & a, lyxstring::value_type const * b)
{
	lyx::Assert(b); // OURS!
	return a.compare(b) < 0;
}


bool operator>=(lyxstring const & a, lyxstring const & b)
{
	return a.compare(b) >= 0;
}


bool operator>=(lyxstring::value_type const * a, lyxstring const & b)
{
	lyx::Assert(a); // OURS!
	return b.compare(a) <= 0; // since we reverse the parameters
}


bool operator>=(lyxstring const & a, lyxstring::value_type const * b)
{
	lyx::Assert(b); // OURS!
	return a.compare(b) >= 0;
}


bool operator<=(lyxstring const & a, lyxstring const & b)
{
	return a.compare(b) <= 0;
}


bool operator<=(lyxstring::value_type const * a, lyxstring const & b)
{
	lyx::Assert(a); // OURS!
	return b.compare(a) >= 0; // since we reverse the parameters
}


bool operator<=(lyxstring const & a, lyxstring::value_type const * b)
{
	lyx::Assert(b); // OURS!
	return a.compare(b) <= 0;
}


lyxstring operator+(lyxstring const & a, lyxstring const & b)
{
	lyxstring tmp(a);
	tmp += b;
	return tmp;
}


lyxstring operator+(lyxstring::value_type const * a, lyxstring const & b)
{
	lyx::Assert(a); // OURS!
	lyxstring tmp(a);
	tmp += b;
	return tmp;
}


lyxstring operator+(lyxstring::value_type a, lyxstring const & b)
{
	lyxstring tmp;
	tmp += a;
	tmp += b;
	return tmp;
}


lyxstring operator+(lyxstring const & a, lyxstring::value_type const * b)
{
	lyx::Assert(b); // OURS!
	lyxstring tmp(a);
	tmp += b;
	return tmp;
}


lyxstring operator+(lyxstring const & a, lyxstring::value_type b)
{
	lyxstring tmp(a);
	tmp += b;
	return tmp;
}


void swap(lyxstring & str1, lyxstring & str2)
{
	str1.swap(str2);
}


#include <iostream>

istream & operator>>(istream & is, lyxstring & s)
{
#if 0
	// very bad solution
	char * nome = new char[1024];
	is >> nome;
	lyxstring tmp(nome);
	delete [] nome;
	if (!tmp.empty()) s = tmp;
#else
	// better solution
	int w = is.width(0);
	s.clear();
	char c = 0;
	bool skipspace = true;
	while (is.get(c)) {
		if (isspace(c)) {
			if (!skipspace) {
				is.putback(c);
				break;
			}
		} else {
			s += c;
			skipspace = false;
		}
		if (--w == 1) break;
	}
	if (s.empty()) is.setstate(std::ios::failbit);
#endif
	return is;
}


ostream & operator<<(ostream & o, lyxstring const & s)
{
	return o.write(s.data(), s.length());
}


istream & getline(istream & is, lyxstring & s,
		  lyxstring::value_type delim)
{
	// very bad solution
	char tmp = 0;
	s.erase();
	while (is) {
		is.get(tmp);
		if (tmp != delim) {
			s += tmp;
		} else {
			break;
		}
	}
	return is;
}

#ifdef TEST_MAIN
int main() {
	lyxstring a = "abcac";
	cout << a.rfind("ab") << endl;
	cout << a.rfind("c") << endl;
	cout << a.rfind("d") << endl;
}
#endif