Move string_ref to Boost.Utility; first crack at docs

[SVN r81972]

doc/Jamfile.v2

@@ -62,7 +62,22 @@ boostbook standalone
         
      ;
 
+xml string_ref : string_ref.qbk ;
+boostbook standalone
+    :
+        string_ref
+    :
+        # File name of HTML output:
+        <xsl:param>root.filename=string_ref
+        # How far down we chunk nested sections, basically all of them:
+        <xsl:param>chunk.section.depth=0
+        # Don't put the first section on the same page as the TOC:
+        <xsl:param>chunk.first.sections=0
+        # How far down sections get TOC's
+        <xsl:param>toc.section.depth=1
+        # Max depth in each TOC:
+        <xsl:param>toc.max.depth=1
+        # How far down we go with TOC's
+        <xsl:param>generate.section.toc.level=1
         
-
+     ;
-
-

doc/string_ref.qbk

@@ -0,0 +1,100 @@
+[/
+ / Copyright (c) 2012 Marshall Clow
+ /
+ / Distributed under the Boost Software License, Version 1.0. (See accompanying
+ / file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+ /]
+
+[article String_Ref
+    [quickbook 1.5]
+    [authors [Clow, Marshall]]
+    [copyright 2012 Marshall Clow]
+    [license
+        Distributed under the Boost Software License, Version 1.0.
+        (See accompanying file LICENSE_1_0.txt or copy at
+        [@http://www.boost.org/LICENSE_1_0.txt])
+    ]
+]
+
+[/===============]
+[section Overview]
+[/===============]
+
+Boost.StringRef is an implementation of Jeffrey Yaskin's [@http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3442.html N3442:
+string_ref: a non-owning reference to a string]. 
+
+When you are parsing/processing strings from some external source, frequently you want to pass a piece of text to a procedure for specialized processing. The canonical way to do this is as a `std::string`, but that has certain drawbacks:
+
+1) If you are processing a buffer of text (say a HTTP response or the contents of a file), then you have to create the string from the text you want to pass, which involves memory allocation and copying of data.
+
+2) if a routine receives a constant `std::string` and wants to pass a portion of that string to another routine, then it must create a new string of that substring.
+
+3) A routine receives a constant `std::string` and wants to return a portion of the string, then it must create a new string to return.
+
+`string_ref` is designed to solve these efficiency problems. A `string_ref` is a read-only reference to a contiguous sequence of characters, and provides much of the functionality of `std::string`. A `string_ref` is cheap to create, copy and pass by value, because it does not actually own the storage that it points to. 
+
+A `string_ref` is implemented as a small struct that contains a pointer to the start of the character data and a count. A `string_ref` is cheap to create and cheap to copy.
+
+`string_ref` acts as a container; it includes all the methods that you would expect in a container, including iteration support, `operator []`, `at` and `size`. It can be used with any of the iterator-based algorithms in the STL - as long as you don't need to change the underlying data (`sort` and `remove`, for example, will not work)
+
+Besides generic container functionality, `string_ref` provides a subset of the interface of `std::string`. This makes it easy to replace parameters of type `const std::string &` with `boost::string_ref`. 
+
+Because a `string_ref` does not own the data that it "points to", it introduces lifetime issues into code that uses it. The programmer must ensure that the data that a `string_ref` refers to exists as long as the `string_ref` does.
+
+[endsect]
+
+
+[/===============]
+[section Examples]
+[/===============]
+
+Integrating `string_ref` into your code is fairly simple. Wherever you pass a `const std::string &` or `std::string` as a parameter, that's a candidate for passing a `boost::string_ref`.
+
+	std::string extract_part ( const std::string &bar ) {
+		return bar.substr ( 2, 3 );
+		}
+		
+	if ( extract_part ( "ABCDEFG" ).front() == "C" ) { /* do something */ }
+	
+Let's figure out what happens in this (contrived) example.
+
+First, a temporary string is created from the string literal `"ABCDEFG"`, and it is passed (by reference) to the routine `extract_part`. Then a second string is created in the call `std::string::substr` and returned to `extract_part` (this copy may be elided by RVO). Then `extract_part` returns that string back to the caller (again this copy may be elided). The first temporary string is deallocated, and `front` is called on the second string, and then it is deallocated as well.
+
+Two `std::string`s are created, and two copy operations. That's (potentially) four memory allocations and deallocations, and the associated copying of data.
+
+Now let's look at the same code with `string_ref`:
+
+	boost::string_ref extract_part ( boost::string_ref bar ) {
+		return bar.substr ( 2, 3 );
+		}
+		
+	if ( extract_part ( "ABCDEFG" ).front() == "C" ) { /* do something */ }
+
+No memory allocations. No copying of character data. No changes to the code other than the types. There are two `string_ref`s created, and two `string_ref`s copied, but those are cheap operations.
+
+[endsect]
+
+
+[/=================]
+[section:reference Reference ]
+[/=================]
+
+The header file "string_ref.hpp" defines a template `boost::basic_string_ref`, and four specializations - for `char` / `wchar_t` / `char16_t` / `char32_t` .
+
+`#include <boost/utility/string_ref.hpp>`
+
+[endsect]
+
+[/===============]
+[section History]
+[/===============]
+
+[heading boost 1.53]
+* Introduced
+ 	
+
+[endsect]
+
+
+
+

include/boost/utility/string_ref.hpp

@@ -0,0 +1,386 @@
+/* 
+   Copyright (c) Marshall Clow 2012-2012.
+
+   Distributed under the Boost Software License, Version 1.0. (See accompanying
+   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+    For more information, see http://www.boost.org
+    
+    Based on the StringRef implementation in LLVM (http://llvm.org) and
+    N3422 by Jeffrey Yasskin
+        http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3442.html
+
+*/
+
+#ifndef BOOST_STRING_REF_HPP
+#define BOOST_STRING_REF_HPP
+
+#include <boost/config.hpp>
+#include <boost/detail/workaround.hpp>
+
+#include <stdexcept>
+#include <algorithm>
+#include <functional>
+#include <string>
+
+namespace boost {
+    
+    namespace detail {
+    //  A helper functor because sometimes we don't have lambdas
+        template <typename charT, typename traits>
+        class string_ref_traits_eq {
+        public:
+            string_ref_traits_eq ( charT ch ) : ch_(ch) {}
+            bool operator () ( charT val ) const { return traits::eq ( ch_, val ); }
+            charT ch_;
+            };
+        }
+    
+    template<typename charT, typename traits> class basic_string_ref;
+    typedef basic_string_ref<char,     std::char_traits<char> >        string_ref;
+    typedef basic_string_ref<wchar_t,  std::char_traits<wchar_t> >    wstring_ref;
+
+#ifndef BOOST_NO_CXX11_CHAR16_T
+    typedef basic_string_ref<char16_t, std::char_traits<char16_t> > u16string_ref;
+#endif
+
+#ifndef BOOST_NO_CXX11_CHAR32_T
+    typedef basic_string_ref<char32_t, std::char_traits<char32_t> > u32string_ref;
+#endif
+    
+    template<typename charT, typename traits>
+    class basic_string_ref {
+    public:
+        // types
+        typedef charT value_type;
+        typedef const charT* pointer;
+        typedef const charT& reference;
+        typedef const charT& const_reference;
+        typedef pointer const_iterator; // impl-defined
+        typedef const_iterator iterator;
+        typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
+        typedef const_reverse_iterator reverse_iterator;
+        typedef std::size_t size_type;
+        typedef ptrdiff_t difference_type;
+        static BOOST_CONSTEXPR_OR_CONST size_type npos = size_type(-1);
+        
+        // construct/copy
+        BOOST_CONSTEXPR basic_string_ref ()
+            : ptr_(NULL), len_(0) {}
+
+        BOOST_CONSTEXPR basic_string_ref (const basic_string_ref &rhs)
+            : ptr_(rhs.ptr_), len_(rhs.len_) {}
+
+        basic_string_ref& operator=(const basic_string_ref &rhs) {
+            ptr_ = rhs.ptr_;
+            len_ = rhs.len_;
+            return *this;
+            }
+            
+        basic_string_ref(const charT* str)
+            : ptr_(str), len_(traits::length(str)) {}
+
+        template<typename Allocator>
+        basic_string_ref(const std::basic_string<charT, traits, Allocator>& str)
+            : ptr_(str.data()), len_(str.length()) {}
+
+        BOOST_CONSTEXPR basic_string_ref(const charT* str, size_type len)
+            : ptr_(str), len_(len) {}
+
+#ifndef BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS
+        template<typename Allocator>
+        explicit operator std::basic_string<charT, traits, Allocator>() const {
+            return std::basic_string<charT, traits, Allocator> ( ptr_, len_ );
+            }
+#endif
+        
+        // iterators
+        BOOST_CONSTEXPR const_iterator   begin() const { return ptr_; }
+        BOOST_CONSTEXPR const_iterator  cbegin() const { return ptr_; }
+        BOOST_CONSTEXPR const_iterator     end() const { return ptr_ + len_; }
+        BOOST_CONSTEXPR const_iterator    cend() const { return ptr_ + len_; }
+                const_reverse_iterator  rbegin() const { return const_reverse_iterator (end()); }
+                const_reverse_iterator crbegin() const { return const_reverse_iterator (end()); }
+                const_reverse_iterator    rend() const { return const_reverse_iterator (begin()); }
+                const_reverse_iterator   crend() const { return const_reverse_iterator (begin()); }
+        
+        // capacity
+        BOOST_CONSTEXPR size_type size()     const { return len_; }
+        BOOST_CONSTEXPR size_type length()   const { return len_; }
+        BOOST_CONSTEXPR size_type max_size() const { return len_; }
+        BOOST_CONSTEXPR bool empty()         const { return len_ == 0; }
+        
+        // element access
+        BOOST_CONSTEXPR const charT& operator[](size_type pos) const { return ptr_[pos]; }
+
+        const charT& at(size_t pos) const {
+            if ( pos >= len_ )
+                throw std::out_of_range ( "boost::string_ref::at" );
+            return ptr_[pos];
+            }
+            
+        BOOST_CONSTEXPR const charT& front() const { return ptr_[0]; }
+        BOOST_CONSTEXPR const charT& back()  const { return ptr_[len_-1]; }
+        BOOST_CONSTEXPR const charT* data()  const { return ptr_; }
+        
+        // modifiers
+        void clear() { len_ = 0; }
+        void remove_prefix(size_type n) {
+            if ( n > len_ )
+                n = len_;
+            ptr_ += n;
+            len_ -= n;
+            }
+            
+        void remove_suffix(size_type n) {
+            if ( n > len_ )
+                n = len_;
+            len_ -= n;
+            }
+            
+        
+        // basic_string_ref string operations
+        BOOST_CONSTEXPR
+        basic_string_ref substr(size_type pos, size_type n=npos) const {
+#if BOOST_WORKAROUND(BOOST_MSVC, <= 1600)
+            // Looks like msvc 8 and 9 have a codegen bug when one branch of
+            // a conditional operator is a throw expression. -EAN 2012/12/04
+            if ( pos > size()) throw std::out_of_range ( "string_ref::substr" );
+            if ( n == npos || pos + n > size()) n = size () - pos;
+            return basic_string_ref ( data() + pos, n );
+#else
+            return pos > size() ? throw std::out_of_range ( "string_ref::substr" ) :
+                basic_string_ref ( data() + pos, n == npos || pos + n > size() ? size() - pos : n );
+#endif
+            }
+        
+        int compare(basic_string_ref x) const {
+            int cmp = traits::compare ( ptr_, x.ptr_, (std::min)(len_, x.len_));
+            return cmp != 0 ? cmp : ( len_ == x.len_ ? 0 : len_ < x.len_ ? -1 : 1 );
+            }
+        
+        bool starts_with(charT c) const { return !empty() && traits::eq ( c, front()); }
+        bool starts_with(basic_string_ref x) const {
+            return len_ >= x.len_ && traits::compare ( ptr_, x.ptr_, x.len_ ) == 0;
+            }
+        
+        bool ends_with(charT c) const { return !empty() && traits::eq ( c, back()); }
+        bool ends_with(basic_string_ref x) const {
+            return len_ >= x.len_ && traits::compare ( ptr_ + len_ - x.len_, x.ptr_, x.len_ ) == 0;
+            }
+
+        size_type find(basic_string_ref s) const {
+            const_iterator iter = std::search ( this->cbegin (), this->cend (), 
+                                                s.cbegin (), s.cend (), traits::eq );
+            return iter = this->cend () ? npos : std::distance ( this->cbegin (), iter );
+            }
+        
+        size_type find(charT c) const {
+            const_iterator iter = std::find_if ( this->cbegin (), this->cend (), 
+                                    detail::string_ref_traits_eq<charT, traits> ( c ));
+            return iter == this->cend () ? npos : std::distance ( this->cbegin (), iter );
+            }
+                        
+        size_type rfind(basic_string_ref s) const {
+            const_reverse_iterator iter = std::search ( this->crbegin (), this->crend (), 
+                                                s.crbegin (), s.crend (), traits::eq );
+            return iter == this->crend () ? npos : reverse_distance ( this->crbegin (), iter );
+            }
+
+        size_type rfind(charT c) const {
+            const_reverse_iterator iter = std::find_if ( this->crbegin (), this->crend (), 
+                                    detail::string_ref_traits_eq<charT, traits> ( c ));
+            return iter == this->crend () ? npos : reverse_distance ( this->crbegin (), iter );
+            }
+        
+        size_type find_first_of(charT c) const { return  find (c); }
+        size_type find_last_of (charT c) const { return rfind (c); }
+        
+        size_type find_first_of(basic_string_ref s) const {
+            const_iterator iter = std::find_first_of 
+            	( this->cbegin (), this->cend (), s.cbegin (), s.cend (), traits::eq );
+            return iter == this->cend () ? npos : std::distance ( this->cbegin (), iter );
+            }
+        
+        size_type find_last_of(basic_string_ref s) const {
+            const_reverse_iterator iter = std::find_first_of 
+                ( this->crbegin (), this->crend (), s.cbegin (), s.cend (), traits::eq );
+            return iter == this->crend () ? npos : reverse_distance ( this->crbegin (), iter);
+            }
+        
+        size_type find_first_not_of(basic_string_ref s) const {
+        	const_iterator iter = find_not_of ( this->cbegin (), this->cend (), s );
+            return iter == this->cend () ? npos : std::distance ( this->cbegin (), iter );
+            }
+        
+        size_type find_first_not_of(charT c) const {
+            for ( const_iterator iter = this->cbegin (); iter != this->cend (); ++iter )
+                if ( !traits::eq ( c, *iter ))
+                    return std::distance ( this->cbegin (), iter );
+            return npos;
+            }
+        
+        size_type find_last_not_of(basic_string_ref s) const {
+        	const_reverse_iterator iter = find_not_of ( this->crbegin (), this->crend (), s );
+            return iter == this->crend () ? npos : reverse_distance ( this->crbegin (), iter );
+            }
+        
+        size_type find_last_not_of(charT c) const {
+            for ( const_reverse_iterator iter = this->crbegin (); iter != this->crend (); ++iter )
+                if ( !traits::eq ( c, *iter ))
+                    return reverse_distance ( this->crbegin (), iter );
+            return npos;
+            }
+
+    private:
+        template <typename r_iter>
+        size_type reverse_distance ( r_iter first, r_iter last ) const {
+            return len_ - 1 - std::distance ( first, last );
+            }
+        
+        template <typename Iterator>
+        Iterator find_not_of ( Iterator first, Iterator last, basic_string_ref s ) const {
+			for ( ; first != last ; ++first )
+				if ( 0 == traits::find ( s.ptr_, s.len_, *first ))
+					return first;
+			return last;
+			}
+		
+       		
+        
+        const charT *ptr_;
+        std::size_t len_;
+        };
+    
+    // Comparison operators
+    template<typename charT, typename traits>
+    bool operator==(basic_string_ref<charT, traits> x, basic_string_ref<charT, traits> y) {
+        if ( x.size () != y.size ()) return false;
+        return x.compare(y) == 0;
+        }
+    
+    template<typename charT, typename traits>
+    bool operator!=(basic_string_ref<charT, traits> x, basic_string_ref<charT, traits> y) {
+        if ( x.size () != y.size ()) return true;
+        return x.compare(y) != 0;
+        }
+
+    template<typename charT, typename traits>
+    bool operator<(basic_string_ref<charT, traits> x, basic_string_ref<charT, traits> y) {
+        return x.compare(y) < 0;
+        }
+
+    template<typename charT, typename traits>
+    bool operator>(basic_string_ref<charT, traits> x, basic_string_ref<charT, traits> y) {
+        return x.compare(y) > 0;
+        }
+
+    template<typename charT, typename traits>
+    bool operator<=(basic_string_ref<charT, traits> x, basic_string_ref<charT, traits> y) {
+        return x.compare(y) <= 0;
+        }
+
+    template<typename charT, typename traits>
+    bool operator>=(basic_string_ref<charT, traits> x, basic_string_ref<charT, traits> y) {
+        return x.compare(y) >= 0;
+        }
+
+    
+    // Inserter
+    template<class charT, class traits>
+    std::basic_ostream<charT, traits>&
+    operator<<(std::basic_ostream<charT, traits>& os, const basic_string_ref<charT,traits>& str) {
+#ifdef BOOST_NO_CXX11_RANGE_BASED_FOR
+        for ( typename basic_string_ref<charT, traits>::const_iterator iter = str.begin (); iter != str.end (); ++iter )
+            os << *iter;
+#else
+        for ( charT x : str )
+            os << x;
+#endif
+        return os;
+        }
+    
+#if 0
+    // numeric conversions
+    //
+    //  These are short-term implementations.
+    //  In a production environment, I would rather avoid the copying.
+    //
+    int stoi (string_ref str, size_t* idx=0, int base=10) {
+        return std::stoi ( std::string(str), idx, base );
+        }
+    
+    long stol (string_ref str, size_t* idx=0, int base=10) {
+        return std::stol ( std::string(str), idx, base );
+        }
+        
+    unsigned long stoul (string_ref str, size_t* idx=0, int base=10) {
+        return std::stoul ( std::string(str), idx, base );
+        }
+        
+    long long stoll (string_ref str, size_t* idx=0, int base=10) {
+        return std::stoll ( std::string(str), idx, base );
+        }
+    
+    unsigned long long stoull (string_ref str, size_t* idx=0, int base=10) {
+        return std::stoull ( std::string(str), idx, base );
+        }
+    
+    float stof (string_ref str, size_t* idx=0) {
+        return std::stof ( std::string(str), idx );
+        }
+        
+    double stod (string_ref str, size_t* idx=0) {
+        return std::stod ( std::string(str), idx );
+        }
+        
+    long double stold (string_ref str, size_t* idx=0)  {
+        return std::stold ( std::string(str), idx );
+        }
+    
+    int  stoi (wstring_ref str, size_t* idx=0, int base=10) {
+        return std::stoi ( std::wstring(str), idx, base );
+        }
+        
+    long stol (wstring_ref str, size_t* idx=0, int base=10) {
+        return std::stol ( std::wstring(str), idx, base );
+        }
+        
+    unsigned long stoul (wstring_ref str, size_t* idx=0, int base=10) {
+        return std::stoul ( std::wstring(str), idx, base );
+        }
+        
+    long long stoll (wstring_ref str, size_t* idx=0, int base=10) {
+        return std::stoll ( std::wstring(str), idx, base );
+        }
+        
+    unsigned long long stoull (wstring_ref str, size_t* idx=0, int base=10) {
+        return std::stoull ( std::wstring(str), idx, base );
+        }
+    
+    float  stof (wstring_ref str, size_t* idx=0) {
+        return std::stof ( std::wstring(str), idx );
+        }
+        
+    double stod (wstring_ref str, size_t* idx=0) {
+        return std::stod ( std::wstring(str), idx );
+        }
+        
+    long double stold (wstring_ref str, size_t* idx=0) {
+        return std::stold ( std::wstring(str), idx );
+        }
+#endif
+
+}
+
+#if 0
+namespace std {
+    // Hashing
+    template<> struct hash<boost::string_ref>;
+    template<> struct hash<boost::u16string_ref>;
+    template<> struct hash<boost::u32string_ref>;
+    template<> struct hash<boost::wstring_ref>;
+}
+#endif
+
+#endif

index.html

@@ -34,6 +34,7 @@
 				<a href="swap.html">swap</a><br>
 				<a href="throw_exception.html">throw_exception</a><br>
 				<a href="utility.htm">utility</a><br>
+            <a href="doc/html/string_ref.html">string_ref</a><br>
             <a href="value_init.htm">value_init</a>
          </p>
 		</blockquote>

test/Jamfile.v2

@@ -31,6 +31,8 @@ test-suite utility
         [ run ../ref_test.cpp ../../test/build//boost_test_exec_monitor/<link>static ]
         [ compile result_of_test.cpp ]
         [ run ../shared_iterator_test.cpp ]
+        [ run string_ref_test1.cpp ]
+        [ run string_ref_test2.cpp ]
         [ run ../value_init_test.cpp ]
         [ run ../value_init_workaround_test.cpp ]
         [ run ../initialized_test.cpp ]

test/string_ref_test1.cpp

@@ -0,0 +1,111 @@
+/* 
+   Copyright (c) Marshall Clow 2012-2012.
+
+   Distributed under the Boost Software License, Version 1.0. (See accompanying
+   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+    For more information, see http://www.boost.org
+*/
+
+#include <iostream>
+#include <algorithm>
+#include <string>
+
+#include <boost/utility/string_ref.hpp>
+
+
+#include <boost/test/included/test_exec_monitor.hpp>
+
+typedef boost::string_ref string_ref;
+
+//  Should be equal
+void interop ( const std::string &str, string_ref ref ) {
+//  BOOST_CHECK ( str == ref );
+    BOOST_CHECK ( str.size () == ref.size ());
+    BOOST_CHECK ( std::equal ( str.begin (),  str.end (),  ref.begin ()));
+    BOOST_CHECK ( std::equal ( str.rbegin (), str.rend (), ref.rbegin ()));
+    }
+
+void null_tests ( const char *p ) {
+//  All zero-length string-refs should be equal
+    string_ref sr1; // NULL, 0
+    string_ref sr2 ( NULL, 0 );
+    string_ref sr3 ( p, 0 );
+    string_ref sr4 ( p );
+    sr4.clear ();
+    
+    BOOST_CHECK ( sr1 == sr2 );
+    BOOST_CHECK ( sr1 == sr3 );
+    BOOST_CHECK ( sr2 == sr3 );
+    BOOST_CHECK ( sr1 == sr4 );    
+    }
+
+//  make sure that substrings work just like strings
+void test_substr ( const std::string &str ) {
+    const size_t sz = str.size ();
+    string_ref ref ( str );
+    
+//  Substrings at the end
+    for ( size_t i = 0; i <= sz; ++ i )
+        interop ( str.substr ( i ), ref.substr ( i ));
+        
+//  Substrings at the beginning
+    for ( size_t i = 0; i <= sz; ++ i )
+        interop ( str.substr ( 0, i ), ref.substr ( 0, i ));
+        
+//  All possible substrings
+    for ( size_t i = 0; i < sz; ++i )
+        for ( size_t j = i; j < sz; ++j )
+            interop ( str.substr ( i, j ), ref.substr ( i, j ));    
+    }
+
+//  make sure that removing prefixes and suffixes work just like strings
+void test_remove ( const std::string &str ) {
+    const size_t sz = str.size ();
+    std::string work;
+    string_ref ref;
+    
+    for ( size_t i = 1; i <= sz; ++i ) {
+      work = str;
+      ref  = str;     
+      while ( ref.size () >= i ) {
+          interop ( work, ref );
+          work.erase ( 0, i );
+          ref.remove_prefix (i);
+          }
+      }
+    
+    for ( size_t i = 1; i < sz; ++ i ) {
+      work = str;
+      ref  = str;     
+      while ( ref.size () >= i ) {
+          interop ( work, ref );
+          work.erase ( work.size () - i, i );
+          ref.remove_suffix (i);
+          }
+      }
+    }
+
+const char *test_strings [] = {
+    "",
+    "1",
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZ",
+    "0123456789",
+    NULL
+    };
+    
+int test_main( int , char* [] ) {
+
+    const char **p = &test_strings[0];
+
+    while ( *p != NULL ) {
+        interop ( *p, *p );
+        test_substr ( *p );
+        test_remove ( *p );
+        null_tests ( *p );
+    
+        p++;
+        }
+
+    return 0;
+    }

test/string_ref_test2.cpp

@@ -0,0 +1,256 @@
+/* 
+   Copyright (c) Marshall Clow 2012-2012.
+
+   Distributed under the Boost Software License, Version 1.0. (See accompanying
+   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+    For more information, see http://www.boost.org
+*/
+
+#include <iostream>
+#include <cstring>    // for std::strchr
+
+#include <boost/utility/string_ref.hpp>
+
+#include <boost/test/included/test_exec_monitor.hpp>
+
+typedef boost::string_ref string_ref;
+
+void ends_with ( const char *arg ) {
+    const size_t sz = strlen ( arg );
+    string_ref sr ( arg );
+    string_ref sr2 ( arg );
+    const char *p = arg;
+
+    while ( !*p ) {
+        BOOST_CHECK ( sr.ends_with ( p ));
+        ++p;
+        }
+
+    while ( !sr2.empty ()) {
+        BOOST_CHECK ( sr.ends_with ( sr2 ));
+        sr2.remove_prefix (1);
+        }
+
+    sr2 = arg;
+    while ( !sr2.empty ()) {
+        BOOST_CHECK ( sr.ends_with ( sr2 ));
+        sr2.remove_prefix (1);
+        }
+
+    char ch = sz == 0 ? '\0' : arg [ sz - 1 ];
+    sr2 = arg;
+    if ( sz > 0 )
+      BOOST_CHECK ( sr2.ends_with ( ch ));
+    BOOST_CHECK ( !sr2.ends_with ( ++ch ));
+    BOOST_CHECK ( sr2.ends_with ( string_ref ()));
+    }
+    
+void starts_with ( const char *arg ) {
+    const size_t sz = strlen ( arg );
+    string_ref sr  ( arg );
+    string_ref sr2 ( arg );
+    const char *p = arg + std::strlen ( arg ) - 1;
+    while ( p >= arg ) {
+        std::string foo ( arg, p + 1 );
+        BOOST_CHECK ( sr.starts_with ( foo ));
+        --p;
+        }
+
+    while ( !sr2.empty ()) {
+        BOOST_CHECK ( sr.starts_with ( sr2 ));
+        sr2.remove_suffix (1);
+        }
+
+    char ch = *arg;
+    sr2 = arg;
+  if ( sz > 0 )
+    BOOST_CHECK ( sr2.starts_with ( ch ));
+    BOOST_CHECK ( !sr2.starts_with ( ++ch ));
+    BOOST_CHECK ( sr2.starts_with ( string_ref ()));
+    }
+
+void reverse ( const char *arg ) {
+//  Round trip
+    string_ref sr1 ( arg );
+    std::string string1 ( sr1.rbegin (), sr1.rend ());
+    string_ref sr2 ( string1 );
+    std::string string2 ( sr2.rbegin (), sr2.rend ());
+
+    BOOST_CHECK ( std::equal ( sr2.rbegin (), sr2.rend (), arg ));
+    BOOST_CHECK ( string2 == arg );
+    BOOST_CHECK ( std::equal ( sr1.begin (), sr1.end (), string2.begin ()));
+    }
+
+//	This helper function eliminates signed vs. unsigned warnings
+string_ref::size_type ptr_diff ( const char *res, const char *base ) {
+	BOOST_CHECK ( res >= base );
+	return static_cast<string_ref::size_type> ( res - base );
+	}
+
+void find ( const char *arg ) {
+    string_ref sr1;
+    string_ref sr2;
+    const char *p;
+
+//  Look for each character in the string(searching from the start)
+  p = arg;
+  sr1 = arg;
+  while ( *p ) {
+    string_ref::size_type pos = sr1.find(*p);
+    BOOST_CHECK ( pos != string_ref::npos && ( pos <= ptr_diff ( p, arg )));
+    ++p;
+    }
+  
+//  Look for each character in the string (searching from the end)
+    p = arg;
+    sr1 = arg;
+    while ( *p ) {
+    string_ref::size_type pos = sr1.rfind(*p);
+    BOOST_CHECK ( pos != string_ref::npos && pos < sr1.size () && ( pos >= ptr_diff ( p, arg )));
+    ++p;
+    }
+
+    sr1 = arg;
+    p = arg;
+//  for all possible chars, see if we find them in the right place.
+//  Note that strchr will/might do the _wrong_ thing if we search for NULL
+    for ( int ch = 1; ch < 256; ++ch ) {
+        string_ref::size_type pos = sr1.find(ch);
+        const char *strp = std::strchr ( arg, ch );
+        BOOST_CHECK (( strp == NULL ) == ( pos == string_ref::npos ));
+        if ( strp != NULL )
+            BOOST_CHECK ( ptr_diff ( strp, arg ) == pos );
+    }
+
+    sr1 = arg;
+    p = arg;
+//  for all possible chars, see if we find them in the right place.
+//  Note that strchr will/might do the _wrong_ thing if we search for NULL
+    for ( int ch = 1; ch < 256; ++ch ) {
+        string_ref::size_type pos = sr1.rfind(ch);
+        const char *strp = std::strrchr ( arg, ch );
+        BOOST_CHECK (( strp == NULL ) == ( pos == string_ref::npos ));
+        if ( strp != NULL )
+            BOOST_CHECK ( ptr_diff ( strp, arg ) == pos );
+    }
+
+
+//  Find everything at the start
+    p = arg;
+    sr1 = arg;
+    while ( !sr1.empty ()) {
+        string_ref::size_type pos = sr1.find(*p);
+        BOOST_CHECK ( pos == 0 );
+        sr1.remove_prefix (1);
+        ++p;
+        }
+
+//  Find everything at the end
+    sr1  = arg;
+    p    = arg + strlen ( arg ) - 1;
+    while ( !sr1.empty ()) {
+        string_ref::size_type pos = sr1.rfind(*p);
+        BOOST_CHECK ( pos == sr1.size () - 1 );
+        sr1.remove_suffix (1);
+        --p;
+        }
+        
+//  Find everything at the start
+    sr1  = arg;
+    p    = arg;
+    while ( !sr1.empty ()) {
+        string_ref::size_type pos = sr1.find_first_of(*p);
+        BOOST_CHECK ( pos == 0 );
+        sr1.remove_prefix (1);
+        ++p;
+        }
+
+
+//  Find everything at the end
+    sr1  = arg;
+    p    = arg + strlen ( arg ) - 1;
+    while ( !sr1.empty ()) {
+        string_ref::size_type pos = sr1.find_last_of(*p);
+        BOOST_CHECK ( pos == sr1.size () - 1 );
+        sr1.remove_suffix (1);
+        --p;
+        }
+        
+//  Basic sanity checking for "find_first_of / find_first_not_of"
+    sr1 = arg;
+    sr2 = arg;
+    while ( !sr1.empty() ) {
+        BOOST_CHECK ( sr1.find_first_of ( sr2 )     == 0 );
+        BOOST_CHECK ( sr1.find_first_not_of ( sr2 ) == string_ref::npos );
+        sr1.remove_prefix ( 1 );
+        }
+
+    p = arg;
+    sr1 = arg;
+    while ( *p ) {
+        string_ref::size_type pos1 = sr1.find_first_of(*p);
+        string_ref::size_type pos2 = sr1.find_first_not_of(*p);
+        BOOST_CHECK ( pos1 != string_ref::npos && pos1 < sr1.size () && pos1 <= ptr_diff ( p, arg ));
+        if ( pos2 != string_ref::npos ) {
+            for ( size_t i = 0 ; i < pos2; ++i )
+                BOOST_CHECK ( sr1[i] == *p );
+            BOOST_CHECK ( sr1 [ pos2 ] != *p );
+            }
+
+        BOOST_CHECK ( pos2 != pos1 );
+        ++p;
+        }
+        
+//  Basic sanity checking for "find_last_of / find_last_not_of"
+    sr1 = arg;
+    sr2 = arg;
+    while ( !sr1.empty() ) {
+        BOOST_CHECK ( sr1.find_last_of ( sr2 )     == ( sr1.size () - 1 ));
+        BOOST_CHECK ( sr1.find_last_not_of ( sr2 ) == string_ref::npos );
+        sr1.remove_suffix ( 1 );
+        }
+
+    p = arg;
+    sr1 = arg;
+    while ( *p ) {
+        string_ref::size_type pos1 = sr1.find_last_of(*p);
+        string_ref::size_type pos2 = sr1.find_last_not_of(*p);
+        BOOST_CHECK ( pos1 != string_ref::npos && pos1 < sr1.size () && pos1 >= ptr_diff ( p, arg ));
+        BOOST_CHECK ( pos2 == string_ref::npos || pos1 < sr1.size ());
+        if ( pos2 != string_ref::npos ) {
+            for ( size_t i = sr1.size () -1 ; i > pos2; --i )
+                BOOST_CHECK ( sr1[i] == *p );
+            BOOST_CHECK ( sr1 [ pos2 ] != *p );
+            }
+         
+        BOOST_CHECK ( pos2 != pos1 );
+        ++p;
+        }
+
+    }
+
+const char *test_strings [] = {
+    "",
+    "0",
+    "abc",
+    "AAA",  // all the same
+    "adsfadadiaef;alkdg;aljt;j agl;sjrl;tjs;lga;lretj;srg[w349u5209dsfadfasdfasdfadsf",
+    "abc\0asdfadsfasf",
+    NULL
+    };
+    
+int test_main( int , char* [] ) {
+    const char **p = &test_strings[0];
+    
+    while ( *p != NULL ) {
+        starts_with ( *p );
+        ends_with ( *p );
+        reverse ( *p );
+        find ( *p );
+
+        p++;
+        }
+
+    return 0;
+    }