www.pudn.com > greta-2_6_4.zip > restack.h
//+---------------------------------------------------------------------------
//
// Copyright ( C ) Microsoft, 1994 - 2002.
//
// File: restack.h
//
// Functions: a quick-'n'-dirty, type-unsafe stack used by the iterative
// regular expression algorithm
//
// Notes: Care must be taken when using this stack. You must pop off
// the correct type of object, otherwise you get garbage. Also,
// if you push anything that has a non-trivial destructor, then
// be sure to explicitely pop everything off the stack and don't
// use the unsafe_long_jump method.
//
// Author: Eric Niebler ( ericne@microsoft.com )
//
// History: 11/15/2001 ericne Created
//
//----------------------------------------------------------------------------
#ifndef HETERO_STACK_H
#define HETERO_STACK_H
#include
#include
#include
#include
#include
#ifndef REGEX_CDECL
#ifdef _MSC_VER
#define REGEX_CDECL __cdecl
#else
#define REGEX_CDECL
#endif
#endif
#define COMMA ,
#if !defined(_MSC_VER) | 1200 < _MSC_VER
# define REGEX_VC6(x)
# define REGEX_NVC6(x) x
#else
# define REGEX_VC6(x) x
# define REGEX_NVC6(x)
#endif
namespace regex
{
namespace detail
{
// For compile-time assertions that generate
// no run-time overhead.
template< bool f > struct static_assert;
template<> struct static_assert { static_assert() {} };
// Work-around for a template-template parameter problem on VC7.0
template< typename T > struct type2type { typedef T type; };
template< bool F > struct bool2type { enum { value = F }; };
typedef bool2type true_t;
typedef bool2type false_t;
#ifdef _MSC_VER
// warning C4127: conditional expression is constant
// warning C4189: local variable is initialized but not referenced
// warning C4244: conversion from 'T' to 'int', possible loss of data
// warning C4510: default constructor could not be generated
// warning C4610: struct can never be instantiated - user defined constructor required
// warning C4800: forcing value to bool 'true' or 'false' (performance warning)
#pragma warning( push )
#pragma warning( disable : 4127 4189 4244 4510 4610 4800 )
// Make sure nobody has tampered with the packing before defining the
// alignof structure
#pragma pack( push )
#pragma pack() // use the default packing
#endif
template< typename T >
class alignof
{
struct helper
{
helper();
char m_c;
T m_t;
};
public:
enum { value = sizeof(helper)-sizeof(T) < sizeof(T) ? sizeof(helper)-sizeof(T) : sizeof(T) };
};
#ifdef _MSC_VER
#pragma pack( pop )
#endif
//
// Type traits
//
typedef char (&yes_type)[1];
typedef char (&no_type)[2];
template< bool >
struct select_helper
{
template< typename T, typename U >
struct nested
{
typedef T type;
};
};
template<>
struct select_helper
{
template< typename T, typename U >
struct nested
{
typedef U type;
};
};
// For use in conditional typedefs
template< bool F, typename T, typename U >
struct select
{
typedef typename select_helper::template nested::type type;
};
template< typename U >
struct convertible_helper
{
static yes_type check( U );
static no_type REGEX_CDECL check(...);
};
template< typename T >
struct factory
{
static T& make();
};
template< typename T, typename U >
struct is_convertible
{
enum { value = (sizeof(convertible_helper::check(factory::make()))==sizeof(yes_type)) };
};
template< size_t N >
struct is_power_of_two
{
enum { value = 1==N || 0==(N%2) && is_power_of_two::value };
};
template<>
struct is_power_of_two<0>
{
enum { value = false };
};
// Very primative implementation of is_scalar. This doesn't work
// for void, reference types, array types or function types, but
// we don't use those types from hetero_stack.
struct bool_convertible { bool_convertible(bool); };
template< typename T >
struct is_scalar
{
enum { value = is_convertible::value };
};
template< typename T >
struct has_trivial_copy
{
enum { value = is_scalar::value };
};
template< typename T >
struct has_trivial_assignment
{
enum { value = is_scalar::value };
};
template< typename T >
struct has_trivial_destructor
{
enum { value = is_scalar::value };
};
template< bool > struct destroyer_helper
{
template< typename T >
static void destroy( T const * pT )
{
pT, pT->~T();
}
};
template<> struct destroyer_helper
{
template< typename T >
static void destroy( T const * )
{
}
};
template< typename T >
void destroy( T const * pT )
{
destroyer_helper::value>::destroy( pT );
}
struct type_vtable
{
std::type_info const * typeinfo_ptr;
size_t size;
size_t aligned_size;
void (*destroy)( void * );
void (*copy)( void *, void const * );
};
template< typename T, size_t AlignmentT >
class type_info_ex
{
static void destroy( void * pv )
{
T const * pT = static_cast( pv );
regex::detail::destroy( pT );
(void)pv;
(void)pT;
}
static void copy( void * dst, void const * src )
{
new ( dst ) T( *static_cast( src ) );
}
public:
static type_vtable const vtable;
static bool equals( type_vtable const * ptm )
{
return ptm == & vtable || *ptm->typeinfo_ptr == typeid(T);
}
};
template< typename T,size_t AlignmentT >
type_vtable const type_info_ex::vtable =
{
&typeid(T),
sizeof(T),
( sizeof(T) + AlignmentT - 1 ) & ~( AlignmentT - 1 ),
has_trivial_destructor::value ? 0 : &type_info_ex::destroy,
&type_info_ex::copy
};
template< typename T >
inline T & to_type( void * pv )
{
return *static_cast( pv );
}
} // namespace detail
// --------------------------------------------------------------------------
//
// Class: hetero_stack
//
// Description: Fast, heterogeneous stack.
//
// Methods: allocate - reserve space on stack
// unwind - unwind the stack
// hetero_stack - c'tor
// ~hetero_stack - d'tor, release all dynamic memory
// push - push an object on the stack
// pop - pop an object from the stack
//
// Members: m_first_node -
// m_current_node -
//
// Typedefs: byte_t -
//
// History: 10/19/2001 - ericne - Created
//
// --------------------------------------------------------------------------
template
<
size_t AlignmentT = sizeof(void*),
bool RuntimeTypeCheckT = true, // should we perform run-time type checking?
bool AssumePodT = false, // assume non-throwing copy/assign/destroy for better perf
size_t DynamicBlockSizeT = 4096, // blocks allocated from heap are this size
size_t StaticBlockSizeT = 1024 // initial block on stack is this size
>
class hetero_stack
{
typedef unsigned char byte_t;
typedef detail::type_vtable const* vtable_ptr;
public:
typedef hetero_stack stack_type;
template< typename T >
struct aligned_sizeof
{
enum
{
// round up sizeof(T) to the nearest multiple of AlignmentT
no_rtti = ( sizeof( T ) + AlignmentT - 1 ) & ~( AlignmentT - 1 ),
with_rtti = RuntimeTypeCheckT ?
no_rtti + aligned_sizeof::no_rtti :
no_rtti
};
};
private:
struct stack_node
{
struct header
{
stack_node * m_back;
stack_node * m_next;
byte_t * m_current; // ptr into m_mem. alloc from here
byte_t * m_end; // ptr to last+1 byte_t in m_mem
};
union
{
header m_head;
byte_t m_align[ aligned_sizeof::no_rtti ];
};
// This is the buffer into which values will be pushed and popped.
// It is guaranteed to meet the AlignmentT requirements because of
// the union above.
byte_t m_mem[1];
size_t size() const // throw()
{
return static_cast( m_head.m_end - m_mem );
}
};
enum
{
DYNAMIC_BLOCK_SIZE =
DynamicBlockSizeT > sizeof( stack_node ) ?
DynamicBlockSizeT : sizeof( stack_node )
};
union
{
stack_node m_node;
byte_t m_buf[ aligned_sizeof::no_rtti + StaticBlockSizeT ];
} m_first_node;
stack_node * m_current_node;
// Cache these for faster access
byte_t * m_begin;
byte_t * m_current;
byte_t * m_end;
byte_t * grow( size_t size ) // throw(std::bad_alloc)
{
// write the cached value of current into the node.
// OK to do this even if later statements throw.
m_current_node->m_head.m_current = m_current;
// Do we have a node with available memory already?
if( m_current_node->m_head.m_next )
{
// Does this node have enough room?
if( size <= m_current_node->m_head.m_next->size() )
{
m_current_node = m_current_node->m_head.m_next;
m_current = m_current_node->m_head.m_current = m_current_node->m_mem + size;
m_end = m_current_node->m_head.m_end;
return m_begin = m_current_node->m_mem;
}
// Create a new node and insert it into the list
stack_node * new_node = static_cast(
::operator new( size + offsetof( stack_node, m_mem ) ) );
new_node->m_head.m_back = m_current_node;
new_node->m_head.m_next = m_current_node->m_head.m_next;
m_current = m_end = new_node->m_head.m_current =
new_node->m_head.m_end = new_node->m_mem + size;
m_current_node->m_head.m_next->m_head.m_back = new_node;
m_current_node->m_head.m_next = new_node;
m_current_node = new_node;
return m_begin = m_current_node->m_mem;
}
// We need to create a new node from scratch
size_t new_size = detail::regex_max( size,
static_cast(DYNAMIC_BLOCK_SIZE) - offsetof( stack_node, m_mem ) );
stack_node * new_node = static_cast(
::operator new( new_size + offsetof( stack_node, m_mem ) ) );
new_node->m_head.m_back = m_current_node;
new_node->m_head.m_next = 0;
m_current = new_node->m_head.m_current = new_node->m_mem + size;
m_end = new_node->m_head.m_end = new_node->m_mem + new_size;
m_current_node->m_head.m_next = new_node;
m_current_node = new_node;
return m_begin = m_current_node->m_mem;
}
byte_t * allocate( size_t size ) // throw(std::bad_alloc)
{
// This is the ptr to return
byte_t * mem = m_current;
// Advance the high-water mark
m_current += size;
// Check to see if we have overflowed this buffer
if( std::less()( m_end, m_current ) ) // if( m_end < m_current )
{
// oops, back this out.
m_current = mem;
// allocate a new block and return a ptr to the new memory
return grow( size );
}
return mem;
}
byte_t * unwind( byte_t * pb ) // throw()
{
// roll back the stack
m_current = pb;
// If we've unwound this whole block, then make the
// previous node the current node
if( m_current == m_begin )
{
// write the cached value of m_current into m_current_node
m_current_node->m_head.m_current = m_current;
m_current_node = m_current_node->m_head.m_back;
// update the cache
m_begin = m_current_node->m_mem;
m_current = m_current_node->m_head.m_current;
m_end = m_current_node->m_head.m_end;
}
return pb;
}
byte_t * unwind( size_t size ) // throw()
{
return unwind( m_current - size );
}
void long_jump_impl( void * jump_ptr, detail::bool2type ) // throw()
{
safe_long_jump( jump_ptr );
}
void long_jump_impl( void * jump_ptr, detail::bool2type ) // throw()
{
unsafe_long_jump( jump_ptr );
}
struct real_unwinder;
friend struct real_unwinder;
struct real_unwinder
{
real_unwinder( stack_type * pstack, size_t size ) // throw()
: m_pstack(pstack), m_size(size) {}
~real_unwinder() // throw()
{
if( m_pstack )
m_pstack->unwind( m_size );
}
void dismiss() // throw()
{
m_pstack = 0;
}
private:
real_unwinder( real_unwinder const & );
real_unwinder & operator=( real_unwinder const & );
stack_type * m_pstack;
size_t m_size;
};
struct dummy_unwinder
{
dummy_unwinder( stack_type *, size_t ) {} // throw()
void dismiss() {} // throw()
};
// Disallow these for now. Might implement them later.
hetero_stack( hetero_stack const & );
hetero_stack & operator=( hetero_stack const & );
public:
class type_error : public std::logic_error
{
std::type_info const * m_prequested_type;
std::type_info const * m_pactual_type;
public:
type_error
(
std::type_info const & requested_type,
std::type_info const & actual_type,
std::string const & s = "type error in hetero_stack"
) // throw()
: std::logic_error( s + " (requested type: " + requested_type.name()
+ ", actual type: " + actual_type.name() + ")" )
, m_prequested_type( &requested_type )
, m_pactual_type( &actual_type )
{
}
std::type_info const & requested_type() const // throw()
{
return *m_prequested_type;
}
std::type_info const & actual_type() const // throw()
{
return *m_pactual_type;
}
};
hetero_stack() // throw()
: m_current_node( &m_first_node.m_node )
{
m_first_node.m_node.m_head.m_back = & m_first_node.m_node;
m_first_node.m_node.m_head.m_next = 0;
m_begin = m_current = m_first_node.m_node.m_head.m_current = m_first_node.m_node.m_mem;
m_end = m_first_node.m_node.m_head.m_end = m_first_node.m_buf + sizeof( m_first_node );
}
~hetero_stack() // throw()
{
// AlignmentT must be a power of two
detail::static_assert< detail::is_power_of_two::value > const align_test;
// Call any destructors for objects still on the stack
if( RuntimeTypeCheckT && ! AssumePodT )
{
long_jump( m_first_node.m_node.m_mem );
}
// delete all the memory blocks
m_current_node = m_first_node.m_node.m_head.m_next;
for( stack_node * next_node; m_current_node; m_current_node = next_node )
{
next_node = m_current_node->m_head.m_next;
::operator delete( static_cast( m_current_node ) );
}
}
template< typename T >
inline void push( T const & t ) // throw(std::bad_alloc,...)
{
// Make sure that the alignment for type T is not worse
// than our declared alignment.
detail::static_assert<( AlignmentT >= detail::alignof::value )> const align_test;
static_cast(align_test);
// If T won't throw in copy c'tor then we don't need to use an unwinder object.
typedef typename detail::select< AssumePodT || detail::has_trivial_copy::value,
dummy_unwinder, real_unwinder >::type unwinder;
// If this throws, it doesn't change state,
// so there is nothing to roll back.
byte_t * pb = allocate( aligned_sizeof::with_rtti );
// Rolls back the allocate if later steps throw
// BUGBUG we can do the alloc, but not update m_current until after
// the copy c'tor to avoid the need for an unwinder object
unwinder guard( this, aligned_sizeof::with_rtti );
new ( pb ) T( t ); // Could throw if ! has_trivial_copy::value
// If we are debugging the stack, then push a pointer to the type_info
// for this type T. It will be checked in pop().
if( RuntimeTypeCheckT )
{
detail::to_type( pb + aligned_sizeof::no_rtti ) = & detail::type_info_ex::vtable;
}
// ok, everything succeeded -- dismiss the guard
guard.dismiss();
}
template< typename T >
inline void pop( T & t ) // throw(...)
{
detail::static_assert<( AlignmentT >= detail::alignof::value )> const align_test;
static_cast(align_test);
// If we are debugging the stack, then in push() we pushed a pointer
// to the type_info struct for this type T. Check it now.
if( RuntimeTypeCheckT )
{
byte_t * pti = m_current - aligned_sizeof::no_rtti;
if( ! detail::type_info_ex::equals( detail::to_type( pti ) ) )
throw type_error( typeid( T ), *detail::to_type( pti )->typeinfo_ptr );
}
// Don't change state yet because assignment op could throw!
byte_t * pT = m_current - aligned_sizeof::with_rtti;
t = detail::to_type( pT ); // could throw
T const & ref = detail::to_type( pT );
regex::detail::destroy( &ref );
unwind( pT );
}
// Call this version of pop when you don't need the popped value
template< typename T >
inline void pop( REGEX_VC6(detail::type2type COMMA int) ) // throw(type_error,...)
{
detail::static_assert<( AlignmentT >= detail::alignof::value )> const align_test;
static_cast(align_test);
// If we are debugging the stack, then in push() we pushed a pointer
// to the type_info struct for this type T. Check it now.
if( RuntimeTypeCheckT )
{
byte_t * pti = m_current - aligned_sizeof::no_rtti;
if( ! detail::type_info_ex::equals( detail::to_type( pti ) ) )
throw type_error( typeid( T ), *detail::to_type( pti )->typeinfo_ptr );
}
byte_t * pv = unwind( aligned_sizeof::with_rtti );
T const & ref = detail::to_type( pv );
regex::detail::destroy( &ref );
}
// Call this version of pop when you don't need the popped value and
// throwing an exception isn't an option
template< typename T >
inline bool pop( std::nothrow_t const & ) // throw()
{
detail::static_assert<( AlignmentT >= detail::alignof::value )> const align_test;
static_cast(align_test);
// If we are debugging the stack, then in push() we pushed a pointer
// to the type_info struct for this type T. Check it now.
if( RuntimeTypeCheckT )
{
byte_t * pti = m_current - aligned_sizeof::no_rtti;
if( ! detail::type_info_ex::equals( detail::to_type( pti ) ) )
return false; // type error, can't throw so bail.
}
byte_t * pv = unwind( aligned_sizeof::with_rtti );
T const & ref = detail::to_type( pv );
regex::detail::destroy( &ref );
return true;
}
template< typename T >
inline T & top( REGEX_VC6(detail::type2type) ) const // throw(type_error,...)
{
detail::static_assert<( AlignmentT >= detail::alignof::value )> const align_test;
static_cast(align_test);
if( RuntimeTypeCheckT )
{
// If we are debugging the stack, then the top of the stack is a
// pointer to a type_info struct. Assert that we have the correct type.
byte_t * pti = m_current - aligned_sizeof::no_rtti;
if( ! detail::type_info_ex::equals( detail::to_type( pti ) ) )
throw type_error( typeid( T ), *detail::to_type( pti )->typeinfo_ptr );
}
byte_t * pT = m_current - aligned_sizeof::with_rtti;
return detail::to_type( pT );
}
// Fetch the type_info for the element at the top of the stack
std::type_info const & top_type() const // throw()
{
detail::static_assert< RuntimeTypeCheckT > const type_check;
static_cast(type_check);
byte_t * pti = m_current - aligned_sizeof::no_rtti;
return *detail::to_type( pti )->typeinfo_ptr;
}
// Get a pointer to the top of the stack
void * set_jump() const // throw()
{
return m_current;
}
// Quick and dirty stack unwind. Does not call destructors.
void unsafe_long_jump( void *const jump_ptr ) // throw()
{
for( ;; )
{
if( std::less()( jump_ptr, m_current_node->m_mem ) ||
std::less()( m_current_node->m_head.m_end, jump_ptr ) )
{
m_current_node->m_head.m_current = m_current_node->m_mem;
m_current_node = m_current_node->m_head.m_back;
}
else
{
m_begin = m_current_node->m_mem;
m_current = m_current_node->m_head.m_current = static_cast( jump_ptr );
m_end = m_current_node->m_head.m_end;
return;
}
}
}
// Safe long jump; does call destructors if RuntimeTypeCheckT is true.
void safe_long_jump( void *const jump_ptr ) // throw()
{
detail::static_assert< RuntimeTypeCheckT > const type_check;
static_cast(type_check);
while( m_current != jump_ptr )
{
// The top of the stack is a pointer to a type_vtable struct.
m_current -= aligned_sizeof::no_rtti;
vtable_ptr pvtable = detail::to_type( m_current );
// find the start of the object
m_current -= pvtable->aligned_size;
// call the destructor for T
if( pvtable->destroy )
{
pvtable->destroy( m_current );
}
// move to the previous buffer if necessary
if( m_current == m_begin && m_current != jump_ptr )
{
m_current_node->m_head.m_current = m_current;
m_current_node = m_current_node->m_head.m_back;
m_begin = m_current_node->m_mem;
m_current = m_current_node->m_head.m_current;
m_end = m_current_node->m_head.m_end;
}
}
}
// Stack unwind. If RuntimeTypeCheckT && !AssumePodT, then destructors
// are called. Otherwise they are not.
void long_jump( void * jump_ptr ) // throw()
{
long_jump_impl( jump_ptr, detail::bool2type() );
}
struct stack_guard
{
stack_type * m_ps;
void * m_jump_ptr;
explicit stack_guard( stack_type * ps )
: m_ps( ps )
, m_jump_ptr( ps->set_jump() )
{
}
~stack_guard()
{
m_ps->long_jump( m_jump_ptr );
}
};
bool empty() const // throw()
{
return m_current == m_first_node.m_node.m_mem;
}
// Use scoped_push for automatically pushing/popping
// things to and from the stack. This is especially useful
// if you want to push a bunch of things "atomically". For
// instance:
//
// typedef hetero_stack<>::scoped_pop scoped_pop;
// scoped_pop p1 = stack.scoped_push( int(1) ); // could throw
// scoped_pop p2 = stack.scoped_push( std::string("foo") ); // could throw
// stack.push( float(3.14159) ); // could throw
// p2.dismiss(); // ok, nothing threw, so ...
// p1.dismiss(); // ... dismiss the scoped_pops
//
// If p2 and p1 are not dismissed, as in the case when an
// exception gets thrown, then they automatically pop their
// arguments from the stack.
class scoped_pop_base
{
scoped_pop_base & operator=( scoped_pop_base const & ); // disallow assignment
protected:
mutable stack_type * m_pstack;
explicit scoped_pop_base( stack_type * pstack ) // throw(std::bad_alloc,...)
: m_pstack( pstack )
{
}
scoped_pop_base( scoped_pop_base const & right ) // throw() // destructive copy
: m_pstack( right.m_pstack )
{
right.dismiss();
}
public:
void dismiss() const // throw()
{
m_pstack = 0;
}
};
template< typename T >
class scoped_pop_t : public scoped_pop_base
{
scoped_pop_t & operator=( scoped_pop_t const & ); // disallow assignment
public:
scoped_pop_t( stack_type * pstack, T const & t ) // throw(std::bad_alloc,...)
: scoped_pop_base( pstack )
{
// Note that if this throws an exception the destructor
// will not get called, which is what we want.
m_pstack->push( t );
}
~scoped_pop_t() // throw()
{
// If we own this stack space, pop it.
if( m_pstack )
m_pstack->template pop( std::nothrow );
}
};
template< typename T >
scoped_pop_t scoped_push( T const & t ) // throw(...)
{
return scoped_pop_t( this, t );
}
typedef scoped_pop_base const & scoped_pop;
};
#ifdef _MSC_VER
#pragma warning( pop )
#endif
} // namespace regex
#endif