/* Vector API for GNU compiler. Copyright (C) 2004-2021 Free Software Foundation, Inc. Contributed by Nathan Sidwell Re-implemented in C++ by Diego Novillo This file is part of GCC. GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GCC; see the file COPYING3. If not see . */ #ifndef GCC_VEC_H #define GCC_VEC_H /* Some gen* file have no ggc support as the header file gtype-desc.h is missing. Provide these definitions in case ggc.h has not been included. This is not a problem because any code that runs before gengtype is built will never need to use GC vectors.*/ extern void ggc_free (void *); extern size_t ggc_round_alloc_size (size_t requested_size); extern void *ggc_realloc (void *, size_t MEM_STAT_DECL); /* Templated vector type and associated interfaces. The interface functions are typesafe and use inline functions, sometimes backed by out-of-line generic functions. The vectors are designed to interoperate with the GTY machinery. There are both 'index' and 'iterate' accessors. The index accessor is implemented by operator[]. The iterator returns a boolean iteration condition and updates the iteration variable passed by reference. Because the iterator will be inlined, the address-of can be optimized away. Each operation that increases the number of active elements is available in 'quick' and 'safe' variants. The former presumes that there is sufficient allocated space for the operation to succeed (it dies if there is not). The latter will reallocate the vector, if needed. Reallocation causes an exponential increase in vector size. If you know you will be adding N elements, it would be more efficient to use the reserve operation before adding the elements with the 'quick' operation. This will ensure there are at least as many elements as you ask for, it will exponentially increase if there are too few spare slots. If you want reserve a specific number of slots, but do not want the exponential increase (for instance, you know this is the last allocation), use the reserve_exact operation. You can also create a vector of a specific size from the get go. You should prefer the push and pop operations, as they append and remove from the end of the vector. If you need to remove several items in one go, use the truncate operation. The insert and remove operations allow you to change elements in the middle of the vector. There are two remove operations, one which preserves the element ordering 'ordered_remove', and one which does not 'unordered_remove'. The latter function copies the end element into the removed slot, rather than invoke a memmove operation. The 'lower_bound' function will determine where to place an item in the array using insert that will maintain sorted order. Vectors are template types with three arguments: the type of the elements in the vector, the allocation strategy, and the physical layout to use Four allocation strategies are supported: - Heap: allocation is done using malloc/free. This is the default allocation strategy. - GC: allocation is done using ggc_alloc/ggc_free. - GC atomic: same as GC with the exception that the elements themselves are assumed to be of an atomic type that does not need to be garbage collected. This means that marking routines do not need to traverse the array marking the individual elements. This increases the performance of GC activities. Two physical layouts are supported: - Embedded: The vector is structured using the trailing array idiom. The last member of the structure is an array of size 1. When the vector is initially allocated, a single memory block is created to hold the vector's control data and the array of elements. These vectors cannot grow without reallocation (see discussion on embeddable vectors below). - Space efficient: The vector is structured as a pointer to an embedded vector. This is the default layout. It means that vectors occupy a single word of storage before initial allocation. Vectors are allowed to grow (the internal pointer is reallocated but the main vector instance does not need to relocate). The type, allocation and layout are specified when the vector is declared. If you need to directly manipulate a vector, then the 'address' accessor will return the address of the start of the vector. Also the 'space' predicate will tell you whether there is spare capacity in the vector. You will not normally need to use these two functions. Notes on the different layout strategies * Embeddable vectors (vec) These vectors are suitable to be embedded in other data structures so that they can be pre-allocated in a contiguous memory block. Embeddable vectors are implemented using the trailing array idiom, thus they are not resizeable without changing the address of the vector object itself. This means you cannot have variables or fields of embeddable vector type -- always use a pointer to a vector. The one exception is the final field of a structure, which could be a vector type. You will have to use the embedded_size & embedded_init calls to create such objects, and they will not be resizeable (so the 'safe' allocation variants are not available). Properties of embeddable vectors: - The whole vector and control data are allocated in a single contiguous block. It uses the trailing-vector idiom, so allocation must reserve enough space for all the elements in the vector plus its control data. - The vector cannot be re-allocated. - The vector cannot grow nor shrink. - No indirections needed for access/manipulation. - It requires 2 words of storage (prior to vector allocation). * Space efficient vector (vec) These vectors can grow dynamically and are allocated together with their control data. They are suited to be included in data structures. Prior to initial allocation, they only take a single word of storage. These vectors are implemented as a pointer to embeddable vectors. The semantics allow for this pointer to be NULL to represent empty vectors. This way, empty vectors occupy minimal space in the structure containing them. Properties: - The whole vector and control data are allocated in a single contiguous block. - The whole vector may be re-allocated. - Vector data may grow and shrink. - Access and manipulation requires a pointer test and indirection. - It requires 1 word of storage (prior to vector allocation). An example of their use would be, struct my_struct { // A space-efficient vector of tree pointers in GC memory. vec v; }; struct my_struct *s; if (s->v.length ()) { we have some contents } s->v.safe_push (decl); // append some decl onto the end for (ix = 0; s->v.iterate (ix, &elt); ix++) { do something with elt } */ /* Support function for statistics. */ extern void dump_vec_loc_statistics (void); /* Hashtable mapping vec addresses to descriptors. */ extern htab_t vec_mem_usage_hash; /* Control data for vectors. This contains the number of allocated and used slots inside a vector. */ struct vec_prefix { /* FIXME - These fields should be private, but we need to cater to compilers that have stricter notions of PODness for types. */ /* Memory allocation support routines in vec.c. */ void register_overhead (void *, size_t, size_t CXX_MEM_STAT_INFO); void release_overhead (void *, size_t, size_t, bool CXX_MEM_STAT_INFO); static unsigned calculate_allocation (vec_prefix *, unsigned, bool); static unsigned calculate_allocation_1 (unsigned, unsigned); /* Note that vec_prefix should be a base class for vec, but we use offsetof() on vector fields of tree structures (e.g., tree_binfo::base_binfos), and offsetof only supports base types. To compensate, we make vec_prefix a field inside vec and make vec a friend class of vec_prefix so it can access its fields. */ template friend struct vec; /* The allocator types also need access to our internals. */ friend struct va_gc; friend struct va_gc_atomic; friend struct va_heap; unsigned m_alloc : 31; unsigned m_using_auto_storage : 1; unsigned m_num; }; /* Calculate the number of slots to reserve a vector, making sure that RESERVE slots are free. If EXACT grow exactly, otherwise grow exponentially. PFX is the control data for the vector. */ inline unsigned vec_prefix::calculate_allocation (vec_prefix *pfx, unsigned reserve, bool exact) { if (exact) return (pfx ? pfx->m_num : 0) + reserve; else if (!pfx) return MAX (4, reserve); return calculate_allocation_1 (pfx->m_alloc, pfx->m_num + reserve); } template struct vec; /* Valid vector layouts vl_embed - Embeddable vector that uses the trailing array idiom. vl_ptr - Space efficient vector that uses a pointer to an embeddable vector. */ struct vl_embed { }; struct vl_ptr { }; /* Types of supported allocations va_heap - Allocation uses malloc/free. va_gc - Allocation uses ggc_alloc. va_gc_atomic - Same as GC, but individual elements of the array do not need to be marked during collection. */ /* Allocator type for heap vectors. */ struct va_heap { /* Heap vectors are frequently regular instances, so use the vl_ptr layout for them. */ typedef vl_ptr default_layout; template static void reserve (vec *&, unsigned, bool CXX_MEM_STAT_INFO); template static void release (vec *&); }; /* Allocator for heap memory. Ensure there are at least RESERVE free slots in V. If EXACT is true, grow exactly, else grow exponentially. As a special case, if the vector had not been allocated and RESERVE is 0, no vector will be created. */ template inline void va_heap::reserve (vec *&v, unsigned reserve, bool exact MEM_STAT_DECL) { size_t elt_size = sizeof (T); unsigned alloc = vec_prefix::calculate_allocation (v ? &v->m_vecpfx : 0, reserve, exact); gcc_checking_assert (alloc); if (GATHER_STATISTICS && v) v->m_vecpfx.release_overhead (v, elt_size * v->allocated (), v->allocated (), false); size_t size = vec::embedded_size (alloc); unsigned nelem = v ? v->length () : 0; v = static_cast *> (xrealloc (v, size)); v->embedded_init (alloc, nelem); if (GATHER_STATISTICS) v->m_vecpfx.register_overhead (v, alloc, elt_size PASS_MEM_STAT); } #if GCC_VERSION >= 4007 #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wfree-nonheap-object" #endif /* Free the heap space allocated for vector V. */ template void va_heap::release (vec *&v) { size_t elt_size = sizeof (T); if (v == NULL) return; if (GATHER_STATISTICS) v->m_vecpfx.release_overhead (v, elt_size * v->allocated (), v->allocated (), true); ::free (v); v = NULL; } #if GCC_VERSION >= 4007 #pragma GCC diagnostic pop #endif /* Allocator type for GC vectors. Notice that we need the structure declaration even if GC is not enabled. */ struct va_gc { /* Use vl_embed as the default layout for GC vectors. Due to GTY limitations, GC vectors must always be pointers, so it is more efficient to use a pointer to the vl_embed layout, rather than using a pointer to a pointer as would be the case with vl_ptr. */ typedef vl_embed default_layout; template static void reserve (vec *&, unsigned, bool CXX_MEM_STAT_INFO); template static void release (vec *&v); }; /* Free GC memory used by V and reset V to NULL. */ template inline void va_gc::release (vec *&v) { if (v) ::ggc_free (v); v = NULL; } /* Allocator for GC memory. Ensure there are at least RESERVE free slots in V. If EXACT is true, grow exactly, else grow exponentially. As a special case, if the vector had not been allocated and RESERVE is 0, no vector will be created. */ template void va_gc::reserve (vec *&v, unsigned reserve, bool exact MEM_STAT_DECL) { unsigned alloc = vec_prefix::calculate_allocation (v ? &v->m_vecpfx : 0, reserve, exact); if (!alloc) { ::ggc_free (v); v = NULL; return; } /* Calculate the amount of space we want. */ size_t size = vec::embedded_size (alloc); /* Ask the allocator how much space it will really give us. */ size = ::ggc_round_alloc_size (size); /* Adjust the number of slots accordingly. */ size_t vec_offset = sizeof (vec_prefix); size_t elt_size = sizeof (T); alloc = (size - vec_offset) / elt_size; /* And finally, recalculate the amount of space we ask for. */ size = vec_offset + alloc * elt_size; unsigned nelem = v ? v->length () : 0; v = static_cast *> (::ggc_realloc (v, size PASS_MEM_STAT)); v->embedded_init (alloc, nelem); } /* Allocator type for GC vectors. This is for vectors of types atomics w.r.t. collection, so allocation and deallocation is completely inherited from va_gc. */ struct va_gc_atomic : va_gc { }; /* Generic vector template. Default values for A and L indicate the most commonly used strategies. FIXME - Ideally, they would all be vl_ptr to encourage using regular instances for vectors, but the existing GTY machinery is limited in that it can only deal with GC objects that are pointers themselves. This means that vector operations that need to deal with potentially NULL pointers, must be provided as free functions (see the vec_safe_* functions above). */ template struct GTY((user)) vec { }; /* Allow C++11 range-based 'for' to work directly on vec*. */ template T* begin (vec *v) { return v ? v->begin () : nullptr; } template T* end (vec *v) { return v ? v->end () : nullptr; } template const T* begin (const vec *v) { return v ? v->begin () : nullptr; } template const T* end (const vec *v) { return v ? v->end () : nullptr; } /* Generic vec<> debug helpers. These need to be instantiated for each vec used throughout the compiler like this: DEFINE_DEBUG_VEC (TYPE) The reason we have a debug_helper() is because GDB can't disambiguate a plain call to debug(some_vec), and it must be called like debug(some_vec). */ template void debug_helper (vec &ref) { unsigned i; for (i = 0; i < ref.length (); ++i) { fprintf (stderr, "[%d] = ", i); debug_slim (ref[i]); fputc ('\n', stderr); } } /* We need a separate va_gc variant here because default template argument for functions cannot be used in c++-98. Once this restriction is removed, those variant should be folded with the above debug_helper. */ template void debug_helper (vec &ref) { unsigned i; for (i = 0; i < ref.length (); ++i) { fprintf (stderr, "[%d] = ", i); debug_slim (ref[i]); fputc ('\n', stderr); } } /* Macro to define debug(vec) and debug(vec) helper functions for a type T. */ #define DEFINE_DEBUG_VEC(T) \ template void debug_helper (vec &); \ template void debug_helper (vec &); \ /* Define the vec debug functions. */ \ DEBUG_FUNCTION void \ debug (vec &ref) \ { \ debug_helper (ref); \ } \ DEBUG_FUNCTION void \ debug (vec *ptr) \ { \ if (ptr) \ debug (*ptr); \ else \ fprintf (stderr, "\n"); \ } \ /* Define the vec debug functions. */ \ DEBUG_FUNCTION void \ debug (vec &ref) \ { \ debug_helper (ref); \ } \ DEBUG_FUNCTION void \ debug (vec *ptr) \ { \ if (ptr) \ debug (*ptr); \ else \ fprintf (stderr, "\n"); \ } /* Default-construct N elements in DST. */ template inline void vec_default_construct (T *dst, unsigned n) { #ifdef BROKEN_VALUE_INITIALIZATION /* Versions of GCC before 4.4 sometimes leave certain objects uninitialized when value initialized, though if the type has user defined default ctor, that ctor is invoked. As a workaround perform clearing first and then the value initialization, which fixes the case when value initialization doesn't initialize due to the bugs and should initialize to all zeros, but still allows vectors for types with user defined default ctor that initializes some or all elements to non-zero. If T has no user defined default ctor and some non-static data members have user defined default ctors that initialize to non-zero the workaround will still not work properly; in that case we just need to provide user defined default ctor. */ memset (dst, '\0', sizeof (T) * n); #endif for ( ; n; ++dst, --n) ::new (static_cast(dst)) T (); } /* Copy-construct N elements in DST from *SRC. */ template inline void vec_copy_construct (T *dst, const T *src, unsigned n) { for ( ; n; ++dst, ++src, --n) ::new (static_cast(dst)) T (*src); } /* Type to provide NULL values for vec. This is used to provide nil initializers for vec instances. Since vec must be a POD, we cannot have proper ctor/dtor for it. To initialize a vec instance, you can assign it the value vNULL. This isn't needed for file-scope and function-local static vectors, which are zero-initialized by default. */ struct vnull { template CONSTEXPR operator vec () const { return vec(); } }; extern vnull vNULL; /* Embeddable vector. These vectors are suitable to be embedded in other data structures so that they can be pre-allocated in a contiguous memory block. Embeddable vectors are implemented using the trailing array idiom, thus they are not resizeable without changing the address of the vector object itself. This means you cannot have variables or fields of embeddable vector type -- always use a pointer to a vector. The one exception is the final field of a structure, which could be a vector type. You will have to use the embedded_size & embedded_init calls to create such objects, and they will not be resizeable (so the 'safe' allocation variants are not available). Properties: - The whole vector and control data are allocated in a single contiguous block. It uses the trailing-vector idiom, so allocation must reserve enough space for all the elements in the vector plus its control data. - The vector cannot be re-allocated. - The vector cannot grow nor shrink. - No indirections needed for access/manipulation. - It requires 2 words of storage (prior to vector allocation). */ template struct GTY((user)) vec { public: unsigned allocated (void) const { return m_vecpfx.m_alloc; } unsigned length (void) const { return m_vecpfx.m_num; } bool is_empty (void) const { return m_vecpfx.m_num == 0; } T *address (void) { return m_vecdata; } const T *address (void) const { return m_vecdata; } T *begin () { return address (); } const T *begin () const { return address (); } T *end () { return address () + length (); } const T *end () const { return address () + length (); } const T &operator[] (unsigned) const; T &operator[] (unsigned); T &last (void); bool space (unsigned) const; bool iterate (unsigned, T *) const; bool iterate (unsigned, T **) const; vec *copy (ALONE_CXX_MEM_STAT_INFO) const; void splice (const vec &); void splice (const vec *src); T *quick_push (const T &); T &pop (void); void truncate (unsigned); void quick_insert (unsigned, const T &); void ordered_remove (unsigned); void unordered_remove (unsigned); void block_remove (unsigned, unsigned); void qsort (int (*) (const void *, const void *)); void sort (int (*) (const void *, const void *, void *), void *); T *bsearch (const void *key, int (*compar)(const void *, const void *)); T *bsearch (const void *key, int (*compar)(const void *, const void *, void *), void *); unsigned lower_bound (T, bool (*)(const T &, const T &)) const; bool contains (const T &search) const; static size_t embedded_size (unsigned); void embedded_init (unsigned, unsigned = 0, unsigned = 0); void quick_grow (unsigned len); void quick_grow_cleared (unsigned len); /* vec class can access our internal data and functions. */ template friend struct vec; /* The allocator types also need access to our internals. */ friend struct va_gc; friend struct va_gc_atomic; friend struct va_heap; /* FIXME - These fields should be private, but we need to cater to compilers that have stricter notions of PODness for types. */ vec_prefix m_vecpfx; T m_vecdata[1]; }; /* Convenience wrapper functions to use when dealing with pointers to embedded vectors. Some functionality for these vectors must be provided via free functions for these reasons: 1- The pointer may be NULL (e.g., before initial allocation). 2- When the vector needs to grow, it must be reallocated, so the pointer will change its value. Because of limitations with the current GC machinery, all vectors in GC memory *must* be pointers. */ /* If V contains no room for NELEMS elements, return false. Otherwise, return true. */ template inline bool vec_safe_space (const vec *v, unsigned nelems) { return v ? v->space (nelems) : nelems == 0; } /* If V is NULL, return 0. Otherwise, return V->length(). */ template inline unsigned vec_safe_length (const vec *v) { return v ? v->length () : 0; } /* If V is NULL, return NULL. Otherwise, return V->address(). */ template inline T * vec_safe_address (vec *v) { return v ? v->address () : NULL; } /* If V is NULL, return true. Otherwise, return V->is_empty(). */ template inline bool vec_safe_is_empty (vec *v) { return v ? v->is_empty () : true; } /* If V does not have space for NELEMS elements, call V->reserve(NELEMS, EXACT). */ template inline bool vec_safe_reserve (vec *&v, unsigned nelems, bool exact = false CXX_MEM_STAT_INFO) { bool extend = nelems ? !vec_safe_space (v, nelems) : false; if (extend) A::reserve (v, nelems, exact PASS_MEM_STAT); return extend; } template inline bool vec_safe_reserve_exact (vec *&v, unsigned nelems CXX_MEM_STAT_INFO) { return vec_safe_reserve (v, nelems, true PASS_MEM_STAT); } /* Allocate GC memory for V with space for NELEMS slots. If NELEMS is 0, V is initialized to NULL. */ template inline void vec_alloc (vec *&v, unsigned nelems CXX_MEM_STAT_INFO) { v = NULL; vec_safe_reserve (v, nelems, false PASS_MEM_STAT); } /* Free the GC memory allocated by vector V and set it to NULL. */ template inline void vec_free (vec *&v) { A::release (v); } /* Grow V to length LEN. Allocate it, if necessary. */ template inline void vec_safe_grow (vec *&v, unsigned len, bool exact = false CXX_MEM_STAT_INFO) { unsigned oldlen = vec_safe_length (v); gcc_checking_assert (len >= oldlen); vec_safe_reserve (v, len - oldlen, exact PASS_MEM_STAT); v->quick_grow (len); } /* If V is NULL, allocate it. Call V->safe_grow_cleared(LEN). */ template inline void vec_safe_grow_cleared (vec *&v, unsigned len, bool exact = false CXX_MEM_STAT_INFO) { unsigned oldlen = vec_safe_length (v); vec_safe_grow (v, len, exact PASS_MEM_STAT); vec_default_construct (v->address () + oldlen, len - oldlen); } /* Assume V is not NULL. */ template inline void vec_safe_grow_cleared (vec *&v, unsigned len, bool exact = false CXX_MEM_STAT_INFO) { v->safe_grow_cleared (len, exact PASS_MEM_STAT); } /* If V does not have space for NELEMS elements, call V->reserve(NELEMS, EXACT). */ template inline bool vec_safe_reserve (vec *&v, unsigned nelems, bool exact = false CXX_MEM_STAT_INFO) { return v->reserve (nelems, exact); } /* If V is NULL return false, otherwise return V->iterate(IX, PTR). */ template inline bool vec_safe_iterate (const vec *v, unsigned ix, T **ptr) { if (v) return v->iterate (ix, ptr); else { *ptr = 0; return false; } } template inline bool vec_safe_iterate (const vec *v, unsigned ix, T *ptr) { if (v) return v->iterate (ix, ptr); else { *ptr = 0; return false; } } /* If V has no room for one more element, reallocate it. Then call V->quick_push(OBJ). */ template inline T * vec_safe_push (vec *&v, const T &obj CXX_MEM_STAT_INFO) { vec_safe_reserve (v, 1, false PASS_MEM_STAT); return v->quick_push (obj); } /* if V has no room for one more element, reallocate it. Then call V->quick_insert(IX, OBJ). */ template inline void vec_safe_insert (vec *&v, unsigned ix, const T &obj CXX_MEM_STAT_INFO) { vec_safe_reserve (v, 1, false PASS_MEM_STAT); v->quick_insert (ix, obj); } /* If V is NULL, do nothing. Otherwise, call V->truncate(SIZE). */ template inline void vec_safe_truncate (vec *v, unsigned size) { if (v) v->truncate (size); } /* If SRC is not NULL, return a pointer to a copy of it. */ template inline vec * vec_safe_copy (vec *src CXX_MEM_STAT_INFO) { return src ? src->copy (ALONE_PASS_MEM_STAT) : NULL; } /* Copy the elements from SRC to the end of DST as if by memcpy. Reallocate DST, if necessary. */ template inline void vec_safe_splice (vec *&dst, const vec *src CXX_MEM_STAT_INFO) { unsigned src_len = vec_safe_length (src); if (src_len) { vec_safe_reserve_exact (dst, vec_safe_length (dst) + src_len PASS_MEM_STAT); dst->splice (*src); } } /* Return true if SEARCH is an element of V. Note that this is O(N) in the size of the vector and so should be used with care. */ template inline bool vec_safe_contains (vec *v, const T &search) { return v ? v->contains (search) : false; } /* Index into vector. Return the IX'th element. IX must be in the domain of the vector. */ template inline const T & vec::operator[] (unsigned ix) const { gcc_checking_assert (ix < m_vecpfx.m_num); return m_vecdata[ix]; } template inline T & vec::operator[] (unsigned ix) { gcc_checking_assert (ix < m_vecpfx.m_num); return m_vecdata[ix]; } /* Get the final element of the vector, which must not be empty. */ template inline T & vec::last (void) { gcc_checking_assert (m_vecpfx.m_num > 0); return (*this)[m_vecpfx.m_num - 1]; } /* If this vector has space for NELEMS additional entries, return true. You usually only need to use this if you are doing your own vector reallocation, for instance on an embedded vector. This returns true in exactly the same circumstances that vec::reserve will. */ template inline bool vec::space (unsigned nelems) const { return m_vecpfx.m_alloc - m_vecpfx.m_num >= nelems; } /* Return iteration condition and update PTR to point to the IX'th element of this vector. Use this to iterate over the elements of a vector as follows, for (ix = 0; vec::iterate (v, ix, &ptr); ix++) continue; */ template inline bool vec::iterate (unsigned ix, T *ptr) const { if (ix < m_vecpfx.m_num) { *ptr = m_vecdata[ix]; return true; } else { *ptr = 0; return false; } } /* Return iteration condition and update *PTR to point to the IX'th element of this vector. Use this to iterate over the elements of a vector as follows, for (ix = 0; v->iterate (ix, &ptr); ix++) continue; This variant is for vectors of objects. */ template inline bool vec::iterate (unsigned ix, T **ptr) const { if (ix < m_vecpfx.m_num) { *ptr = CONST_CAST (T *, &m_vecdata[ix]); return true; } else { *ptr = 0; return false; } } /* Return a pointer to a copy of this vector. */ template inline vec * vec::copy (ALONE_MEM_STAT_DECL) const { vec *new_vec = NULL; unsigned len = length (); if (len) { vec_alloc (new_vec, len PASS_MEM_STAT); new_vec->embedded_init (len, len); vec_copy_construct (new_vec->address (), m_vecdata, len); } return new_vec; } /* Copy the elements from SRC to the end of this vector as if by memcpy. The vector must have sufficient headroom available. */ template inline void vec::splice (const vec &src) { unsigned len = src.length (); if (len) { gcc_checking_assert (space (len)); vec_copy_construct (end (), src.address (), len); m_vecpfx.m_num += len; } } template inline void vec::splice (const vec *src) { if (src) splice (*src); } /* Push OBJ (a new element) onto the end of the vector. There must be sufficient space in the vector. Return a pointer to the slot where OBJ was inserted. */ template inline T * vec::quick_push (const T &obj) { gcc_checking_assert (space (1)); T *slot = &m_vecdata[m_vecpfx.m_num++]; *slot = obj; return slot; } /* Pop and return the last element off the end of the vector. */ template inline T & vec::pop (void) { gcc_checking_assert (length () > 0); return m_vecdata[--m_vecpfx.m_num]; } /* Set the length of the vector to SIZE. The new length must be less than or equal to the current length. This is an O(1) operation. */ template inline void vec::truncate (unsigned size) { gcc_checking_assert (length () >= size); m_vecpfx.m_num = size; } /* Insert an element, OBJ, at the IXth position of this vector. There must be sufficient space. */ template inline void vec::quick_insert (unsigned ix, const T &obj) { gcc_checking_assert (length () < allocated ()); gcc_checking_assert (ix <= length ()); T *slot = &m_vecdata[ix]; memmove (slot + 1, slot, (m_vecpfx.m_num++ - ix) * sizeof (T)); *slot = obj; } /* Remove an element from the IXth position of this vector. Ordering of remaining elements is preserved. This is an O(N) operation due to memmove. */ template inline void vec::ordered_remove (unsigned ix) { gcc_checking_assert (ix < length ()); T *slot = &m_vecdata[ix]; memmove (slot, slot + 1, (--m_vecpfx.m_num - ix) * sizeof (T)); } /* Remove elements in [START, END) from VEC for which COND holds. Ordering of remaining elements is preserved. This is an O(N) operation. */ #define VEC_ORDERED_REMOVE_IF_FROM_TO(vec, read_index, write_index, \ elem_ptr, start, end, cond) \ { \ gcc_assert ((end) <= (vec).length ()); \ for (read_index = write_index = (start); read_index < (end); \ ++read_index) \ { \ elem_ptr = &(vec)[read_index]; \ bool remove_p = (cond); \ if (remove_p) \ continue; \ \ if (read_index != write_index) \ (vec)[write_index] = (vec)[read_index]; \ \ write_index++; \ } \ \ if (read_index - write_index > 0) \ (vec).block_remove (write_index, read_index - write_index); \ } /* Remove elements from VEC for which COND holds. Ordering of remaining elements is preserved. This is an O(N) operation. */ #define VEC_ORDERED_REMOVE_IF(vec, read_index, write_index, elem_ptr, \ cond) \ VEC_ORDERED_REMOVE_IF_FROM_TO ((vec), read_index, write_index, \ elem_ptr, 0, (vec).length (), (cond)) /* Remove an element from the IXth position of this vector. Ordering of remaining elements is destroyed. This is an O(1) operation. */ template inline void vec::unordered_remove (unsigned ix) { gcc_checking_assert (ix < length ()); m_vecdata[ix] = m_vecdata[--m_vecpfx.m_num]; } /* Remove LEN elements starting at the IXth. Ordering is retained. This is an O(N) operation due to memmove. */ template inline void vec::block_remove (unsigned ix, unsigned len) { gcc_checking_assert (ix + len <= length ()); T *slot = &m_vecdata[ix]; m_vecpfx.m_num -= len; memmove (slot, slot + len, (m_vecpfx.m_num - ix) * sizeof (T)); } /* Sort the contents of this vector with qsort. CMP is the comparison function to pass to qsort. */ template inline void vec::qsort (int (*cmp) (const void *, const void *)) { if (length () > 1) gcc_qsort (address (), length (), sizeof (T), cmp); } /* Sort the contents of this vector with qsort. CMP is the comparison function to pass to qsort. */ template inline void vec::sort (int (*cmp) (const void *, const void *, void *), void *data) { if (length () > 1) gcc_sort_r (address (), length (), sizeof (T), cmp, data); } /* Search the contents of the sorted vector with a binary search. CMP is the comparison function to pass to bsearch. */ template inline T * vec::bsearch (const void *key, int (*compar) (const void *, const void *)) { const void *base = this->address (); size_t nmemb = this->length (); size_t size = sizeof (T); /* The following is a copy of glibc stdlib-bsearch.h. */ size_t l, u, idx; const void *p; int comparison; l = 0; u = nmemb; while (l < u) { idx = (l + u) / 2; p = (const void *) (((const char *) base) + (idx * size)); comparison = (*compar) (key, p); if (comparison < 0) u = idx; else if (comparison > 0) l = idx + 1; else return (T *)const_cast(p); } return NULL; } /* Search the contents of the sorted vector with a binary search. CMP is the comparison function to pass to bsearch. */ template inline T * vec::bsearch (const void *key, int (*compar) (const void *, const void *, void *), void *data) { const void *base = this->address (); size_t nmemb = this->length (); size_t size = sizeof (T); /* The following is a copy of glibc stdlib-bsearch.h. */ size_t l, u, idx; const void *p; int comparison; l = 0; u = nmemb; while (l < u) { idx = (l + u) / 2; p = (const void *) (((const char *) base) + (idx * size)); comparison = (*compar) (key, p, data); if (comparison < 0) u = idx; else if (comparison > 0) l = idx + 1; else return (T *)const_cast(p); } return NULL; } /* Return true if SEARCH is an element of V. Note that this is O(N) in the size of the vector and so should be used with care. */ template inline bool vec::contains (const T &search) const { unsigned int len = length (); for (unsigned int i = 0; i < len; i++) if ((*this)[i] == search) return true; return false; } /* Find and return the first position in which OBJ could be inserted without changing the ordering of this vector. LESSTHAN is a function that returns true if the first argument is strictly less than the second. */ template unsigned vec::lower_bound (T obj, bool (*lessthan)(const T &, const T &)) const { unsigned int len = length (); unsigned int half, middle; unsigned int first = 0; while (len > 0) { half = len / 2; middle = first; middle += half; T middle_elem = (*this)[middle]; if (lessthan (middle_elem, obj)) { first = middle; ++first; len = len - half - 1; } else len = half; } return first; } /* Return the number of bytes needed to embed an instance of an embeddable vec inside another data structure. Use these methods to determine the required size and initialization of a vector V of type T embedded within another structure (as the final member): size_t vec::embedded_size (unsigned alloc); void v->embedded_init (unsigned alloc, unsigned num); These allow the caller to perform the memory allocation. */ template inline size_t vec::embedded_size (unsigned alloc) { struct alignas (T) U { char data[sizeof (T)]; }; typedef vec vec_embedded; typedef typename std::conditional::value, vec, vec_embedded>::type vec_stdlayout; static_assert (sizeof (vec_stdlayout) == sizeof (vec), ""); static_assert (alignof (vec_stdlayout) == alignof (vec), ""); return offsetof (vec_stdlayout, m_vecdata) + alloc * sizeof (T); } /* Initialize the vector to contain room for ALLOC elements and NUM active elements. */ template inline void vec::embedded_init (unsigned alloc, unsigned num, unsigned aut) { m_vecpfx.m_alloc = alloc; m_vecpfx.m_using_auto_storage = aut; m_vecpfx.m_num = num; } /* Grow the vector to a specific length. LEN must be as long or longer than the current length. The new elements are uninitialized. */ template inline void vec::quick_grow (unsigned len) { gcc_checking_assert (length () <= len && len <= m_vecpfx.m_alloc); m_vecpfx.m_num = len; } /* Grow the vector to a specific length. LEN must be as long or longer than the current length. The new elements are initialized to zero. */ template inline void vec::quick_grow_cleared (unsigned len) { unsigned oldlen = length (); size_t growby = len - oldlen; quick_grow (len); if (growby != 0) vec_default_construct (address () + oldlen, growby); } /* Garbage collection support for vec. */ template void gt_ggc_mx (vec *v) { extern void gt_ggc_mx (T &); for (unsigned i = 0; i < v->length (); i++) gt_ggc_mx ((*v)[i]); } template void gt_ggc_mx (vec *v ATTRIBUTE_UNUSED) { /* Nothing to do. Vectors of atomic types wrt GC do not need to be traversed. */ } /* PCH support for vec. */ template void gt_pch_nx (vec *v) { extern void gt_pch_nx (T &); for (unsigned i = 0; i < v->length (); i++) gt_pch_nx ((*v)[i]); } template void gt_pch_nx (vec *v, gt_pointer_operator op, void *cookie) { for (unsigned i = 0; i < v->length (); i++) op (&((*v)[i]), cookie); } template void gt_pch_nx (vec *v, gt_pointer_operator op, void *cookie) { extern void gt_pch_nx (T *, gt_pointer_operator, void *); for (unsigned i = 0; i < v->length (); i++) gt_pch_nx (&((*v)[i]), op, cookie); } /* Space efficient vector. These vectors can grow dynamically and are allocated together with their control data. They are suited to be included in data structures. Prior to initial allocation, they only take a single word of storage. These vectors are implemented as a pointer to an embeddable vector. The semantics allow for this pointer to be NULL to represent empty vectors. This way, empty vectors occupy minimal space in the structure containing them. Properties: - The whole vector and control data are allocated in a single contiguous block. - The whole vector may be re-allocated. - Vector data may grow and shrink. - Access and manipulation requires a pointer test and indirection. - It requires 1 word of storage (prior to vector allocation). Limitations: These vectors must be PODs because they are stored in unions. (http://en.wikipedia.org/wiki/Plain_old_data_structures). As long as we use C++03, we cannot have constructors nor destructors in classes that are stored in unions. */ template struct vec { public: /* Memory allocation and deallocation for the embedded vector. Needed because we cannot have proper ctors/dtors defined. */ void create (unsigned nelems CXX_MEM_STAT_INFO); void release (void); /* Vector operations. */ bool exists (void) const { return m_vec != NULL; } bool is_empty (void) const { return m_vec ? m_vec->is_empty () : true; } unsigned length (void) const { return m_vec ? m_vec->length () : 0; } T *address (void) { return m_vec ? m_vec->m_vecdata : NULL; } const T *address (void) const { return m_vec ? m_vec->m_vecdata : NULL; } T *begin () { return address (); } const T *begin () const { return address (); } T *end () { return begin () + length (); } const T *end () const { return begin () + length (); } const T &operator[] (unsigned ix) const { return (*m_vec)[ix]; } bool operator!=(const vec &other) const { return !(*this == other); } bool operator==(const vec &other) const { return address () == other.address (); } T &operator[] (unsigned ix) { return (*m_vec)[ix]; } T &last (void) { return m_vec->last (); } bool space (int nelems) const { return m_vec ? m_vec->space (nelems) : nelems == 0; } bool iterate (unsigned ix, T *p) const; bool iterate (unsigned ix, T **p) const; vec copy (ALONE_CXX_MEM_STAT_INFO) const; bool reserve (unsigned, bool = false CXX_MEM_STAT_INFO); bool reserve_exact (unsigned CXX_MEM_STAT_INFO); void splice (const vec &); void safe_splice (const vec & CXX_MEM_STAT_INFO); T *quick_push (const T &); T *safe_push (const T &CXX_MEM_STAT_INFO); T &pop (void); void truncate (unsigned); void safe_grow (unsigned, bool = false CXX_MEM_STAT_INFO); void safe_grow_cleared (unsigned, bool = false CXX_MEM_STAT_INFO); void quick_grow (unsigned); void quick_grow_cleared (unsigned); void quick_insert (unsigned, const T &); void safe_insert (unsigned, const T & CXX_MEM_STAT_INFO); void ordered_remove (unsigned); void unordered_remove (unsigned); void block_remove (unsigned, unsigned); void qsort (int (*) (const void *, const void *)); void sort (int (*) (const void *, const void *, void *), void *); T *bsearch (const void *key, int (*compar)(const void *, const void *)); T *bsearch (const void *key, int (*compar)(const void *, const void *, void *), void *); unsigned lower_bound (T, bool (*)(const T &, const T &)) const; bool contains (const T &search) const; void reverse (void); bool using_auto_storage () const; /* FIXME - This field should be private, but we need to cater to compilers that have stricter notions of PODness for types. */ vec *m_vec; }; /* auto_vec is a subclass of vec that automatically manages creating and releasing the internal vector. If N is non zero then it has N elements of internal storage. The default is no internal storage, and you probably only want to ask for internal storage for vectors on the stack because if the size of the vector is larger than the internal storage that space is wasted. */ template class auto_vec : public vec { public: auto_vec () { m_auto.embedded_init (MAX (N, 2), 0, 1); this->m_vec = &m_auto; } auto_vec (size_t s) { if (s > N) { this->create (s); return; } m_auto.embedded_init (MAX (N, 2), 0, 1); this->m_vec = &m_auto; } ~auto_vec () { this->release (); } private: vec m_auto; T m_data[MAX (N - 1, 1)]; }; /* auto_vec is a sub class of vec whose storage is released when it is destroyed. */ template class auto_vec : public vec { public: auto_vec () { this->m_vec = NULL; } auto_vec (size_t n) { this->create (n); } ~auto_vec () { this->release (); } auto_vec (vec&& r) { gcc_assert (!r.using_auto_storage ()); this->m_vec = r.m_vec; r.m_vec = NULL; } auto_vec& operator= (vec&& r) { gcc_assert (!r.using_auto_storage ()); this->release (); this->m_vec = r.m_vec; r.m_vec = NULL; return *this; } }; /* Allocate heap memory for pointer V and create the internal vector with space for NELEMS elements. If NELEMS is 0, the internal vector is initialized to empty. */ template inline void vec_alloc (vec *&v, unsigned nelems CXX_MEM_STAT_INFO) { v = new vec; v->create (nelems PASS_MEM_STAT); } /* A subclass of auto_vec that frees all of its elements on deletion. */ class auto_string_vec : public auto_vec { public: ~auto_string_vec (); }; /* A subclass of auto_vec that deletes all of its elements on destruction. This is a crude way for a vec to "own" the objects it points to and clean up automatically. For example, no attempt is made to delete elements when an item within the vec is overwritten. We can't rely on gnu::unique_ptr within a container, since we can't rely on move semantics in C++98. */ template class auto_delete_vec : public auto_vec { public: auto_delete_vec () {} auto_delete_vec (size_t s) : auto_vec (s) {} ~auto_delete_vec (); private: DISABLE_COPY_AND_ASSIGN(auto_delete_vec); }; /* Conditionally allocate heap memory for VEC and its internal vector. */ template inline void vec_check_alloc (vec *&vec, unsigned nelems CXX_MEM_STAT_INFO) { if (!vec) vec_alloc (vec, nelems PASS_MEM_STAT); } /* Free the heap memory allocated by vector V and set it to NULL. */ template inline void vec_free (vec *&v) { if (v == NULL) return; v->release (); delete v; v = NULL; } /* Return iteration condition and update PTR to point to the IX'th element of this vector. Use this to iterate over the elements of a vector as follows, for (ix = 0; v.iterate (ix, &ptr); ix++) continue; */ template inline bool vec::iterate (unsigned ix, T *ptr) const { if (m_vec) return m_vec->iterate (ix, ptr); else { *ptr = 0; return false; } } /* Return iteration condition and update *PTR to point to the IX'th element of this vector. Use this to iterate over the elements of a vector as follows, for (ix = 0; v->iterate (ix, &ptr); ix++) continue; This variant is for vectors of objects. */ template inline bool vec::iterate (unsigned ix, T **ptr) const { if (m_vec) return m_vec->iterate (ix, ptr); else { *ptr = 0; return false; } } /* Convenience macro for forward iteration. */ #define FOR_EACH_VEC_ELT(V, I, P) \ for (I = 0; (V).iterate ((I), &(P)); ++(I)) #define FOR_EACH_VEC_SAFE_ELT(V, I, P) \ for (I = 0; vec_safe_iterate ((V), (I), &(P)); ++(I)) /* Likewise, but start from FROM rather than 0. */ #define FOR_EACH_VEC_ELT_FROM(V, I, P, FROM) \ for (I = (FROM); (V).iterate ((I), &(P)); ++(I)) /* Convenience macro for reverse iteration. */ #define FOR_EACH_VEC_ELT_REVERSE(V, I, P) \ for (I = (V).length () - 1; \ (V).iterate ((I), &(P)); \ (I)--) #define FOR_EACH_VEC_SAFE_ELT_REVERSE(V, I, P) \ for (I = vec_safe_length (V) - 1; \ vec_safe_iterate ((V), (I), &(P)); \ (I)--) /* auto_string_vec's dtor, freeing all contained strings, automatically chaining up to ~auto_vec , which frees the internal buffer. */ inline auto_string_vec::~auto_string_vec () { int i; char *str; FOR_EACH_VEC_ELT (*this, i, str) free (str); } /* auto_delete_vec's dtor, deleting all contained items, automatically chaining up to ~auto_vec , which frees the internal buffer. */ template inline auto_delete_vec::~auto_delete_vec () { int i; T *item; FOR_EACH_VEC_ELT (*this, i, item) delete item; } /* Return a copy of this vector. */ template inline vec vec::copy (ALONE_MEM_STAT_DECL) const { vec new_vec = vNULL; if (length ()) new_vec.m_vec = m_vec->copy (ALONE_PASS_MEM_STAT); return new_vec; } /* Ensure that the vector has at least RESERVE slots available (if EXACT is false), or exactly RESERVE slots available (if EXACT is true). This may create additional headroom if EXACT is false. Note that this can cause the embedded vector to be reallocated. Returns true iff reallocation actually occurred. */ template inline bool vec::reserve (unsigned nelems, bool exact MEM_STAT_DECL) { if (space (nelems)) return false; /* For now play a game with va_heap::reserve to hide our auto storage if any, this is necessary because it doesn't have enough information to know the embedded vector is in auto storage, and so should not be freed. */ vec *oldvec = m_vec; unsigned int oldsize = 0; bool handle_auto_vec = m_vec && using_auto_storage (); if (handle_auto_vec) { m_vec = NULL; oldsize = oldvec->length (); nelems += oldsize; } va_heap::reserve (m_vec, nelems, exact PASS_MEM_STAT); if (handle_auto_vec) { vec_copy_construct (m_vec->address (), oldvec->address (), oldsize); m_vec->m_vecpfx.m_num = oldsize; } return true; } /* Ensure that this vector has exactly NELEMS slots available. This will not create additional headroom. Note this can cause the embedded vector to be reallocated. Returns true iff reallocation actually occurred. */ template inline bool vec::reserve_exact (unsigned nelems MEM_STAT_DECL) { return reserve (nelems, true PASS_MEM_STAT); } /* Create the internal vector and reserve NELEMS for it. This is exactly like vec::reserve, but the internal vector is unconditionally allocated from scratch. The old one, if it existed, is lost. */ template inline void vec::create (unsigned nelems MEM_STAT_DECL) { m_vec = NULL; if (nelems > 0) reserve_exact (nelems PASS_MEM_STAT); } /* Free the memory occupied by the embedded vector. */ template inline void vec::release (void) { if (!m_vec) return; if (using_auto_storage ()) { m_vec->m_vecpfx.m_num = 0; return; } va_heap::release (m_vec); } /* Copy the elements from SRC to the end of this vector as if by memcpy. SRC and this vector must be allocated with the same memory allocation mechanism. This vector is assumed to have sufficient headroom available. */ template inline void vec::splice (const vec &src) { if (src.length ()) m_vec->splice (*(src.m_vec)); } /* Copy the elements in SRC to the end of this vector as if by memcpy. SRC and this vector must be allocated with the same mechanism. If there is not enough headroom in this vector, it will be reallocated as needed. */ template inline void vec::safe_splice (const vec &src MEM_STAT_DECL) { if (src.length ()) { reserve_exact (src.length ()); splice (src); } } /* Push OBJ (a new element) onto the end of the vector. There must be sufficient space in the vector. Return a pointer to the slot where OBJ was inserted. */ template inline T * vec::quick_push (const T &obj) { return m_vec->quick_push (obj); } /* Push a new element OBJ onto the end of this vector. Reallocates the embedded vector, if needed. Return a pointer to the slot where OBJ was inserted. */ template inline T * vec::safe_push (const T &obj MEM_STAT_DECL) { reserve (1, false PASS_MEM_STAT); return quick_push (obj); } /* Pop and return the last element off the end of the vector. */ template inline T & vec::pop (void) { return m_vec->pop (); } /* Set the length of the vector to LEN. The new length must be less than or equal to the current length. This is an O(1) operation. */ template inline void vec::truncate (unsigned size) { if (m_vec) m_vec->truncate (size); else gcc_checking_assert (size == 0); } /* Grow the vector to a specific length. LEN must be as long or longer than the current length. The new elements are uninitialized. Reallocate the internal vector, if needed. */ template inline void vec::safe_grow (unsigned len, bool exact MEM_STAT_DECL) { unsigned oldlen = length (); gcc_checking_assert (oldlen <= len); reserve (len - oldlen, exact PASS_MEM_STAT); if (m_vec) m_vec->quick_grow (len); else gcc_checking_assert (len == 0); } /* Grow the embedded vector to a specific length. LEN must be as long or longer than the current length. The new elements are initialized to zero. Reallocate the internal vector, if needed. */ template inline void vec::safe_grow_cleared (unsigned len, bool exact MEM_STAT_DECL) { unsigned oldlen = length (); size_t growby = len - oldlen; safe_grow (len, exact PASS_MEM_STAT); if (growby != 0) vec_default_construct (address () + oldlen, growby); } /* Same as vec::safe_grow but without reallocation of the internal vector. If the vector cannot be extended, a runtime assertion will be triggered. */ template inline void vec::quick_grow (unsigned len) { gcc_checking_assert (m_vec); m_vec->quick_grow (len); } /* Same as vec::quick_grow_cleared but without reallocation of the internal vector. If the vector cannot be extended, a runtime assertion will be triggered. */ template inline void vec::quick_grow_cleared (unsigned len) { gcc_checking_assert (m_vec); m_vec->quick_grow_cleared (len); } /* Insert an element, OBJ, at the IXth position of this vector. There must be sufficient space. */ template inline void vec::quick_insert (unsigned ix, const T &obj) { m_vec->quick_insert (ix, obj); } /* Insert an element, OBJ, at the IXth position of the vector. Reallocate the embedded vector, if necessary. */ template inline void vec::safe_insert (unsigned ix, const T &obj MEM_STAT_DECL) { reserve (1, false PASS_MEM_STAT); quick_insert (ix, obj); } /* Remove an element from the IXth position of this vector. Ordering of remaining elements is preserved. This is an O(N) operation due to a memmove. */ template inline void vec::ordered_remove (unsigned ix) { m_vec->ordered_remove (ix); } /* Remove an element from the IXth position of this vector. Ordering of remaining elements is destroyed. This is an O(1) operation. */ template inline void vec::unordered_remove (unsigned ix) { m_vec->unordered_remove (ix); } /* Remove LEN elements starting at the IXth. Ordering is retained. This is an O(N) operation due to memmove. */ template inline void vec::block_remove (unsigned ix, unsigned len) { m_vec->block_remove (ix, len); } /* Sort the contents of this vector with qsort. CMP is the comparison function to pass to qsort. */ template inline void vec::qsort (int (*cmp) (const void *, const void *)) { if (m_vec) m_vec->qsort (cmp); } /* Sort the contents of this vector with qsort. CMP is the comparison function to pass to qsort. */ template inline void vec::sort (int (*cmp) (const void *, const void *, void *), void *data) { if (m_vec) m_vec->sort (cmp, data); } /* Search the contents of the sorted vector with a binary search. CMP is the comparison function to pass to bsearch. */ template inline T * vec::bsearch (const void *key, int (*cmp) (const void *, const void *)) { if (m_vec) return m_vec->bsearch (key, cmp); return NULL; } /* Search the contents of the sorted vector with a binary search. CMP is the comparison function to pass to bsearch. */ template inline T * vec::bsearch (const void *key, int (*cmp) (const void *, const void *, void *), void *data) { if (m_vec) return m_vec->bsearch (key, cmp, data); return NULL; } /* Find and return the first position in which OBJ could be inserted without changing the ordering of this vector. LESSTHAN is a function that returns true if the first argument is strictly less than the second. */ template inline unsigned vec::lower_bound (T obj, bool (*lessthan)(const T &, const T &)) const { return m_vec ? m_vec->lower_bound (obj, lessthan) : 0; } /* Return true if SEARCH is an element of V. Note that this is O(N) in the size of the vector and so should be used with care. */ template inline bool vec::contains (const T &search) const { return m_vec ? m_vec->contains (search) : false; } /* Reverse content of the vector. */ template inline void vec::reverse (void) { unsigned l = length (); T *ptr = address (); for (unsigned i = 0; i < l / 2; i++) std::swap (ptr[i], ptr[l - i - 1]); } template inline bool vec::using_auto_storage () const { return m_vec->m_vecpfx.m_using_auto_storage; } /* Release VEC and call release of all element vectors. */ template inline void release_vec_vec (vec > &vec) { for (unsigned i = 0; i < vec.length (); i++) vec[i].release (); vec.release (); } // Provide a subset of the std::span functionality. (We can't use std::span // itself because it's a C++20 feature.) // // In addition, provide an invalid value that is distinct from all valid // sequences (including the empty sequence). This can be used to return // failure without having to use std::optional. // // There is no operator bool because it would be ambiguous whether it is // testing for a valid value or an empty sequence. template class array_slice { template friend class array_slice; public: using value_type = T; using iterator = T *; using const_iterator = const T *; array_slice () : m_base (nullptr), m_size (0) {} template array_slice (array_slice other) : m_base (other.m_base), m_size (other.m_size) {} array_slice (iterator base, unsigned int size) : m_base (base), m_size (size) {} template array_slice (T (&array)[N]) : m_base (array), m_size (N) {} template array_slice (const vec &v) : m_base (v.address ()), m_size (v.length ()) {} iterator begin () { return m_base; } iterator end () { return m_base + m_size; } const_iterator begin () const { return m_base; } const_iterator end () const { return m_base + m_size; } value_type &front (); value_type &back (); value_type &operator[] (unsigned int i); const value_type &front () const; const value_type &back () const; const value_type &operator[] (unsigned int i) const; size_t size () const { return m_size; } size_t size_bytes () const { return m_size * sizeof (T); } bool empty () const { return m_size == 0; } // An invalid array_slice that represents a failed operation. This is // distinct from an empty slice, which is a valid result in some contexts. static array_slice invalid () { return { nullptr, ~0U }; } // True if the array is valid, false if it is an array like INVALID. bool is_valid () const { return m_base || m_size == 0; } private: iterator m_base; unsigned int m_size; }; template inline typename array_slice::value_type & array_slice::front () { gcc_checking_assert (m_size); return m_base[0]; } template inline const typename array_slice::value_type & array_slice::front () const { gcc_checking_assert (m_size); return m_base[0]; } template inline typename array_slice::value_type & array_slice::back () { gcc_checking_assert (m_size); return m_base[m_size - 1]; } template inline const typename array_slice::value_type & array_slice::back () const { gcc_checking_assert (m_size); return m_base[m_size - 1]; } template inline typename array_slice::value_type & array_slice::operator[] (unsigned int i) { gcc_checking_assert (i < m_size); return m_base[i]; } template inline const typename array_slice::value_type & array_slice::operator[] (unsigned int i) const { gcc_checking_assert (i < m_size); return m_base[i]; } template array_slice make_array_slice (T *base, unsigned int size) { return array_slice (base, size); } #if (GCC_VERSION >= 3000) # pragma GCC poison m_vec m_vecpfx m_vecdata #endif #endif // GCC_VEC_H