Re: add vector container type

Daniel Jacobowitz
2006-08-15T19:09:56Z

On Mon, Jul 10, 2006 at 11:09:01AM +0100, Nathan Sidwell wrote:
> This patch imports GCC's VEC API to gdb. The gdb version is much simpler,
> as we only have to deal with heap allocated vectors, rather than the heap
> or GC'd vectors of GCC.
>
> The brief outline of this API is that it allows you to define variable
> length vectors of scalars, pointers or objects, and then have type-safe
> accessor and manipulator functions. GCC has been using this for about 2
> years now.
>
> We (CSL) are using this API for some upcoming patches implementing the
> flash programming model that has previously been discussed here.
>
> ok?

This revised version includes mostly whitespace fixes from Nathan's
last posted copy (and the most recent patch was corrupted). Once we
have a user for this code (one's coming up next), this is the version I
propose to commit.

--
Daniel Jacobowitz
CodeSourcery

2006-07-14 Nathan Sidwell <nathan@codesourcery.com>

* vec.h: New file.
* vec.c: New file.
* Makefile.in (SFILES): Add vec.c.
(vec_h): New.
(COMMON_OBJS): Add vec.o.
(vec.o): New target.
* doc/gdbint.texinfo (Array Containers): New section.

---
gdb/Makefile.in | 6
gdb/doc/gdbint.texinfo | 175 ++++++++
gdb/vec.c | 120 +++++
gdb/vec.h | 1000 +++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 1299 insertions(+), 2 deletions(-)

Index: src/gdb/vec.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ src/gdb/vec.h 2006-08-10 23:31:19.000000000 -0400
@@ -0,0 +1,1000 @@
+/* Vector API for GDB.
+ Copyright (C) 2004, 2005, 2006 Free Software Foundation, Inc.
+ Contributed by Nathan Sidwell <nathan@codesourcery.com>
+
+ This file is part of GDB.
+
+ This program 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 2 of the License, or
+ (at your option) any later version.
+
+ This program 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 this program; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ Boston, MA 02110-1301, USA. */
+
+#if !defined (GDB_VEC_H)
+#define GDB_VEC_H
+
+#include <stddef.h>
+#include "gdb_string.h"
+#include "gdb_assert.h"
+
+/* The macros here implement a set of templated vector types and
+ associated interfaces. These templates are implemented with
+ macros, as we're not in C++ land. The interface functions are
+ typesafe and use static inline functions, sometimes backed by
+ out-of-line generic functions.
+
+ Because of the different behavior of structure objects, scalar
+ objects and of pointers, there are three flavors, one for each of
+ these variants. Both the structure object and pointer variants
+ pass pointers to objects around -- in the former case the pointers
+ are stored into the vector and in the latter case the pointers are
+ dereferenced and the objects copied into the vector. The scalar
+ object variant is suitable for int-like objects, and the vector
+ elements are returned by value.
+
+ There are both 'index' and 'iterate' accessors. 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.
+
+ The 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
+ 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 probably not be resizeable (so
+ don't use the 'safe' allocation variants). The trailing array
+ idiom is used (rather than a pointer to an array of data), because,
+ if we allow NULL to also represent an empty vector, empty vectors
+ occupy minimal space in the structure containing them.
+
+ 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 a
+ negative number for reservation. 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.
+
+ 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.
+
+ Vector types are defined using a DEF_VEC_{O,P,I}(TYPEDEF) macro.
+ Variables of vector type are declared using a VEC(TYPEDEF) macro.
+ The characters O, P and I indicate whether TYPEDEF is a pointer
+ (P), object (O) or integral (I) type. Be careful to pick the
+ correct one, as you'll get an awkward and inefficient API if you
+ use the wrong one. There is a check, which results in a
+ compile-time warning, for the P and I versions, but there is no
+ check for the O versions, as that is not possible in plain C.
+
+ An example of their use would be,
+
+ DEF_VEC_P(tree); // non-managed tree vector.
+
+ struct my_struct {
+ VEC(tree) *v; // A (pointer to) a vector of tree pointers.
+ };
+
+ struct my_struct *s;
+
+ if (VEC_length(tree, s->v)) { we have some contents }
+ VEC_safe_push(tree, s->v, decl); // append some decl onto the end
+ for (ix = 0; VEC_iterate(tree, s->v, ix, elt); ix++)
+ { do something with elt }
+
+*/
+
+/* Macros to invoke API calls. A single macro works for both pointer
+ and object vectors, but the argument and return types might well be
+ different. In each macro, T is the typedef of the vector elements.
+ Some of these macros pass the vector, V, by reference (by taking
+ its address), this is noted in the descriptions. */
+
+/* Length of vector
+ unsigned VEC_T_length(const VEC(T) *v);
+
+ Return the number of active elements in V. V can be NULL, in which
+ case zero is returned. */
+
+#define VEC_length(T,V) (VEC_OP(T,length)(V))
+
+
+/* Check if vector is empty
+ int VEC_T_empty(const VEC(T) *v);
+
+ Return nonzero if V is an empty vector (or V is NULL), zero otherwise. */
+
+#define VEC_empty(T,V) (VEC_length (T,V) == 0)
+
+
+/* Get the final element of the vector.
+ T VEC_T_last(VEC(T) *v); // Integer
+ T VEC_T_last(VEC(T) *v); // Pointer
+ T *VEC_T_last(VEC(T) *v); // Object
+
+ Return the final element. V must not be empty. */
+
+#define VEC_last(T,V) (VEC_OP(T,last)(V VEC_ASSERT_INFO))
+
+/* Index into vector
+ T VEC_T_index(VEC(T) *v, unsigned ix); // Integer
+ T VEC_T_index(VEC(T) *v, unsigned ix); // Pointer
+ T *VEC_T_index(VEC(T) *v, unsigned ix); // Object
+
+ Return the IX'th element. If IX must be in the domain of V. */
+
+#define VEC_index(T,V,I) (VEC_OP(T,index)(V,I VEC_ASSERT_INFO))
+
+/* Iterate over vector
+ int VEC_T_iterate(VEC(T) *v, unsigned ix, T &ptr); // Integer
+ int VEC_T_iterate(VEC(T) *v, unsigned ix, T &ptr); // Pointer
+ int VEC_T_iterate(VEC(T) *v, unsigned ix, T *&ptr); // Object
+
+ Return iteration condition and update PTR to point to the IX'th
+ element. At the end of iteration, sets PTR to NULL. Use this to
+ iterate over the elements of a vector as follows,
+
+ for (ix = 0; VEC_iterate(T,v,ix,ptr); ix++)
+ continue; */
+
+#define VEC_iterate(T,V,I,P) (VEC_OP(T,iterate)(V,I,&(P)))
+
+/* Allocate new vector.
+ VEC(T,A) *VEC_T_alloc(int reserve);
+
+ Allocate a new vector with space for RESERVE objects. If RESERVE
+ is zero, NO vector is created. */
+
+#define VEC_alloc(T,N) (VEC_OP(T,alloc)(N))
+
+/* Free a vector.
+ void VEC_T_free(VEC(T,A) *&);
+
+ Free a vector and set it to NULL. */
+
+#define VEC_free(T,V) (VEC_OP(T,free)(&V))
+
+/* Use these to determine the required size and initialization of a
+ vector embedded within another structure (as the final member).
+
+ size_t VEC_T_embedded_size(int reserve);
+ void VEC_T_embedded_init(VEC(T) *v, int reserve);
+
+ These allow the caller to perform the memory allocation. */
+
+#define VEC_embedded_size(T,N) (VEC_OP(T,embedded_size)(N))
+#define VEC_embedded_init(T,O,N) (VEC_OP(T,embedded_init)(VEC_BASE(O),N))
+
+/* Copy a vector.
+ VEC(T,A) *VEC_T_copy(VEC(T) *);
+
+ Copy the live elements of a vector into a new vector. The new and
+ old vectors need not be allocated by the same mechanism. */
+
+#define VEC_copy(T,V) (VEC_OP(T,copy)(V))
+
+/* Determine if a vector has additional capacity.
+
+ int VEC_T_space (VEC(T) *v,int reserve)
+
+ If V has space for RESERVE additional entries, return nonzero. You
+ usually only need to use this if you are doing your own vector
+ reallocation, for instance on an embedded vector. This returns
+ nonzero in exactly the same circumstances that VEC_T_reserve
+ will. */
+
+#define VEC_space(T,V,R) (VEC_OP(T,space)(V,R VEC_ASSERT_INFO))
+
+/* Reserve space.
+ int VEC_T_reserve(VEC(T,A) *&v, int reserve);
+
+ Ensure that V has at least abs(RESERVE) slots available. The
+ signedness of RESERVE determines the reallocation behavior. A
+ negative value will not create additional headroom beyond that
+ requested. A positive value will create additional headroom. Note
+ this can cause V to be reallocated. Returns nonzero iff
+ reallocation actually occurred. */
+
+#define VEC_reserve(T,V,R) (VEC_OP(T,reserve)(&(V),R VEC_ASSERT_INFO))
+
+/* Push object with no reallocation
+ T *VEC_T_quick_push (VEC(T) *v, T obj); // Integer
+ T *VEC_T_quick_push (VEC(T) *v, T obj); // Pointer
+ T *VEC_T_quick_push (VEC(T) *v, T *obj); // Object
+
+ Push a new element onto the end, returns a pointer to the slot
+ filled in. For object vectors, the new value can be NULL, in which
+ case NO initialization is performed. There must
+ be sufficient space in the vector. */
+
+#define VEC_quick_push(T,V,O) (VEC_OP(T,quick_push)(V,O VEC_ASSERT_INFO))
+
+/* Push object with reallocation
+ T *VEC_T_safe_push (VEC(T,A) *&v, T obj); // Integer
+ T *VEC_T_safe_push (VEC(T,A) *&v, T obj); // Pointer
+ T *VEC_T_safe_push (VEC(T,A) *&v, T *obj); // Object
+
+ Push a new element onto the end, returns a pointer to the slot
+ filled in. For object vectors, the new value can be NULL, in which
+ case NO initialization is performed. Reallocates V, if needed. */
+
+#define VEC_safe_push(T,V,O) (VEC_OP(T,safe_push)(&(V),O VEC_ASSERT_INFO))
+
+/* Pop element off end
+ T VEC_T_pop (VEC(T) *v); // Integer
+ T VEC_T_pop (VEC(T) *v); // Pointer
+ void VEC_T_pop (VEC(T) *v); // Object
+
+ Pop the last element off the end. Returns the element popped, for
+ pointer vectors. */
+
+#define VEC_pop(T,V) (VEC_OP(T,pop)(V VEC_ASSERT_INFO))
+
+/* Truncate to specific length
+ void VEC_T_truncate (VEC(T) *v, unsigned len);
+
+ Set the length as specified. The new length must be less than or
+ equal to the current length. This is an O(1) operation. */
+
+#define VEC_truncate(T,V,I) \
+ (VEC_OP(T,truncate)(V,I VEC_ASSERT_INFO))
+
+/* Grow to a specific length.
+ void VEC_T_safe_grow (VEC(T,A) *&v, int len);
+
+ Grow the vector to a specific length. The LEN must be as
+ long or longer than the current length. The new elements are
+ uninitialized. */
+
+#define VEC_safe_grow(T,V,I) \
+ (VEC_OP(T,safe_grow)(&(V),I VEC_ASSERT_INFO))
+
+/* Replace element
+ T VEC_T_replace (VEC(T) *v, unsigned ix, T val); // Integer
+ T VEC_T_replace (VEC(T) *v, unsigned ix, T val); // Pointer
+ T *VEC_T_replace (VEC(T) *v, unsigned ix, T *val); // Object
+
+ Replace the IXth element of V with a new value, VAL. For pointer
+ vectors returns the original value. For object vectors returns a
+ pointer to the new value. For object vectors the new value can be
+ NULL, in which case no overwriting of the slot is actually
+ performed. */
+
+#define VEC_replace(T,V,I,O) (VEC_OP(T,replace)(V,I,O VEC_ASSERT_INFO))
+
+/* Insert object with no reallocation
+ T *VEC_T_quick_insert (VEC(T) *v, unsigned ix, T val); // Integer
+ T *VEC_T_quick_insert (VEC(T) *v, unsigned ix, T val); // Pointer
+ T *VEC_T_quick_insert (VEC(T) *v, unsigned ix, T *val); // Object
+
+ Insert an element, VAL, at the IXth position of V. Return a pointer
+ to the slot created. For vectors of object, the new value can be
+ NULL, in which case no initialization of the inserted slot takes
+ place. There must be sufficient space. */
+
+#define VEC_quick_insert(T,V,I,O) \
+ (VEC_OP(T,quick_insert)(V,I,O VEC_ASSERT_INFO))
+
+/* Insert object with reallocation
+ T *VEC_T_safe_insert (VEC(T,A) *&v, unsigned ix, T val); // Integer
+ T *VEC_T_safe_insert (VEC(T,A) *&v, unsigned ix, T val); // Pointer
+ T *VEC_T_safe_insert (VEC(T,A) *&v, unsigned ix, T *val); // Object
+
+ Insert an element, VAL, at the IXth position of V. Return a pointer
+ to the slot created. For vectors of object, the new value can be
+ NULL, in which case no initialization of the inserted slot takes
+ place. Reallocate V, if necessary. */
+
+#define VEC_safe_insert(T,V,I,O) \
+ (VEC_OP(T,safe_insert)(&(V),I,O VEC_ASSERT_INFO))
+
+/* Remove element retaining order
+ T VEC_T_ordered_remove (VEC(T) *v, unsigned ix); // Integer
+ T VEC_T_ordered_remove (VEC(T) *v, unsigned ix); // Pointer
+ void VEC_T_ordered_remove (VEC(T) *v, unsigned ix); // Object
+
+ Remove an element from the IXth position of V. Ordering of
+ remaining elements is preserved. For pointer vectors returns the
+ removed object. This is an O(N) operation due to a memmove. */
+
+#define VEC_ordered_remove(T,V,I) \
+ (VEC_OP(T,ordered_remove)(V,I VEC_ASSERT_INFO))
+
+/* Remove element destroying order
+ T VEC_T_unordered_remove (VEC(T) *v, unsigned ix); // Integer
+ T VEC_T_unordered_remove (VEC(T) *v, unsigned ix); // Pointer
+ void VEC_T_unordered_remove (VEC(T) *v, unsigned ix); // Object
+
+ Remove an element from the IXth position of V. Ordering of
+ remaining elements is destroyed. For pointer vectors returns the
+ removed object. This is an O(1) operation. */
+
+#define VEC_unordered_remove(T,V,I) \
+ (VEC_OP(T,unordered_remove)(V,I VEC_ASSERT_INFO))
+
+/* Remove a block of elements
+ void VEC_T_block_remove (VEC(T) *v, unsigned ix, unsigned len);
+
+ Remove LEN elements starting at the IXth. Ordering is retained.
+ This is an O(1) operation. */
+
+#define VEC_block_remove(T,V,I,L) \
+ (VEC_OP(T,block_remove)(V,I,L) VEC_ASSERT_INFO)
+
+/* Get the address of the array of elements
+ T *VEC_T_address (VEC(T) v)
+
+ If you need to directly manipulate the array (for instance, you
+ want to feed it to qsort), use this accessor. */
+
+#define VEC_address(T,V) (VEC_OP(T,address)(V))
+
+/* Find the first index in the vector not less than the object.
+ unsigned VEC_T_lower_bound (VEC(T) *v, const T val,
+ int (*lessthan) (const T, const T)); // Integer
+ unsigned VEC_T_lower_bound (VEC(T) *v, const T val,
+ int (*lessthan) (const T, const T)); // Pointer
+ unsigned VEC_T_lower_bound (VEC(T) *v, const T *val,
+ int (*lessthan) (const T*, const T*)); // Object
+
+ Find the first position in which VAL could be inserted without
+ changing the ordering of V. LESSTHAN is a function that returns
+ true if the first argument is strictly less than the second. */
+
+#define VEC_lower_bound(T,V,O,LT) \
+ (VEC_OP(T,lower_bound)(V,O,LT VEC_ASSERT_INFO))
+
+/* Reallocate an array of elements with prefix. */
+extern void *vec_p_reserve (void *, int);
+extern void *vec_o_reserve (void *, int, size_t, size_t);
+#define vec_free(V) xfree (V)
+
+#define VEC_ASSERT_INFO ,__FILE__,__LINE__
+#define VEC_ASSERT_DECL ,const char *file_,unsigned line_
+#define VEC_ASSERT_PASS ,file_,line_
+#define vec_assert(expr, op) \
+ ((void)((expr) ? 0 : (gdb_assert_fail (op, file_, line_, ASSERT_FUNCTION), 0)))
+
+#define VEC(T) VEC_##T
+#define VEC_OP(T,OP) VEC_##T##_##OP
+
+#define VEC_T(T) \
+typedef struct VEC(T) \
+{ \
+ unsigned num; \
+ unsigned alloc; \
+ T vec[1]; \
+} VEC(T)
+
+/* Vector of integer-like object. */
+#define DEF_VEC_I(T) \
+static inline void VEC_OP (T,must_be_integral_type) (void) \
+{ \
+ (void)~(T)0; \
+} \
+ \
+VEC_T(T); \
+DEF_VEC_FUNC_P(T) \
+DEF_VEC_ALLOC_FUNC_I(T) \
+struct vec_swallow_trailing_semi
+
+/* Vector of pointer to object. */
+#define DEF_VEC_P(T) \
+static inline void VEC_OP (T,must_be_pointer_type) (void) \
+{ \
+ (void)((T)1 == (void *)1); \
+} \
+ \
+VEC_T(T); \
+DEF_VEC_FUNC_P(T) \
+DEF_VEC_ALLOC_FUNC_P(T) \
+struct vec_swallow_trailing_semi
+
+/* Vector of object. */
+#define DEF_VEC_O(T) \
+VEC_T(T); \
+DEF_VEC_FUNC_O(T) \
+DEF_VEC_ALLOC_FUNC_O(T) \
+struct vec_swallow_trailing_semi
+
+#define DEF_VEC_ALLOC_FUNC_I(T) \
+static inline VEC(T) *VEC_OP (T,alloc) \
+ (int alloc_) \
+{ \
+ /* We must request exact size allocation, hence the negation. */ \
+ return (VEC(T) *) vec_o_reserve (NULL, -alloc_, \
+ offsetof (VEC(T),vec), sizeof (T)); \
+} \
+ \
+static inline VEC(T) *VEC_OP (T,copy) (VEC(T) *vec_) \
+{ \
+ size_t len_ = vec_ ? vec_->num : 0; \
+ VEC (T) *new_vec_ = NULL; \
+ \
+ if (len_) \
+ { \
+ /* We must request exact size allocation, hence the negation. */ \
+ new_vec_ = (VEC (T) *) \
+ vec_o_reserve (NULL, -len_, offsetof (VEC(T),vec), sizeof (T)); \
+ \
+ new_vec_->num = len_; \
+ memcpy (new_vec_->vec, vec_->vec, sizeof (T) * len_); \
+ } \
+ return new_vec_; \
+} \
+ \
+static inline void VEC_OP (T,free) \
+ (VEC(T) **vec_) \
+{ \
+ if (*vec_) \
+ vec_free (*vec_); \
+ *vec_ = NULL; \
+} \
+ \
+static inline int VEC_OP (T,reserve) \
+ (VEC(T) **vec_, int alloc_ VEC_ASSERT_DECL) \
+{ \
+ int extend = !VEC_OP (T,space) \
+ (*vec_, alloc_ < 0 ? -alloc_ : alloc_ VEC_ASSERT_PASS); \
+ \
+ if (extend) \
+ *vec_ = (VEC(T) *) vec_o_reserve (*vec_, alloc_, \
+ offsetof (VEC(T),vec), sizeof (T)); \
+ \
+ return extend; \
+} \
+ \
+static inline void VEC_OP (T,safe_grow) \
+ (VEC(T) **vec_, int size_ VEC_ASSERT_DECL) \
+{ \
+ vec_assert (size_ >= 0 && VEC_OP(T,length) (*vec_) <= (unsigned)size_, \
+ "safe_grow"); \
+ VEC_OP (T,reserve) (vec_, (int)(*vec_ ? (*vec_)->num : 0) - size_ \
+ VEC_ASSERT_PASS); \
+ (*vec_)->num = size_; \
+} \
+ \
+static inline T *VEC_OP (T,safe_push) \
+ (VEC(T) **vec_, const T obj_ VEC_ASSERT_DECL) \
+{ \
+ VEC_OP (T,reserve) (vec_, 1 VEC_ASSERT_PASS); \
+ \
+ return VEC_OP (T,quick_push) (*vec_, obj_ VEC_ASSERT_PASS); \
+} \
+ \
+static inline T *VEC_OP (T,safe_insert) \
+ (VEC(T) **vec_, unsigned ix_, const T obj_ VEC_ASSERT_DECL) \
+{ \
+ VEC_OP (T,reserve) (vec_, 1 VEC_ASSERT_PASS); \
+ \
+ return VEC_OP (T,quick_insert) (*vec_, ix_, obj_ VEC_ASSERT_PASS); \
+}
+
+#define DEF_VEC_FUNC_P(T) \
+static inline unsigned VEC_OP (T,length) (const VEC(T) *vec_) \
+{ \
+ return vec_ ? vec_->num : 0; \
+} \
+ \
+static inline T VEC_OP (T,last) \
+ (const VEC(T) *vec_ VEC_ASSERT_DECL) \
+{ \
+ vec_assert (vec_ && vec_->num, "last"); \
+ \
+ return vec_->vec[vec_->num - 1]; \
+} \
+ \
+static inline T VEC_OP (T,index) \
+ (const VEC(T) *vec_, unsigned ix_ VEC_ASSERT_DECL) \
+{ \
+ vec_assert (vec_ && ix_ < vec_->num, "index"); \
+ \
+ return vec_->vec[ix_]; \
+} \
+ \
+static inline int VEC_OP (T,iterate) \
+ (const VEC(T) *vec_, unsigned ix_, T *ptr) \
+{ \
+ if (vec_ && ix_ < vec_->num) \
+ { \
+ *ptr = vec_->vec[ix_]; \
+ return 1; \
+ } \
+ else \
+ { \
+ *ptr = 0; \
+ return 0; \
+ } \
+} \
+ \
+static inline size_t VEC_OP (T,embedded_size) \
+ (int alloc_) \
+{ \
+ return offsetof (VEC(T),vec) + alloc_ * sizeof(T); \
+} \
+ \
+static inline void VEC_OP (T,embedded_init) \
+ (VEC(T) *vec_, int alloc_) \
+{ \
+ vec_->num = 0; \
+ vec_->alloc = alloc_; \
+} \
+ \
+static inline int VEC_OP (T,space) \
+ (VEC(T) *vec_, int alloc_ VEC_ASSERT_DECL) \
+{ \
+ vec_assert (alloc_ >= 0, "space"); \
+ return vec_ ? vec_->alloc - vec_->num >= (unsigned)alloc_ : !alloc_; \
+} \
+ \
+static inline T *VEC_OP (T,quick_push) \
+ (VEC(T) *vec_, T obj_ VEC_ASSERT_DECL) \
+{ \
+ T *slot_; \
+ \
+ vec_assert (vec_->num < vec_->alloc, "quick_push"); \
+ slot_ = &vec_->vec[vec_->num++]; \
+ *slot_ = obj_; \
+ \
+ return slot_; \
+} \
+ \
+static inline T VEC_OP (T,pop) (VEC(T) *vec_ VEC_ASSERT_DECL) \
+{ \
+ T obj_; \
+ \
+ vec_assert (vec_->num, "pop"); \
+ obj_ = vec_->vec[--vec_->num]; \
+ \
+ return obj_; \
+} \
+ \
+static inline void VEC_OP (T,truncate) \
+ (VEC(T) *vec_, unsigned size_ VEC_ASSERT_DECL) \
+{ \
+ vec_assert (vec_ ? vec_->num >= size_ : !size_, "truncate"); \
+ if (vec_) \
+ vec_->num = size_; \
+} \
+ \
+static inline T VEC_OP (T,replace) \
+ (VEC(T) *vec_, unsigned ix_, T obj_ VEC_ASSERT_DECL) \
+{ \
+ T old_obj_; \
+ \
+ vec_assert (ix_ < vec_->num, "replace"); \
+ old_obj_ = vec_->vec[ix_]; \
+ vec_->vec[ix_] = obj_; \
+ \
+ return old_obj_; \
+} \
+ \
+static inline T *VEC_OP (T,quick_insert) \
+ (VEC(T) *vec_, unsigned ix_, T obj_ VEC_ASSERT_DECL) \
+{ \
+ T *slot_; \
+ \
+ vec_assert (vec_->num < vec_->alloc && ix_ <= vec_->num, "quick_insert"); \
+ slot_ = &vec_->vec[ix_]; \
+ memmove (slot_ + 1, slot_, (vec_->num++ - ix_) * sizeof (T)); \
+ *slot_ = obj_; \
+ \
+ return slot_; \
+} \
+ \
+static inline T VEC_OP (T,ordered_remove) \
+ (VEC(T) *vec_, unsigned ix_ VEC_ASSERT_DECL) \
+{ \
+ T *slot_; \
+ T obj_; \
+ \
+ vec_assert (ix_ < vec_->num, "ordered_remove"); \
+ slot_ = &vec_->vec[ix_]; \
+ obj_ = *slot_; \
+ memmove (slot_, slot_ + 1, (--vec_->num - ix_) * sizeof (T)); \
+ \
+ return obj_; \
+} \
+ \
+static inline T VEC_OP (T,unordered_remove) \
+ (VEC(T) *vec_, unsigned ix_ VEC_ASSERT_DECL) \
+{ \
+ T *slot_; \
+ T obj_; \
+ \
+ vec_assert (ix_ < vec_->num, "unordered_remove"); \
+ slot_ = &vec_->vec[ix_]; \
+ obj_ = *slot_; \
+ *slot_ = vec_->vec[--vec_->num]; \
+ \
+ return obj_; \
+} \
+ \
+static inline void VEC_OP (T,block_remove) \
+ (VEC(T) *vec_, unsigned ix_, unsigned len_ VEC_ASSERT_DECL) \
+{ \
+ T *slot_; \
+ \
+ vec_assert (ix_ + len_ <= vec_->num, "block_remove"); \
+ slot_ = &vec_->vec[ix_]; \
+ vec_->num -= len_; \
+ memmove (slot_, slot_ + len_, (vec_->num - ix_) * sizeof (T)); \
+} \
+ \
+static inline T *VEC_OP (T,address) \
+ (VEC(T) *vec_) \
+{ \
+ return vec_ ? vec_->vec : 0; \
+} \
+ \
+static inline unsigned VEC_OP (T,lower_bound) \
+ (VEC(T) *vec_, const T obj_, \
+ int (*lessthan_)(const T, const T) VEC_ASSERT_DECL) \
+{ \
+ unsigned int len_ = VEC_OP (T, length) (vec_); \
+ unsigned int half_, middle_; \
+ unsigned int first_ = 0; \
+ while (len_ > 0) \
+ { \
+ T middle_elem_; \
+ half_ = len_ >> 1; \
+ middle_ = first_; \
+ middle_ += half_; \
+ middle_elem_ = VEC_OP (T,index) (vec_, middle_ VEC_ASSERT_PASS); \
+ if (lessthan_ (middle_elem_, obj_)) \
+ { \
+ first_ = middle_; \
+ ++first_; \
+ len_ = len_ - half_ - 1; \
+ } \
+ else \
+ len_ = half_; \
+ } \
+ return first_; \
+}
+
+#define DEF_VEC_ALLOC_FUNC_P(T) \
+static inline VEC(T) *VEC_OP (T,alloc) \
+ (int alloc_) \
+{ \
+ /* We must request exact size allocation, hence the negation. */ \
+ return (VEC(T) *) vec_p_reserve (NULL, -alloc_); \
+} \
+ \
+static inline void VEC_OP (T,free) \
+ (VEC(T) **vec_) \
+{ \
+ if (*vec_) \
+ vec_free (*vec_); \
+ *vec_ = NULL; \
+} \
+ \
+static inline VEC(T) *VEC_OP (T,copy) (VEC(T) *vec_) \
+{ \
+ size_t len_ = vec_ ? vec_->num : 0; \
+ VEC (T) *new_vec_ = NULL; \
+ \
+ if (len_) \
+ { \
+ /* We must request exact size allocation, hence the negation. */ \
+ new_vec_ = (VEC (T) *)(vec_p_reserve (NULL, -len_)); \
+ \
+ new_vec_->num = len_; \
+ memcpy (new_vec_->vec, vec_->vec, sizeof (T) * len_); \
+ } \
+ return new_vec_; \
+} \
+ \
+static inline int VEC_OP (T,reserve) \
+ (VEC(T) **vec_, int alloc_ VEC_ASSERT_DECL) \
+{ \
+ int extend = !VEC_OP (T,space) \
+ (*vec_, alloc_ < 0 ? -alloc_ : alloc_ VEC_ASSERT_PASS); \
+ \
+ if (extend) \
+ *vec_ = (VEC(T) *) vec_p_reserve (*vec_, alloc_); \
+ \
+ return extend; \
+} \
+ \
+static inline void VEC_OP (T,safe_grow) \
+ (VEC(T) **vec_, int size_ VEC_ASSERT_DECL) \
+{ \
+ vec_assert (size_ >= 0 && VEC_OP(T,length) (*vec_) <= (unsigned)size_, \
+ "safe_grow"); \
+ VEC_OP (T,reserve) \
+ (vec_, (int)(*vec_ ? (*vec_)->num : 0) - size_ VEC_ASSERT_PASS); \
+ (*vec_)->num = size_; \
+} \
+ \
+static inline T *VEC_OP (T,safe_push) \
+ (VEC(T) **vec_, T obj_ VEC_ASSERT_DECL) \
+{ \
+ VEC_OP (T,reserve) (vec_, 1 VEC_ASSERT_PASS); \
+ \
+ return VEC_OP (T,quick_push) (*vec_, obj_ VEC_ASSERT_PASS); \
+} \
+ \
+static inline T *VEC_OP (T,safe_insert) \
+ (VEC(T) **vec_, unsigned ix_, T obj_ VEC_ASSERT_DECL) \
+{ \
+ VEC_OP (T,reserve) (vec_, 1 VEC_ASSERT_PASS); \
+ \
+ return VEC_OP (T,quick_insert) (*vec_, ix_, obj_ VEC_ASSERT_PASS); \
+}
+
+#define DEF_VEC_FUNC_O(T) \
+static inline unsigned VEC_OP (T,length) (const VEC(T) *vec_) \
+{ \
+ return vec_ ? vec_->num : 0; \
+} \
+ \
+static inline T *VEC_OP (T,last) (VEC(T) *vec_ VEC_ASSERT_DECL) \
+{ \
+ vec_assert (vec_ && vec_->num, "last"); \
+ \
+ return &vec_->vec[vec_->num - 1]; \
+} \
+ \
+static inline T *VEC_OP (T,index) \
+ (VEC(T) *vec_, unsigned ix_ VEC_ASSERT_DECL) \
+{ \
+ vec_assert (vec_ && ix_ < vec_->num, "index"); \
+ \
+ return &vec_->vec[ix_]; \
+} \
+ \
+static inline int VEC_OP (T,iterate) \
+ (VEC(T) *vec_, unsigned ix_, T **ptr) \
+{ \
+ if (vec_ && ix_ < vec_->num) \
+ { \
+ *ptr = &vec_->vec[ix_]; \
+ return 1; \
+ } \
+ else \
+ { \
+ *ptr = 0; \
+ return 0; \
+ } \
+} \
+ \
+static inline size_t VEC_OP (T,embedded_size) \
+ (int alloc_) \
+{ \
+ return offsetof (VEC(T),vec) + alloc_ * sizeof(T); \
+} \
+ \
+static inline void VEC_OP (T,embedded_init) \
+ (VEC(T) *vec_, int alloc_) \
+{ \
+ vec_->num = 0; \
+ vec_->alloc = alloc_; \
+} \
+ \
+static inline int VEC_OP (T,space) \
+ (VEC(T) *vec_, int alloc_ VEC_ASSERT_DECL) \
+{ \
+ vec_assert (alloc_ >= 0, "space"); \
+ return vec_ ? vec_->alloc - vec_->num >= (unsigned)alloc_ : !alloc_; \
+} \
+ \
+static inline T *VEC_OP (T,quick_push) \
+ (VEC(T) *vec_, const T *obj_ VEC_ASSERT_DECL) \
+{ \
+ T *slot_; \
+ \
+ vec_assert (vec_->num < vec_->alloc, "quick_push"); \
+ slot_ = &vec_->vec[vec_->num++]; \
+ if (obj_) \
+ *slot_ = *obj_; \
+ \
+ return slot_; \
+} \
+ \
+static inline void VEC_OP (T,pop) (VEC(T) *vec_ VEC_ASSERT_DECL) \
+{ \
+ vec_assert (vec_->num, "pop"); \
+ --vec_->num; \
+} \
+ \
+static inline void VEC_OP (T,truncate) \
+ (VEC(T) *vec_, unsigned size_ VEC_ASSERT_DECL) \
+{ \
+ vec_assert (vec_ ? vec_->num >= size_ : !size_, "truncate"); \
+ if (vec_) \
+ vec_->num = size_; \
+} \
+ \
+static inline T *VEC_OP (T,replace) \
+ (VEC(T) *vec_, unsigned ix_, const T *obj_ VEC_ASSERT_DECL) \
+{ \
+ T *slot_; \
+ \
+ vec_assert (ix_ < vec_->num, "replace"); \
+ slot_ = &vec_->vec[ix_]; \
+ if (obj_) \
+ *slot_ = *obj_; \
+ \
+ return slot_; \
+} \
+ \
+static inline T *VEC_OP (T,quick_insert) \
+ (VEC(T) *vec_, unsigned ix_, const T *obj_ VEC_ASSERT_DECL) \
+{ \
+ T *slot_; \
+ \
+ vec_assert (vec_->num < vec_->alloc && ix_ <= vec_->num, "quick_insert"); \
+ slot_ = &vec_->vec[ix_]; \
+ memmove (slot_ + 1, slot_, (vec_->num++ - ix_) * sizeof (T)); \
+ if (obj_) \
+ *slot_ = *obj_; \
+ \
+ return slot_; \
+} \
+ \
+static inline void VEC_OP (T,ordered_remove) \
+ (VEC(T) *vec_, unsigned ix_ VEC_ASSERT_DECL) \
+{ \
+ T *slot_; \
+ \
+ vec_assert (ix_ < vec_->num, "ordered_remove"); \
+ slot_ = &vec_->vec[ix_]; \
+ memmove (slot_, slot_ + 1, (--vec_->num - ix_) * sizeof (T)); \
+} \
+ \
+static inline void VEC_OP (T,unordered_remove) \
+ (VEC(T) *vec_, unsigned ix_ VEC_ASSERT_DECL) \
+{ \
+ vec_assert (ix_ < vec_->num, "unordered_remove"); \
+ vec_->vec[ix_] = vec_->vec[--vec_->num]; \
+} \
+ \
+static inline void VEC_OP (T,block_remove) \
+ (VEC(T) *vec_, unsigned ix_, unsigned len_ VEC_ASSERT_DECL) \
+{ \
+ T *slot_; \
+ \
+ vec_assert (ix_ + len_ <= vec_->num, "block_remove"); \
+ slot_ = &vec_->vec[ix_]; \
+ vec_->num -= len_; \
+ memmove (slot_, slot_ + len_, (vec_->num - ix_) * sizeof (T)); \
+} \
+ \
+static inline T *VEC_OP (T,address) \
+ (VEC(T) *vec_) \
+{ \
+ return vec_ ? vec_->vec : 0; \
+} \
+ \
+static inline unsigned VEC_OP (T,lower_bound) \
+ (VEC(T) *vec_, const T *obj_, \
+ int (*lessthan_)(const T *, const T *) VEC_ASSERT_DECL) \
+{ \
+ unsigned int len_ = VEC_OP (T, length) (vec_); \
+ unsigned int half_, middle_; \
+ unsigned int first_ = 0; \
+ while (len_ > 0) \
+ { \
+ T *middle_elem_; \
+ half_ = len_ >> 1; \
+ middle_ = first_; \
+ middle_ += half_; \
+ middle_elem_ = VEC_OP (T,index) (vec_, middle_ VEC_ASSERT_PASS); \
+ if (lessthan_ (middle_elem_, obj_)) \
+ { \
+ first_ = middle_; \
+ ++first_; \
+ len_ = len_ - half_ - 1; \
+ } \
+ else \
+ len_ = half_; \
+ } \
+ return first_; \
+}
+
+#define DEF_VEC_ALLOC_FUNC_O(T) \
+static inline VEC(T) *VEC_OP (T,alloc) \
+ (int alloc_) \
+{ \
+ /* We must request exact size allocation, hence the negation. */ \
+ return (VEC(T) *) vec_o_reserve (NULL, -alloc_, \
+ offsetof (VEC(T),vec), sizeof (T)); \
+} \
+ \
+static inline VEC(T) *VEC_OP (T,copy) (VEC(T) *vec_) \
+{ \
+ size_t len_ = vec_ ? vec_->num : 0; \
+ VEC (T) *new_vec_ = NULL; \
+ \
+ if (len_) \
+ { \
+ /* We must request exact size allocation, hence the negation. */ \
+ new_vec_ = (VEC (T) *) \
+ vec_o_reserve (NULL, -len_, offsetof (VEC(T),vec), sizeof (T)); \
+ \
+ new_vec_->num = len_; \
+ memcpy (new_vec_->vec, vec_->vec, sizeof (T) * len_); \
+ } \
+ return new_vec_; \
+} \
+ \
+static inline void VEC_OP (T,free) \
+ (VEC(T) **vec_) \
+{ \
+ if (*vec_) \
+ vec_free (*vec_); \
+ *vec_ = NULL; \
+} \
+ \
+static inline int VEC_OP (T,reserve) \
+ (VEC(T) **vec_, int alloc_ VEC_ASSERT_DECL) \
+{ \
+ int extend = !VEC_OP (T,space) (*vec_, alloc_ < 0 ? -alloc_ : alloc_ \
+ VEC_ASSERT_PASS); \
+ \
+ if (extend) \
+ *vec_ = (VEC(T) *) \
+ vec_o_reserve (*vec_, alloc_, offsetof (VEC(T),vec), sizeof (T)); \
+ \
+ return extend; \
+} \
+ \
+static inline void VEC_OP (T,safe_grow) \
+ (VEC(T) **vec_, int size_ VEC_ASSERT_DECL) \
+{ \
+ vec_assert (size_ >= 0 && VEC_OP(T,length) (*vec_) <= (unsigned)size_, \
+ "safe_grow"); \
+ VEC_OP (T,reserve) \
+ (vec_, (int)(*vec_ ? (*vec_)->num : 0) - size_ VEC_ASSERT_PASS); \
+ (*vec_)->num = size_; \
+} \
+ \
+static inline T *VEC_OP (T,safe_push) \
+ (VEC(T) **vec_, const T *obj_ VEC_ASSERT_DECL) \
+{ \
+ VEC_OP (T,reserve) (vec_, 1 VEC_ASSERT_PASS); \
+ \
+ return VEC_OP (T,quick_push) (*vec_, obj_ VEC_ASSERT_PASS); \
+} \
+ \
+static inline T *VEC_OP (T,safe_insert) \
+ (VEC(T) **vec_, unsigned ix_, const T *obj_ VEC_ASSERT_DECL) \
+{ \
+ VEC_OP (T,reserve) (vec_, 1 VEC_ASSERT_PASS); \
+ \
+ return VEC_OP (T,quick_insert) (*vec_, ix_, obj_ VEC_ASSERT_PASS); \
+}
+
+#endif /* GDB_VEC_H */
Index: src/gdb/vec.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ src/gdb/vec.c 2006-08-10 23:31:19.000000000 -0400
@@ -0,0 +1,120 @@
+/* Vector API for GDB.
+ Copyright (C) 2004, 2005, 2006 Free Software Foundation, Inc.
+ Contributed by Nathan Sidwell <nathan@codesourcery.com>
+
+ This file is part of GDB.
+
+ This program 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 2 of the License, or
+ (at your option) any later version.
+
+ This program 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 this program; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ Boston, MA 02110-1301, USA. */
+
+#include "vec.h"
+#include "defs.h"
+
+struct vec_prefix
+{
+ unsigned num;
+ unsigned alloc;
+ void *vec[1];
+};
+
+/* Calculate the new ALLOC value, making sure that abs(RESERVE) slots
+ are free. If RESERVE < 0 grow exactly, otherwise grow
+ exponentially. */
+
+static inline unsigned
+calculate_allocation (const struct vec_prefix *pfx, int reserve)
+{
+ unsigned alloc = 0;
+ unsigned num = 0;
+
+ if (pfx)
+ {
+ alloc = pfx->alloc;
+ num = pfx->num;
+ }
+ else if (!reserve)
+ /* If there's no prefix, and we've not requested anything, then we
+ will create a NULL vector. */
+ return 0;
+
+ /* We must have run out of room. */
+ gdb_assert (alloc - num < (unsigned)(reserve < 0 ? -reserve : reserve));
+
+ if (reserve < 0)
+ /* Exact size. */
+ alloc = num + -reserve;
+ else
+ {
+ /* Exponential growth. */
+ if (!alloc)
+ alloc = 4;
+ else if (alloc < 16)
+ /* Double when small. */
+ alloc = alloc * 2;
+ else
+ /* Grow slower when large. */
+ alloc = (alloc * 3 / 2);
+
+ /* If this is still too small, set it to the right size. */
+ if (alloc < num + reserve)
+ alloc = num + reserve;
+ }
+ return alloc;
+}
+
+/* Ensure there are at least abs(RESERVE) free slots in VEC. If
+ RESERVE < 0 grow exactly, else grow exponentially. As a special
+ case, if VEC is NULL, and RESERVE is 0, no vector will be created. */
+
+void *
+vec_p_reserve (void *vec, int reserve)
+{
+ return vec_o_reserve (vec, reserve,
+ offsetof (struct vec_prefix, vec), sizeof (void *));
+}
+
+/* As vec_p_reserve, but for object vectors. The vector's trailing
+ array is at VEC_OFFSET offset and consists of ELT_SIZE sized
+ elements. */
+
+void *
+vec_o_reserve (void *vec, int reserve, size_t vec_offset, size_t elt_size)
+{
+ struct vec_prefix *pfx = vec;
+ unsigned alloc = calculate_allocation (pfx, reserve);
+
+ if (!alloc)
+ return NULL;
+
+ vec = xrealloc (vec, vec_offset + alloc * elt_size);
+ ((struct vec_prefix *)vec)->alloc = alloc;
+ if (!pfx)
+ ((struct vec_prefix *)vec)->num = 0;
+
+ return vec;
+}
+
+#if 0
+/* Example uses. */
+DEF_VEC_I (int);
+typedef struct X
+{
+ int i;
+} obj_t;
+typedef obj_t *ptr_t;
+
+DEF_VEC_P (ptr_t);
+DEF_VEC_O (obj_t);
+#endif
Index: src/gdb/Makefile.in
===================================================================
--- src.orig/gdb/Makefile.in 2006-08-10 23:21:32.000000000 -0400
+++ src/gdb/Makefile.in 2006-08-11 10:31:57.000000000 -0400
@@ -557,7 +557,7 @@ SFILES = ada-exp.y ada-lang.c ada-typepr
typeprint.c \
ui-out.c utils.c ui-file.h ui-file.c \
user-regs.c \
- valarith.c valops.c valprint.c value.c varobj.c \
+ valarith.c valops.c valprint.c value.c varobj.c vec.c \
wrapper.c

LINTFILES = $(SFILES) $(YYFILES) $(CONFIG_SRCS) init.c
@@ -812,6 +812,7 @@ value_h = value.h $(doublest_h) $(frame_
$(expression_h)
varobj_h = varobj.h $(symtab_h) $(gdbtypes_h)
vax_tdep_h = vax-tdep.h
+vec_h = vec.h $(gdb_assert_h) $(gdb_string_h)
version_h = version.h
wince_stub_h = wince-stub.h
wrapper_h = wrapper.h $(gdb_h)
@@ -937,7 +938,7 @@ COMMON_OBS = $(DEPFILES) $(CONFIG_OBS) $
dwarf2expr.o dwarf2loc.o dwarf2-frame.o \
ada-lang.o c-lang.o f-lang.o objc-lang.o \
ui-out.o cli-out.o \
- varobj.o wrapper.o \
+ varobj.o vec.o wrapper.o \
jv-lang.o jv-valprint.o jv-typeprint.o \
m2-lang.o p-lang.o p-typeprint.o p-valprint.o \
scm-exp.o scm-lang.o scm-valprint.o \
@@ -2822,6 +2823,7 @@ vax-tdep.o: vax-tdep.c $(defs_h) $(arch_
$(float_format_h) $(frame_h) $(frame_base_h) $(frame_unwind_h) \
$(gdbcore_h) $(gdbtypes_h) $(osabi_h) $(regcache_h) $(regset_h) \
$(trad_frame_h) $(value_h) $(gdb_string_h) $(vax_tdep_h)
+vec.o: vec.c $(defs_h) $(vec_h)
win32-nat.o: win32-nat.c $(defs_h) $(frame_h) $(inferior_h) $(target_h) \
$(exceptions_h) $(gdbcore_h) $(command_h) $(completer_h) \
$(regcache_h) $(top_h) $(buildsym_h) $(symfile_h) $(objfiles_h) \
Index: src/gdb/doc/gdbint.texinfo
===================================================================
--- src.orig/gdb/doc/gdbint.texinfo 2006-08-10 23:21:32.000000000 -0400
+++ src/gdb/doc/gdbint.texinfo 2006-08-10 23:31:20.000000000 -0400
@@ -4865,6 +4865,181 @@ Regex conditionals.
@item sparc
@end table

+@section Array Containers
+@cindex Array Containers
+@cindex VEC
+
+Often it is necessary to manipulate a dynamic array of a set of
+objects. C forces some bookkeeping on this, which can get cumbersome
+and repetative. The @file{vec.h} file contains macros for defining
+and using a typesafe vector type. The functions defined will be
+inlined when compiling, and so the abstraction cost should be zero.
+Domain checks are added to detect programming errors.
+
+An example use would be an array of symbols or section information.
+The array can be grown as symbols are read in (or preallocated), and
+the accessor macros provided keep care of all the necessary
+bookkeeping. Because the arrays are type safe, there is no danger of
+accidentally mixing up the contents. Think of these as C++ templates,
+but implemented in C.
+
+Because of the different behavior of structure objects, scalar objects
+and of pointers, there are three flavors of vector, one for each of
+these variants. Both the structure object and pointer variants pass
+pointers to objects around --- in the former case the pointers are
+stored into the vector and in the latter case the pointers are
+dereferenced and the objects copied into the vector. The scalar
+object variant is suitable for @code{int}-like objects, and the vector
+elements are returned by value.
+
+There are both @code{index} and @code{iterate} accessors. 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.
+
+The 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 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 @code{embedded_size} & @code{embedded_init} calls to create
+such objects, and they will probably not be resizeable (so don't use
+the @dfn{safe} allocation variants). The trailing array idiom is used
+(rather than a pointer to an array of data), because, if we allow
+@code{NULL} to also represent an empty vector, empty vectors occupy
+minimal space in the structure containing them.
+
+Each operation that increases the number of active elements is
+available in @dfn{quick} and @dfn{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
+@dfn{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 a negative number for reservation. 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 @code{ordered_remove}, and one which does not
+@code{unordered_remove}. The latter function copies the end element
+into the removed slot, rather than invoke a memmove operation. The
+@code{lower_bound} function will determine where to place an item in
+the array using insert that will maintain sorted order.
+
+If you need to directly manipulate a vector, then the @code{address}
+accessor will return the address of the start of the vector. Also the
+@code{space} predicate will tell you whether there is spare capacity in the
+vector. You will not normally need to use these two functions.
+
+Vector types are defined using a
+@code{DEF_VEC_@{O,P,I@}(@var{typename})} macro. Variables of vector
+type are declared using a @code{VEC(@var{typename})} macro. The
+characters @code{O}, @code{P} and @code{I} indicate whether
+@var{typename} is an object (@code{O}), pointer (@code{P}) or integral
+(@code{I}) type. Be careful to pick the correct one, as you'll get an
+awkward and inefficient API if you use the wrong one. There is a
+check, which results in a compile-time warning, for the @code{P} and
+@code{I} versions, but there is no check for the @code{O} versions, as
+that is not possible in plain C.
+
+An example of their use would be,
+
+@smallexample
+DEF_VEC_P(tree); // non-managed tree vector.
+
+struct my_struct @{
+ VEC(tree) *v; // A (pointer to) a vector of tree pointers.
+@};
+
+struct my_struct *s;
+
+if (VEC_length(tree, s->v)) @{ we have some contents @}
+VEC_safe_push(tree, s->v, decl); // append some decl onto the end
+for (ix = 0; VEC_iterate(tree, s->v, ix, elt); ix++)
+ @{ do something with elt @}
+
+@end smallexample
+
+The @file{vec.h} file provides details on how to invoke the various
+accessors provided. They are enumerated here:
+
+@table @code
+@item VEC_length
+Return the number of items in the array,
+
+@item VEC_empty
+Return true if the array has no elements.
+
+@item VEC_last
+@itemx VEC_index
+Return the last or arbitrary item in the array.
+
+@item VEC_iterate
+Access an array element and indicate whether the array has been
+traversed.
+
+@item VEC_alloc
+@itemx VEC_free
+Create and destroy an array.
+
+@item VEC_embedded_size
+@itemx VEC_embedded_init
+Helpers for embedding an array as the final element of another struct.
+
+@item VEC_copy
+Duplicate an array.
+
+@item VEC_space
+Return the amount of free space in an array.
+
+@item VEC_reserve
+Ensure a certain amount of free space.
+
+@item VEC_quick_push
+@itemx VEC_safe_push
+Append to an array, either assuming the space is available, or making
+sure that it is.
+
+@item VEC_pop
+Remove the last item from an array.
+
+@item VEC_truncate
+Remove several items from the end of an array.
+
+@item VEC_safe_grow
+Add several items to the end of an array.
+
+@item VEC_replace
+Overwrite an item in the array.
+
+@item VEC_quick_insert
+@itemx VEC_safe_insert
+Insert an item into the middle of the array. Either the space must
+already exist, or the space is created.
+
+@item VEC_ordered_remove
+@itemx VEC_unordered_remove
+Remove an item from the array, preserving order or not.
+
+@item VEC_block_remove
+Remove a set of items from the array.
+
+@item VEC_address
+Provide the address of the first element.
+
+@item VEC_lower_bound
+Binary search the array.
+
+@end table
+
@section include

@node Coding