]> git.ipfire.org Git - thirdparty/asterisk.git/commitdiff
include/asterisk/vector.h: Backport vector.h to Asterisk 11 13/313/1
authorMatt Jordan <mjordan@digium.com>
Thu, 30 Apr 2015 16:04:04 +0000 (11:04 -0500)
committerMatt Jordan <mjordan@digium.com>
Thu, 30 Apr 2015 16:09:48 +0000 (11:09 -0500)
Vectors are very useful constructs. As a container, they prevent having
to calloc/realloc arrays manually. They also have advantages over linked
lists, which require elements in the list to be a struct. This patch
backports vectors to Asterisk 11 for use in future patches.

Change-Id: Idc9d74d246a0158b0b36ccb250e7acc71bab078d

include/asterisk/vector.h [new file with mode: 0644]

diff --git a/include/asterisk/vector.h b/include/asterisk/vector.h
new file mode 100644 (file)
index 0000000..0053d8a
--- /dev/null
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+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2013, Digium, Inc.
+ *
+ * David M. Lee, II <dlee@digium.com>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+#ifndef _ASTERISK_VECTOR_H
+#define _ASTERISK_VECTOR_H
+
+/*! \file
+ *
+ * \brief Vector container support.
+ *
+ * A vector is a variable length array, with properties that can be useful when
+ * order doesn't matter.
+ *  - Appends are asymptotically constant time.
+ *  - Unordered removes are constant time.
+ *  - Search is linear time
+ *
+ * \author David M. Lee, II <dlee@digium.com>
+ * \since 12
+ */
+
+/*!
+ * \brief Define a vector structure
+ *
+ * \param name Optional vector struct name.
+ * \param type Vector element type.
+ */
+#define AST_VECTOR(name, type)                 \
+       struct name {                           \
+               type *elems;                    \
+               size_t max;                     \
+               size_t current;                 \
+       }
+
+/*!
+ * \brief Initialize a vector
+ *
+ * If \a size is 0, then no space will be allocated until the vector is
+ * appended to.
+ *
+ * \param vec Vector to initialize.
+ * \param size Initial size of the vector.
+ *
+ * \return 0 on success.
+ * \return Non-zero on failure.
+ */
+#define AST_VECTOR_INIT(vec, size) ({                                  \
+       size_t __size = (size);                                         \
+       size_t alloc_size = __size * sizeof(*((vec)->elems));           \
+       (vec)->elems = alloc_size ? ast_calloc(1, alloc_size) : NULL;   \
+       (vec)->current = 0;                                             \
+       if ((vec)->elems) {                                             \
+               (vec)->max = __size;                                    \
+       } else {                                                        \
+               (vec)->max = 0;                                         \
+       }                                                               \
+       (alloc_size == 0 || (vec)->elems != NULL) ? 0 : -1;             \
+})
+
+/*!
+ * \brief Deallocates this vector.
+ *
+ * If any code to free the elements of this vector need to be run, that should
+ * be done prior to this call.
+ *
+ * \param vec Vector to deallocate.
+ */
+#define AST_VECTOR_FREE(vec) do {              \
+       ast_free((vec)->elems);                 \
+       (vec)->elems = NULL;                    \
+       (vec)->max = 0;                         \
+       (vec)->current = 0;                     \
+} while (0)
+
+/*!
+ * \brief Append an element to a vector, growing the vector if needed.
+ *
+ * \param vec Vector to append to.
+ * \param elem Element to append.
+ *
+ * \return 0 on success.
+ * \return Non-zero on failure.
+ */
+#define AST_VECTOR_APPEND(vec, elem) ({                                                \
+       int res = 0;                                                            \
+       do {                                                                    \
+               if ((vec)->current + 1 > (vec)->max) {                          \
+                       size_t new_max = (vec)->max ? 2 * (vec)->max : 1;       \
+                       typeof((vec)->elems) new_elems = ast_realloc(           \
+                               (vec)->elems, new_max * sizeof(*new_elems));    \
+                       if (new_elems) {                                        \
+                               (vec)->elems = new_elems;                       \
+                               (vec)->max = new_max;                           \
+                       } else {                                                \
+                               res = -1;                                       \
+                               break;                                          \
+                       }                                                       \
+               }                                                               \
+               (vec)->elems[(vec)->current++] = (elem);                        \
+       } while (0);                                                            \
+       res;                                                                    \
+})
+
+/*!
+ * \brief Insert an element at a specific position in a vector, growing the vector if needed.
+ *
+ * \param vec Vector to insert into.
+ * \param idx Position to insert at.
+ * \param elem Element to insert.
+ *
+ * \return 0 on success.
+ * \return Non-zero on failure.
+ *
+ * \warning This macro will overwrite anything already present at the position provided.
+ *
+ * \warning Use of this macro with the expectation that the element will remain at the provided
+ * index means you can not use the UNORDERED assortment of macros. These macros alter the ordering
+ * of the vector itself.
+ */
+#define AST_VECTOR_INSERT(vec, idx, elem) ({                                   \
+       int res = 0;                                                                                            \
+       do {                                                                                                            \
+               if (((idx) + 1) > (vec)->max) {                                                 \
+                       size_t new_max = ((idx) + 1) * 2;                                       \
+                       typeof((vec)->elems) new_elems = ast_calloc(1,          \
+                               new_max * sizeof(*new_elems));                                  \
+                       if (new_elems) {                                                                        \
+                               memcpy(new_elems, (vec)->elems,                                 \
+                                       (vec)->current * sizeof(*new_elems));           \
+                               ast_free((vec)->elems);                                                 \
+                               (vec)->elems = new_elems;                                               \
+                               (vec)->max = new_max;                                                   \
+                       } else {                                                                                        \
+                               res = -1;                                                                               \
+                               break;                                                                                  \
+                       }                                                                                                       \
+               }                                                                                                               \
+               (vec)->elems[(idx)] = (elem);                                                   \
+               if (((idx) + 1) > (vec)->current) {                                             \
+                       (vec)->current = (idx) + 1;                                                     \
+               }                                                                                                               \
+       } while(0);                                                                                                     \
+       res;                                                                                                            \
+})
+
+/*!
+ * \brief Remove an element from a vector by index.
+ *
+ * Note that elements in the vector may be reordered, so that the remove can
+ * happen in constant time.
+ *
+ * \param vec Vector to remove from.
+ * \param idx Index of the element to remove.
+ * \return The element that was removed.
+ */
+#define AST_VECTOR_REMOVE_UNORDERED(vec, idx) ({               \
+       typeof((vec)->elems[0]) res;                            \
+       size_t __idx = (idx);                                   \
+       ast_assert(__idx < (vec)->current);                     \
+       res = (vec)->elems[__idx];                              \
+       (vec)->elems[__idx] = (vec)->elems[--(vec)->current];   \
+       res;                                                    \
+})
+
+/*!
+ * \brief Remove an element from a vector by index while maintaining order.
+ *
+ * \param vec Vector to remove from.
+ * \param idx Index of the element to remove.
+ * \return The element that was removed.
+ */
+#define AST_VECTOR_REMOVE_ORDERED(vec, idx) ({                         \
+       typeof((vec)->elems[0]) res;                                    \
+       size_t __idx = (idx);                                           \
+       size_t __move;                                                  \
+       ast_assert(__idx < (vec)->current);                             \
+       res = (vec)->elems[__idx];                                      \
+       __move = ((vec)->current - (__idx) - 1) * sizeof(typeof((vec)->elems[0])); \
+       memmove(&(vec)->elems[__idx], &(vec)->elems[__idx + 1], __move); \
+       (vec)->current--;                                               \
+       res;                                                            \
+})
+
+
+/*!
+ * \brief Remove an element from a vector that matches the given comparison
+ *
+ * \param vec Vector to remove from.
+ * \param value Value to pass into comparator.
+ * \param cmp Comparator function/macros (called as \c cmp(elem, value))
+ * \param cleanup How to cleanup a removed element macro/function.
+ *
+ * \return 0 if element was removed.
+ * \return Non-zero if element was not in the vector.
+ */
+#define AST_VECTOR_REMOVE_CMP_UNORDERED(vec, value, cmp, cleanup) ({   \
+       int res = -1;                                                   \
+       size_t idx;                                                     \
+       typeof(value) __value = (value);                                \
+       for (idx = 0; idx < (vec)->current; ++idx) {                    \
+               if (cmp((vec)->elems[idx], __value)) {                  \
+                       cleanup((vec)->elems[idx]);                     \
+                       AST_VECTOR_REMOVE_UNORDERED((vec), idx);        \
+                       res = 0;                                        \
+                       break;                                          \
+               }                                                       \
+       }                                                               \
+       res;                                                            \
+})
+
+/*!
+ * \brief Remove an element from a vector that matches the given comparison while maintaining order
+ *
+ * \param vec Vector to remove from.
+ * \param value Value to pass into comparator.
+ * \param cmp Comparator function/macros (called as \c cmp(elem, value))
+ * \param cleanup How to cleanup a removed element macro/function.
+ *
+ * \return 0 if element was removed.
+ * \return Non-zero if element was not in the vector.
+ */
+#define AST_VECTOR_REMOVE_CMP_ORDERED(vec, value, cmp, cleanup) ({     \
+       int res = -1;                                                   \
+       size_t idx;                                                     \
+       typeof(value) __value = (value);                                \
+       for (idx = 0; idx < (vec)->current; ++idx) {                    \
+               if (cmp((vec)->elems[idx], __value)) {                  \
+                       cleanup((vec)->elems[idx]);                     \
+                       AST_VECTOR_REMOVE_ORDERED((vec), idx);  \
+                       res = 0;                                        \
+                       break;                                          \
+               }                                                       \
+       }                                                               \
+       res;                                                            \
+})
+
+/*!
+ * \brief Default comparator for AST_VECTOR_REMOVE_ELEM_UNORDERED()
+ *
+ * \param elem Element to compare against
+ * \param value Value to compare with the vector element.
+ *
+ * \return 0 if element does not match.
+ * \return Non-zero if element matches.
+ */
+#define AST_VECTOR_ELEM_DEFAULT_CMP(elem, value) ((elem) == (value))
+
+/*!
+ * \brief Vector element cleanup that does nothing.
+ *
+ * \param elem Element to cleanup
+ *
+ * \return Nothing
+ */
+#define AST_VECTOR_ELEM_CLEANUP_NOOP(elem)
+
+/*!
+ * \brief Remove an element from a vector.
+ *
+ * \param vec Vector to remove from.
+ * \param elem Element to remove
+ * \param cleanup How to cleanup a removed element macro/function.
+ *
+ * \return 0 if element was removed.
+ * \return Non-zero if element was not in the vector.
+ */
+#define AST_VECTOR_REMOVE_ELEM_UNORDERED(vec, elem, cleanup) ({        \
+       AST_VECTOR_REMOVE_CMP_UNORDERED((vec), (elem),          \
+               AST_VECTOR_ELEM_DEFAULT_CMP, cleanup);          \
+})
+
+/*!
+ * \brief Remove an element from a vector while maintaining order.
+ *
+ * \param vec Vector to remove from.
+ * \param elem Element to remove
+ * \param cleanup How to cleanup a removed element macro/function.
+ *
+ * \return 0 if element was removed.
+ * \return Non-zero if element was not in the vector.
+ */
+#define AST_VECTOR_REMOVE_ELEM_ORDERED(vec, elem, cleanup) ({  \
+       AST_VECTOR_REMOVE_CMP_ORDERED((vec), (elem),            \
+               AST_VECTOR_ELEM_DEFAULT_CMP, cleanup);          \
+})
+
+/*!
+ * \brief Get the number of elements in a vector.
+ *
+ * \param vec Vector to query.
+ * \return Number of elements in the vector.
+ */
+#define AST_VECTOR_SIZE(vec) (vec)->current
+
+/*!
+ * \brief Get an address of element in a vector.
+ *
+ * \param vec Vector to query.
+ * \param idx Index of the element to get address of.
+ */
+#define AST_VECTOR_GET_ADDR(vec, idx) ({       \
+       size_t __idx = (idx);                   \
+       ast_assert(__idx < (vec)->current);     \
+       &(vec)->elems[__idx];                   \
+})
+
+/*!
+ * \brief Get an element from a vector.
+ *
+ * \param vec Vector to query.
+ * \param idx Index of the element to get.
+ */
+#define AST_VECTOR_GET(vec, idx) ({            \
+       size_t __idx = (idx);                   \
+       ast_assert(__idx < (vec)->current);     \
+       (vec)->elems[__idx];                    \
+})
+
+#endif /* _ASTERISK_VECTOR_H */