lib/port-array.h

   1 /*
   2  * Copyright (c) 2008, 2009, 2010 Nicira Networks.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #ifndef PORT_ARRAY_H
  18 #define PORT_ARRAY_H 1
  19
  20 #include <assert.h>
  21 #include "openflow/openflow.h"
  22 #include "util.h"
  23
  24 static inline uint16_t
  25 port_array_extract_bits__(uint16_t data, int start, int count)
  26 {
  27     return (data >> start) & ((1u << count) - 1);
  28 }
  29
  30 /* Level 1: most-significant bits. */
  31 #define PORT_ARRAY_L1_BITS 5
  32 #define PORT_ARRAY_L1_SHIFT (PORT_ARRAY_L3_BITS + PORT_ARRAY_L2_BITS)
  33 #define PORT_ARRAY_L1_SIZE (1u << PORT_ARRAY_L1_BITS)
  34 #define PORT_ARRAY_L1(IDX) \
  35     port_array_extract_bits__(IDX, PORT_ARRAY_L1_SHIFT, PORT_ARRAY_L1_BITS)
  36
  37 /* Level 2: middle bits. */
  38 #define PORT_ARRAY_L2_BITS 5
  39 #define PORT_ARRAY_L2_SHIFT PORT_ARRAY_L3_BITS
  40 #define PORT_ARRAY_L2_SIZE (1u << PORT_ARRAY_L2_BITS)
  41 #define PORT_ARRAY_L2(IDX) \
  42     port_array_extract_bits__(IDX, PORT_ARRAY_L2_SHIFT, PORT_ARRAY_L2_BITS)
  43
  44 /* Level 3: least-significant bits. */
  45 #define PORT_ARRAY_L3_BITS 6
  46 #define PORT_ARRAY_L3_SHIFT 0
  47 #define PORT_ARRAY_L3_SIZE (1u << PORT_ARRAY_L3_BITS)
  48 #define PORT_ARRAY_L3(IDX) \
  49     port_array_extract_bits__(IDX, PORT_ARRAY_L3_SHIFT, PORT_ARRAY_L3_BITS)
  50
  51 #define PORT_ARRAY_SIZE (1u << (PORT_ARRAY_L1_BITS      \
  52                                 + PORT_ARRAY_L2_BITS    \
  53                                 + PORT_ARRAY_L3_BITS))
  54
  55 BUILD_ASSERT_DECL(PORT_ARRAY_SIZE > 0xffff);
  56
  57 /* A "sparse array" of up to 65536 elements (numbered 0...65535), implemented
  58  * as a 3-level trie.  Most efficient when the elements are clustered
  59  * together. */
  60 struct port_array {
  61     struct port_array_l2 *l1[1u << PORT_ARRAY_L1_BITS];
  62 };
  63
  64 struct port_array_l2 {
  65     struct port_array_l3 *l2[1u << PORT_ARRAY_L2_BITS];
  66 };
  67
  68 struct port_array_l3 {
  69     void *l3[1u << PORT_ARRAY_L3_BITS];
  70 };
  71
  72 /* Returns the value of the element numbered 'idx' in 'pa', or a null pointer
  73  * if no element numbered 'idx' has been set. */
  74 static inline void *
  75 port_array_get(const struct port_array *pa, uint16_t idx)
  76 {
  77     unsigned int l1_idx = PORT_ARRAY_L1(idx);
  78     unsigned int l2_idx = PORT_ARRAY_L2(idx);
  79     unsigned int l3_idx = PORT_ARRAY_L3(idx);
  80     return pa->l1[l1_idx]->l2[l2_idx]->l3[l3_idx];
  81 }
  82
  83 void port_array_init(struct port_array *);
  84 void port_array_destroy(struct port_array *);
  85 void port_array_clear(struct port_array *);
  86 void port_array_set(struct port_array *, uint16_t idx, void *);
  87 void port_array_delete(struct port_array *, uint16_t idx);
  88 void *port_array_first(const struct port_array *, unsigned int *);
  89 void *port_array_next(const struct port_array *, unsigned int *);
  90 unsigned int port_array_count(const struct port_array *);
  91
  92 #define PORT_ARRAY_FOR_EACH(DATA, ARRAY, PORT_NO)                       \
  93     for ((DATA) = port_array_first(ARRAY, &(PORT_NO)); (DATA) != NULL;  \
  94          (DATA) = port_array_next(ARRAY, &(PORT_NO)))
  95
  96 #endif /* port-array.h */