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+/*
+ * Copyright (c) 2015 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/*
+ Copyright (c) 2005 Eliot Dresselhaus
+
+ Permission is hereby granted, free of charge, to any person obtaining
+ a copy of this software and associated documentation files (the
+ "Software"), to deal in the Software without restriction, including
+ without limitation the rights to use, copy, modify, merge, publish,
+ distribute, sublicense, and/or sell copies of the Software, and to
+ permit persons to whom the Software is furnished to do so, subject to
+ the following conditions:
+
+ The above copyright notice and this permission notice shall be
+ included in all copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+#ifndef included_fifo_h
+#define included_fifo_h
+
+#include <vppinfra/cache.h>
+#include <vppinfra/error.h> /* for ASSERT */
+#include <vppinfra/vec.h>
+
+typedef struct
+{
+ /* First index of valid data in fifo. */
+ u32 head_index;
+
+ /* One beyond last index in fifo. */
+ u32 tail_index;
+} clib_fifo_header_t;
+
+always_inline clib_fifo_header_t *
+clib_fifo_header (void *f)
+{
+ return vec_header (f, sizeof (clib_fifo_header_t));
+}
+
+/* Aliases. */
+#define clib_fifo_len(v) vec_len(v)
+#define _clib_fifo_len(v) _vec_len(v)
+#define clib_fifo_end(v) vec_end(v)
+
+always_inline uword
+clib_fifo_elts (void *v)
+{
+ word l, r;
+ clib_fifo_header_t *f = clib_fifo_header (v);
+
+ if (!v)
+ return 0;
+
+ l = _clib_fifo_len (v);
+ r = (word) f->tail_index - (word) f->head_index;
+ r = r < 0 ? r + l : r;
+ ASSERT (r >= 0 && r <= l);
+ return r;
+}
+
+always_inline uword
+clib_fifo_free_elts (void *v)
+{
+ return clib_fifo_len (v) - clib_fifo_elts (v);
+}
+
+always_inline void
+clib_fifo_reset (void *v)
+{
+ clib_fifo_header_t *f = clib_fifo_header (v);
+ if (v)
+ {
+ f->head_index = f->tail_index = 0;
+ _vec_len (v) = 0;
+ }
+}
+
+/* External resize function. */
+void *_clib_fifo_resize (void *v, uword n_elts, uword elt_bytes);
+
+#define clib_fifo_resize(f,n_elts) \
+ f = _clib_fifo_resize ((f), (n_elts), sizeof ((f)[0]))
+
+always_inline void *
+_clib_fifo_validate (void *v, uword n_elts, uword elt_bytes)
+{
+ if (clib_fifo_free_elts (v) < n_elts)
+ v = _clib_fifo_resize (v, n_elts, elt_bytes);
+ return v;
+}
+
+#define clib_fifo_validate(f,n_elts) \
+ f = _clib_fifo_validate ((f), (n_elts), sizeof (f[0]))
+
+/* Advance tail pointer by N_ELTS which can be either positive or negative. */
+always_inline void *
+_clib_fifo_advance_tail (void *v, word n_elts, uword elt_bytes,
+ uword * tail_return)
+{
+ word i, l, n_free;
+ clib_fifo_header_t *f;
+
+ n_free = clib_fifo_free_elts (v);
+ if (n_free < n_elts)
+ {
+ v = _clib_fifo_resize (v, n_elts, elt_bytes);
+ n_free = clib_fifo_free_elts (v);
+ }
+
+ ASSERT (n_free >= n_elts);
+ n_free -= n_elts;
+
+ f = clib_fifo_header (v);
+ l = _clib_fifo_len (v);
+ i = f->tail_index;
+
+ if (n_free == 0)
+ {
+ /* Mark fifo full. */
+ f->tail_index = f->head_index + l;
+ }
+ else
+ {
+ word n = f->tail_index + n_elts;
+ if (n >= l)
+ n -= l;
+ else if (n < 0)
+ n += l;
+ ASSERT (n >= 0 && n < l);
+ f->tail_index = n;
+ }
+
+ ASSERT (clib_fifo_free_elts (v) == n_free);
+
+ if (tail_return)
+ *tail_return = n_elts > 0 ? i : f->tail_index;
+
+ return v;
+}
+
+#define clib_fifo_advance_tail(f,n_elts) \
+({ \
+ uword _i; \
+ (f) = _clib_fifo_advance_tail ((f), (n_elts), sizeof ((f)[0]), &_i); \
+ (f) + _i; \
+})
+
+always_inline uword
+clib_fifo_advance_head (void *v, uword n_elts)
+{
+ clib_fifo_header_t *f;
+ uword l, i, n;
+
+ ASSERT (clib_fifo_elts (v) >= n_elts);
+ f = clib_fifo_header (v);
+ l = _clib_fifo_len (v);
+
+ /* If fifo was full, restore tail pointer. */
+ if (f->tail_index == f->head_index + l)
+ f->tail_index = f->head_index;
+
+ n = i = f->head_index;
+ n += n_elts;
+ n = n >= l ? n - l : n;
+ ASSERT (n < l);
+ f->head_index = n;
+
+ return i;
+}
+
+/* Add given element to fifo. */
+#define clib_fifo_add1(f,e) \
+do { \
+ uword _i; \
+ (f) = _clib_fifo_advance_tail ((f), 1, sizeof ((f)[0]), &_i); \
+ (f)[_i] = (e); \
+} while (0)
+
+/* Add element to fifo; return pointer to new element. */
+#define clib_fifo_add2(f,p) \
+do { \
+ uword _i; \
+ (f) = _clib_fifo_advance_tail ((f), 1, sizeof ((f)[0]), &_i); \
+ (p) = (f) + _i; \
+} while (0)
+
+/* Add several elements to fifo. */
+#define clib_fifo_add(f,e,n) \
+do { \
+ uword _i, _l; word _n0, _n1; \
+ \
+ _n0 = (n); \
+ (f) = _clib_fifo_advance_tail ((f), _n0, sizeof ((f)[0]), &_i); \
+ _l = clib_fifo_len (f); \
+ _n1 = _i + _n0 - _l; \
+ _n1 = _n1 < 0 ? 0 : _n1; \
+ _n0 -= _n1; \
+ clib_memcpy ((f) + _i, (e), _n0 * sizeof ((f)[0])); \
+ if (_n1) \
+ clib_memcpy ((f) + 0, (e) + _n0, _n1 * sizeof ((f)[0])); \
+} while (0)
+
+/* Subtract element from fifo. */
+#define clib_fifo_sub1(f,e) \
+do { \
+ uword _i; \
+ ASSERT (clib_fifo_elts (f) >= 1); \
+ _i = clib_fifo_advance_head ((f), 1); \
+ (e) = (f)[_i]; \
+} while (0)
+
+#define clib_fifo_sub2(f,p) \
+do { \
+ uword _i; \
+ ASSERT (clib_fifo_elts (f) >= 1); \
+ _i = clib_fifo_advance_head ((f), 1); \
+ (p) = (f) + _i; \
+} while (0)
+
+always_inline uword
+clib_fifo_head_index (void *v)
+{
+ clib_fifo_header_t *f = clib_fifo_header (v);
+ return v ? f->head_index : 0;
+}
+
+always_inline uword
+clib_fifo_tail_index (void *v)
+{
+ clib_fifo_header_t *f = clib_fifo_header (v);
+ return v ? f->tail_index : 0;
+}
+
+#define clib_fifo_head(v) ((v) + clib_fifo_head_index (v))
+#define clib_fifo_tail(v) ((v) + clib_fifo_tail_index (v))
+
+#define clib_fifo_free(f) vec_free_h((f),sizeof(clib_fifo_header_t))
+
+always_inline uword
+clib_fifo_elt_index (void *v, uword i)
+{
+ clib_fifo_header_t *f = clib_fifo_header (v);
+ uword result = 0;
+
+ ASSERT (i < clib_fifo_elts (v));
+
+ if (v)
+ {
+ result = f->head_index + i;
+ if (result >= _vec_len (v))
+ result -= _vec_len (v);
+ }
+
+ return result;
+}
+
+#define clib_fifo_elt_at_index(v,i) ((v) + clib_fifo_elt_index (v, (i)))
+
+#define clib_fifo_foreach(v,f,body) \
+do { \
+ uword _i, _l, _n; \
+ \
+ _i = clib_fifo_head_index (f); \
+ _l = clib_fifo_len (f); \
+ _n = clib_fifo_elts (f); \
+ while (_n > 0) \
+ { \
+ (v) = (f) + _i; \
+ do { body; } while (0); \
+ _n--; \
+ _i++; \
+ _i = _i >= _l ? 0 : _i; \
+ } \
+} while (0)
+
+#endif /* included_fifo_h */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */