053d093524
Type: improvement Signed-off-by: Dave Barach <dave@barachs.net> Change-Id: Id28299a188feefa1899d835fd499f018af95d81b
167 lines
4.9 KiB
C
167 lines
4.9 KiB
C
/*
|
|
* 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) 2001, 2002, 2003 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_zvec_h
|
|
#define included_zvec_h
|
|
|
|
#include <vppinfra/clib.h>
|
|
#include <vppinfra/error.h> /* for ASSERT */
|
|
#include <vppinfra/format.h>
|
|
|
|
/* zvec: compressed vectors.
|
|
|
|
Data is entropy coded with 32 bit "codings".
|
|
|
|
Consider coding as bitmap, coding = 2^c_0 + 2^c_1 + ... + 2^c_n
|
|
With c_0 < c_1 < ... < c_n. coding == 0 represents c_n = BITS (uword).
|
|
|
|
Unsigned integers i = 0 ... are represented as follows:
|
|
|
|
0 <= i < 2^c_0 (i << 1) | (1 << 0) binary: i 1
|
|
2^c_0 <= i < 2^c_0 + 2^c_1 (i << 2) | (1 << 1) binary: i 1 0
|
|
... binary: i 0 ... 0
|
|
|
|
Smaller numbers use less bits. Coding is chosen so that encoding
|
|
of given histogram of typical values gives smallest number of bits.
|
|
The number and position of coding bits c_i are used to best fit the
|
|
histogram of typical values.
|
|
*/
|
|
|
|
typedef struct
|
|
{
|
|
/* Smallest coding for given histogram of typical data. */
|
|
u32 coding;
|
|
|
|
/* Number of data in histogram. */
|
|
u32 n_data;
|
|
|
|
/* Number of codes (unique values) in histogram. */
|
|
u32 n_codes;
|
|
|
|
/* Number of bits in smallest coding of data. */
|
|
u32 min_coding_bits;
|
|
|
|
/* Average number of bits per code. */
|
|
f64 ave_coding_bits;
|
|
} zvec_coding_info_t;
|
|
|
|
/* Encode/decode data. */
|
|
uword zvec_encode (uword coding, uword data, uword * n_result_bits);
|
|
uword zvec_decode (uword coding, uword zdata, uword * n_zdata_bits);
|
|
|
|
format_function_t format_zvec_coding;
|
|
|
|
typedef u32 zvec_histogram_count_t;
|
|
|
|
#define zvec_coding_from_histogram(h,count_field,len,max_value_to_encode,zc) \
|
|
_zvec_coding_from_histogram ((h), (len), \
|
|
STRUCT_OFFSET_OF_VAR (h, count_field), \
|
|
sizeof (h[0]), \
|
|
max_value_to_encode, \
|
|
(zc))
|
|
|
|
uword
|
|
_zvec_coding_from_histogram (void *_histogram,
|
|
uword histogram_len,
|
|
uword histogram_elt_count_offset,
|
|
uword histogram_elt_bytes,
|
|
uword max_value_to_encode,
|
|
zvec_coding_info_t * coding_info_return);
|
|
|
|
#define _(TYPE,IS_SIGNED) \
|
|
uword * zvec_encode_##TYPE (uword * zvec, uword * zvec_n_bits, uword coding, \
|
|
void * data, uword data_stride, uword n_data);
|
|
|
|
_(u8, /* is_signed */ 0);
|
|
_(u16, /* is_signed */ 0);
|
|
_(u32, /* is_signed */ 0);
|
|
_(u64, /* is_signed */ 0);
|
|
_(i8, /* is_signed */ 1);
|
|
_(i16, /* is_signed */ 1);
|
|
_(i32, /* is_signed */ 1);
|
|
_(i64, /* is_signed */ 1);
|
|
|
|
#undef _
|
|
|
|
#define _(TYPE,IS_SIGNED) \
|
|
void zvec_decode_##TYPE (uword * zvec, \
|
|
uword * zvec_n_bits, \
|
|
uword coding, \
|
|
void * data, \
|
|
uword data_stride, \
|
|
uword n_data)
|
|
|
|
_(u8, /* is_signed */ 0);
|
|
_(u16, /* is_signed */ 0);
|
|
_(u32, /* is_signed */ 0);
|
|
_(u64, /* is_signed */ 0);
|
|
_(i8, /* is_signed */ 1);
|
|
_(i16, /* is_signed */ 1);
|
|
_(i32, /* is_signed */ 1);
|
|
_(i64, /* is_signed */ 1);
|
|
|
|
#undef _
|
|
|
|
/* Signed <=> unsigned conversion.
|
|
-1, -2, -3, ... => 1, 3, 5, ... odds
|
|
0, +1, +2, +3, ... => 0, 2, 4, 6, ... evens */
|
|
always_inline uword
|
|
zvec_signed_to_unsigned (word s)
|
|
{
|
|
uword a = s < 0;
|
|
s = 2 * s + a;
|
|
return a ? -s : s;
|
|
}
|
|
|
|
always_inline word
|
|
zvec_unsigned_to_signed (uword u)
|
|
{
|
|
uword a = u & 1;
|
|
u >>= 1;
|
|
return a ? -u : u;
|
|
}
|
|
|
|
#endif /* included_zvec_h */
|
|
|
|
/*
|
|
* fd.io coding-style-patch-verification: ON
|
|
*
|
|
* Local Variables:
|
|
* eval: (c-set-style "gnu")
|
|
* End:
|
|
*/
|