63 lines
2.1 KiB
C
63 lines
2.1 KiB
C
/*
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Copyright (c) 2015 Harm Hanemaaijer <fgenfb@yahoo.com>
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Permission to use, copy, modify, and/or distribute this software for any
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purpose with or without fee is hereby granted, provided that the above
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copyright notice and this permission notice appear in all copies.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/* Data structure used to extract bits from 128-bit bitstring. */
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typedef struct {
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uint64_t data0;
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uint64_t data1;
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int index;
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} detexBlock128;
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uint32_t detexBlock128ExtractBits(detexBlock128 *block, int nu_bits);
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/* Return bitfield from bit0 to bit1 from 64-bit bitstring. */
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static DETEX_INLINE_ONLY uint32_t detexGetBits64(uint64_t data, int bit0, int bit1) {
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return (data & (((uint64_t)1 << (bit1 + 1)) - 1)) >> bit0;
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}
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/* Return reversed bitfield (bit1 to bit0) from 64-bit bitstring. */
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static DETEX_INLINE_ONLY uint32_t detexGetBits64Reversed(uint64_t data, int bit0, int bit1) {
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// Assumes bit0 > bit1.
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// Reverse the bits.
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uint32_t val = 0;
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for (int i = 0; i <= bit0 - bit1; i++) {
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int shift_right = bit0 - 2 * i;
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if (shift_right >= 0)
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val |= (data & ((uint64_t)1 << (bit0 - i))) >> shift_right;
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else
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val |= (data & ((uint64_t)1 << (bit0 - i))) << (- shift_right);
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}
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return val;
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}
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/* Clear bit0 to bit1 of 64-bit bitstring. */
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static DETEX_INLINE_ONLY uint64_t detexClearBits64(uint64_t data, int bit0, int bit1) {
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uint64_t mask = ~(((uint64_t)1 << (bit1 + 1)) - 1);
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mask |= ((uint64_t)1 << bit0) - 1;
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return data & mask;
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}
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/* Set bit0 to bit1 of 64-bit bitstring. */
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static DETEX_INLINE_ONLY uint64_t detexSetBits64(uint64_t data, int bit0, int bit1, uint64_t val) {
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uint64_t d = detexClearBits64(data, bit0, bit1);
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d |= val << bit0;
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return d;
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}
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