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/* Copyright (c) 2012 Shlomi Fish
*
* 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.
*/
/*
* var_base_reader.h - read from a packed integer using digits of variable
* bases. Also see var_base_writer.h which complements it.
*
*/
#ifndef FC_SOLVE__VAR_BASE_READER_H
#define FC_SOLVE__VAR_BASE_READER_H
#include <assert.h>
#include <gmp.h>
#include "inline.h"
typedef struct
{
mpz_t data;
/* To avoid memory fragmentation, we keep those here and re use them. */
mpz_t data_byte_offset;
mpz_t r;
} fcs_var_base_reader_t;
static GCC_INLINE void fc_solve_var_base_reader_init(
fcs_var_base_reader_t * s
)
{
mpz_init(s->data);
mpz_init(s->data_byte_offset);
mpz_init(s->r);
}
static GCC_INLINE void fc_solve_var_base_reader_start(
fcs_var_base_reader_t * s,
const unsigned char * data,
size_t data_len
)
{
size_t count;
unsigned long shift_count = 0;
mpz_set_ui(s->data, 0);
#define NUM_BITS 8
for (count = 0; count < data_len ; count++, shift_count += NUM_BITS)
{
mpz_set_ui(s->data_byte_offset, (unsigned long)data[count]);
mpz_mul_2exp(s->data_byte_offset, s->data_byte_offset, shift_count);
mpz_add(s->data, s->data, s->data_byte_offset);
}
}
static GCC_INLINE int fc_solve_var_base_reader_read(
fcs_var_base_reader_t * reader,
int base
)
{
mpz_fdiv_qr_ui(reader->data, reader->r, reader->data, (unsigned long)base);
return (int)mpz_get_ui(reader->r);
}
static GCC_INLINE void fc_solve_var_base_reader_release(
fcs_var_base_reader_t * s
)
{
mpz_clear(s->data);
mpz_clear(s->r);
mpz_clear(s->data_byte_offset);
}
#endif /* FC_SOLVE__VAR_BASE_READER_H */
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