1#include "fr.h"
  2#include <stdio.h>
  3#include <stdlib.h>
  4#include <gmp.h>
  5#include <assert.h>
  6
  7mpz_t q;
  8mpz_t zero;
  9mpz_t one;
 10mpz_t mask;
 11size_t nBits;
 12
 13
 14void Fr_toMpz(mpz_t r, PFrElement pE) {
 15    Fr_toNormal(pE);
 16    if (!(pE->type & Fr_LONG)) {
 17        mpz_set_si(r, pE->shortVal);
 18        if (pE->shortVal<0) {
 19            mpz_add(r, r, q);
 20        }
 21    } else {
 22        mpz_import(r, Fr_N64, -1, 8, -1, 0, (const void *)pE->longVal);
 23    }
 24}
 25
 26void Fr_fromMpz(PFrElement pE, mpz_t v) {
 27    if (mpz_fits_sint_p(v)) {
 28        pE->type = Fr_SHORT;
 29        pE->shortVal = mpz_get_si(v);
 30    } else {
 31        pE->type = Fr_LONG;
 32        for (int i=0; i<Fr_N64; i++) pE->longVal[i] = 0;
 33        mpz_export((void *)(pE->longVal), NULL, -1, 8, -1, 0, v);
 34    }
 35}
 36
 37
 38void Fr_init() {
 39    mpz_init(q);
 40    mpz_import(q, Fr_N64, -1, 8, -1, 0, (const void *)Fr_q.longVal);
 41    mpz_init_set_ui(zero, 0);
 42    mpz_init_set_ui(one, 1);
 43    nBits = mpz_sizeinbase (q, 2);
 44    mpz_init(mask);
 45    mpz_mul_2exp(mask, one, nBits-1);
 46    mpz_sub(mask, mask, one);
 47
 48}
 49
 50void Fr_str2element(PFrElement pE, char const *s) {
 51    mpz_t mr;
 52    mpz_init_set_str(mr, s, 10);
 53    Fr_fromMpz(pE, mr);
 54}
 55
 56char *Fr_element2str(PFrElement pE) {
 57    mpz_t r;
 58    if (!(pE->type & Fr_LONG)) {
 59        if (pE->shortVal>=0) {
 60            char *r = new char[32];
 61            sprintf(r, "%d", pE->shortVal);
 62            return r;
 63        } else {
 64            mpz_init_set_si(r, pE->shortVal);
 65            mpz_add(r, r, q);
 66            mpz_clear(q);
 67        }
 68    } else {
 69        Fr_toNormal(pE);
 70        mpz_init(r);
 71        mpz_import(r, Fr_N64, -1, 8, -1, 0, (const void *)pE->longVal);
 72    }
 73    char *res = mpz_get_str (0, 10, r);
 74    mpz_clear(r);
 75    return res;
 76}
 77
 78void Fr_idiv(PFrElement r, PFrElement a, PFrElement b) {
 79    mpz_t ma;
 80    mpz_t mb;
 81    mpz_t mr;
 82    mpz_init(ma);
 83    mpz_init(mb);
 84    mpz_init(mr);
 85
 86    Fr_toMpz(ma, a);
 87    // char *s1 = mpz_get_str (0, 10, ma);
 88    // printf("s1 %s\n", s1);
 89    Fr_toMpz(mb, b);
 90    // char *s2 = mpz_get_str (0, 10, mb);
 91    // printf("s2 %s\n", s2);
 92    mpz_fdiv_q(mr, ma, mb);
 93    // char *sr = mpz_get_str (0, 10, mr);
 94    // printf("r %s\n", sr);
 95    Fr_fromMpz(r, mr);
 96}
 97
 98void Fr_mod(PFrElement r, PFrElement a, PFrElement b) {
 99    mpz_t ma;
100    mpz_t mb;
101    mpz_t mr;
102    mpz_init(ma);
103    mpz_init(mb);
104    mpz_init(mr);
105
106    Fr_toMpz(ma, a);
107    Fr_toMpz(mb, b);
108    mpz_fdiv_r(mr, ma, mb);
109    Fr_fromMpz(r, mr);
110}
111
112void Fr_shl(PFrElement r, PFrElement a, PFrElement b) {
113    mpz_t ma;
114    mpz_t mb;
115    mpz_t mr;
116    mpz_init(ma);
117    mpz_init(mb);
118    mpz_init(mr);
119
120    Fr_toMpz(ma, a);
121    Fr_toMpz(mb, b);
122    if (mpz_cmp_ui(mb, nBits) >= 0) {
123        mpz_set(mr, zero);
124    } else {
125        mpz_mul_2exp(mr, ma, mpz_get_ui(mb));
126        mpz_and(mr, mr, mask);
127    }
128    Fr_fromMpz(r, mr);
129}
130
131void Fr_shr(PFrElement r, PFrElement a, PFrElement b) {
132    mpz_t ma;
133    mpz_t mb;
134    mpz_t mr;
135    mpz_init(ma);
136    mpz_init(mb);
137    mpz_init(mr);
138
139    Fr_toMpz(ma, a);
140    Fr_toMpz(mb, b);
141    if (mpz_cmp_ui(mb, nBits) >= 0) {
142        mpz_set(mr, zero);
143    } else {
144        mpz_tdiv_q_2exp(mr, ma, mpz_get_ui(mb));
145        mpz_and(mr, mr, mask);
146    }
147    Fr_fromMpz(r, mr);
148}
149
150
151void Fr_pow(PFrElement r, PFrElement a, PFrElement b) {
152    mpz_t ma;
153    mpz_t mb;
154    mpz_t mr;
155    mpz_init(ma);
156    mpz_init(mb);
157    mpz_init(mr);
158
159    Fr_toMpz(ma, a);
160    Fr_toMpz(mb, b);
161    mpz_powm(mr, ma, mb, q);
162    Fr_fromMpz(r, mr);
163}
164
165void Fr_inv(PFrElement r, PFrElement a) {
166    mpz_t ma;
167    mpz_t mr;
168    mpz_init(ma);
169    mpz_init(mr);
170
171    Fr_toMpz(ma, a);
172    mpz_invert(mr, ma, q);
173    Fr_fromMpz(r, mr);
174}
175
176void Fr_div(PFrElement r, PFrElement a, PFrElement b) {
177    FrElement tmp;
178    Fr_inv(&tmp, b);
179    Fr_mul(r, a, &tmp);
180}
181
182int Fr_isTrue(PFrElement pE) {
183    if (!(pE->type & Fr_LONG)) return pE->shortVal != 0;
184    for (int i=0; i< Fr_N64; i++) {
185        if (pE->longVal[i]) return 1;
186    }
187    return 0;
188}
189
190int Fr_toInt(PFrElement pE) {
191    Fr_toNormal(pE);
192    if (!(pE->type & Fr_LONG)) {
193        return pE->shortVal;
194    } else {
195        mpz_t ma;
196        mpz_init(ma);
197        Fr_toMpz(ma, pE);
198        if (mpz_fits_sint_p(ma)) {
199            return mpz_get_si(ma);
200        }
201
202        mpz_sub(ma, ma, q);
203        if (mpz_fits_sint_p(ma)) {
204            return mpz_get_si(ma);
205        } else {
206            assert(false);
207        }
208    }
209}
210