precompute_ecmult_gen.c

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/*********************************************************************************
 * Copyright (c) 2013, 2014, 2015, 2021 Thomas Daede, Cory Fields, Pieter Wuille *
 * Distributed under the MIT software license, see the accompanying              *
 * file COPYING or https://www.opensource.org/licenses/mit-license.php.          *
 *********************************************************************************/
 
#include <inttypes.h>
#include <stdio.h>
 
#include "../include/secp256k1.h"
#include "assumptions.h"
#include "util.h"
#include "group.h"
#include "ecmult_gen.h"
#include "ecmult_gen_compute_table_impl.h"
 
int main(int argc, char **argv) {
    const char outfile[] = "src/precomputed_ecmult_gen.c";
    FILE* fp;
    int bits;
 
    (void)argc;
    (void)argv;
 
    fp = fopen(outfile, "w");
    if (fp == NULL) {
        fprintf(stderr, "Could not open %s for writing!\n", outfile);
        return -1;
    }
 
    fprintf(fp, "/* This file was automatically generated by precompute_ecmult_gen. */\n");
    fprintf(fp, "/* See ecmult_gen_impl.h for details about the contents of this file. */\n");
    fprintf(fp, "#if defined HAVE_CONFIG_H\n");
    fprintf(fp, "#    include \"libsecp256k1-config.h\"\n");
    fprintf(fp, "#endif\n");
    fprintf(fp, "#include \"../include/secp256k1.h\"\n");
    fprintf(fp, "#include \"group.h\"\n");
    fprintf(fp, "#include \"ecmult_gen.h\"\n");
    fprintf(fp, "#include \"precomputed_ecmult_gen.h\"\n");
    fprintf(fp, "#ifdef EXHAUSTIVE_TEST_ORDER\n");
    fprintf(fp, "#    error Cannot compile precomputed_ecmult_gen.c in exhaustive test mode\n");
    fprintf(fp, "#endif /* EXHAUSTIVE_TEST_ORDER */\n");
    fprintf(fp, "#define S(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p) SECP256K1_GE_STORAGE_CONST(0x##a##u,0x##b##u,0x##c##u,0x##d##u,0x##e##u,0x##f##u,0x##g##u,0x##h##u,0x##i##u,0x##j##u,0x##k##u,0x##l##u,0x##m##u,0x##n##u,0x##o##u,0x##p##u)\n");
    fprintf(fp, "const secp256k1_ge_storage secp256k1_ecmult_gen_prec_table[ECMULT_GEN_PREC_N(ECMULT_GEN_PREC_BITS)][ECMULT_GEN_PREC_G(ECMULT_GEN_PREC_BITS)] = {\n");
 
    for (bits = 2; bits <= 8; bits *= 2) {
        int g = ECMULT_GEN_PREC_G(bits);
        int n = ECMULT_GEN_PREC_N(bits);
        int inner, outer;
 
        secp256k1_ge_storage* table = checked_malloc(&default_error_callback, n * g * sizeof(secp256k1_ge_storage));
        secp256k1_ecmult_gen_compute_table(table, &secp256k1_ge_const_g, bits);
 
        fprintf(fp, "#if ECMULT_GEN_PREC_BITS == %d\n", bits);
        for(outer = 0; outer != n; outer++) {
            fprintf(fp,"{");
            for(inner = 0; inner != g; inner++) {
                fprintf(fp, "S(%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32
                            ",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32")",
                        SECP256K1_GE_STORAGE_CONST_GET(table[outer * g + inner]));
                if (inner != g - 1) {
                    fprintf(fp,",\n");
                } 
            }
            if (outer != n - 1) {
                fprintf(fp,"},\n");
            } else {
                fprintf(fp,"}\n");
            }
        }
        fprintf(fp, "#endif\n");
        free(table);
    }
 
    fprintf(fp, "};\n");
    fprintf(fp, "#undef S\n");
    fclose(fp);
 
    return 0;
}