Add m-esr52 at 52.6.0

1 files changed, 171 insertions, 0 deletions

diff --git a/security/nss/lib/freebl/mpi/utils/pi.c b/security/nss/lib/freebl/mpi/utils/pi.c
new file mode 100644
index 000000000..7e3109786
--- /dev/null
+++ b/security/nss/lib/freebl/mpi/utils/pi.c
@@ -0,0 +1,171 @@
+/*
+ * pi.c
+ *
+ * Compute pi to an arbitrary number of digits.  Uses Machin's formula,
+ * like everyone else on the planet:
+ *
+ *    pi = 16 * arctan(1/5) - 4 * arctan(1/239)
+ *
+ * This is pretty effective for up to a few thousand digits, but it
+ * gets pretty slow after that.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#include <time.h>
+
+#include "mpi.h"
+
+mp_err arctan(mp_digit mul, mp_digit x, mp_digit prec, mp_int *sum);
+
+int
+main(int argc, char *argv[])
+{
+    mp_err res;
+    mp_digit ndigits;
+    mp_int sum1, sum2;
+    clock_t start, stop;
+    int out = 0;
+
+    /* Make the user specify precision on the command line */
+    if (argc < 2) {
+        fprintf(stderr, "Usage: %s <num-digits>\n", argv[0]);
+        return 1;
+    }
+
+    if ((ndigits = abs(atoi(argv[1]))) == 0) {
+        fprintf(stderr, "%s: you must request at least 1 digit\n", argv[0]);
+        return 1;
+    }
+
+    start = clock();
+    mp_init(&sum1);
+    mp_init(&sum2);
+
+    /* sum1 = 16 * arctan(1/5)  */
+    if ((res = arctan(16, 5, ndigits, &sum1)) != MP_OKAY) {
+        fprintf(stderr, "%s: arctan: %s\n", argv[0], mp_strerror(res));
+        out = 1;
+        goto CLEANUP;
+    }
+
+    /* sum2 = 4 * arctan(1/239) */
+    if ((res = arctan(4, 239, ndigits, &sum2)) != MP_OKAY) {
+        fprintf(stderr, "%s: arctan: %s\n", argv[0], mp_strerror(res));
+        out = 1;
+        goto CLEANUP;
+    }
+
+    /* pi = sum1 - sum2         */
+    if ((res = mp_sub(&sum1, &sum2, &sum1)) != MP_OKAY) {
+        fprintf(stderr, "%s: mp_sub: %s\n", argv[0], mp_strerror(res));
+        out = 1;
+        goto CLEANUP;
+    }
+    stop = clock();
+
+    /* Write the output in decimal */
+    {
+        char *buf = malloc(mp_radix_size(&sum1, 10));
+
+        if (buf == NULL) {
+            fprintf(stderr, "%s: out of memory\n", argv[0]);
+            out = 1;
+            goto CLEANUP;
+        }
+        mp_todecimal(&sum1, buf);
+        printf("%s\n", buf);
+        free(buf);
+    }
+
+    fprintf(stderr, "Computation took %.2f sec.\n",
+            (double)(stop - start) / CLOCKS_PER_SEC);
+
+CLEANUP:
+    mp_clear(&sum1);
+    mp_clear(&sum2);
+
+    return out;
+}
+
+/* Compute sum := mul * arctan(1/x), to 'prec' digits of precision */
+mp_err
+arctan(mp_digit mul, mp_digit x, mp_digit prec, mp_int *sum)
+{
+    mp_int t, v;
+    mp_digit q = 1, rd;
+    mp_err res;
+    int sign = 1;
+
+    prec += 3; /* push inaccuracies off the end */
+
+    mp_init(&t);
+    mp_set(&t, 10);
+    mp_init(&v);
+    if ((res = mp_expt_d(&t, prec, &t)) != MP_OKAY || /* get 10^prec    */
+        (res = mp_mul_d(&t, mul, &t)) != MP_OKAY ||   /* ... times mul  */
+        (res = mp_mul_d(&t, x, &t)) != MP_OKAY)       /* ... times x    */
+        goto CLEANUP;
+
+    /*
+    The extra multiplication by x in the above takes care of what
+    would otherwise have to be a special case for 1 / x^1 during the
+    first loop iteration.  A little sneaky, but effective.
+
+    We compute arctan(1/x) by the formula:
+
+         1     1       1       1
+     - - ----- + ----- - ----- + ...
+     x   3 x^3   5 x^5   7 x^7
+
+    We multiply through by 'mul' beforehand, which gives us a couple
+    more iterations and more precision
+   */
+
+    x *= x; /* works as long as x < sqrt(RADIX), which it is here */
+
+    mp_zero(sum);
+
+    do {
+        if ((res = mp_div_d(&t, x, &t, &rd)) != MP_OKAY)
+            goto CLEANUP;
+
+        if (sign < 0 && rd != 0)
+            mp_add_d(&t, 1, &t);
+
+        if ((res = mp_div_d(&t, q, &v, &rd)) != MP_OKAY)
+            goto CLEANUP;
+
+        if (sign < 0 && rd != 0)
+            mp_add_d(&v, 1, &v);
+
+        if (sign > 0)
+            res = mp_add(sum, &v, sum);
+        else
+            res = mp_sub(sum, &v, sum);
+
+        if (res != MP_OKAY)
+            goto CLEANUP;
+
+        sign *= -1;
+        q += 2;
+
+    } while (mp_cmp_z(&t) != 0);
+
+    /* Chop off inaccurate low-order digits */
+    mp_div_d(sum, 1000, sum, NULL);
+
+CLEANUP:
+    mp_clear(&v);
+    mp_clear(&t);
+
+    return res;
+}
+
+/*------------------------------------------------------------------------*/
+/* HERE THERE BE DRAGONS                                                  */