Add gmp_kronecker()

Exposes the mpz_kronecker(), mpz_si_kronecker() and
mpz_kronecher_si() for computing the Kronecker symbol.

Author: nikic

NEWS

@@ -51,6 +51,7 @@ PHP                                                                        NEWS
   . Added gmp_binomial(n, k). (Nikita)
   . Added gmp_lcm(a, b). (Nikita)
   . Added gmp_perfect_power(a). (Nikita)
+  . Added gmp_kronecker(a, b). (Nikita)
 
 - intl:
   . Fixed bug #75317 (UConverter::setDestinationEncoding changes source instead 

UPGRADING

@@ -89,6 +89,7 @@ GMP:
   . Added gmp_binomial(n, k) for calculating binomial coefficients.
   . Added gmp_lcm(a, b) for calculating the least common multiple.
   . Added gmp_perfect_power(a) to check if number is a perfect power.
+  . Added gmp_kronecker(a, b) to compute the Kronecker symbol.
 
 Intl:
   . Added void Spoofchecker::setRestrictionLevel(int $level) method, available

ext/gmp/gmp.c

@@ -172,6 +172,7 @@ const zend_function_entry gmp_functions[] = {
 	ZEND_FE(gmp_invert,		arginfo_gmp_binary)
 	ZEND_FE(gmp_jacobi,		arginfo_gmp_binary)
 	ZEND_FE(gmp_legendre,	arginfo_gmp_binary)
+	ZEND_FE(gmp_kronecker,	arginfo_gmp_binary)
 	ZEND_FE(gmp_cmp,		arginfo_gmp_binary)
 	ZEND_FE(gmp_sign,		arginfo_gmp_unary)
 	ZEND_DEP_FE(gmp_random,		arginfo_gmp_random)
@@ -1782,6 +1783,50 @@ ZEND_FUNCTION(gmp_legendre)
 }
 /* }}} */
 
+/* {{{ proto int gmp_kronecker(mixed a, mixed b)
+   Computes the Kronecker symbol */
+ZEND_FUNCTION(gmp_kronecker)
+{
+	zval *a_arg, *b_arg;
+	mpz_ptr gmpnum_a, gmpnum_b;
+	gmp_temp_t temp_a, temp_b;
+	zend_bool use_a_si = 0, use_b_si = 0;
+	int result;
+
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "zz", &a_arg, &b_arg) == FAILURE){
+		return;
+	}
+
+	if (Z_TYPE_P(a_arg) == IS_LONG && Z_TYPE_P(b_arg) != IS_LONG) {
+		use_a_si = 1;
+		temp_a.is_used = 0;
+	} else {
+		FETCH_GMP_ZVAL(gmpnum_a, a_arg, temp_a);
+	}
+
+	if (Z_TYPE_P(b_arg) == IS_LONG) {
+		use_b_si = 1;
+		temp_b.is_used = 0;
+	} else {
+		FETCH_GMP_ZVAL_DEP(gmpnum_b, b_arg, temp_b, temp_a);
+	}
+
+	if (use_a_si) {
+		ZEND_ASSERT(use_b_si == 0);
+		result = mpz_si_kronecker((gmp_long) Z_LVAL_P(a_arg), gmpnum_b);
+	} else if (use_b_si) {
+		result = mpz_kronecker_si(gmpnum_a, (gmp_long) Z_LVAL_P(b_arg));
+	} else {
+		result = mpz_kronecker(gmpnum_a, gmpnum_b);
+	}
+
+	FREE_GMP_TEMP(temp_a);
+	FREE_GMP_TEMP(temp_b);
+
+	RETURN_LONG(result);
+}
+/* }}} */
+
 /* {{{ proto int gmp_cmp(mixed a, mixed b)
    Compares two numbers */
 ZEND_FUNCTION(gmp_cmp)

ext/gmp/php_gmp.h

@@ -61,6 +61,7 @@ ZEND_FUNCTION(gmp_gcdext);
 ZEND_FUNCTION(gmp_invert);
 ZEND_FUNCTION(gmp_jacobi);
 ZEND_FUNCTION(gmp_legendre);
+ZEND_FUNCTION(gmp_kronecker);
 ZEND_FUNCTION(gmp_cmp);
 ZEND_FUNCTION(gmp_sign);
 ZEND_FUNCTION(gmp_and);

ext/gmp/tests/gmp_kronecker.phpt

@@ -0,0 +1,31 @@
+--TEST--
+gmp_kronecker(): Kronecker symbol
+--FILE--
+<?php
+
+var_dump(gmp_kronecker(23, 12));
+var_dump(gmp_kronecker(gmp_init(23), 12));
+var_dump(gmp_kronecker(23, gmp_init(12)));
+var_dump(gmp_kronecker(gmp_init(23), gmp_init(12)));
+var_dump(gmp_kronecker("23", 12));
+var_dump(gmp_kronecker(23, "12"));
+var_dump(gmp_kronecker("23", "12"));
+echo "\n";
+
+var_dump(gmp_kronecker(23, -12));
+var_dump(gmp_kronecker(-23, 12));
+var_dump(gmp_kronecker(-23, -12));
+
+?>
+--EXPECT--
+int(-1)
+int(-1)
+int(-1)
+int(-1)
+int(-1)
+int(-1)
+int(-1)
+
+int(-1)
+int(1)
+int(-1)