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| author | Christoph M. Becker <cmbecker69@gmx.de> | 2017-09-07 00:30:05 +0200 |
|---|---|---|
| committer | Christoph M. Becker <cmbecker69@gmx.de> | 2017-09-07 00:30:05 +0200 |
| commit | b2919853f867ca7948e1c80c48eb868eae4ba882 (patch) | |
| tree | 0b20f01dd25f8bd4204e07d257d44e84ec809802 | |
| parent | dea41f3c3a003a22893b27eead429f963d3230c3 (diff) | |
| download | php-git-b2919853f867ca7948e1c80c48eb868eae4ba882.tar.gz | |
Fixed bug #54598 (bcpowmod() may return 1 if modulus is 1)
`x mod 1` is always zero; we have to take the scale into account,
though.
| -rw-r--r-- | NEWS | 1 | ||||
| -rw-r--r-- | ext/bcmath/libbcmath/src/raisemod.c | 23 | ||||
| -rw-r--r-- | ext/bcmath/tests/bug54598.phpt | 16 |
3 files changed, 32 insertions, 8 deletions
@@ -7,6 +7,7 @@ PHP NEWS - BCMath: . Fixed bug #44995 (bcpowmod() fails if scale != 0). (cmb) + . Fixed bug #54598 (bcpowmod() may return 1 if modulus is 1). (okano1220, cmb) - CLI server: . Fixed bug #70470 (Built-in server truncates headers spanning over TCP diff --git a/ext/bcmath/libbcmath/src/raisemod.c b/ext/bcmath/libbcmath/src/raisemod.c index 72a838a364..84a7321ea7 100644 --- a/ext/bcmath/libbcmath/src/raisemod.c +++ b/ext/bcmath/libbcmath/src/raisemod.c @@ -75,17 +75,24 @@ bc_raisemod (bc_num base, bc_num expo, bc_num mod, bc_num *result, int scale) /* Do the calculation. */ rscale = MAX(scale, base->n_scale); - while ( !bc_is_zero(exponent) ) + if ( !bc_compare(mod, BCG(_one_)) ) { - (void) bc_divmod (exponent, BCG(_two_), &exponent, &parity, 0); - if ( !bc_is_zero(parity) ) + temp = bc_new_num (1, scale); + } + else + { + while ( !bc_is_zero(exponent) ) { - bc_multiply (temp, power, &temp, rscale); - (void) bc_modulo (temp, mod, &temp, scale); + (void) bc_divmod (exponent, BCG(_two_), &exponent, &parity, 0); + if ( !bc_is_zero(parity) ) + { + bc_multiply (temp, power, &temp, rscale); + (void) bc_modulo (temp, mod, &temp, scale); + } + + bc_multiply (power, power, &power, rscale); + (void) bc_modulo (power, mod, &power, scale); } - - bc_multiply (power, power, &power, rscale); - (void) bc_modulo (power, mod, &power, scale); } /* Assign the value. */ diff --git a/ext/bcmath/tests/bug54598.phpt b/ext/bcmath/tests/bug54598.phpt new file mode 100644 index 0000000000..6ccd61a2d0 --- /dev/null +++ b/ext/bcmath/tests/bug54598.phpt @@ -0,0 +1,16 @@ +--TEST-- +Bug #54598 (bcpowmod() may return 1 if modulus is 1) +--SKIPIF-- +<?php +if (!extension_loaded('bcmath')) die('skip bcmath extension is not available'); +?> +--FILE-- +<?php +var_dump(bcpowmod(5, 0, 1)); +var_dump(bcpowmod(5, 0, 1, 3)); +?> +===DONE=== +--EXPECT-- +string(1) "0" +string(5) "0.000" +===DONE=== |