diff options
Diffstat (limited to 'Modules/structmodule.c')
| -rw-r--r-- | Modules/structmodule.c | 49 |
1 files changed, 37 insertions, 12 deletions
diff --git a/Modules/structmodule.c b/Modules/structmodule.c index d4f8d86..2210c33 100644 --- a/Modules/structmodule.c +++ b/Modules/structmodule.c @@ -224,12 +224,8 @@ pack_float(double x, /* The number to pack */ return -1; } - if (e >= 128) { - /* XXX 128 itself is reserved for Inf/NaN */ - PyErr_SetString(PyExc_OverflowError, - "float too large to pack with f format"); - return -1; - } + if (e >= 128) + goto Overflow; else if (e < -126) { /* Gradual underflow */ f = ldexp(f, 126 + e); @@ -242,6 +238,14 @@ pack_float(double x, /* The number to pack */ f *= 8388608.0; /* 2**23 */ fbits = (long) floor(f + 0.5); /* Round */ + assert(fbits <= 8388608); + if (fbits >> 23) { + /* The carry propagated out of a string of 23 1 bits. */ + fbits = 0; + ++e; + if (e >= 255) + goto Overflow; + } /* First byte */ *p = (s<<7) | (e>>1); @@ -260,6 +264,11 @@ pack_float(double x, /* The number to pack */ /* Done */ return 0; + + Overflow: + PyErr_SetString(PyExc_OverflowError, + "float too large to pack with f format"); + return -1; } static int @@ -295,12 +304,8 @@ pack_double(double x, /* The number to pack */ return -1; } - if (e >= 1024) { - /* XXX 1024 itself is reserved for Inf/NaN */ - PyErr_SetString(PyExc_OverflowError, - "float too large to pack with d format"); - return -1; - } + if (e >= 1024) + goto Overflow; else if (e < -1022) { /* Gradual underflow */ f = ldexp(f, 1022 + e); @@ -314,9 +319,24 @@ pack_double(double x, /* The number to pack */ /* fhi receives the high 28 bits; flo the low 24 bits (== 52 bits) */ f *= 268435456.0; /* 2**28 */ fhi = (long) floor(f); /* Truncate */ + assert(fhi < 268435456); + f -= (double)fhi; f *= 16777216.0; /* 2**24 */ flo = (long) floor(f + 0.5); /* Round */ + assert(flo <= 16777216); + if (flo >> 24) { + /* The carry propagated out of a string of 24 1 bits. */ + flo = 0; + ++fhi; + if (fhi >> 28) { + /* And it also progagated out of the next 28 bits. */ + fhi = 0; + ++e; + if (e >= 2047) + goto Overflow; + } + } /* First byte */ *p = (s<<7) | (e>>4); @@ -352,6 +372,11 @@ pack_double(double x, /* The number to pack */ /* Done */ return 0; + + Overflow: + PyErr_SetString(PyExc_OverflowError, + "float too large to pack with d format"); + return -1; } static PyObject * |