diff options
Diffstat (limited to 'Modules/_io/bufferedio.c')
| -rw-r--r-- | Modules/_io/bufferedio.c | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c index 8a9ae47..dc723b1 100644 --- a/Modules/_io/bufferedio.c +++ b/Modules/_io/bufferedio.c @@ -1157,9 +1157,20 @@ buffered_seek(buffered *self, PyObject *args) if (!PyArg_ParseTuple(args, "O|i:seek", &targetobj, &whence)) { return NULL; } - if (whence < 0 || whence > 2) { + + /* Do some error checking instead of trusting OS 'seek()' + ** error detection, just in case. + */ + if ((whence < 0 || whence >2) +#ifdef SEEK_HOLE + && (whence != SEEK_HOLE) +#endif +#ifdef SEEK_DATA + && (whence != SEEK_DATA) +#endif + ) { PyErr_Format(PyExc_ValueError, - "whence must be between 0 and 2, not %d", whence); + "whence value %d unsupported", whence); return NULL; } @@ -1172,7 +1183,11 @@ buffered_seek(buffered *self, PyObject *args) if (target == -1 && PyErr_Occurred()) return NULL; - if (whence != 2 && self->readable) { + /* SEEK_SET and SEEK_CUR are special because we could seek inside the + buffer. Other whence values must be managed without this optimization. + Some Operating Systems can provide additional values, like + SEEK_HOLE/SEEK_DATA. */ + if (((whence == 0) || (whence == 1)) && self->readable) { Py_off_t current, avail; /* Check if seeking leaves us inside the current buffer, so as to return quickly if possible. Also, we needn't take the |