Mercurial > hg
diff mercurial/cext/revlog.c @ 40703:d5b300ec2e89
sparse-revlog: add a `index_get_start` function in C
We are about to implement a native version of `slicechunktodensity`. For
clarity, we introduce the helper functions first. This new function provides
an efficient way to retrieve some of the information needed by
`slicechunktodensity`.
author | Boris Feld <boris.feld@octobus.net> |
---|---|
date | Tue, 20 Nov 2018 14:49:18 +0000 |
parents | fa33196088c4 |
children | 7da3729d4b45 |
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--- a/mercurial/cext/revlog.c Fri Nov 23 06:32:32 2018 +0100 +++ b/mercurial/cext/revlog.c Tue Nov 20 14:49:18 2018 +0000 @@ -185,6 +185,40 @@ return 0; } +static inline int64_t index_get_start(indexObject *self, Py_ssize_t rev) +{ + uint64_t offset; + if (rev >= self->length) { + PyObject *tuple; + PyObject *pylong; + PY_LONG_LONG tmp; + tuple = PyList_GET_ITEM(self->added, rev - self->length); + pylong = PyTuple_GET_ITEM(tuple, 0); + tmp = PyLong_AsLongLong(pylong); + if (tmp == -1 && PyErr_Occurred()) { + return -1; + } + if (tmp < 0) { + PyErr_Format(PyExc_OverflowError, + "revlog entry size out of bound (%lld)", + (long long)tmp); + return -1; + } + offset = (uint64_t)tmp; + } else { + const char *data = index_deref(self, rev); + offset = getbe32(data + 4); + if (rev == 0) { + /* mask out version number for the first entry */ + offset &= 0xFFFF; + } else { + uint32_t offset_high = getbe32(data); + offset |= ((uint64_t)offset_high) << 32; + } + } + return (int64_t)(offset >> 16); +} + /* * RevlogNG format (all in big endian, data may be inlined): * 6 bytes: offset