From: Zooko O'Whielacronx zooko@zooko.com Date: Tue, 30 Jan 2007 16:37:35 +0000 (+0530) Subject: pyfec: fix preconditions, tighten internal C types, fix bugs in the file-encoding... X-Git-Url: https://git.rkrishnan.org/vdrive/%22doc.html/reliability?a=commitdiff_plain;h=166bb308f69492c4d60f69904ec72d4ed38a231a;p=tahoe-lafs%2Fzfec.git pyfec: fix preconditions, tighten internal C types, fix bugs in the file-encoding and benchmarking utility functions darcs-hash:bad6972889e6779e8331ed4249dc419415d56753 --- diff --git a/pyfec/fec/_fecmodule.c b/pyfec/fec/_fecmodule.c index e69f5a1..6ea18d8 100644 --- a/pyfec/fec/_fecmodule.c +++ b/pyfec/fec/_fecmodule.c @@ -135,14 +135,14 @@ Encoder_encode(Encoder *self, PyObject *args) { gf* check_shares_produced[self->mm - self->kk]; /* This is an upper bound -- we will actually use only num_check_shares_produced of these elements (see below). */ PyObject* pystrs_produced[self->mm - self->kk]; /* This is an upper bound -- we will actually use only num_check_shares_produced of these elements (see below). */ - unsigned num_check_shares_produced = 0; /* The first num_check_shares_produced elements of the check_shares_produced array and of the pystrs_produced array will be used. */ + unsigned char num_check_shares_produced = 0; /* The first num_check_shares_produced elements of the check_shares_produced array and of the pystrs_produced array will be used. */ const gf* incshares[self->kk]; unsigned char num_desired_shares; PyObject* fast_desired_shares_ids = NULL; PyObject** fast_desired_shares_ids_items; unsigned char c_desired_shares_ids[self->mm]; - unsigned i; - unsigned prev_desired_id = 256; /* impossible value */ + unsigned char c_desired_checkshares_ids[self->mm - self->kk]; + unsigned char i; if (desired_shares_ids) { fast_desired_shares_ids = PySequence_Fast(desired_shares_ids, "Second argument (optional) was not a sequence."); num_desired_shares = PySequence_Fast_GET_SIZE(fast_desired_shares_ids); @@ -151,11 +151,6 @@ Encoder_encode(Encoder *self, PyObject *args) { if (!PyInt_Check(fast_desired_shares_ids_items[i])) goto err; c_desired_shares_ids[i] = PyInt_AsLong(fast_desired_shares_ids_items[i]); - if (prev_desired_id != 256 && prev_desired_id >= c_desired_shares_ids[i]) { - py_raise_fec_error("Precondition violation: first argument is required to be in order -- each requested shareid in the sequence must be a higher number than the previous one. current requested shareid: %u, previous requested shareid: %u\n", c_desired_shares_ids[i], prev_desired_id); - goto err; - } - prev_desired_id = c_desired_shares_ids[i]; if (c_desired_shares_ids[i] >= self->kk) num_check_shares_produced++; } @@ -181,7 +176,7 @@ Encoder_encode(Encoder *self, PyObject *args) { PyObject** fastinsharesitems = PySequence_Fast_ITEMS(fastinshares); if (!fastinsharesitems) goto err; - int sz, oldsz = 0; + Py_ssize_t sz, oldsz = 0; for (i=0; ikk; i++) { if (!PyObject_CheckReadBuffer(fastinsharesitems[i])) { py_raise_fec_error("Precondition violation: %u'th item is required to offer the single-segment read character buffer protocol, but it does not.\n", i); @@ -200,6 +195,7 @@ Encoder_encode(Encoder *self, PyObject *args) { unsigned check_share_index = 0; /* index into the check_shares_produced and (parallel) pystrs_produced arrays */ for (i=0; i= self->kk) { + c_desired_checkshares_ids[check_share_index] = c_desired_shares_ids[i]; pystrs_produced[check_share_index] = PyString_FromStringAndSize(NULL, sz); if (pystrs_produced[check_share_index] == NULL) goto err; @@ -212,7 +208,7 @@ Encoder_encode(Encoder *self, PyObject *args) { assert (check_share_index == num_check_shares_produced); /* Encode any check shares that are needed. */ - fec_encode(self->fec_matrix, incshares, check_shares_produced, c_desired_shares_ids, num_desired_shares, sz); + fec_encode(self->fec_matrix, incshares, check_shares_produced, c_desired_checkshares_ids, num_check_shares_produced, sz); /* Wrap all requested shares up into a Python list of Python strings. */ result = PyList_New(num_desired_shares); @@ -386,14 +382,14 @@ Decoder_decode(Decoder *self, PyObject *args) { PyObject*restrict shareids; PyObject* result = NULL; - if (!PyArg_ParseTuple(args, "O!O!", &PyList_Type, &shares, &PyList_Type, &shareids)) + if (!PyArg_ParseTuple(args, "OO", &shares, &shareids)) return NULL; const gf*restrict cshares[self->kk]; unsigned char cshareids[self->kk]; gf*restrict recoveredcstrs[self->kk]; /* self->kk is actually an upper bound -- we probably won't need all of this space. */ PyObject*restrict recoveredpystrs[self->kk]; /* self->kk is actually an upper bound -- we probably won't need all of this space. */ - unsigned i; + unsigned char i; for (i=0; ikk; i++) recoveredpystrs[i] = NULL; PyObject*restrict fastshares = PySequence_Fast(shares, "First argument was not a sequence."); @@ -413,14 +409,14 @@ Decoder_decode(Decoder *self, PyObject *args) { } /* Construct a C array of gf*'s of the data and another of C ints of the shareids. */ - unsigned needtorecover=0; + unsigned char needtorecover=0; PyObject** fastshareidsitems = PySequence_Fast_ITEMS(fastshareids); if (!fastshareidsitems) goto err; PyObject** fastsharesitems = PySequence_Fast_ITEMS(fastshares); if (!fastsharesitems) goto err; - int sz, oldsz = 0; + Py_ssize_t sz, oldsz = 0; for (i=0; ikk; i++) { if (!PyInt_Check(fastshareidsitems[i])) goto err; @@ -437,7 +433,7 @@ Decoder_decode(Decoder *self, PyObject *args) { py_raise_fec_error("Precondition violation: %u'th item is required to offer the single-segment read character buffer protocol, but it does not.\n", i); goto err; } - if (PyObject_AsReadBuffer(fastsharesitems[i], &(cshares[i]), &sz)) + if (PyObject_AsReadBuffer(fastsharesitems[i], &(cshares[i]), &sz)) goto err; if (oldsz != 0 && oldsz != sz) { py_raise_fec_error("Precondition violation: Input shares are required to be all the same length. oldsz: %Zu, sz: %Zu\n", oldsz, sz); @@ -474,7 +470,7 @@ Decoder_decode(Decoder *self, PyObject *args) { fec_decode(self->fec_matrix, cshares, recoveredcstrs, cshareids, sz); /* Wrap up both original primary shares and decoded shares into a Python list of Python strings. */ - unsigned nextrecoveredix=0; + unsigned char nextrecoveredix=0; result = PyList_New(self->kk); if (result == NULL) goto err; diff --git a/pyfec/fec/filefec.py b/pyfec/fec/filefec.py index 8acc0c9..4899ede 100644 --- a/pyfec/fec/filefec.py +++ b/pyfec/fec/filefec.py @@ -22,21 +22,21 @@ import fec -import array +import array, random def encode_to_files(inf, prefix, k, m): """ Encode inf, writing the shares to named $prefix+$shareid. """ l = [ open(prefix+str(shareid), "wb") for shareid in range(m) ] - def cb(shares, len): + def cb(shares, length): assert len(shares) == len(l) for i in range(len(shares)): - l.write(share) + l[i].write(shares[i]) encode_file(inf, cb, k, m, chunksize=4096) -def decode_from_files(outf, prefix, k, m): +def decode_from_files(outf, filesize, prefix, k, m): """ Decode from the first k files in the current directory whose names begin with prefix, writing the results to outf. @@ -44,7 +44,9 @@ def decode_from_files(outf, prefix, k, m): import os infs = [] shareids = [] - for f in os.listdir("."): + listd = os.listdir(".") + random.shuffle(listd) + for f in listd: if f.startswith(prefix): infs.append(open(f, "rb")) shareids.append(int(f[len(prefix):])) @@ -57,9 +59,12 @@ def decode_from_files(outf, prefix, k, m): x = [ inf.read(CHUNKSIZE) for inf in infs ] decshares = dec.decode(x, shareids) for decshare in decshares: - outf.write(decshare) - if len(x[-1]) != CHUNKSIZE: - break + if filesize >= len(decshare): + outf.write(decshare) + filesize -= len(decshare) + else: + outf.write(decshare[:filesize]) + return def encode_file(inf, cb, k, m, chunksize=4096): """ @@ -110,6 +115,7 @@ def encode_file(inf, cb, k, m, chunksize=4096): # padding a.fromstring("\x00" * (chunksize-len(a))) while (i