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/*
* Copyright (C) 2009 Jelmer Vernooij <jelmer@samba.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; version 2
* of the License or (at your option) a later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*/
#include <Python.h>
#include <stdint.h>
static int py_is_sha(PyObject *sha)
{
if (!PyString_CheckExact(sha))
return 0;
if (PyString_Size(sha) != 20)
return 0;
return 1;
}
static size_t get_delta_header_size(uint8_t *delta, int *index, int length)
{
size_t size = 0;
int i = 0;
while ((*index) < length) {
uint8_t cmd = delta[*index];
(*index)++;
size |= (cmd & ~0x80) << i;
i += 7;
if (!(cmd & 0x80))
break;
}
return size;
}
static PyObject *py_chunked_as_string(PyObject *py_buf)
{
if (PyList_Check(py_buf)) {
PyObject *sep = PyString_FromString("");
if (sep == NULL) {
PyErr_NoMemory();
return NULL;
}
py_buf = _PyString_Join(sep, py_buf);
Py_DECREF(sep);
if (py_buf == NULL) {
PyErr_NoMemory();
return NULL;
}
} else if (PyString_Check(py_buf)) {
Py_INCREF(py_buf);
} else {
PyErr_SetString(PyExc_TypeError,
"src_buf is not a string or a list of chunks");
return NULL;
}
return py_buf;
}
static PyObject *py_apply_delta(PyObject *self, PyObject *args)
{
uint8_t *src_buf, *delta;
int src_buf_len, delta_len;
size_t src_size, dest_size;
size_t outindex = 0;
int index;
uint8_t *out;
PyObject *ret, *py_src_buf, *py_delta, *ret_list;
if (!PyArg_ParseTuple(args, "OO", &py_src_buf, &py_delta))
return NULL;
py_src_buf = py_chunked_as_string(py_src_buf);
if (py_src_buf == NULL)
return NULL;
py_delta = py_chunked_as_string(py_delta);
if (py_delta == NULL) {
Py_DECREF(py_src_buf);
return NULL;
}
src_buf = (uint8_t *)PyString_AS_STRING(py_src_buf);
src_buf_len = PyString_GET_SIZE(py_src_buf);
delta = (uint8_t *)PyString_AS_STRING(py_delta);
delta_len = PyString_GET_SIZE(py_delta);
index = 0;
src_size = get_delta_header_size(delta, &index, delta_len);
if (src_size != src_buf_len) {
PyErr_Format(PyExc_ValueError,
"Unexpected source buffer size: %lu vs %d", src_size, src_buf_len);
Py_DECREF(py_src_buf);
Py_DECREF(py_delta);
return NULL;
}
dest_size = get_delta_header_size(delta, &index, delta_len);
ret = PyString_FromStringAndSize(NULL, dest_size);
if (ret == NULL) {
PyErr_NoMemory();
Py_DECREF(py_src_buf);
Py_DECREF(py_delta);
return NULL;
}
out = (uint8_t *)PyString_AsString(ret);
while (index < delta_len) {
char cmd = delta[index];
index++;
if (cmd & 0x80) {
size_t cp_off = 0, cp_size = 0;
int i;
for (i = 0; i < 4; i++) {
if (cmd & (1 << i)) {
uint8_t x = delta[index];
index++;
cp_off |= x << (i * 8);
}
}
for (i = 0; i < 3; i++) {
if (cmd & (1 << (4+i))) {
uint8_t x = delta[index];
index++;
cp_size |= x << (i * 8);
}
}
if (cp_size == 0)
cp_size = 0x10000;
if (cp_off + cp_size < cp_size ||
cp_off + cp_size > src_size ||
cp_size > dest_size)
break;
memcpy(out+outindex, src_buf+cp_off, cp_size);
outindex += cp_size;
} else if (cmd != 0) {
memcpy(out+outindex, delta+index, cmd);
outindex += cmd;
index += cmd;
} else {
PyErr_SetString(PyExc_ValueError, "Invalid opcode 0");
Py_DECREF(ret);
Py_DECREF(py_delta);
Py_DECREF(py_src_buf);
return NULL;
}
}
Py_DECREF(py_src_buf);
Py_DECREF(py_delta);
if (index != delta_len) {
PyErr_SetString(PyExc_ValueError, "delta not empty");
Py_DECREF(ret);
return NULL;
}
if (dest_size != outindex) {
PyErr_SetString(PyExc_ValueError, "dest size incorrect");
Py_DECREF(ret);
return NULL;
}
ret_list = Py_BuildValue("[N]", ret);
if (ret_list == NULL) {
Py_DECREF(ret);
return NULL;
}
return ret_list;
}
static PyObject *py_bisect_find_sha(PyObject *self, PyObject *args)
{
PyObject *unpack_name;
char *sha;
int sha_len;
int start, end;
if (!PyArg_ParseTuple(args, "iis#O", &start, &end,
&sha, &sha_len, &unpack_name))
return NULL;
if (sha_len != 20) {
PyErr_SetString(PyExc_ValueError, "Sha is not 20 bytes long");
return NULL;
}
if (start > end) {
PyErr_SetString(PyExc_AssertionError, "start > end");
return NULL;
}
while (start <= end) {
PyObject *file_sha;
int i = (start + end)/2;
int cmp;
file_sha = PyObject_CallFunction(unpack_name, "i", i);
if (file_sha == NULL) {
return NULL;
}
if (!py_is_sha(file_sha)) {
PyErr_SetString(PyExc_TypeError, "unpack_name returned non-sha object");
Py_DECREF(file_sha);
return NULL;
}
cmp = memcmp(PyString_AsString(file_sha), sha, 20);
Py_DECREF(file_sha);
if (cmp < 0)
start = i + 1;
else if (cmp > 0)
end = i - 1;
else {
return PyInt_FromLong(i);
}
}
Py_RETURN_NONE;
}
static PyMethodDef py_pack_methods[] = {
{ "apply_delta", (PyCFunction)py_apply_delta, METH_VARARGS, NULL },
{ "bisect_find_sha", (PyCFunction)py_bisect_find_sha, METH_VARARGS, NULL },
{ NULL, NULL, 0, NULL }
};
void init_pack(void)
{
PyObject *m;
m = Py_InitModule3("_pack", py_pack_methods, NULL);
if (m == NULL)
return;
}
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