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/**
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0.
*/
#include "checksums.h"
#include "aws/checksums/crc.h"
#include "aws/common/byte_buf.h"
PyObject *checksums_crc_common(PyObject *args, uint32_t (*checksum_fn)(const uint8_t *, int, uint32_t)) {
Py_buffer input;
PyObject *py_previousCrc;
PyObject *py_result = NULL;
if (!PyArg_ParseTuple(args, "s*O", &input, &py_previousCrc)) {
return NULL;
}
/* Note: PyArg_ParseTuple() doesn't do overflow checking on unsigned values
* so use PyLong_AsUnsignedLong() to get the value of the previousCrc arg */
uint32_t previousCrc = PyLong_AsUnsignedLong(py_previousCrc);
if (previousCrc == (uint32_t)-1 && PyErr_Occurred()) {
goto done;
}
if (!PyBuffer_IsContiguous(&input, 'C')) {
PyErr_SetString(PyExc_ValueError, "input must be contiguous buffer");
goto done;
}
uint32_t val = previousCrc;
/* Releasing the GIL for very small buffers is inefficient
and may lower performance */
if (input.len > 1024 * 5) {
unsigned char *buf = input.buf;
Py_ssize_t len = input.len;
/* clang-format off */
Py_BEGIN_ALLOW_THREADS
/* Avoid truncation of length for very large buffers. crc() takes
length as an int, which may be narrower than Py_ssize_t. */
while ((size_t)len > INT_MAX) {
val = checksum_fn(buf, INT_MAX, val);
buf += (size_t)INT_MAX;
len -= (size_t)INT_MAX;
}
val = checksum_fn(buf, (int)len, val);
Py_END_ALLOW_THREADS
/* clang-format on */
} else {
val = checksum_fn(input.buf, (int)input.len, val);
}
py_result = PyLong_FromUnsignedLong(val);
done:
if (input.obj) {
PyBuffer_Release(&input);
}
return py_result;
}
PyObject *aws_py_checksums_crc32(PyObject *self, PyObject *args) {
(void)self;
return checksums_crc_common(args, aws_checksums_crc32);
}
PyObject *aws_py_checksums_crc32c(PyObject *self, PyObject *args) {
(void)self;
return checksums_crc_common(args, aws_checksums_crc32c);
}
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