Tim Hall | 79d07d2 | 2020-04-27 18:20:16 +0100 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (c) 2020 Arm Limited. All rights reserved. |
| 3 | * |
| 4 | * SPDX-License-Identifier: Apache-2.0 |
| 5 | * |
| 6 | * Licensed under the Apache License, Version 2.0 (the License); you may |
| 7 | * not use this file except in compliance with the License. |
| 8 | * You may obtain a copy of the License at |
| 9 | * |
| 10 | * www.apache.org/licenses/LICENSE-2.0 |
| 11 | * |
| 12 | * Unless required by applicable law or agreed to in writing, software |
| 13 | * distributed under the License is distributed on an AS IS BASIS, WITHOUT |
| 14 | * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 15 | * See the License for the specific language governing permissions and |
| 16 | * limitations under the License. |
| 17 | */ |
| 18 | |
| 19 | #define PY_SSIZE_T_CLEAN |
| 20 | #include <Python.h> |
| 21 | |
| 22 | #include "mlw_decode.h" |
| 23 | #include "mlw_encode.h" |
| 24 | |
| 25 | /* C extension wrapper for mlw_encode |
| 26 | * |
| 27 | * This method is exposed directly in python with the arguments with a |
| 28 | * prototype of the form: |
| 29 | * |
| 30 | * output = mlw_codec.encode(input, verbose=0) |
| 31 | * |
| 32 | * input: [int] |
| 33 | * verbose: int |
| 34 | * output: bytearray |
| 35 | */ |
| 36 | |
| 37 | static PyObject * |
| 38 | method_encode (PyObject *self, PyObject *args) |
| 39 | { |
| 40 | /* Object to hold the input integer list. */ |
| 41 | PyObject *input_list_object; |
| 42 | |
| 43 | /* Object to hold the input verbosity integer, the verbose argument |
| 44 | * is optional so defaulted to 0. |
| 45 | */ |
| 46 | int verbose = 0; |
| 47 | |
| 48 | /* Arguments to the method are delivered as a tuple, unpack the |
| 49 | * tuple to get the individual arguments, note the second is |
| 50 | * optional. |
| 51 | */ |
| 52 | if (!PyArg_ParseTuple(args, "O|i", &input_list_object, &verbose)) |
| 53 | return NULL; |
| 54 | |
| 55 | /* Unpack the length of the input integer list. */ |
| 56 | int input_length = PyObject_Length (input_list_object); |
| 57 | if (input_length < 0) |
| 58 | input_length = 0; |
| 59 | |
| 60 | /* We need to marshall the integer list into an input buffer |
| 61 | * suitable for mlw_encode, use a temporary heap allocated buffer |
| 62 | * for that purpose. |
| 63 | */ |
| 64 | int16_t *input_buffer = (int16_t *) malloc(sizeof(int16_t *) * input_length); |
| 65 | if (input_buffer == NULL) |
| 66 | return PyErr_NoMemory(); |
| 67 | |
| 68 | /* Unpack the input integer list into the temporary buffer. |
| 69 | */ |
| 70 | for (int i = 0; i < input_length; i++) |
| 71 | { |
| 72 | PyObject *item; |
| 73 | item = PyList_GetItem(input_list_object, i); |
| 74 | if (!PyLong_Check(item)) |
| 75 | input_buffer[i] = 0; |
| 76 | input_buffer[i] = PyLong_AsLong(item); |
| 77 | } |
| 78 | |
| 79 | /* We don't know the output length required, we guess worst case, |
| 80 | * the mlw_encode call will do a resize (downwards) anyway. |
| 81 | */ |
| 82 | uint8_t *output_buffer = malloc(input_length); |
| 83 | if (output_buffer == NULL) |
| 84 | return PyErr_NoMemory(); |
| 85 | |
| 86 | int output_length = mlw_encode(input_buffer, input_length, &output_buffer, verbose); |
| 87 | |
| 88 | PyObject *output_byte_array = PyByteArray_FromStringAndSize ((char *) output_buffer, output_length); |
| 89 | |
| 90 | /* Discard the temporary input and output buffers. */ |
| 91 | free (input_buffer); |
| 92 | free (output_buffer); |
| 93 | |
| 94 | return output_byte_array; |
| 95 | } |
| 96 | |
| 97 | /* C extension wrapper for mlw_decode |
| 98 | * |
| 99 | * This method is exposed directly in python with the arguments with a |
| 100 | * prototype of the form: |
| 101 | * |
| 102 | * output = mlw_codec.decode(input, verbose=0) |
| 103 | * |
| 104 | * input: bytearray |
| 105 | * verbose: int |
| 106 | * output: [int] |
| 107 | */ |
| 108 | |
| 109 | static PyObject * |
| 110 | method_decode(PyObject *self, PyObject *args) |
| 111 | { |
| 112 | /* Object to hold the input bytearray. */ |
| 113 | PyObject *input_bytearray_object; |
| 114 | |
| 115 | /* Object to hold the input verbosity integer, the verbose argument |
| 116 | * is optional so defaulted to 0. |
| 117 | */ |
| 118 | int verbose = 0; |
| 119 | |
| 120 | /* Arguments to the method are delivered as a tuple, unpack the |
| 121 | * tuple to get the individual arguments, note the second is |
| 122 | * optional. |
| 123 | */ |
| 124 | if (!PyArg_ParseTuple(args, "Y|i", &input_bytearray_object, &verbose)) |
| 125 | return NULL; |
| 126 | |
| 127 | /* Unpack the input buffer and length from the bytearray object. */ |
| 128 | uint8_t *input_buffer = (uint8_t *) PyByteArray_AsString(input_bytearray_object); |
| 129 | int input_length = PyByteArray_Size(input_bytearray_object); |
| 130 | |
| 131 | /* We don't know the output length required, we guess, but the guess |
| 132 | * will be too small, the mlw_decode call will do a resize (upwards) |
| 133 | * anyway. |
| 134 | */ |
| 135 | int16_t *output_buffer = malloc (input_length); |
| 136 | if (output_buffer == NULL) |
| 137 | return PyErr_NoMemory(); |
| 138 | |
| 139 | int output_length = mlw_decode (input_buffer, input_length, &output_buffer, verbose); |
| 140 | |
| 141 | /* Construct a new integer list and marshall the output buffer |
| 142 | * contents into the list. */ |
| 143 | PyObject *output_list = PyList_New(output_length); |
| 144 | for (int i = 0; i <output_length; i++) |
| 145 | PyList_SetItem (output_list, i, PyLong_FromLong (output_buffer[i])); |
| 146 | |
| 147 | free (output_buffer); |
| 148 | |
| 149 | return output_list; |
| 150 | } |
| 151 | |
| 152 | /* mlw_codec method descriptors. |
| 153 | */ |
| 154 | |
| 155 | static PyMethodDef mlw_methods[] = { |
| 156 | {"decode", method_decode, METH_VARARGS, "Python interface for decode"}, |
| 157 | {"encode", method_encode, METH_VARARGS, "Python interface for encode"}, |
| 158 | {NULL, NULL, 0, NULL} |
| 159 | }; |
| 160 | |
| 161 | /* mlw_codec module descriptor. |
| 162 | */ |
| 163 | |
| 164 | static struct PyModuleDef mlw_codecmodule = { |
| 165 | PyModuleDef_HEAD_INIT, |
| 166 | "mlw_codec", |
| 167 | "Python interface for the mlw encoder", |
| 168 | -1, |
| 169 | mlw_methods |
| 170 | }; |
| 171 | |
| 172 | PyMODINIT_FUNC PyInit_mlw_codec(void) { |
| 173 | return PyModule_Create(&mlw_codecmodule); |
| 174 | } |