]> sigrok.org Git - libsigrokdecode.git/blame - decode.c
decode.c: Simplify sigrokdecode_run_decoder().
[libsigrokdecode.git] / decode.c
CommitLineData
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1/*
2 * This file is part of the sigrok project.
3 *
4 * Copyright (C) 2010 Uwe Hermann <uwe@hermann-uwe.de>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21#include <sigrokdecode.h> /* First, so we avoid a _POSIX_C_SOURCE warning. */
22#include <stdio.h>
5c55017c 23#include <string.h>
7c24d086 24#include <dirent.h>
d842aebe 25#include <config.h>
1c6fa20f 26
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27/* Re-define some string functions for Python >= 3.0. */
28#if PY_VERSION_HEX >= 0x03000000
29#define PyString_AsString PyBytes_AsString
30#define PyString_FromString PyBytes_FromString
31#define PyString_Check PyBytes_Check
32#endif
33
7c24d086 34/* The list of protocol decoders. */
871d21e2 35GSList *list_pds = NULL;
7c24d086 36
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37/*
38 * Here's a quick overview of Python/C API reference counting.
39 *
40 * Check the Python/C API docs for what type of reference a function returns.
41 *
42 * - If it returns a "new reference", you're responsible to Py_DECREF() it.
43 *
44 * - If it returns a "borrowed reference", you MUST NOT Py_DECREF() it.
45 *
46 * - If a function "steals" a reference, you no longer are responsible for
47 * Py_DECREF()ing it (someone else will do it for you at some point).
48 */
49
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50/**
51 * Initialize libsigrokdecode.
52 *
70e44845 53 * @return SIGROKDECODE_OK upon success, a (negative) error code otherwise.
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54 */
55int sigrokdecode_init(void)
56{
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57 DIR *dir;
58 struct dirent *dp;
59 char *tmp;
60
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61 /* Py_Initialize() returns void and usually cannot fail. */
62 Py_Initialize();
63
0895f56a 64 /* Add search directory for the protocol decoders. */
2454527d 65 /* FIXME: Check error code. */
70e44845 66 /* FIXME: What happens if this function is called multiple times? */
0895f56a 67 PyRun_SimpleString("import sys;"
10426068 68 "sys.path.append(r'" DECODERS_DIR "');");
1c6fa20f 69
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70 if (!(dir = opendir(DECODERS_DIR)))
71 return SIGROKDECODE_ERR_DECODERS_DIR;
72
73 while ((dp = readdir(dir)) != NULL) {
276b55eb 74 if (!g_str_has_suffix(dp->d_name, ".py"))
7c24d086 75 continue;
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76 /* For now use the filename (without .py) as decoder name. */
77 if ((tmp = g_strndup(dp->d_name, strlen(dp->d_name) - 3)))
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78 list_pds = g_slist_append(list_pds, tmp);
79 }
80 closedir(dir);
81
70e44845 82 return SIGROKDECODE_OK;
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83}
84
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85/**
86 * Returns the list of supported/loaded protocol decoders.
87 *
88 * This is a GSList containing the names of the decoders as strings.
89 *
90 * @return List of decoders, NULL if none are supported or loaded.
91 */
92GSList *sigrokdecode_list_decoders(void)
93{
94 return list_pds;
95}
96
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97/**
98 * Helper function to handle Python strings.
99 *
100 * TODO: @param entries.
101 *
3a9a7e38 102 * @return SIGROKDECODE_OK upon success, a (negative) error code otherwise.
70e44845 103 * The 'outstr' argument points to a malloc()ed string upon success.
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104 */
105static int h_str(PyObject *py_res, PyObject *py_func, PyObject *py_mod,
106 const char *key, char **outstr)
107{
108 PyObject *py_str;
109 char *str;
110
111 py_str = PyMapping_GetItemString(py_res, (char *)key);
112 if (!py_str || !PyString_Check(py_str)) {
113 if (PyErr_Occurred())
6b08da24 114 PyErr_Print(); /* Returns void. */
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115 Py_DECREF(py_func);
116 Py_DECREF(py_mod);
117 return SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
118 }
119
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120 /*
121 * PyString_AsString()'s returned string refers to an internal buffer
122 * (not a copy), i.e. the data must not be modified, and the memory
123 * must not be free()'d.
124 */
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125 if (!(str = PyString_AsString(py_str))) {
126 if (PyErr_Occurred())
6b08da24 127 PyErr_Print(); /* Returns void. */
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128 Py_DECREF(py_str);
129 Py_DECREF(py_func);
130 Py_DECREF(py_mod);
131 return SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
132 }
133
134 if (!(*outstr = strdup(str))) {
135 if (PyErr_Occurred())
6b08da24 136 PyErr_Print(); /* Returns void. */
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137 Py_DECREF(py_str);
138 Py_DECREF(py_func);
139 Py_DECREF(py_mod);
140 return SIGROKDECODE_ERR_MALLOC;
141 }
142
143 Py_DECREF(py_str);
144
70e44845 145 return SIGROKDECODE_OK;
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146}
147
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148/**
149 * TODO
150 *
151 * @param name TODO
70e44845 152 *
3a9a7e38 153 * @return SIGROKDECODE_OK upon success, a (negative) error code otherwise.
1c6fa20f 154 */
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155int sigrokdecode_load_decoder(const char *name,
156 struct sigrokdecode_decoder **dec)
1c6fa20f 157{
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158 struct sigrokdecode_decoder *d;
159 PyObject *py_name, *py_mod, *py_func, *py_res /* , *py_tuple */;
160 int r;
161
162 /* Get the name of the decoder module as Python string. */
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163 if (!(py_name = PyString_FromString(name))) { /* NEWREF */
164 PyErr_Print(); /* Returns void. */
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165 return SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
166 }
167
168 /* "Import" the Python module. */
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169 if (!(py_mod = PyImport_Import(py_name))) { /* NEWREF */
170 PyErr_Print(); /* Returns void. */
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171 Py_DECREF(py_name);
172 return SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
173 }
174 Py_DECREF(py_name);
175
176 /* Get the 'register' function name as Python callable object. */
6b08da24 177 py_func = PyObject_GetAttrString(py_mod, "register"); /* NEWREF */
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178 if (!py_func || !PyCallable_Check(py_func)) {
179 if (PyErr_Occurred())
6b08da24 180 PyErr_Print(); /* Returns void. */
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181 Py_DECREF(py_mod);
182 return SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
183 }
184
185 /* Call the 'register' function without arguments, get the result. */
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186 if (!(py_res = PyObject_CallFunction(py_func, NULL))) { /* NEWREF */
187 PyErr_Print(); /* Returns void. */
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188 Py_DECREF(py_func);
189 Py_DECREF(py_mod);
190 return SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
191 }
192
193 if (!(d = malloc(sizeof(struct sigrokdecode_decoder))))
194 return SIGROKDECODE_ERR_MALLOC;
195
196 if ((r = h_str(py_res, py_func, py_mod, "id", &(d->id))) < 0)
197 return r;
198
199 if ((r = h_str(py_res, py_func, py_mod, "name", &(d->name))) < 0)
200 return r;
201
202 if ((r = h_str(py_res, py_func, py_mod, "desc", &(d->desc))) < 0)
203 return r;
204
205 d->py_mod = py_mod;
206
207 Py_DECREF(py_res);
208 Py_DECREF(py_func);
209
210 /* Get the 'decode' function name as Python callable object. */
6b08da24 211 py_func = PyObject_GetAttrString(py_mod, "decode"); /* NEWREF */
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212 if (!py_func || !PyCallable_Check(py_func)) {
213 if (PyErr_Occurred())
6b08da24 214 PyErr_Print(); /* Returns void. */
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215 Py_DECREF(py_mod);
216 return SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
217 }
218
219 d->py_func = py_func;
220
221 /* TODO: Handle inputformats, outputformats. */
222
223 *dec = d;
910e5fd8 224
70e44845 225 return SIGROKDECODE_OK;
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226}
227
228/**
229 * Run the specified decoder function.
230 *
5c55017c 231 * @param dec TODO
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232 * @param inbuf TODO
233 * @param inbuflen TODO
234 * @param outbuf TODO
235 * @param outbuflen TODO
70e44845 236 *
3a9a7e38 237 * @return SIGROKDECODE_OK upon success, a (negative) error code otherwise.
1c6fa20f 238 */
5c55017c 239int sigrokdecode_run_decoder(struct sigrokdecode_decoder *dec,
2b45dd71 240 uint8_t *inbuf, uint64_t inbuflen,
241 uint8_t **outbuf, uint64_t *outbuflen)
1c6fa20f 242{
5c55017c 243 PyObject *py_mod, *py_func, *py_args, *py_value, *py_res;
036e6f67 244 int r, ret;
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245
246 /* TODO: Use #defines for the return codes. */
247
248 /* Return an error upon unusable input. */
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249 if (dec == NULL)
250 return SIGROKDECODE_ERR_ARGS; /* TODO: More specific error? */
1c6fa20f 251 if (inbuf == NULL)
5c55017c 252 return SIGROKDECODE_ERR_ARGS; /* TODO: More specific error? */
1c6fa20f 253 if (inbuflen == 0) /* No point in working on empty buffers. */
5c55017c 254 return SIGROKDECODE_ERR_ARGS; /* TODO: More specific error? */
1c6fa20f 255 if (outbuf == NULL)
5c55017c 256 return SIGROKDECODE_ERR_ARGS; /* TODO: More specific error? */
1c6fa20f 257 if (outbuflen == NULL)
5c55017c 258 return SIGROKDECODE_ERR_ARGS; /* TODO: More specific error? */
1c6fa20f 259
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260 /* TODO: Error handling. */
261 py_mod = dec->py_mod;
4fa17efc 262 Py_INCREF(py_mod);
5c55017c 263 py_func = dec->py_func;
4fa17efc 264 Py_INCREF(py_func);
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265
266 /* Create a Python tuple of size 1. */
6b08da24 267 if (!(py_args = PyTuple_New(1))) { /* NEWREF */
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268 ret = SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
269 goto err_run_decref_func;
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270 }
271
272 /* Get the input buffer as Python "string" (byte array). */
273 /* TODO: int vs. uint64_t for 'inbuflen'? */
6b08da24 274 if (!(py_value = Py_BuildValue("s#", inbuf, inbuflen))) { /* NEWREF */
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275 ret = SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
276 goto err_run_decref_args;
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277 }
278
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279 /*
280 * IMPORTANT: PyTuple_SetItem() "steals" a reference to py_value!
281 * That means we are no longer responsible for Py_DECREF()'ing it.
282 * It will automatically be free'd when the 'py_args' tuple is free'd.
283 */
6b08da24 284 if (PyTuple_SetItem(py_args, 0, py_value) != 0) { /* STEAL */
036e6f67 285 ret = SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
f800adc4 286 Py_DECREF(py_value); /* TODO: Ref. stolen upon error? */
036e6f67 287 goto err_run_decref_args;
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288 }
289
6b08da24 290 if (!(py_res = PyObject_CallObject(py_func, py_args))) { /* NEWREF */
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291 ret = SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
292 goto err_run_decref_args;
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293 }
294
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295 if ((r = PyObject_AsCharBuffer(py_res, (const char **)outbuf,
296 (Py_ssize_t *)outbuflen))) {
297 ret = SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
5c55017c 298 Py_DECREF(py_res);
036e6f67 299 goto err_run_decref_args;
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300 }
301
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302 ret = SIGROKDECODE_OK;
303
5c55017c 304 Py_DECREF(py_res);
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305
306err_run_decref_args:
1c6fa20f 307 Py_DECREF(py_args);
036e6f67 308err_run_decref_func:
1c6fa20f 309 Py_DECREF(py_func);
036e6f67 310err_run_decref_mod:
5c55017c 311 Py_DECREF(py_mod);
1c6fa20f 312
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313 if (PyErr_Occurred())
314 PyErr_Print(); /* Returns void. */
315
316 return ret;
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317}
318
319/**
320 * Shutdown libsigrokdecode.
321 *
3a9a7e38 322 * @return SIGROKDECODE_OK upon success, a (negative) error code otherwise.
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323 */
324int sigrokdecode_shutdown(void)
325{
326 /* Py_Finalize() returns void, any finalization errors are ignored. */
327 Py_Finalize();
328
70e44845 329 return SIGROKDECODE_OK;
1c6fa20f 330}