[issue5804] Add an 'offset' argument to zlib.decompress - Code Review (original) (raw)

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1 /* zlibmodule.c -- gzip-compatible data compression */

2 /* See http://www.gzip.org/zlib/ */

4 /* Windows users: read Python's PCbuild\readme.txt */

7 #include "Python.h"

8 #include "zlib.h"

10 #ifdef WITH_THREAD

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179 else

180 zlib_error(zst, err, "while finishing compression");

181

182 error:

183 free(output);

184

185 return ReturnVal;

186 }

187

188 PyDoc_STRVAR(decompress__doc__,

189 "decompress(string[, wbits[, bufsize]]) -- Return decompressed string.\n"

189 "decompress(string[, wbits[, bufsize[, offset]]]) -- Return decompressed string. \n"

190 "\n"

191 "Optional arg wbits is the window buffer size. Optional arg bufsize is\n"

192 "the initial output buffer size.");

192 "the initial output buffer size. Optional arg offset specifies\n"

193 "the start position in the string to start decompresion and, if spceified,\n"

194 "causes the return value to be a tuple, with the second element being\n"

195 "the position in the string just afer the last piece of compressed data.");

193

196

194 static PyObject *

197 static PyObject *

195 PyZlib_decompress(PyObject *self, PyObject *args)

198 PyZlib_decompress(PyObject *self, PyObject *args, PyObject *kw)

196 {

199 {

197 PyObject *result_str;

200 PyObject *result_str;

198 Byte *input;

201 Byte *input;

199 int length, err;

202 int length, err;

200 int wsize=DEF_WBITS;

203 int wsize=DEF_WBITS;

201 Py_ssize_t r_strlen=DEFAULTALLOC;

204 Py_ssize_t r_strlen=DEFAULTALLOC;

205 Py_ssize_t offset = -1;

202 z_stream zst;

206 z_stream zst;

207 char *keywords[] = {"string", "wbits", "bufsize", "offset", 0};

203

208

204 if (!PyArg_ParseTuple(args, "s#|in:decompress",

209 if (!PyArg_ParseTupleAndKeywords(args, kw, "s#|inn:decompress", keywords,

205 » » » &input, &length, &wsize, &r_strlen))

210 » » » &input, &length, &wsize, &r_strlen, &offset))

206 return NULL;

211 return NULL;

207

208 if (r_strlen <= 0)

212 if (r_strlen <= 0)

209 r_strlen = 1;

213 r_strlen = 1;

210

214

215 /* if specified, don't start at the beginning of the input string */

216 if (offset > 0) {

217 if (offset > length)

218 offset = length;

219 length -= offset;

220 input += offset;

221 }

222

211 zst.avail_in = length;

223 zst.avail_in = length;

212 zst.avail_out = r_strlen;

224 zst.avail_out = r_strlen;

213

225

214 if (!(result_str = PyString_FromStringAndSize(NULL, r_strlen)))

226 if (!(result_str = PyString_FromStringAndSize(NULL, r_strlen)))

215 return NULL;

227 return NULL;

216

228

217 zst.zalloc = (alloc_func)NULL;

229 zst.zalloc = (alloc_func)NULL;

218 zst.zfree = (free_func)Z_NULL;

230 zst.zfree = (free_func)Z_NULL;

219 zst.next_out = (Byte *)PyString_AS_STRING(result_str);

231 zst.next_out = (Byte *)PyString_AS_STRING(result_str);

220 zst.next_in = (Byte *)input;

232 zst.next_in = (Byte *)input;

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272 }

284 }

273 } while (err != Z_STREAM_END);

285 } while (err != Z_STREAM_END);

274

286

275 err = inflateEnd(&zst);

287 err = inflateEnd(&zst);

276 if (err != Z_OK) {

288 if (err != Z_OK) {

277 zlib_error(zst, err, "while finishing data decompression");

289 zlib_error(zst, err, "while finishing data decompression");

278 goto error;

290 goto error;

279 }

291 }

280

292

281 _PyString_Resize(&result_str, zst.total_out);

293 _PyString_Resize(&result_str, zst.total_out);

294 if (result_str != NULL && offset >= 0) {

295 /* compute new offset to current pos */

296 offset = length-zst.avail_in+offset;

297 return Py_BuildValue("Nn", result_str, offset);

298 }

282 return result_str;

299 return result_str;

283

300

284 error:

301 error:

285 Py_XDECREF(result_str);

302 Py_XDECREF(result_str);

286 return NULL;

303 return NULL;

287 }

304 }

288

305

289 static PyObject *

306 static PyObject *

290 PyZlib_compressobj(PyObject *selfptr, PyObject *args)

307 PyZlib_compressobj(PyObject *selfptr, PyObject *args)

291 {

308 {

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934 static PyMethodDef zlib_methods[] =

951 static PyMethodDef zlib_methods[] =

935 {

952 {

936 {"adler32", (PyCFunction)PyZlib_adler32, METH_VARARGS,

953 {"adler32", (PyCFunction)PyZlib_adler32, METH_VARARGS,

937 adler32__doc__},

954 adler32__doc__},

938 {"compress", (PyCFunction)PyZlib_compress, METH_VARARGS,

955 {"compress", (PyCFunction)PyZlib_compress, METH_VARARGS,

939 compress__doc__},

956 compress__doc__},

940 {"compressobj", (PyCFunction)PyZlib_compressobj, METH_VARARGS,

957 {"compressobj", (PyCFunction)PyZlib_compressobj, METH_VARARGS,

941 compressobj__doc__},

958 compressobj__doc__},

942 {"crc32", (PyCFunction)PyZlib_crc32, METH_VARARGS,

959 {"crc32", (PyCFunction)PyZlib_crc32, METH_VARARGS,

943 crc32__doc__},

960 crc32__doc__},

944 {"decompress", (PyCFunction)PyZlib_decompress, METH_VARARGS,

961 {"decompress", (PyCFunction)PyZlib_decompress, METH_KEYWORDS,

945 decompress__doc__},

962 decompress__doc__},

946 {"decompressobj", (PyCFunction)PyZlib_decompressobj, METH_VARARGS,

963 {"decompressobj", (PyCFunction)PyZlib_decompressobj, METH_VARARGS,

947 decompressobj__doc__},

964 decompressobj__doc__},

948 {NULL, NULL}

965 {NULL, NULL}

949 };

966 };

950

967

951 static PyTypeObject Comptype = {

968 static PyTypeObject Comptype = {

952 PyVarObject_HEAD_INIT(0, 0)

969 PyVarObject_HEAD_INIT(0, 0)

953 "zlib.Compress",

970 "zlib.Compress",

954 sizeof(compobject),

971 sizeof(compobject),

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1030 ver = PyString_FromString(ZLIB_VERSION);

1047 ver = PyString_FromString(ZLIB_VERSION);

1031 if (ver != NULL)

1048 if (ver != NULL)

1032 PyModule_AddObject(m, "ZLIB_VERSION", ver);

1049 PyModule_AddObject(m, "ZLIB_VERSION", ver);

1033

1050

1034 PyModule_AddStringConstant(m, "__version__", "1.0");

1051 PyModule_AddStringConstant(m, "__version__", "1.0");

1035

1052

1036 #ifdef WITH_THREAD

1053 #ifdef WITH_THREAD

1037 zlib_lock = PyThread_allocate_lock();

1054 zlib_lock = PyThread_allocate_lock();

1038 #endif /* WITH_THREAD */

1055 #endif /* WITH_THREAD */

1039 }

1056 }

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