/* struct module -- pack values into and (out of) bytes objects */ /* New version supporting byte order, alignment and size options, character strings, and unsigned numbers */ #define PY_SSIZE_T_CLEAN #include "Python.h" #include "structseq.h" #include "structmember.h" #include static PyTypeObject PyStructType; /* The translation function for each format character is table driven */ typedef struct _formatdef { char format; Py_ssize_t size; Py_ssize_t alignment; PyObject* (*unpack)(const char *, const struct _formatdef *); int (*pack)(char *, PyObject *, const struct _formatdef *); } formatdef; typedef struct _formatcode { const struct _formatdef *fmtdef; Py_ssize_t offset; Py_ssize_t size; } formatcode; /* Struct object interface */ typedef struct { PyObject_HEAD Py_ssize_t s_size; Py_ssize_t s_len; formatcode *s_codes; PyObject *s_format; PyObject *weakreflist; /* List of weak references */ } PyStructObject; #define PyStruct_Check(op) PyObject_TypeCheck(op, &PyStructType) #define PyStruct_CheckExact(op) (Py_TYPE(op) == &PyStructType) /* Exception */ static PyObject *StructError; /* Define various structs to figure out the alignments of types */ typedef struct { char c; short x; } st_short; typedef struct { char c; int x; } st_int; typedef struct { char c; long x; } st_long; typedef struct { char c; float x; } st_float; typedef struct { char c; double x; } st_double; typedef struct { char c; void *x; } st_void_p; #define SHORT_ALIGN (sizeof(st_short) - sizeof(short)) #define INT_ALIGN (sizeof(st_int) - sizeof(int)) #define LONG_ALIGN (sizeof(st_long) - sizeof(long)) #define FLOAT_ALIGN (sizeof(st_float) - sizeof(float)) #define DOUBLE_ALIGN (sizeof(st_double) - sizeof(double)) #define VOID_P_ALIGN (sizeof(st_void_p) - sizeof(void *)) /* We can't support q and Q in native mode unless the compiler does; in std mode, they're 8 bytes on all platforms. */ #ifdef HAVE_LONG_LONG typedef struct { char c; PY_LONG_LONG x; } s_long_long; #define LONG_LONG_ALIGN (sizeof(s_long_long) - sizeof(PY_LONG_LONG)) #endif #ifdef HAVE_C99_BOOL #define BOOL_TYPE _Bool typedef struct { char c; _Bool x; } s_bool; #define BOOL_ALIGN (sizeof(s_bool) - sizeof(BOOL_TYPE)) #else #define BOOL_TYPE char #define BOOL_ALIGN 0 #endif #define STRINGIFY(x) #x #ifdef __powerc #pragma options align=reset #endif /* Helper for integer format codes: converts an arbitrary Python object to a PyLongObject if possible, otherwise fails. Caller should decref. */ static PyObject * get_pylong(PyObject *v) { assert(v != NULL); if (!PyLong_Check(v)) { /* Not an integer; try to use __index__ to convert. */ if (PyIndex_Check(v)) { v = PyNumber_Index(v); if (v == NULL) return NULL; } else { PyErr_SetString(StructError, "required argument is not an integer"); return NULL; } } else Py_INCREF(v); assert(PyLong_Check(v)); return v; } /* Helper routine to get a C long and raise the appropriate error if it isn't one */ static int get_long(PyObject *v, long *p) { long x; v = get_pylong(v); if (v == NULL) return -1; assert(PyLong_Check(v)); x = PyLong_AsLong(v); Py_DECREF(v); if (x == (long)-1 && PyErr_Occurred()) { if (PyErr_ExceptionMatches(PyExc_OverflowError)) PyErr_SetString(StructError, "argument out of range"); return -1; } *p = x; return 0; } /* Same, but handling unsigned long */ static int get_ulong(PyObject *v, unsigned long *p) { unsigned long x; v = get_pylong(v); if (v == NULL) return -1; assert(PyLong_Check(v)); x = PyLong_AsUnsignedLong(v); Py_DECREF(v); if (x == (unsigned long)-1 && PyErr_Occurred()) { if (PyErr_ExceptionMatches(PyExc_OverflowError)) PyErr_SetString(StructError, "argument out of range"); return -1; } *p = x; return 0; } #ifdef HAVE_LONG_LONG /* Same, but handling native long long. */ static int get_longlong(PyObject *v, PY_LONG_LONG *p) { PY_LONG_LONG x; v = get_pylong(v); if (v == NULL) return -1; assert(PyLong_Check(v)); x = PyLong_AsLongLong(v); Py_DECREF(v); if (x == (PY_LONG_LONG)-1 && PyErr_Occurred()) { if (PyErr_ExceptionMatches(PyExc_OverflowError)) PyErr_SetString(StructError, "argument out of range"); return -1; } *p = x; return 0; } /* Same, but handling native unsigned long long. */ static int get_ulonglong(PyObject *v, unsigned PY_LONG_LONG *p) { unsigned PY_LONG_LONG x; v = get_pylong(v); if (v == NULL) return -1; assert(PyLong_Check(v)); x = PyLong_AsUnsignedLongLong(v); Py_DECREF(v); if (x == (unsigned PY_LONG_LONG)-1 && PyErr_Occurred()) { if (PyErr_ExceptionMatches(PyExc_OverflowError)) PyErr_SetString(StructError, "argument out of range"); return -1; } *p = x; return 0; } #endif #define RANGE_ERROR(x, f, flag, mask) return _range_error(f, flag) /* Floating point helpers */ static PyObject * unpack_float(const char *p, /* start of 4-byte string */ int le) /* true for little-endian, false for big-endian */ { double x; x = _PyFloat_Unpack4((unsigned char *)p, le); if (x == -1.0 && PyErr_Occurred()) return NULL; return PyFloat_FromDouble(x); } static PyObject * unpack_double(const char *p, /* start of 8-byte string */ int le) /* true for little-endian, false for big-endian */ { double x; x = _PyFloat_Unpack8((unsigned char *)p, le); if (x == -1.0 && PyErr_Occurred()) return NULL; return PyFloat_FromDouble(x); } /* Helper to format the range error exceptions */ static int _range_error(const formatdef *f, int is_unsigned) { /* ulargest is the largest unsigned value with f->size bytes. * Note that the simpler: * ((size_t)1 << (f->size * 8)) - 1 * doesn't work when f->size == sizeof(size_t) because C doesn't * define what happens when a left shift count is >= the number of * bits in the integer being shifted; e.g., on some boxes it doesn't * shift at all when they're equal. */ const size_t ulargest = (size_t)-1 >> ((SIZEOF_SIZE_T - f->size)*8); assert(f->size >= 1 && f->size <= SIZEOF_SIZE_T); if (is_unsigned) PyErr_Format(StructError, "'%c' format requires 0 <= number <= %zu", f->format, ulargest); else { const Py_ssize_t largest = (Py_ssize_t)(ulargest >> 1); PyErr_Format(StructError, "'%c' format requires %zd <= number <= %zd", f->format, ~ largest, largest); } return -1; } /* A large number of small routines follow, with names of the form [bln][up]_TYPE [bln] distiguishes among big-endian, little-endian and native. [pu] distiguishes between pack (to struct) and unpack (from struct). TYPE is one of char, byte, ubyte, etc. */ /* Native mode routines. ****************************************************/ /* NOTE: In all n[up]_ routines handling types larger than 1 byte, there is *no* guarantee that the p pointer is properly aligned for each type, therefore memcpy is called. An intermediate variable is used to compensate for big-endian architectures. Normally both the intermediate variable and the memcpy call will be skipped by C optimisation in little-endian architectures (gcc >= 2.91 does this). */ static PyObject * nu_char(const char *p, const formatdef *f) { return PyBytes_FromStringAndSize(p, 1); } static PyObject * nu_byte(const char *p, const formatdef *f) { return PyLong_FromLong((long) *(signed char *)p); } static PyObject * nu_ubyte(const char *p, const formatdef *f) { return PyLong_FromLong((long) *(unsigned char *)p); } static PyObject * nu_short(const char *p, const formatdef *f) { short x; memcpy((char *)&x, p, sizeof x); return PyLong_FromLong((long)x); } static PyObject * nu_ushort(const char *p, const formatdef *f) { unsigned short x; memcpy((char *)&x, p, sizeof x); return PyLong_FromLong((long)x); } static PyObject * nu_int(const char *p, const formatdef *f) { int x; memcpy((char *)&x, p, sizeof x); return PyLong_FromLong((long)x); } static PyObject * nu_uint(const char *p, const formatdef *f) { unsigned int x; memcpy((char *)&x, p, sizeof x); #if (SIZEOF_LONG > SIZEOF_INT) return PyLong_FromLong((long)x); #else if (x <= ((unsigned int)LONG_MAX)) return PyLong_FromLong((long)x); return PyLong_FromUnsignedLong((unsigned long)x); #endif } static PyObject * nu_long(const char *p, const formatdef *f) { long x; memcpy((char *)&x, p, sizeof x); return PyLong_FromLong(x); } static PyObject * nu_ulong(const char *p, const formatdef *f) { unsigned long x; memcpy((char *)&x, p, sizeof x); if (x <= LONG_MAX) return PyLong_FromLong((long)x); return PyLong_FromUnsignedLong(x); } /* Native mode doesn't support q or Q unless the platform C supports long long (or, on Windows, __int64). */ #ifdef HAVE_LONG_LONG static PyObject * nu_longlong(const char *p, const formatdef *f) { PY_LONG_LONG x; memcpy((char *)&x, p, sizeof x); if (x >= LONG_MIN && x <= LONG_MAX) return PyLong_FromLong(Py_SAFE_DOWNCAST(x, PY_LONG_LONG, long)); return PyLong_FromLongLong(x); } static PyObject * nu_ulonglong(const char *p, const formatdef *f) { unsigned PY_LONG_LONG x; memcpy((char *)&x, p, sizeof x); if (x <= LONG_MAX) return PyLong_FromLong(Py_SAFE_DOWNCAST(x, unsigned PY_LONG_LONG, long)); return PyLong_FromUnsignedLongLong(x); } #endif static PyObject * nu_bool(const char *p, const formatdef *f) { BOOL_TYPE x; memcpy((char *)&x, p, sizeof x); return PyBool_FromLong(x != 0); } static PyObject * nu_float(const char *p, const formatdef *f) { float x; memcpy((char *)&x, p, sizeof x); return PyFloat_FromDouble((double)x); } static PyObject * nu_double(const char *p, const formatdef *f) { double x; memcpy((char *)&x, p, sizeof x); return PyFloat_FromDouble(x); } static PyObject * nu_void_p(const char *p, const formatdef *f) { void *x; memcpy((char *)&x, p, sizeof x); return PyLong_FromVoidPtr(x); } static int np_byte(char *p, PyObject *v, const formatdef *f) { long x; if (get_long(v, &x) < 0) return -1; if (x < -128 || x > 127){ PyErr_SetString(StructError, "byte format requires -128 <= number <= 127"); return -1; } *p = (char)x; return 0; } static int np_ubyte(char *p, PyObject *v, const formatdef *f) { long x; if (get_long(v, &x) < 0) return -1; if (x < 0 || x > 255){ PyErr_SetString(StructError, "ubyte format requires 0 <= number <= 255"); return -1; } *p = (char)x; return 0; } static int np_char(char *p, PyObject *v, const formatdef *f) { if (PyUnicode_Check(v)) { v = _PyUnicode_AsDefaultEncodedString(v, NULL); if (v == NULL) return -1; } if (!PyBytes_Check(v) || PyBytes_Size(v) != 1) { PyErr_SetString(StructError, "char format requires bytes or string of length 1"); return -1; } *p = *PyBytes_AsString(v); return 0; } static int np_short(char *p, PyObject *v, const formatdef *f) { long x; short y; if (get_long(v, &x) < 0) return -1; if (x < SHRT_MIN || x > SHRT_MAX){ PyErr_SetString(StructError, "short format requires " STRINGIFY(SHRT_MIN) " <= number <= " STRINGIFY(SHRT_MAX)); return -1; } y = (short)x; memcpy(p, (char *)&y, sizeof y); return 0; } static int np_ushort(char *p, PyObject *v, const formatdef *f) { long x; unsigned short y; if (get_long(v, &x) < 0) return -1; if (x < 0 || x > USHRT_MAX){ PyErr_SetString(StructError, "ushort format requires 0 <= number <= " STRINGIFY(USHRT_MAX)); return -1; } y = (unsigned short)x; memcpy(p, (char *)&y, sizeof y); return 0; } static int np_int(char *p, PyObject *v, const formatdef *f) { long x; int y; if (get_long(v, &x) < 0) return -1; #if (SIZEOF_LONG > SIZEOF_INT) if ((x < ((long)INT_MIN)) || (x > ((long)INT_MAX))) RANGE_ERROR(x, f, 0, -1); #endif y = (int)x; memcpy(p, (char *)&y, sizeof y); return 0; } static int np_uint(char *p, PyObject *v, const formatdef *f) { unsigned long x; unsigned int y; if (get_ulong(v, &x) < 0) return -1; y = (unsigned int)x; #if (SIZEOF_LONG > SIZEOF_INT) if (x > ((unsigned long)UINT_MAX)) RANGE_ERROR(y, f, 1, -1); #endif memcpy(p, (char *)&y, sizeof y); return 0; } static int np_long(char *p, PyObject *v, const formatdef *f) { long x; if (get_long(v, &x) < 0) return -1; memcpy(p, (char *)&x, sizeof x); return 0; } static int np_ulong(char *p, PyObject *v, const formatdef *f) { unsigned long x; if (get_ulong(v, &x) < 0) return -1; memcpy(p, (char *)&x, sizeof x); return 0; } #ifdef HAVE_LONG_LONG static int np_longlong(char *p, PyObject *v, const formatdef *f) { PY_LONG_LONG x; if (get_longlong(v, &x) < 0) return -1; memcpy(p, (char *)&x, sizeof x); return 0; } static int np_ulonglong(char *p, PyObject *v, const formatdef *f) { unsigned PY_LONG_LONG x; if (get_ulonglong(v, &x) < 0) return -1; memcpy(p, (char *)&x, sizeof x); return 0; } #endif static int np_bool(char *p, PyObject *v, const formatdef *f) { int y; BOOL_TYPE x; y = PyObject_IsTrue(v); if (y < 0) return -1; x = y; memcpy(p, (char *)&x, sizeof x); return 0; } static int np_float(char *p, PyObject *v, const formatdef *f) { float x = (float)PyFloat_AsDouble(v); if (x == -1 && PyErr_Occurred()) { PyErr_SetString(StructError, "required argument is not a float"); return -1; } memcpy(p, (char *)&x, sizeof x); return 0; } static int np_double(char *p, PyObject *v, const formatdef *f) { double x = PyFloat_AsDouble(v); if (x == -1 && PyErr_Occurred()) { PyErr_SetString(StructError, "required argument is not a float"); return -1; } memcpy(p, (char *)&x, sizeof(double)); return 0; } static int np_void_p(char *p, PyObject *v, const formatdef *f) { void *x; v = get_pylong(v); if (v == NULL) return -1; assert(PyLong_Check(v)); x = PyLong_AsVoidPtr(v); Py_DECREF(v); if (x == NULL && PyErr_Occurred()) return -1; memcpy(p, (char *)&x, sizeof x); return 0; } static formatdef native_table[] = { {'x', sizeof(char), 0, NULL}, {'b', sizeof(char), 0, nu_byte, np_byte}, {'B', sizeof(char), 0, nu_ubyte, np_ubyte}, {'c', sizeof(char), 0, nu_char, np_char}, {'s', sizeof(char), 0, NULL}, {'p', sizeof(char), 0, NULL}, {'h', sizeof(short), SHORT_ALIGN, nu_short, np_short}, {'H', sizeof(short), SHORT_ALIGN, nu_ushort, np_ushort}, {'i', sizeof(int), INT_ALIGN, nu_int, np_int}, {'I', sizeof(int), INT_ALIGN, nu_uint, np_uint}, {'l', sizeof(long), LONG_ALIGN, nu_long, np_long}, {'L', sizeof(long), LONG_ALIGN, nu_ulong, np_ulong}, #ifdef HAVE_LONG_LONG {'q', sizeof(PY_LONG_LONG), LONG_LONG_ALIGN, nu_longlong, np_longlong}, {'Q', sizeof(PY_LONG_LONG), LONG_LONG_ALIGN, nu_ulonglong,np_ulonglong}, #endif {'?', sizeof(BOOL_TYPE), BOOL_ALIGN, nu_bool, np_bool}, {'f', sizeof(float), FLOAT_ALIGN, nu_float, np_float}, {'d', sizeof(double), DOUBLE_ALIGN, nu_double, np_double}, {'P', sizeof(void *), VOID_P_ALIGN, nu_void_p, np_void_p}, {0} }; /* Big-endian routines. *****************************************************/ static PyObject * bu_int(const char *p, const formatdef *f) { long x = 0; Py_ssize_t i = f->size; const unsigned char *bytes = (const unsigned char *)p; do { x = (x<<8) | *bytes++; } while (--i > 0); /* Extend the sign bit. */ if (SIZEOF_LONG > f->size) x |= -(x & (1L << ((8 * f->size) - 1))); return PyLong_FromLong(x); } static PyObject * bu_uint(const char *p, const formatdef *f) { unsigned long x = 0; Py_ssize_t i = f->size; const unsigned char *bytes = (const unsigned char *)p; do { x = (x<<8) | *bytes++; } while (--i > 0); if (x <= LONG_MAX) return PyLong_FromLong((long)x); return PyLong_FromUnsignedLong(x); } static PyObject * bu_longlong(const char *p, const formatdef *f) { #ifdef HAVE_LONG_LONG PY_LONG_LONG x = 0; Py_ssize_t i = f->size; const unsigned char *bytes = (const unsigned char *)p; do { x = (x<<8) | *bytes++; } while (--i > 0); /* Extend the sign bit. */ if (SIZEOF_LONG_LONG > f->size) x |= -(x & ((PY_LONG_LONG)1 << ((8 * f->size) - 1))); if (x >= LONG_MIN && x <= LONG_MAX) return PyLong_FromLong(Py_SAFE_DOWNCAST(x, PY_LONG_LONG, long)); return PyLong_FromLongLong(x); #else return _PyLong_FromByteArray((const unsigned char *)p, 8, 0, /* little-endian */ 1 /* signed */); #endif } static PyObject * bu_ulonglong(const char *p, const formatdef *f) { #ifdef HAVE_LONG_LONG unsigned PY_LONG_LONG x = 0; Py_ssize_t i = f->size; const unsigned char *bytes = (const unsigned char *)p; do { x = (x<<8) | *bytes++; } while (--i > 0); if (x <= LONG_MAX) return PyLong_FromLong(Py_SAFE_DOWNCAST(x, unsigned PY_LONG_LONG, long)); return PyLong_FromUnsignedLongLong(x); #else return _PyLong_FromByteArray((const unsigned char *)p, 8, 0, /* little-endian */ 0 /* signed */); #endif } static PyObject * bu_float(const char *p, const formatdef *f) { return unpack_float(p, 0); } static PyObject * bu_double(const char *p, const formatdef *f) { return unpack_double(p, 0); } static PyObject * bu_bool(const char *p, const formatdef *f) { char x; memcpy((char *)&x, p, sizeof x); return PyBool_FromLong(x != 0); } static int bp_int(char *p, PyObject *v, const formatdef *f) { long x; Py_ssize_t i; if (get_long(v, &x) < 0) return -1; i = f->size; if (i != SIZEOF_LONG) { if ((i == 2) && (x < -32768 || x > 32767)) RANGE_ERROR(x, f, 0, 0xffffL); #if (SIZEOF_LONG != 4) else if ((i == 4) && (x < -2147483648L || x > 2147483647L)) RANGE_ERROR(x, f, 0, 0xffffffffL); #endif } do { p[--i] = (char)x; x >>= 8; } while (i > 0); return 0; } static int bp_uint(char *p, PyObject *v, const formatdef *f) { unsigned long x; Py_ssize_t i; if (get_ulong(v, &x) < 0) return -1; i = f->size; if (i != SIZEOF_LONG) { unsigned long maxint = 1; maxint <<= (unsigned long)(i * 8); if (x >= maxint) RANGE_ERROR(x, f, 1, maxint - 1); } do { p[--i] = (char)x; x >>= 8; } while (i > 0); return 0; } static int bp_longlong(char *p, PyObject *v, const formatdef *f) { int res; v = get_pylong(v); if (v == NULL) return -1; res = _PyLong_AsByteArray((PyLongObject *)v, (unsigned char *)p, 8, 0, /* little_endian */ 1 /* signed */); Py_DECREF(v); return res; } static int bp_ulonglong(char *p, PyObject *v, const formatdef *f) { int res; v = get_pylong(v); if (v == NULL) return -1; res = _PyLong_AsByteArray((PyLongObject *)v, (unsigned char *)p, 8, 0, /* little_endian */ 0 /* signed */); Py_DECREF(v); return res; } static int bp_float(char *p, PyObject *v, const formatdef *f) { double x = PyFloat_AsDouble(v); if (x == -1 && PyErr_Occurred()) { PyErr_SetString(StructError, "required argument is not a float"); return -1; } return _PyFloat_Pack4(x, (unsigned char *)p, 0); } static int bp_double(char *p, PyObject *v, const formatdef *f) { double x = PyFloat_AsDouble(v); if (x == -1 && PyErr_Occurred()) { PyErr_SetString(StructError, "required argument is not a float"); return -1; } return _PyFloat_Pack8(x, (unsigned char *)p, 0); } static int bp_bool(char *p, PyObject *v, const formatdef *f) { char y; y = PyObject_IsTrue(v); if (y < 0) return -1; memcpy(p, (char *)&y, sizeof y); return 0; } static formatdef bigendian_table[] = { {'x', 1, 0, NULL}, {'b', 1, 0, nu_byte, np_byte}, {'B', 1, 0, nu_ubyte, np_ubyte}, {'c', 1, 0, nu_char, np_char}, {'s', 1, 0, NULL}, {'p', 1, 0, NULL}, {'h', 2, 0, bu_int, bp_int}, {'H', 2, 0, bu_uint, bp_uint}, {'i', 4, 0, bu_int, bp_int}, {'I', 4, 0, bu_uint, bp_uint}, {'l', 4, 0, bu_int, bp_int}, {'L', 4, 0, bu_uint, bp_uint}, {'q', 8, 0, bu_longlong, bp_longlong}, {'Q', 8, 0, bu_ulonglong, bp_ulonglong}, {'?', 1, 0, bu_bool, bp_bool}, {'f', 4, 0, bu_float, bp_float}, {'d', 8, 0, bu_double, bp_double}, {0} }; /* Little-endian routines. *****************************************************/ static PyObject * lu_int(const char *p, const formatdef *f) { long x = 0; Py_ssize_t i = f->size; const unsigned char *bytes = (const unsigned char *)p; do { x = (x<<8) | bytes[--i]; } while (i > 0); /* Extend the sign bit. */ if (SIZEOF_LONG > f->size) x |= -(x & (1L << ((8 * f->size) - 1))); return PyLong_FromLong(x); } static PyObject * lu_uint(const char *p, const formatdef *f) { unsigned long x = 0; Py_ssize_t i = f->size; const unsigned char *bytes = (const unsigned char *)p; do { x = (x<<8) | bytes[--i]; } while (i > 0); if (x <= LONG_MAX) return PyLong_FromLong((long)x); return PyLong_FromUnsignedLong((long)x); } static PyObject * lu_longlong(const char *p, const formatdef *f) { #ifdef HAVE_LONG_LONG PY_LONG_LONG x = 0; Py_ssize_t i = f->size; const unsigned char *bytes = (const unsigned char *)p; do { x = (x<<8) | bytes[--i]; } while (i > 0); /* Extend the sign bit. */ if (SIZEOF_LONG_LONG > f->size) x |= -(x & ((PY_LONG_LONG)1 << ((8 * f->size) - 1))); if (x >= LONG_MIN && x <= LONG_MAX) return PyLong_FromLong(Py_SAFE_DOWNCAST(x, PY_LONG_LONG, long)); return PyLong_FromLongLong(x); #else return _PyLong_FromByteArray((const unsigned char *)p, 8, 1, /* little-endian */ 1 /* signed */); #endif } static PyObject * lu_ulonglong(const char *p, const formatdef *f) { #ifdef HAVE_LONG_LONG unsigned PY_LONG_LONG x = 0; Py_ssize_t i = f->size; const unsigned char *bytes = (const unsigned char *)p; do { x = (x<<8) | bytes[--i]; } while (i > 0); if (x <= LONG_MAX) return PyLong_FromLong(Py_SAFE_DOWNCAST(x, unsigned PY_LONG_LONG, long)); return PyLong_FromUnsignedLongLong(x); #else return _PyLong_FromByteArray((const unsigned char *)p, 8, 1, /* little-endian */ 0 /* signed */); #endif } static PyObject * lu_float(const char *p, const formatdef *f) { return unpack_float(p, 1); } static PyObject * lu_double(const char *p, const formatdef *f) { return unpack_double(p, 1); } static int lp_int(char *p, PyObject *v, const formatdef *f) { long x; Py_ssize_t i; if (get_long(v, &x) < 0) return -1; i = f->size; if (i != SIZEOF_LONG) { if ((i == 2) && (x < -32768 || x > 32767)) RANGE_ERROR(x, f, 0, 0xffffL); #if (SIZEOF_LONG != 4) else if ((i == 4) && (x < -2147483648L || x > 2147483647L)) RANGE_ERROR(x, f, 0, 0xffffffffL); #endif } do { *p++ = (char)x; x >>= 8; } while (--i > 0); return 0; } static int lp_uint(char *p, PyObject *v, const formatdef *f) { unsigned long x; Py_ssize_t i; if (get_ulong(v, &x) < 0) return -1; i = f->size; if (i != SIZEOF_LONG) { unsigned long maxint = 1; maxint <<= (unsigned long)(i * 8); if (x >= maxint) RANGE_ERROR(x, f, 1, maxint - 1); } do { *p++ = (char)x; x >>= 8; } while (--i > 0); return 0; } static int lp_longlong(char *p, PyObject *v, const formatdef *f) { int res; v = get_pylong(v); if (v == NULL) return -1; res = _PyLong_AsByteArray((PyLongObject*)v, (unsigned char *)p, 8, 1, /* little_endian */ 1 /* signed */); Py_DECREF(v); return res; } static int lp_ulonglong(char *p, PyObject *v, const formatdef *f) { int res; v = get_pylong(v); if (v == NULL) return -1; res = _PyLong_AsByteArray((PyLongObject*)v, (unsigned char *)p, 8, 1, /* little_endian */ 0 /* signed */); Py_DECREF(v); return res; } static int lp_float(char *p, PyObject *v, const formatdef *f) { double x = PyFloat_AsDouble(v); if (x == -1 && PyErr_Occurred()) { PyErr_SetString(StructError, "required argument is not a float"); return -1; } return _PyFloat_Pack4(x, (unsigned char *)p, 1); } static int lp_double(char *p, PyObject *v, const formatdef *f) { double x = PyFloat_AsDouble(v); if (x == -1 && PyErr_Occurred()) { PyErr_SetString(StructError, "required argument is not a float"); return -1; } return _PyFloat_Pack8(x, (unsigned char *)p, 1); } static formatdef lilendian_table[] = { {'x', 1, 0, NULL}, {'b', 1, 0, nu_byte, np_byte}, {'B', 1, 0, nu_ubyte, np_ubyte}, {'c', 1, 0, nu_char, np_char}, {'s', 1, 0, NULL}, {'p', 1, 0, NULL}, {'h', 2, 0, lu_int, lp_int}, {'H', 2, 0, lu_uint, lp_uint}, {'i', 4, 0, lu_int, lp_int}, {'I', 4, 0, lu_uint, lp_uint}, {'l', 4, 0, lu_int, lp_int}, {'L', 4, 0, lu_uint, lp_uint}, {'q', 8, 0, lu_longlong, lp_longlong}, {'Q', 8, 0, lu_ulonglong, lp_ulonglong}, {'?', 1, 0, bu_bool, bp_bool}, /* Std rep not endian dep, but potentially different from native rep -- reuse bx_bool funcs. */ {'f', 4, 0, lu_float, lp_float}, {'d', 8, 0, lu_double, lp_double}, {0} }; static const formatdef * whichtable(char **pfmt) { const char *fmt = (*pfmt)++; /* May be backed out of later */ switch (*fmt) { case '<': return lilendian_table; case '>': case '!': /* Network byte order is big-endian */ return bigendian_table; case '=': { /* Host byte order -- different from native in aligment! */ int n = 1; char *p = (char *) &n; if (*p == 1) return lilendian_table; else return bigendian_table; } default: --*pfmt; /* Back out of pointer increment */ /* Fall through */ case '@': return native_table; } } /* Get the table entry for a format code */ static const formatdef * getentry(int c, const formatdef *f) { for (; f->format != '\0'; f++) { if (f->format == c) { return f; } } PyErr_SetString(StructError, "bad char in struct format"); return NULL; } /* Align a size according to a format code. Return -1 on overflow. */ static Py_ssize_t align(Py_ssize_t size, char c, const formatdef *e) { Py_ssize_t extra; if (e->format == c) { if (e->alignment && size > 0) { extra = (e->alignment - 1) - (size - 1) % (e->alignment); if (extra > PY_SSIZE_T_MAX - size) return -1; size += extra; } } return size; } /* calculate the size of a format string */ static int prepare_s(PyStructObject *self) { const formatdef *f; const formatdef *e; formatcode *codes; const char *s; const char *fmt; char c; Py_ssize_t size, len, num, itemsize; fmt = PyBytes_AS_STRING(self->s_format); f = whichtable((char **)&fmt); s = fmt; size = 0; len = 0; while ((c = *s++) != '\0') { if (isspace(Py_CHARMASK(c))) continue; if ('0' <= c && c <= '9') { num = c - '0'; while ('0' <= (c = *s++) && c <= '9') { /* overflow-safe version of if (num*10 + (c - '0') > PY_SSIZE_T_MAX) { ... } */ if (num >= PY_SSIZE_T_MAX / 10 && ( num > PY_SSIZE_T_MAX / 10 || (c - '0') > PY_SSIZE_T_MAX % 10)) goto overflow; num = num*10 + (c - '0'); } if (c == '\0') { PyErr_SetString(StructError, "repeat count given without format specifier"); return -1; } } else num = 1; e = getentry(c, f); if (e == NULL) return -1; switch (c) { case 's': /* fall through */ case 'p': len++; break; case 'x': break; default: len += num; break; } itemsize = e->size; size = align(size, c, e); if (size == -1) goto overflow; /* if (size + num * itemsize > PY_SSIZE_T_MAX) { ... } */ if (num > (PY_SSIZE_T_MAX - size) / itemsize) goto overflow; size += num * itemsize; } /* check for overflow */ if ((len + 1) > (PY_SSIZE_T_MAX / sizeof(formatcode))) { PyErr_NoMemory(); return -1; } self->s_size = size; self->s_len = len; codes = PyMem_MALLOC((len + 1) * sizeof(formatcode)); if (codes == NULL) { PyErr_NoMemory(); return -1; } self->s_codes = codes; s = fmt; size = 0; while ((c = *s++) != '\0') { if (isspace(Py_CHARMASK(c))) continue; if ('0' <= c && c <= '9') { num = c - '0'; while ('0' <= (c = *s++) && c <= '9') num = num*10 + (c - '0'); if (c == '\0') break; } else num = 1; e = getentry(c, f); size = align(size, c, e); if (c == 's' || c == 'p') { codes->offset = size; codes->size = num; codes->fmtdef = e; codes++; size += num; } else if (c == 'x') { size += num; } else { while (--num >= 0) { codes->offset = size; codes->size = e->size; codes->fmtdef = e; codes++; size += e->size; } } } codes->fmtdef = NULL; codes->offset = size; codes->size = 0; return 0; overflow: PyErr_SetString(StructError, "total struct size too long"); return -1; } static PyObject * s_new(PyTypeObject *type, PyObject *args, PyObject *kwds) { PyObject *self; assert(type != NULL && type->tp_alloc != NULL); self = type->tp_alloc(type, 0); if (self != NULL) { PyStructObject *s = (PyStructObject*)self; Py_INCREF(Py_None); s->s_format = Py_None; s->s_codes = NULL; s->s_size = -1; s->s_len = -1; } return self; } static int s_init(PyObject *self, PyObject *args, PyObject *kwds) { PyStructObject *soself = (PyStructObject *)self; PyObject *o_format = NULL; int ret = 0; static char *kwlist[] = {"format", 0}; assert(PyStruct_Check(self)); if (!PyArg_ParseTupleAndKeywords(args, kwds, "O:Struct", kwlist, &o_format)) return -1; if (PyUnicode_Check(o_format)) { o_format = PyUnicode_AsASCIIString(o_format); if (o_format == NULL) return -1; } /* XXX support buffer interface, too */ else { Py_INCREF(o_format); } if (!PyBytes_Check(o_format)) { Py_DECREF(o_format); PyErr_Format(PyExc_TypeError, "Struct() argument 1 must be bytes, not %.200s", Py_TYPE(o_format)->tp_name); return -1; } Py_CLEAR(soself->s_format); soself->s_format = o_format; ret = prepare_s(soself); return ret; } static void s_dealloc(PyStructObject *s) { if (s->weakreflist != NULL) PyObject_ClearWeakRefs((PyObject *)s); if (s->s_codes != NULL) { PyMem_FREE(s->s_codes); } Py_XDECREF(s->s_format); Py_TYPE(s)->tp_free((PyObject *)s); } static PyObject * s_unpack_internal(PyStructObject *soself, char *startfrom) { formatcode *code; Py_ssize_t i = 0; PyObject *result = PyTuple_New(soself->s_len); if (result == NULL) return NULL; for (code = soself->s_codes; code->fmtdef != NULL; code++) { PyObject *v; const formatdef *e = code->fmtdef; const char *res = startfrom + code->offset; if (e->format == 's') { v = PyBytes_FromStringAndSize(res, code->size); } else if (e->format == 'p') { Py_ssize_t n = *(unsigned char*)res; if (n >= code->size) n = code->size - 1; v = PyBytes_FromStringAndSize(res + 1, n); } else { v = e->unpack(res, e); } if (v == NULL) goto fail; PyTuple_SET_ITEM(result, i++, v); } return result; fail: Py_DECREF(result); return NULL; } PyDoc_STRVAR(s_unpack__doc__, "S.unpack(buffer) -> (v1, v2, ...)\n\ \n\ Return a tuple containing values unpacked according to the format\n\ string S.format. Requires len(buffer) == S.size. See help(struct)\n\ for more on format strings."); static PyObject * s_unpack(PyObject *self, PyObject *input) { Py_buffer vbuf; PyObject *result; PyStructObject *soself = (PyStructObject *)self; assert(PyStruct_Check(self)); assert(soself->s_codes != NULL); if (PyObject_GetBuffer(input, &vbuf, PyBUF_SIMPLE) < 0) return NULL; if (vbuf.len != soself->s_size) { PyErr_Format(StructError, "unpack requires a bytes argument of length %zd", soself->s_size); PyBuffer_Release(&vbuf); return NULL; } result = s_unpack_internal(soself, vbuf.buf); PyBuffer_Release(&vbuf); return result; } PyDoc_STRVAR(s_unpack_from__doc__, "S.unpack_from(buffer, offset=0) -> (v1, v2, ...)\n\ \n\ Return a tuple containing values unpacked according to the format\n\ string S.format. Requires len(buffer[offset:]) >= S.size. See\n\ help(struct) for more on format strings."); static PyObject * s_unpack_from(PyObject *self, PyObject *args, PyObject *kwds) { static char *kwlist[] = {"buffer", "offset", 0}; PyObject *input; Py_ssize_t offset = 0; Py_buffer vbuf; PyObject *result; PyStructObject *soself = (PyStructObject *)self; assert(PyStruct_Check(self)); assert(soself->s_codes != NULL); if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|n:unpack_from", kwlist, &input, &offset)) return NULL; if (PyObject_GetBuffer(input, &vbuf, PyBUF_SIMPLE) < 0) return NULL; if (offset < 0) offset += vbuf.len; if (offset < 0 || vbuf.len - offset < soself->s_size) { PyErr_Format(StructError, "unpack_from requires a buffer of at least %zd bytes", soself->s_size); PyBuffer_Release(&vbuf); return NULL; } result = s_unpack_internal(soself, (char*)vbuf.buf + offset); PyBuffer_Release(&vbuf); return result; } /* * Guts of the pack function. * * Takes a struct object, a tuple of arguments, and offset in that tuple of * argument for where to start processing the arguments for packing, and a * character buffer for writing the packed string. The caller must insure * that the buffer may contain the required length for packing the arguments. * 0 is returned on success, 1 is returned if there is an error. * */ static int s_pack_internal(PyStructObject *soself, PyObject *args, int offset, char* buf) { formatcode *code; /* XXX(nnorwitz): why does i need to be a local? can we use the offset parameter or do we need the wider width? */ Py_ssize_t i; memset(buf, '\0', soself->s_size); i = offset; for (code = soself->s_codes; code->fmtdef != NULL; code++) { Py_ssize_t n; PyObject *v = PyTuple_GET_ITEM(args, i++); const formatdef *e = code->fmtdef; char *res = buf + code->offset; if (e->format == 's') { int isstring; void *p; if (PyUnicode_Check(v)) { v = _PyUnicode_AsDefaultEncodedString(v, NULL); if (v == NULL) return -1; } isstring = PyBytes_Check(v); if (!isstring && !PyByteArray_Check(v)) { PyErr_SetString(StructError, "argument for 's' must be a bytes or string"); return -1; } if (isstring) { n = PyBytes_GET_SIZE(v); p = PyBytes_AS_STRING(v); } else { n = PyByteArray_GET_SIZE(v); p = PyByteArray_AS_STRING(v); } if (n > code->size) n = code->size; if (n > 0) memcpy(res, p, n); } else if (e->format == 'p') { int isstring; void *p; if (PyUnicode_Check(v)) { v = _PyUnicode_AsDefaultEncodedString(v, NULL); if (v == NULL) return -1; } isstring = PyBytes_Check(v); if (!isstring && !PyByteArray_Check(v)) { PyErr_SetString(StructError, "argument for 'p' must be a bytes or string"); return -1; } if (isstring) { n = PyBytes_GET_SIZE(v); p = PyBytes_AS_STRING(v); } else { n = PyByteArray_GET_SIZE(v); p = PyByteArray_AS_STRING(v); } if (n > (code->size - 1)) n = code->size - 1; if (n > 0) memcpy(res + 1, p, n); if (n > 255) n = 255; *res = Py_SAFE_DOWNCAST(n, Py_ssize_t, unsigned char); } else { if (e->pack(res, v, e) < 0) { if (PyLong_Check(v) && PyErr_ExceptionMatches(PyExc_OverflowError)) PyErr_SetString(StructError, "long too large to convert to int"); return -1; } } } /* Success */ return 0; } PyDoc_STRVAR(s_pack__doc__, "S.pack(v1, v2, ...) -> bytes\n\ \n\ Return a bytes object containing values v1, v2, ... packed according\n\ to the format string S.format. See help(struct) for more on format\n\ strings."); static PyObject * s_pack(PyObject *self, PyObject *args) { PyStructObject *soself; PyObject *result; /* Validate arguments. */ soself = (PyStructObject *)self; assert(PyStruct_Check(self)); assert(soself->s_codes != NULL); if (PyTuple_GET_SIZE(args) != soself->s_len) { PyErr_Format(StructError, "pack requires exactly %zd arguments", soself->s_len); return NULL; } /* Allocate a new string */ result = PyBytes_FromStringAndSize((char *)NULL, soself->s_size); if (result == NULL) return NULL; /* Call the guts */ if ( s_pack_internal(soself, args, 0, PyBytes_AS_STRING(result)) != 0 ) { Py_DECREF(result); return NULL; } return result; } PyDoc_STRVAR(s_pack_into__doc__, "S.pack_into(buffer, offset, v1, v2, ...)\n\ \n\ Pack the values v1, v2, ... according to the format string S.format\n\ and write the packed bytes into the writable buffer buf starting at\n\ offset. Note that the offset is a required argument. See\n\ help(struct) for more on format strings."); static PyObject * s_pack_into(PyObject *self, PyObject *args) { PyStructObject *soself; char *buffer; Py_ssize_t buffer_len, offset; /* Validate arguments. +1 is for the first arg as buffer. */ soself = (PyStructObject *)self; assert(PyStruct_Check(self)); assert(soself->s_codes != NULL); if (PyTuple_GET_SIZE(args) != (soself->s_len + 2)) { PyErr_Format(StructError, "pack_into requires exactly %zd arguments", (soself->s_len + 2)); return NULL; } /* Extract a writable memory buffer from the first argument */ if ( PyObject_AsWriteBuffer(PyTuple_GET_ITEM(args, 0), (void**)&buffer, &buffer_len) == -1 ) { return NULL; } assert( buffer_len >= 0 ); /* Extract the offset from the first argument */ offset = PyNumber_AsSsize_t(PyTuple_GET_ITEM(args, 1), PyExc_IndexError); if (offset == -1 && PyErr_Occurred()) return NULL; /* Support negative offsets. */ if (offset < 0) offset += buffer_len; /* Check boundaries */ if (offset < 0 || (buffer_len - offset) < soself->s_size) { PyErr_Format(StructError, "pack_into requires a buffer of at least %zd bytes", soself->s_size); return NULL; } /* Call the guts */ if ( s_pack_internal(soself, args, 2, buffer + offset) != 0 ) { return NULL; } Py_RETURN_NONE; } static PyObject * s_get_format(PyStructObject *self, void *unused) { Py_INCREF(self->s_format); return self->s_format; } static PyObject * s_get_size(PyStructObject *self, void *unused) { return PyLong_FromSsize_t(self->s_size); } /* List of functions */ static struct PyMethodDef s_methods[] = { {"pack", s_pack, METH_VARARGS, s_pack__doc__}, {"pack_into", s_pack_into, METH_VARARGS, s_pack_into__doc__}, {"unpack", s_unpack, METH_O, s_unpack__doc__}, {"unpack_from", (PyCFunction)s_unpack_from, METH_VARARGS|METH_KEYWORDS, s_unpack_from__doc__}, {NULL, NULL} /* sentinel */ }; PyDoc_STRVAR(s__doc__, "Struct(fmt) --> compiled struct object\n" "\n" "Return a new Struct object which writes and reads binary data according to\n" "the format string fmt. See help(struct) for more on format strings."); #define OFF(x) offsetof(PyStructObject, x) static PyGetSetDef s_getsetlist[] = { {"format", (getter)s_get_format, (setter)NULL, "struct format string", NULL}, {"size", (getter)s_get_size, (setter)NULL, "struct size in bytes", NULL}, {NULL} /* sentinel */ }; static PyTypeObject PyStructType = { PyVarObject_HEAD_INIT(NULL, 0) "Struct", sizeof(PyStructObject), 0, (destructor)s_dealloc, /* tp_dealloc */ 0, /* tp_print */ 0, /* tp_getattr */ 0, /* tp_setattr */ 0, /* tp_reserved */ 0, /* tp_repr */ 0, /* tp_as_number */ 0, /* tp_as_sequence */ 0, /* tp_as_mapping */ 0, /* tp_hash */ 0, /* tp_call */ 0, /* tp_str */ PyObject_GenericGetAttr, /* tp_getattro */ PyObject_GenericSetAttr, /* tp_setattro */ 0, /* tp_as_buffer */ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */ s__doc__, /* tp_doc */ 0, /* tp_traverse */ 0, /* tp_clear */ 0, /* tp_richcompare */ offsetof(PyStructObject, weakreflist), /* tp_weaklistoffset */ 0, /* tp_iter */ 0, /* tp_iternext */ s_methods, /* tp_methods */ NULL, /* tp_members */ s_getsetlist, /* tp_getset */ 0, /* tp_base */ 0, /* tp_dict */ 0, /* tp_descr_get */ 0, /* tp_descr_set */ 0, /* tp_dictoffset */ s_init, /* tp_init */ PyType_GenericAlloc,/* tp_alloc */ s_new, /* tp_new */ PyObject_Del, /* tp_free */ }; /* ---- Standalone functions ---- */ #define MAXCACHE 100 static PyObject *cache = NULL; static PyObject * cache_struct(PyObject *fmt) { PyObject * s_object; if (cache == NULL) { cache = PyDict_New(); if (cache == NULL) return NULL; } s_object = PyDict_GetItem(cache, fmt); if (s_object != NULL) { Py_INCREF(s_object); return s_object; } s_object = PyObject_CallFunctionObjArgs((PyObject *)(&PyStructType), fmt, NULL); if (s_object != NULL) { if (PyDict_Size(cache) >= MAXCACHE) PyDict_Clear(cache); /* Attempt to cache the result */ if (PyDict_SetItem(cache, fmt, s_object) == -1) PyErr_Clear(); } return s_object; } PyDoc_STRVAR(clearcache_doc, "Clear the internal cache."); static PyObject * clearcache(PyObject *self) { Py_CLEAR(cache); Py_RETURN_NONE; } PyDoc_STRVAR(calcsize_doc, "calcsize(fmt) -> integer\n\ \n\ Return size in bytes of the struct described by the format string fmt."); static PyObject * calcsize(PyObject *self, PyObject *fmt) { Py_ssize_t n; PyObject *s_object = cache_struct(fmt); if (s_object == NULL) return NULL; n = ((PyStructObject *)s_object)->s_size; Py_DECREF(s_object); return PyLong_FromSsize_t(n); } PyDoc_STRVAR(pack_doc, "pack(fmt, v1, v2, ...) -> bytes\n\ \n\ Return a bytes object containing the values v1, v2, ... packed according\n\ to the format string fmt. See help(struct) for more on format strings."); static PyObject * pack(PyObject *self, PyObject *args) { PyObject *s_object, *fmt, *newargs, *result; Py_ssize_t n = PyTuple_GET_SIZE(args); if (n == 0) { PyErr_SetString(PyExc_TypeError, "missing format argument"); return NULL; } fmt = PyTuple_GET_ITEM(args, 0); newargs = PyTuple_GetSlice(args, 1, n); if (newargs == NULL) return NULL; s_object = cache_struct(fmt); if (s_object == NULL) { Py_DECREF(newargs); return NULL; } result = s_pack(s_object, newargs); Py_DECREF(newargs); Py_DECREF(s_object); return result; } PyDoc_STRVAR(pack_into_doc, "pack_into(fmt, buffer, offset, v1, v2, ...)\n\ \n\ Pack the values v1, v2, ... according to the format string fmt and write\n\ the packed bytes into the writable buffer buf starting at offset. Note\n\ that the offset is a required argument. See help(struct) for more\n\ on format strings."); static PyObject * pack_into(PyObject *self, PyObject *args) { PyObject *s_object, *fmt, *newargs, *result; Py_ssize_t n = PyTuple_GET_SIZE(args); if (n == 0) { PyErr_SetString(PyExc_TypeError, "missing format argument"); return NULL; } fmt = PyTuple_GET_ITEM(args, 0); newargs = PyTuple_GetSlice(args, 1, n); if (newargs == NULL) return NULL; s_object = cache_struct(fmt); if (s_object == NULL) { Py_DECREF(newargs); return NULL; } result = s_pack_into(s_object, newargs); Py_DECREF(newargs); Py_DECREF(s_object); return result; } PyDoc_STRVAR(unpack_doc, "unpack(fmt, buffer) -> (v1, v2, ...)\n\ \n\ Return a tuple containing values unpacked according to the format string\n\ fmt. Requires len(buffer) == calcsize(fmt). See help(struct) for more\n\ on format strings."); static PyObject * unpack(PyObject *self, PyObject *args) { PyObject *s_object, *fmt, *inputstr, *result; if (!PyArg_UnpackTuple(args, "unpack", 2, 2, &fmt, &inputstr)) return NULL; s_object = cache_struct(fmt); if (s_object == NULL) return NULL; result = s_unpack(s_object, inputstr); Py_DECREF(s_object); return result; } PyDoc_STRVAR(unpack_from_doc, "unpack_from(fmt, buffer, offset=0) -> (v1, v2, ...)\n\ \n\ Return a tuple containing values unpacked according to the format string\n\ fmt. Requires len(buffer[offset:]) >= calcsize(fmt). See help(struct)\n\ for more on format strings."); static PyObject * unpack_from(PyObject *self, PyObject *args, PyObject *kwds) { PyObject *s_object, *fmt, *newargs, *result; Py_ssize_t n = PyTuple_GET_SIZE(args); if (n == 0) { PyErr_SetString(PyExc_TypeError, "missing format argument"); return NULL; } fmt = PyTuple_GET_ITEM(args, 0); newargs = PyTuple_GetSlice(args, 1, n); if (newargs == NULL) return NULL; s_object = cache_struct(fmt); if (s_object == NULL) { Py_DECREF(newargs); return NULL; } result = s_unpack_from(s_object, newargs, kwds); Py_DECREF(newargs); Py_DECREF(s_object); return result; } static struct PyMethodDef module_functions[] = { {"_clearcache", (PyCFunction)clearcache, METH_NOARGS, clearcache_doc}, {"calcsize", calcsize, METH_O, calcsize_doc}, {"pack", pack, METH_VARARGS, pack_doc}, {"pack_into", pack_into, METH_VARARGS, pack_into_doc}, {"unpack", unpack, METH_VARARGS, unpack_doc}, {"unpack_from", (PyCFunction)unpack_from, METH_VARARGS|METH_KEYWORDS, unpack_from_doc}, {NULL, NULL} /* sentinel */ }; /* Module initialization */ PyDoc_STRVAR(module_doc, "Functions to convert between Python values and C structs.\n\ Python bytes objects are used to hold the data representing the C struct\n\ and also as format strings (explained below) to describe the layout of data\n\ in the C struct.\n\ \n\ The optional first format char indicates byte order, size and alignment:\n\ @: native order, size & alignment (default)\n\ =: native order, std. size & alignment\n\ <: little-endian, std. size & alignment\n\ >: big-endian, std. size & alignment\n\ !: same as >\n\ \n\ The remaining chars indicate types of args and must match exactly;\n\ these can be preceded by a decimal repeat count:\n\ x: pad byte (no data); c:char; b:signed byte; B:unsigned byte;\n\ ?: _Bool (requires C99; if not available, char is used instead)\n\ h:short; H:unsigned short; i:int; I:unsigned int;\n\ l:long; L:unsigned long; f:float; d:double.\n\ Special cases (preceding decimal count indicates length):\n\ s:string (array of char); p: pascal string (with count byte).\n\ Special case (only available in native format):\n\ P:an integer type that is wide enough to hold a pointer.\n\ Special case (not in native mode unless 'long long' in platform C):\n\ q:long long; Q:unsigned long long\n\ Whitespace between formats is ignored.\n\ \n\ The variable struct.error is an exception raised on errors.\n"); static struct PyModuleDef _structmodule = { PyModuleDef_HEAD_INIT, "_struct", module_doc, -1, module_functions, NULL, NULL, NULL, NULL }; PyMODINIT_FUNC PyInit__struct(void) { PyObject *m; m = PyModule_Create(&_structmodule); if (m == NULL) return NULL; Py_TYPE(&PyStructType) = &PyType_Type; if (PyType_Ready(&PyStructType) < 0) return NULL; /* Check endian and swap in faster functions */ { int one = 1; formatdef *native = native_table; formatdef *other, *ptr; if ((int)*(unsigned char*)&one) other = lilendian_table; else other = bigendian_table; /* Scan through the native table, find a matching entry in the endian table and swap in the native implementations whenever possible (64-bit platforms may not have "standard" sizes) */ while (native->format != '\0' && other->format != '\0') { ptr = other; while (ptr->format != '\0') { if (ptr->format == native->format) { /* Match faster when formats are listed in the same order */ if (ptr == other) other++; /* Only use the trick if the size matches */ if (ptr->size != native->size) break; /* Skip float and double, could be "unknown" float format */ if (ptr->format == 'd' || ptr->format == 'f') break; ptr->pack = native->pack; ptr->unpack = native->unpack; break; } ptr++; } native++; } } /* Add some symbolic constants to the module */ if (StructError == NULL) { StructError = PyErr_NewException("struct.error", NULL, NULL); if (StructError == NULL) return NULL; } Py_INCREF(StructError); PyModule_AddObject(m, "error", StructError); Py_INCREF((PyObject*)&PyStructType); PyModule_AddObject(m, "Struct", (PyObject*)&PyStructType); return m; }