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author | Tim Peters <tim.peters@gmail.com> | 2001-06-10 23:40:19 (GMT) |
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committer | Tim Peters <tim.peters@gmail.com> | 2001-06-10 23:40:19 (GMT) |
commit | 7b9542a3f747787aedf056ddaef99e4469777aa9 (patch) | |
tree | bcbb8eb84c0606c27c8890f528f4378eaed25996 /Modules/structmodule.c | |
parent | fcc54cab100108f97c5b5641e3df11b7614993c2 (diff) | |
download | cpython-7b9542a3f747787aedf056ddaef99e4469777aa9.zip cpython-7b9542a3f747787aedf056ddaef99e4469777aa9.tar.gz cpython-7b9542a3f747787aedf056ddaef99e4469777aa9.tar.bz2 |
Initial support for 'q' and 'Q' struct format codes: for now, only in
native mode, and only when config #defines HAVE_LONG_LONG. Standard mode
will eventually treat them as 8-byte ints across all platforms, but that
likely requires a new set of routines in longobject.c first (while
sizeof(long) >= 4 is guaranteed by C, there's nothing in C we can rely
on x-platform to hold 8 bytes of int, so we'll have to roll our own;
I'm thinking of a simple pair of conversion functions, Python long
to/from sized vector of unsigned bytes; that may be useful for GMP
conversions too; std q/Q would call them with size fixed at 8).
test_struct.py: In addition to adding some native-mode 'q' and 'Q' tests,
got rid of unused code, and repaired a non-portable assumption about
native sizeof(short) (it isn't 2 on some Cray boxes).
libstruct.tex: In addition to adding a bit of 'q'/'Q' docs (more needed
later), removed an erroneous footnote about 'I' behavior.
Diffstat (limited to 'Modules/structmodule.c')
-rw-r--r-- | Modules/structmodule.c | 187 |
1 files changed, 186 insertions, 1 deletions
diff --git a/Modules/structmodule.c b/Modules/structmodule.c index 9d1c436..a168b9f 100644 --- a/Modules/structmodule.c +++ b/Modules/structmodule.c @@ -22,9 +22,11 @@ these can be preceded by a decimal repeat count:\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 (w. count byte).\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."; @@ -65,6 +67,18 @@ typedef struct { char c; void *x; } s_void_p; #define DOUBLE_ALIGN (sizeof(s_double) - sizeof(double)) #define VOID_P_ALIGN (sizeof(s_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; LONG_LONG x; } s_long_long; +#define LONG_LONG_ALIGN (sizeof(s_long_long) - sizeof(LONG_LONG)) + +#else +static char qQ_error_msg[] = +"q and Q unavailable in native mode on this platform; use a standard mode.\0"; + +#endif + #define STRINGIFY(x) #x #ifdef __powerc @@ -106,6 +120,93 @@ get_ulong(PyObject *v, unsigned long *p) } } +#ifdef HAVE_LONG_LONG + +/* Same, but handling native long long. */ + +static int +get_longlong(PyObject *v, LONG_LONG *p) +{ + LONG_LONG x; + int v_needs_decref = 0; + + if (PyInt_Check(v)) { + x = (LONG_LONG)PyInt_AS_LONG(v); + *p = x; + return 0; + } + if (!PyLong_Check(v)) { + PyNumberMethods *m = v->ob_type->tp_as_number; + if (m != NULL && m->nb_long != NULL) { + v = m->nb_long(v); + if (v == NULL) + return -1; + v_needs_decref = 1; + } + if (!PyLong_Check(v)) { + PyErr_SetString(StructError, + "cannot convert argument to long"); + if (v_needs_decref) + Py_DECREF(v); + return -1; + } + } + assert(PyLong_Check(v)); + x = PyLong_AsLongLong(v); + if (v_needs_decref) + Py_DECREF(v); + if (x == (LONG_LONG)-1 && PyErr_Occurred()) + return -1; + *p = x; + return 0; +} + +/* Same, but handling native unsigned long long. */ + +static int +get_ulonglong(PyObject *v, unsigned LONG_LONG *p) +{ + unsigned LONG_LONG x; + int v_needs_decref = 0; + + if (PyInt_Check(v)) { + long i = PyInt_AS_LONG(v); + if (i < 0) { + PyErr_SetString(StructError, "can't convert negative " + "int to unsigned"); + return -1; + } + x = (unsigned LONG_LONG)i; + *p = x; + return 0; + } + if (!PyLong_Check(v)) { + PyNumberMethods *m = v->ob_type->tp_as_number; + if (m != NULL && m->nb_long != NULL) { + v = m->nb_long(v); + if (v == NULL) + return -1; + v_needs_decref = 1; + } + if (!PyLong_Check(v)) { + PyErr_SetString(StructError, + "cannot convert argument to long"); + if (v_needs_decref) + Py_DECREF(v); + return -1; + } + } + assert(PyLong_Check(v)); + x = PyLong_AsUnsignedLongLong(v); + if (v_needs_decref) + Py_DECREF(v); + if (x == (unsigned LONG_LONG)-1 && PyErr_Occurred()) + return -1; + *p = x; + return 0; +} + +#endif /* Floating point helpers */ @@ -395,6 +496,17 @@ typedef struct _formatdef { const struct _formatdef *); } formatdef; +/* 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. */ + static PyObject * nu_char(const char *p, const formatdef *f) { @@ -450,6 +562,34 @@ nu_ulong(const char *p, const formatdef *f) return PyLong_FromUnsignedLong(*(unsigned long *)p); } +/* 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) +{ + return PyLong_FromLongLong(*(LONG_LONG *)p); +} + +static PyObject * +nu_ulonglong(const char *p, const formatdef *f) +{ + return PyLong_FromUnsignedLongLong(*(unsigned LONG_LONG *)p); +} + +#else + +static PyObject * +nu_qQerror(const char *p, const formatdef *f) +{ + PyErr_SetString(StructError, qQ_error_msg); + return NULL; +} + +#endif + static PyObject * nu_float(const char *p, const formatdef *f) { @@ -585,6 +725,39 @@ np_ulong(char *p, PyObject *v, const formatdef *f) return 0; } +#ifdef HAVE_LONG_LONG + +static int +np_longlong(char *p, PyObject *v, const formatdef *f) +{ + LONG_LONG x; + if (get_longlong(v, &x) < 0) + return -1; + * (LONG_LONG *)p = x; + return 0; +} + +static int +np_ulonglong(char *p, PyObject *v, const formatdef *f) +{ + unsigned LONG_LONG x; + if (get_ulonglong(v, &x) < 0) + return -1; + * (unsigned LONG_LONG *)p = x; + return 0; +} + +#else + +static int +np_qQerror(char *p, PyObject *v, const formatdef *f) +{ + PyErr_SetString(StructError, qQ_error_msg); + return -1; +} + +#endif + static int np_float(char *p, PyObject *v, const formatdef *f) { @@ -642,6 +815,18 @@ static formatdef native_table[] = { {'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}, +#ifdef HAVE_LONG_LONG + {'q', sizeof(LONG_LONG), LONG_LONG_ALIGN, nu_longlong, np_longlong}, + {'Q', sizeof(LONG_LONG), LONG_LONG_ALIGN, nu_ulonglong,np_ulonglong}, +#else + /* n[pu]_qQerror just raise errors, but give them "the expected" size + and alignment anyway so that calcsize returns something reasonable, + and so unpack code that works on a 'long long' platform ends up in + the error routine instead of with a mysterious "unpack str size + does not match format" msg when run on a non-'long long' box. */ + {'q', 8, 8, nu_qQerror, np_qQerror}, + {'Q', 8, 8, nu_qQerror, np_qQerror}, +#endif {0} }; 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