cpython/Modules/python.c

/* Minimal main program -- everything is loaded from the library */

#include "Python.h"
#include <locale.h>

#ifdef __FreeBSD__
#include <floatingpoint.h>
#endif

#ifdef MS_WINDOWS
int
wmain(int argc, wchar_t **argv)
{
	return Py_Main(argc, argv);
}
#else
static wchar_t*
char2wchar(char* arg)
{
	wchar_t *res;
#ifdef HAVE_BROKEN_MBSTOWCS
	/* Some platforms have a broken implementation of
	 * mbstowcs which does not count the characters that
	 * would result from conversion.  Use an upper bound.
	 */
	size_t argsize = strlen(arg);
#else
	size_t argsize = mbstowcs(NULL, arg, 0);
#endif
	size_t count;
	unsigned char *in;
	wchar_t *out;
#ifdef HAVE_MBRTOWC
	mbstate_t mbs;
#endif
	if (argsize != (size_t)-1) {
		res = (wchar_t *)PyMem_Malloc((argsize+1)*sizeof(wchar_t));
		if (!res)
			goto oom;
		count = mbstowcs(res, arg, argsize+1);
		if (count != (size_t)-1) {
			wchar_t *tmp;
			/* Only use the result if it contains no
			   surrogate characters. */
			for (tmp = res; *tmp != 0 &&
				     (*tmp < 0xd800 || *tmp > 0xdfff); tmp++)
				;
			if (*tmp == 0)
				return res;
		}
		PyMem_Free(res);
	}
	/* Conversion failed. Fall back to escaping with surrogateescape. */
#ifdef HAVE_MBRTOWC
	/* Try conversion with mbrtwoc (C99), and escape non-decodable bytes. */
	
	/* Overallocate; as multi-byte characters are in the argument, the
	   actual output could use less memory. */
	argsize = strlen(arg) + 1;
	res = PyMem_Malloc(argsize*sizeof(wchar_t));
	if (!res) goto oom;
	in = (unsigned char*)arg;
	out = res;
	memset(&mbs, 0, sizeof mbs);
	while (argsize) {
		size_t converted = mbrtowc(out, (char*)in, argsize, &mbs);
		if (converted == 0)
			/* Reached end of string; null char stored. */
			break;
		if (converted == (size_t)-2) {
			/* Incomplete character. This should never happen,
			   since we provide everything that we have -
			   unless there is a bug in the C library, or I 
			   misunderstood how mbrtowc works. */
			fprintf(stderr, "unexpected mbrtowc result -2\n");
			return NULL;
		}
		if (converted == (size_t)-1) {
			/* Conversion error. Escape as UTF-8b, and start over
			   in the initial shift state. */
			*out++ = 0xdc00 + *in++;
			argsize--;
			memset(&mbs, 0, sizeof mbs);
			continue;
		}
		if (*out >= 0xd800 && *out <= 0xdfff) {
			/* Surrogate character.  Escape the original
			   byte sequence with surrogateescape. */
			argsize -= converted;
			while (converted--)
				*out++ = 0xdc00 + *in++;
			continue;
		}
		/* successfully converted some bytes */
		in += converted;
		argsize -= converted;
		out++;
	}
#else
	/* Cannot use C locale for escaping; manually escape as if charset
	   is ASCII (i.e. escape all bytes > 128. This will still roundtrip
	   correctly in the locale's charset, which must be an ASCII superset. */
	res = PyMem_Malloc((strlen(arg)+1)*sizeof(wchar_t));
	if (!res) goto oom;
	in = (unsigned char*)arg;
	out = res;
	while(*in)
		if(*in < 128)
			*out++ = *in++;
		else
			*out++ = 0xdc00 + *in++;
	*out = 0;
#endif
	return res;
oom:
	fprintf(stderr, "out of memory\n");
	return NULL;
}

int
main(int argc, char **argv)
{
	wchar_t **argv_copy = (wchar_t **)PyMem_Malloc(sizeof(wchar_t*)*argc);
	/* We need a second copies, as Python might modify the first one. */
	wchar_t **argv_copy2 = (wchar_t **)PyMem_Malloc(sizeof(wchar_t*)*argc);
	int i, res;
	char *oldloc;
	/* 754 requires that FP exceptions run in "no stop" mode by default,
	 * and until C vendors implement C99's ways to control FP exceptions,
	 * Python requires non-stop mode.  Alas, some platforms enable FP
	 * exceptions by default.  Here we disable them.
	 */
#ifdef __FreeBSD__
	fp_except_t m;

	m = fpgetmask();
	fpsetmask(m & ~FP_X_OFL);
#endif
	if (!argv_copy || !argv_copy2) {
		fprintf(stderr, "out of memory\n");
		return 1;
	}
	oldloc = strdup(setlocale(LC_ALL, NULL));
	setlocale(LC_ALL, "");
	for (i = 0; i < argc; i++) {
		argv_copy2[i] = argv_copy[i] = char2wchar(argv[i]);
		if (!argv_copy[i])
			return 1;
	}
	setlocale(LC_ALL, oldloc);
	free(oldloc);
	res = Py_Main(argc, argv_copy);
	for (i = 0; i < argc; i++) {
		PyMem_Free(argv_copy2[i]);
	}
	PyMem_Free(argv_copy);
	PyMem_Free(argv_copy2);
	return res;
}
#endif