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