cpython/Objects/bytes_methods.c

#define PY_SSIZE_T_CLEAN
#include "Python.h"
#include "bytes_methods.h"

PyDoc_STRVAR_shared(_Py_isspace__doc__,
"B.isspace() -> bool\n\
\n\
Return True if all characters in B are whitespace\n\
and there is at least one character in B, False otherwise.");

PyObject*
_Py_bytes_isspace(const char *cptr, Py_ssize_t len)
{
    const unsigned char *p
        = (unsigned char *) cptr;
    const unsigned char *e;

    /* Shortcut for single character strings */
    if (len == 1 && Py_ISSPACE(*p))
        Py_RETURN_TRUE;

    /* Special case for empty strings */
    if (len == 0)
        Py_RETURN_FALSE;

    e = p + len;
    for (; p < e; p++) {
        if (!Py_ISSPACE(*p))
            Py_RETURN_FALSE;
    }
    Py_RETURN_TRUE;
}


PyDoc_STRVAR_shared(_Py_isalpha__doc__,
"B.isalpha() -> bool\n\
\n\
Return True if all characters in B are alphabetic\n\
and there is at least one character in B, False otherwise.");

PyObject*
_Py_bytes_isalpha(const char *cptr, Py_ssize_t len)
{
    const unsigned char *p
        = (unsigned char *) cptr;
    const unsigned char *e;

    /* Shortcut for single character strings */
    if (len == 1 && Py_ISALPHA(*p))
        Py_RETURN_TRUE;

    /* Special case for empty strings */
    if (len == 0)
        Py_RETURN_FALSE;

    e = p + len;
    for (; p < e; p++) {
        if (!Py_ISALPHA(*p))
            Py_RETURN_FALSE;
    }
    Py_RETURN_TRUE;
}


PyDoc_STRVAR_shared(_Py_isalnum__doc__,
"B.isalnum() -> bool\n\
\n\
Return True if all characters in B are alphanumeric\n\
and there is at least one character in B, False otherwise.");

PyObject*
_Py_bytes_isalnum(const char *cptr, Py_ssize_t len)
{
    const unsigned char *p
        = (unsigned char *) cptr;
    const unsigned char *e;

    /* Shortcut for single character strings */
    if (len == 1 && Py_ISALNUM(*p))
        Py_RETURN_TRUE;

    /* Special case for empty strings */
    if (len == 0)
        Py_RETURN_FALSE;

    e = p + len;
    for (; p < e; p++) {
        if (!Py_ISALNUM(*p))
            Py_RETURN_FALSE;
    }
    Py_RETURN_TRUE;
}


PyDoc_STRVAR_shared(_Py_isdigit__doc__,
"B.isdigit() -> bool\n\
\n\
Return True if all characters in B are digits\n\
and there is at least one character in B, False otherwise.");

PyObject*
_Py_bytes_isdigit(const char *cptr, Py_ssize_t len)
{
    const unsigned char *p
        = (unsigned char *) cptr;
    const unsigned char *e;

    /* Shortcut for single character strings */
    if (len == 1 && Py_ISDIGIT(*p))
        Py_RETURN_TRUE;

    /* Special case for empty strings */
    if (len == 0)
        Py_RETURN_FALSE;

    e = p + len;
    for (; p < e; p++) {
        if (!Py_ISDIGIT(*p))
            Py_RETURN_FALSE;
    }
    Py_RETURN_TRUE;
}


PyDoc_STRVAR_shared(_Py_islower__doc__,
"B.islower() -> bool\n\
\n\
Return True if all cased characters in B are lowercase and there is\n\
at least one cased character in B, False otherwise.");

PyObject*
_Py_bytes_islower(const char *cptr, Py_ssize_t len)
{
    const unsigned char *p
        = (unsigned char *) cptr;
    const unsigned char *e;
    int cased;

    /* Shortcut for single character strings */
    if (len == 1)
        return PyBool_FromLong(Py_ISLOWER(*p));

    /* Special case for empty strings */
    if (len == 0)
        Py_RETURN_FALSE;

    e = p + len;
    cased = 0;
    for (; p < e; p++) {
        if (Py_ISUPPER(*p))
            Py_RETURN_FALSE;
        else if (!cased && Py_ISLOWER(*p))
            cased = 1;
    }
    return PyBool_FromLong(cased);
}


PyDoc_STRVAR_shared(_Py_isupper__doc__,
"B.isupper() -> bool\n\
\n\
Return True if all cased characters in B are uppercase and there is\n\
at least one cased character in B, False otherwise.");

PyObject*
_Py_bytes_isupper(const char *cptr, Py_ssize_t len)
{
    const unsigned char *p
        = (unsigned char *) cptr;
    const unsigned char *e;
    int cased;

    /* Shortcut for single character strings */
    if (len == 1)
        return PyBool_FromLong(Py_ISUPPER(*p));

    /* Special case for empty strings */
    if (len == 0)
        Py_RETURN_FALSE;

    e = p + len;
    cased = 0;
    for (; p < e; p++) {
        if (Py_ISLOWER(*p))
            Py_RETURN_FALSE;
        else if (!cased && Py_ISUPPER(*p))
            cased = 1;
    }
    return PyBool_FromLong(cased);
}


PyDoc_STRVAR_shared(_Py_istitle__doc__,
"B.istitle() -> bool\n\
\n\
Return True if B is a titlecased string and there is at least one\n\
character in B, i.e. uppercase characters may only follow uncased\n\
characters and lowercase characters only cased ones. Return False\n\
otherwise.");

PyObject*
_Py_bytes_istitle(const char *cptr, Py_ssize_t len)
{
    const unsigned char *p
        = (unsigned char *) cptr;
    const unsigned char *e;
    int cased, previous_is_cased;

    /* Shortcut for single character strings */
    if (len == 1)
        return PyBool_FromLong(Py_ISUPPER(*p));

    /* Special case for empty strings */
    if (len == 0)
        Py_RETURN_FALSE;

    e = p + len;
    cased = 0;
    previous_is_cased = 0;
    for (; p < e; p++) {
        const unsigned char ch = *p;

        if (Py_ISUPPER(ch)) {
            if (previous_is_cased)
                Py_RETURN_FALSE;
            previous_is_cased = 1;
            cased = 1;
        }
        else if (Py_ISLOWER(ch)) {
            if (!previous_is_cased)
                Py_RETURN_FALSE;
            previous_is_cased = 1;
            cased = 1;
        }
        else
            previous_is_cased = 0;
    }
    return PyBool_FromLong(cased);
}


PyDoc_STRVAR_shared(_Py_lower__doc__,
"B.lower() -> copy of B\n\
\n\
Return a copy of B with all ASCII characters converted to lowercase.");

void
_Py_bytes_lower(char *result, const char *cptr, Py_ssize_t len)
{
    Py_ssize_t i;

    for (i = 0; i < len; i++) {
        result[i] = Py_TOLOWER((unsigned char) cptr[i]);
    }
}


PyDoc_STRVAR_shared(_Py_upper__doc__,
"B.upper() -> copy of B\n\
\n\
Return a copy of B with all ASCII characters converted to uppercase.");

void
_Py_bytes_upper(char *result, const char *cptr, Py_ssize_t len)
{
    Py_ssize_t i;

    for (i = 0; i < len; i++) {
        result[i] = Py_TOUPPER((unsigned char) cptr[i]);
    }
}


PyDoc_STRVAR_shared(_Py_title__doc__,
"B.title() -> copy of B\n\
\n\
Return a titlecased version of B, i.e. ASCII words start with uppercase\n\
characters, all remaining cased characters have lowercase.");

void
_Py_bytes_title(char *result, const char *s, Py_ssize_t len)
{
    Py_ssize_t i;
    int previous_is_cased = 0;

    for (i = 0; i < len; i++) {
        int c = Py_CHARMASK(*s++);
        if (Py_ISLOWER(c)) {
            if (!previous_is_cased)
                c = Py_TOUPPER(c);
            previous_is_cased = 1;
        } else if (Py_ISUPPER(c)) {
            if (previous_is_cased)
                c = Py_TOLOWER(c);
            previous_is_cased = 1;
        } else
            previous_is_cased = 0;
        *result++ = c;
    }
}


PyDoc_STRVAR_shared(_Py_capitalize__doc__,
"B.capitalize() -> copy of B\n\
\n\
Return a copy of B with only its first character capitalized (ASCII)\n\
and the rest lower-cased.");

void
_Py_bytes_capitalize(char *result, const char *s, Py_ssize_t len)
{
    Py_ssize_t i;

    if (0 < len) {
        int c = Py_CHARMASK(*s++);
        if (Py_ISLOWER(c))
            *result = Py_TOUPPER(c);
        else
            *result = c;
        result++;
    }
    for (i = 1; i < len; i++) {
        int c = Py_CHARMASK(*s++);
        if (Py_ISUPPER(c))
            *result = Py_TOLOWER(c);
        else
            *result = c;
        result++;
    }
}


PyDoc_STRVAR_shared(_Py_swapcase__doc__,
"B.swapcase() -> copy of B\n\
\n\
Return a copy of B with uppercase ASCII characters converted\n\
to lowercase ASCII and vice versa.");

void
_Py_bytes_swapcase(char *result, const char *s, Py_ssize_t len)
{
    Py_ssize_t i;

    for (i = 0; i < len; i++) {
        int c = Py_CHARMASK(*s++);
        if (Py_ISLOWER(c)) {
            *result = Py_TOUPPER(c);
        }
        else if (Py_ISUPPER(c)) {
            *result = Py_TOLOWER(c);
        }
        else
            *result = c;
        result++;
    }
}


PyDoc_STRVAR_shared(_Py_maketrans__doc__,
"B.maketrans(frm, to) -> translation table\n\
\n\
Return a translation table (a bytes object of length 256) suitable\n\
for use in the bytes or bytearray translate method where each byte\n\
in frm is mapped to the byte at the same position in to.\n\
The bytes objects frm and to must be of the same length.");

PyObject *
_Py_bytes_maketrans(Py_buffer *frm, Py_buffer *to)
{
    PyObject *res = NULL;
    Py_ssize_t i;
    char *p;

    if (frm->len != to->len) {
        PyErr_Format(PyExc_ValueError,
                     "maketrans arguments must have same length");
        return NULL;
    }
    res = PyBytes_FromStringAndSize(NULL, 256);
    if (!res)
        return NULL;
    p = PyBytes_AS_STRING(res);
    for (i = 0; i < 256; i++)
        p[i] = (char) i;
    for (i = 0; i < frm->len; i++) {
        p[((unsigned char *)frm->buf)[i]] = ((char *)to->buf)[i];
    }

    return res;
}

#define FASTSEARCH fastsearch
#define STRINGLIB(F) stringlib_##F
#define STRINGLIB_CHAR char
#define STRINGLIB_SIZEOF_CHAR 1

#include "stringlib/fastsearch.h"
#include "stringlib/count.h"
#include "stringlib/find.h"

/*
Wraps stringlib_parse_args_finds() and additionally checks whether the
first argument is an integer in range(0, 256).

If this is the case, writes the integer value to the byte parameter
and sets subobj to NULL. Otherwise, sets the first argument to subobj
and doesn't touch byte. The other parameters are similar to those of
stringlib_parse_args_finds().
*/

Py_LOCAL_INLINE(int)
parse_args_finds_byte(const char *function_name, PyObject *args,
                      PyObject **subobj, char *byte,
                      Py_ssize_t *start, Py_ssize_t *end)
{
    PyObject *tmp_subobj;
    Py_ssize_t ival;
    PyObject *err;

    if(!stringlib_parse_args_finds(function_name, args, &tmp_subobj,
                                   start, end))
        return 0;

    if (!PyNumber_Check(tmp_subobj)) {
        *subobj = tmp_subobj;
        return 1;
    }

    ival = PyNumber_AsSsize_t(tmp_subobj, PyExc_OverflowError);
    if (ival == -1) {
        err = PyErr_Occurred();
        if (err && !PyErr_GivenExceptionMatches(err, PyExc_OverflowError)) {
            PyErr_Clear();
            *subobj = tmp_subobj;
            return 1;
        }
    }

    if (ival < 0 || ival > 255) {
        PyErr_SetString(PyExc_ValueError, "byte must be in range(0, 256)");
        return 0;
    }

    *subobj = NULL;
    *byte = (char)ival;
    return 1;
}

/* helper macro to fixup start/end slice values */
#define ADJUST_INDICES(start, end, len)         \
    if (end > len)                          \
        end = len;                          \
    else if (end < 0) {                     \
        end += len;                         \
        if (end < 0)                        \
        end = 0;                        \
    }                                       \
    if (start < 0) {                        \
        start += len;                       \
        if (start < 0)                      \
        start = 0;                      \
    }

Py_LOCAL_INLINE(Py_ssize_t)
find_internal(const char *str, Py_ssize_t len,
              const char *function_name, PyObject *args, int dir)
{
    PyObject *subobj;
    char byte;
    Py_buffer subbuf;
    const char *sub;
    Py_ssize_t sub_len;
    Py_ssize_t start = 0, end = PY_SSIZE_T_MAX;
    Py_ssize_t res;

    if (!parse_args_finds_byte(function_name, args,
                               &subobj, &byte, &start, &end))
        return -2;

    if (subobj) {
        if (PyObject_GetBuffer(subobj, &subbuf, PyBUF_SIMPLE) != 0)
            return -2;

        sub = subbuf.buf;
        sub_len = subbuf.len;
    }
    else {
        sub = &byte;
        sub_len = 1;
    }

    ADJUST_INDICES(start, end, len);
    if (end - start < sub_len)
        res = -1;
    else if (sub_len == 1) {
        if (dir > 0)
            res = stringlib_find_char(
                str + start, end - start,
                *sub);
        else
            res = stringlib_rfind_char(
                str + start, end - start,
                *sub);
        if (res >= 0)
            res += start;
    }
    else {
        if (dir > 0)
            res = stringlib_find_slice(
                str, len,
                sub, sub_len, start, end);
        else
            res = stringlib_rfind_slice(
                str, len,
                sub, sub_len, start, end);
    }

    if (subobj)
        PyBuffer_Release(&subbuf);

    return res;
}

PyDoc_STRVAR_shared(_Py_find__doc__,
"B.find(sub[, start[, end]]) -> int\n\
\n\
Return the lowest index in B where subsection sub is found,\n\
such that sub is contained within B[start,end].  Optional\n\
arguments start and end are interpreted as in slice notation.\n\
\n\
Return -1 on failure.");

PyObject *
_Py_bytes_find(const char *str, Py_ssize_t len, PyObject *args)
{
    Py_ssize_t result = find_internal(str, len, "find", args, +1);
    if (result == -2)
        return NULL;
    return PyLong_FromSsize_t(result);
}

PyDoc_STRVAR_shared(_Py_index__doc__,
"B.index(sub[, start[, end]]) -> int\n\
\n\
Like B.find() but raise ValueError when the subsection is not found.");

PyObject *
_Py_bytes_index(const char *str, Py_ssize_t len, PyObject *args)
{
    Py_ssize_t result = find_internal(str, len, "index", args, +1);
    if (result == -2)
        return NULL;
    if (result == -1) {
        PyErr_SetString(PyExc_ValueError,
                        "subsection not found");
        return NULL;
    }
    return PyLong_FromSsize_t(result);
}

PyDoc_STRVAR_shared(_Py_rfind__doc__,
"B.rfind(sub[, start[, end]]) -> int\n\
\n\
Return the highest index in B where subsection sub is found,\n\
such that sub is contained within B[start,end].  Optional\n\
arguments start and end are interpreted as in slice notation.\n\
\n\
Return -1 on failure.");

PyObject *
_Py_bytes_rfind(const char *str, Py_ssize_t len, PyObject *args)
{
    Py_ssize_t result = find_internal(str, len, "rfind", args, -1);
    if (result == -2)
        return NULL;
    return PyLong_FromSsize_t(result);
}

PyDoc_STRVAR_shared(_Py_rindex__doc__,
"B.rindex(sub[, start[, end]]) -> int\n\
\n\
Like B.rfind() but raise ValueError when the subsection is not found.");

PyObject *
_Py_bytes_rindex(const char *str, Py_ssize_t len, PyObject *args)
{
    Py_ssize_t result = find_internal(str, len, "rindex", args, -1);
    if (result == -2)
        return NULL;
    if (result == -1) {
        PyErr_SetString(PyExc_ValueError,
                        "subsection not found");
        return NULL;
    }
    return PyLong_FromSsize_t(result);
}

PyDoc_STRVAR_shared(_Py_count__doc__,
"B.count(sub[, start[, end]]) -> int\n\
\n\
Return the number of non-overlapping occurrences of subsection sub in\n\
bytes B[start:end].  Optional arguments start and end are interpreted\n\
as in slice notation.");

PyObject *
_Py_bytes_count(const char *str, Py_ssize_t len, PyObject *args)
{
    PyObject *sub_obj;
    const char *sub;
    Py_ssize_t sub_len;
    char byte;
    Py_ssize_t start = 0, end = PY_SSIZE_T_MAX;

    Py_buffer vsub;
    PyObject *count_obj;

    if (!parse_args_finds_byte("count", args,
                               &sub_obj, &byte, &start, &end))
        return NULL;

    if (sub_obj) {
        if (PyObject_GetBuffer(sub_obj, &vsub, PyBUF_SIMPLE) != 0)
            return NULL;

        sub = vsub.buf;
        sub_len = vsub.len;
    }
    else {
        sub = &byte;
        sub_len = 1;
    }

    ADJUST_INDICES(start, end, len);

    count_obj = PyLong_FromSsize_t(
        stringlib_count(str + start, end - start, sub, sub_len, PY_SSIZE_T_MAX)
        );

    if (sub_obj)
        PyBuffer_Release(&vsub);

    return count_obj;
}

int
_Py_bytes_contains(const char *str, Py_ssize_t len, PyObject *arg)
{
    Py_ssize_t ival = PyNumber_AsSsize_t(arg, NULL);
    if (ival == -1 && PyErr_Occurred()) {
        Py_buffer varg;
        Py_ssize_t pos;
        PyErr_Clear();
        if (PyObject_GetBuffer(arg, &varg, PyBUF_SIMPLE) != 0)
            return -1;
        pos = stringlib_find(str, len,
                             varg.buf, varg.len, 0);
        PyBuffer_Release(&varg);
        return pos >= 0;
    }
    if (ival < 0 || ival >= 256) {
        PyErr_SetString(PyExc_ValueError, "byte must be in range(0, 256)");
        return -1;
    }

    return memchr(str, (int) ival, len) != NULL;
}


/* Matches the end (direction >= 0) or start (direction < 0) of the buffer
 * against substr, using the start and end arguments. Returns
 * -1 on error, 0 if not found and 1 if found.
 */
static int
tailmatch(const char *str, Py_ssize_t len, PyObject *substr,
          Py_ssize_t start, Py_ssize_t end, int direction)
{
    Py_buffer sub_view = {NULL, NULL};
    const char *sub;
    Py_ssize_t slen;

    if (PyBytes_Check(substr)) {
        sub = PyBytes_AS_STRING(substr);
        slen = PyBytes_GET_SIZE(substr);
    }
    else {
        if (PyObject_GetBuffer(substr, &sub_view, PyBUF_SIMPLE) != 0)
            return -1;
        sub = sub_view.buf;
        slen = sub_view.len;
    }

    ADJUST_INDICES(start, end, len);

    if (direction < 0) {
        /* startswith */
        if (start + slen > len)
            goto notfound;
    } else {
        /* endswith */
        if (end - start < slen || start > len)
            goto notfound;

        if (end - slen > start)
            start = end - slen;
    }
    if (end - start < slen)
        goto notfound;
    if (memcmp(str + start, sub, slen) != 0)
        goto notfound;

    PyBuffer_Release(&sub_view);
    return 1;

notfound:
    PyBuffer_Release(&sub_view);
    return 0;
}

static PyObject *
_Py_bytes_tailmatch(const char *str, Py_ssize_t len,
                    const char *function_name, PyObject *args,
                    int direction)
{
    Py_ssize_t start = 0;
    Py_ssize_t end = PY_SSIZE_T_MAX;
    PyObject *subobj;
    int result;

    if (!stringlib_parse_args_finds(function_name, args, &subobj, &start, &end))
        return NULL;
    if (PyTuple_Check(subobj)) {
        Py_ssize_t i;
        for (i = 0; i < PyTuple_GET_SIZE(subobj); i++) {
            result = tailmatch(str, len, PyTuple_GET_ITEM(subobj, i),
                               start, end, direction);
            if (result == -1)
                return NULL;
            else if (result) {
                Py_RETURN_TRUE;
            }
        }
        Py_RETURN_FALSE;
    }
    result = tailmatch(str, len, subobj, start, end, direction);
    if (result == -1) {
        if (PyErr_ExceptionMatches(PyExc_TypeError))
            PyErr_Format(PyExc_TypeError,
                         "%s first arg must be bytes or a tuple of bytes, "
                         "not %s",
                         function_name, Py_TYPE(subobj)->tp_name);
        return NULL;
    }
    else
        return PyBool_FromLong(result);
}

PyDoc_STRVAR_shared(_Py_startswith__doc__,
"B.startswith(prefix[, start[, end]]) -> bool\n\
\n\
Return True if B starts with the specified prefix, False otherwise.\n\
With optional start, test B beginning at that position.\n\
With optional end, stop comparing B at that position.\n\
prefix can also be a tuple of bytes to try.");

PyObject *
_Py_bytes_startswith(const char *str, Py_ssize_t len, PyObject *args)
{
    return _Py_bytes_tailmatch(str, len, "startswith", args, -1);
}

PyDoc_STRVAR_shared(_Py_endswith__doc__,
"B.endswith(suffix[, start[, end]]) -> bool\n\
\n\
Return True if B ends with the specified suffix, False otherwise.\n\
With optional start, test B beginning at that position.\n\
With optional end, stop comparing B at that position.\n\
suffix can also be a tuple of bytes to try.");

PyObject *
_Py_bytes_endswith(const char *str, Py_ssize_t len, PyObject *args)
{
    return _Py_bytes_tailmatch(str, len, "endswith", args, +1);
}

PyDoc_STRVAR_shared(_Py_expandtabs__doc__,
"B.expandtabs(tabsize=8) -> copy of B\n\
\n\
Return a copy of B where all tab characters are expanded using spaces.\n\
If tabsize is not given, a tab size of 8 characters is assumed.");

PyDoc_STRVAR_shared(_Py_ljust__doc__,
"B.ljust(width[, fillchar]) -> copy of B\n"
"\n"
"Return B left justified in a string of length width. Padding is\n"
"done using the specified fill character (default is a space).");

PyDoc_STRVAR_shared(_Py_rjust__doc__,
"B.rjust(width[, fillchar]) -> copy of B\n"
"\n"
"Return B right justified in a string of length width. Padding is\n"
"done using the specified fill character (default is a space)");

PyDoc_STRVAR_shared(_Py_center__doc__,
"B.center(width[, fillchar]) -> copy of B\n"
"\n"
"Return B centered in a string of length width.  Padding is\n"
"done using the specified fill character (default is a space).");

PyDoc_STRVAR_shared(_Py_zfill__doc__,
"B.zfill(width) -> copy of B\n"
"\n"
"Pad a numeric string B with zeros on the left, to fill a field\n"
"of the specified width.  B is never truncated.");