cpython/Objects/stringlib/localeutil.h

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/* stringlib: locale related helpers implementation */
#ifndef STRINGLIB_LOCALEUTIL_H
#define STRINGLIB_LOCALEUTIL_H
#include <locale.h>
/**
* _Py_InsertThousandsGrouping:
* @buffer: A pointer to the start of a string.
* @n_buffer: The length of the string.
* @n_digits: The number of digits in the string, in which we want
* to put the grouping chars.
* @buf_size: The maximum size of the buffer pointed to by buffer.
* @count: If non-NULL, points to a variable that will receive the
* number of characters we need to insert (and no formatting
* will actually occur).
* @append_zero_char: If non-zero, put a trailing zero at the end of
* of the resulting string, if and only if we modified the
* string.
*
* Inserts thousand grouping characters (as defined in the current
* locale) into the string between buffer and buffer+n_digits. If
* count is non-NULL, don't do any formatting, just count the number
* of characters to insert. This is used by the caller to
* appropriately resize the buffer, if needed. If count is non-NULL,
* buffer can be NULL (it is not dereferenced at all in that case).
*
* Return value: 0 on error, else 1. Note that no error can occur if
* count is non-NULL.
*
* This name won't be used, the includer of this file should define
* it to be the actual function name, based on unicode or string.
**/
int
_Py_InsertThousandsGrouping(STRINGLIB_CHAR *buffer,
Py_ssize_t n_buffer,
Py_ssize_t n_digits,
Py_ssize_t buf_size,
Py_ssize_t *count,
int append_zero_char)
{
struct lconv *locale_data = localeconv();
const char *grouping = locale_data->grouping;
const char *thousands_sep = locale_data->thousands_sep;
Py_ssize_t thousands_sep_len = strlen(thousands_sep);
STRINGLIB_CHAR *pend = NULL; /* current end of buffer */
STRINGLIB_CHAR *pmax = NULL; /* max of buffer */
char current_grouping;
Py_ssize_t remaining = n_digits; /* Number of chars remaining to
be looked at */
/* Initialize the character count, if we're just counting. */
if (count)
*count = 0;
else {
/* We're not just counting, we're modifying buffer */
pend = buffer + n_buffer;
pmax = buffer + buf_size;
}
/* Starting at the end and working right-to-left, keep track of
what grouping needs to be added and insert that. */
current_grouping = *grouping++;
/* If the first character is 0, perform no grouping at all. */
if (current_grouping == 0)
return 1;
while (remaining > current_grouping) {
/* Always leave buffer and pend valid at the end of this
loop, since we might leave with a return statement. */
remaining -= current_grouping;
if (count) {
/* We're only counting, not touching the memory. */
*count += thousands_sep_len;
}
else {
/* Do the formatting. */
STRINGLIB_CHAR *plast = buffer + remaining;
/* Is there room to insert thousands_sep_len chars? */
if (pmax - pend < thousands_sep_len)
/* No room. */
return 0;
/* Move the rest of the string down. */
memmove(plast + thousands_sep_len,
plast,
(pend - plast) * sizeof(STRINGLIB_CHAR));
/* Copy the thousands_sep chars into the buffer. */
#if STRINGLIB_IS_UNICODE
/* Convert from the char's of the thousands_sep from
the locale into unicode. */
{
Py_ssize_t i;
for (i = 0; i < thousands_sep_len; ++i)
plast[i] = thousands_sep[i];
}
#else
/* No conversion, just memcpy the thousands_sep. */
memcpy(plast, thousands_sep, thousands_sep_len);
#endif
}
/* Adjust end pointer. */
pend += thousands_sep_len;
/* Move to the next grouping character, unless we're
repeating (which is designated by a grouping of 0). */
if (*grouping != 0) {
current_grouping = *grouping++;
if (current_grouping == CHAR_MAX)
/* We're done. */
break;
}
}
if (append_zero_char) {
/* Append a zero character to mark the end of the string,
if there's room. */
if (pend - (buffer + remaining) < 1)
/* No room, error. */
return 0;
*pend = 0;
}
return 1;
}
#endif /* STRINGLIB_LOCALEUTIL_H */