/* 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 */