/Objects/stringlib/localeutil.h

  1/* stringlib: locale related helpers implementation */
  2
  3#ifndef STRINGLIB_LOCALEUTIL_H
  4#define STRINGLIB_LOCALEUTIL_H
  5
  6#include <locale.h>
  7
  8/**
  9 * _Py_InsertThousandsGrouping:
 10 * @buffer: A pointer to the start of a string.
 11 * @n_buffer: The length of the string.
 12 * @n_digits: The number of digits in the string, in which we want
 13 *            to put the grouping chars.
 14 * @buf_size: The maximum size of the buffer pointed to by buffer.
 15 * @count: If non-NULL, points to a variable that will receive the
 16 *         number of characters we need to insert (and no formatting
 17 *         will actually occur).
 18 * @append_zero_char: If non-zero, put a trailing zero at the end of
 19 *         of the resulting string, if and only if we modified the
 20 *         string.
 21 *
 22 * Inserts thousand grouping characters (as defined in the current
 23 *  locale) into the string between buffer and buffer+n_digits.  If
 24 *  count is non-NULL, don't do any formatting, just count the number
 25 *  of characters to insert.  This is used by the caller to
 26 *  appropriately resize the buffer, if needed.  If count is non-NULL,
 27 *  buffer can be NULL (it is not dereferenced at all in that case).
 28 *
 29 * Return value: 0 on error, else 1.  Note that no error can occur if
 30 *  count is non-NULL.
 31 *
 32 * This name won't be used, the includer of this file should define
 33 *  it to be the actual function name, based on unicode or string.
 34 **/
 35int
 36_Py_InsertThousandsGrouping(STRINGLIB_CHAR *buffer,
 37			    Py_ssize_t n_buffer,
 38			    Py_ssize_t n_digits,
 39			    Py_ssize_t buf_size,
 40			    Py_ssize_t *count,
 41			    int append_zero_char)
 42{
 43	struct lconv *locale_data = localeconv();
 44	const char *grouping = locale_data->grouping;
 45	const char *thousands_sep = locale_data->thousands_sep;
 46	Py_ssize_t thousands_sep_len = strlen(thousands_sep);
 47	STRINGLIB_CHAR *pend = NULL; /* current end of buffer */
 48	STRINGLIB_CHAR *pmax = NULL; /* max of buffer */
 49	char current_grouping;
 50	Py_ssize_t remaining = n_digits; /* Number of chars remaining to
 51					    be looked at */
 52
 53	/* Initialize the character count, if we're just counting. */
 54	if (count)
 55		*count = 0;
 56	else {
 57		/* We're not just counting, we're modifying buffer */
 58		pend = buffer + n_buffer;
 59		pmax = buffer + buf_size;
 60	}
 61
 62	/* Starting at the end and working right-to-left, keep track of
 63	   what grouping needs to be added and insert that. */
 64	current_grouping = *grouping++;
 65
 66	/* If the first character is 0, perform no grouping at all. */
 67	if (current_grouping == 0)
 68		return 1;
 69
 70	while (remaining > current_grouping) {
 71		/* Always leave buffer and pend valid at the end of this
 72		   loop, since we might leave with a return statement. */
 73
 74		remaining -= current_grouping;
 75		if (count) {
 76			/* We're only counting, not touching the memory. */
 77			*count += thousands_sep_len;
 78		}
 79		else {
 80			/* Do the formatting. */
 81
 82			STRINGLIB_CHAR *plast = buffer + remaining;
 83
 84			/* Is there room to insert thousands_sep_len chars? */
 85			if (pmax - pend < thousands_sep_len)
 86				/* No room. */
 87				return 0;
 88
 89			/* Move the rest of the string down. */
 90			memmove(plast + thousands_sep_len,
 91				plast,
 92				(pend - plast) * sizeof(STRINGLIB_CHAR));
 93			/* Copy the thousands_sep chars into the buffer. */
 94#if STRINGLIB_IS_UNICODE
 95			/* Convert from the char's of the thousands_sep from
 96			   the locale into unicode. */
 97			{
 98				Py_ssize_t i;
 99				for (i = 0; i < thousands_sep_len; ++i)
100					plast[i] = thousands_sep[i];
101			}
102#else
103			/* No conversion, just memcpy the thousands_sep. */
104			memcpy(plast, thousands_sep, thousands_sep_len);
105#endif
106		}
107
108		/* Adjust end pointer. */
109		pend += thousands_sep_len;
110
111		/* Move to the next grouping character, unless we're
112		   repeating (which is designated by a grouping of 0). */
113		if (*grouping != 0) {
114			current_grouping = *grouping++;
115			if (current_grouping == CHAR_MAX)
116				/* We're done. */
117				break;
118		}
119	}
120	if (append_zero_char) {
121		/* Append a zero character to mark the end of the string,
122		   if there's room. */
123		if (pend - (buffer + remaining) < 1)
124			/* No room, error. */
125			return 0;
126		*pend = 0;
127	}
128	return 1;
129}
130#endif /* STRINGLIB_LOCALEUTIL_H */