The other half of Issue #1580: use short float repr where possible.
Addresses the float -> string conversion, using David Gay's code which
was added in Mark Dickinson's checkin r71663.
Also addresses these, which are intertwined with the short repr
changes:
- Issue #5772: format(1e100, '<') produces '1e+100', not '1.0e+100'
- Issue #5515: 'n' formatting with commas no longer works poorly
with leading zeros.
- PEP 378 Format Specifier for Thousands Separator: implemented
for floats.
diff --git a/Objects/stringlib/localeutil.h b/Objects/stringlib/localeutil.h
index 9254c09..f548133 100644
--- a/Objects/stringlib/localeutil.h
+++ b/Objects/stringlib/localeutil.h
@@ -5,161 +5,208 @@
#include <locale.h>
+#define MAX(x, y) ((x) < (y) ? (y) : (x))
+#define MIN(x, y) ((x) < (y) ? (x) : (y))
+
+typedef struct {
+ const char *grouping;
+ char previous;
+ Py_ssize_t i; /* Where we're currently pointing in grouping. */
+} GroupGenerator;
+
+static void
+_GroupGenerator_init(GroupGenerator *self, const char *grouping)
+{
+ self->grouping = grouping;
+ self->i = 0;
+ self->previous = 0;
+}
+
+/* Returns the next grouping, or 0 to signify end. */
+static Py_ssize_t
+_GroupGenerator_next(GroupGenerator *self)
+{
+ /* Note that we don't really do much error checking here. If a
+ grouping string contains just CHAR_MAX, for example, then just
+ terminate the generator. That shouldn't happen, but at least we
+ fail gracefully. */
+ switch (self->grouping[self->i]) {
+ case 0:
+ return self->previous;
+ case CHAR_MAX:
+ /* Stop the generator. */
+ return 0;
+ default: {
+ char ch = self->grouping[self->i];
+ self->previous = ch;
+ self->i++;
+ return (Py_ssize_t)ch;
+ }
+ }
+}
+
+/* Fill in some digits, leading zeros, and thousands separator. All
+ are optional, depending on when we're called. */
+static void
+fill(STRINGLIB_CHAR **digits_end, STRINGLIB_CHAR **buffer_end,
+ Py_ssize_t n_chars, Py_ssize_t n_zeros, const char* thousands_sep,
+ Py_ssize_t thousands_sep_len)
+{
+#if STRINGLIB_IS_UNICODE
+ Py_ssize_t i;
+#endif
+
+ if (thousands_sep) {
+ *buffer_end -= thousands_sep_len;
+
+ /* 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. */
+ for (i = 0; i < thousands_sep_len; ++i)
+ (*buffer_end)[i] = thousands_sep[i];
+#else
+ /* No conversion, just memcpy the thousands_sep. */
+ memcpy(*buffer_end, thousands_sep, thousands_sep_len);
+#endif
+ }
+
+ *buffer_end -= n_chars;
+ *digits_end -= n_chars;
+ memcpy(*buffer_end, *digits_end, n_chars * sizeof(STRINGLIB_CHAR));
+
+ *buffer_end -= n_zeros;
+ STRINGLIB_FILL(*buffer_end, '0', n_zeros);
+}
+
/**
* _Py_InsertThousandsGrouping:
* @buffer: A pointer to the start of a string.
- * @n_buffer: The length of the string.
+ * @n_buffer: Number of characters in @buffer.
+ * @digits: A pointer to the digits we're reading from. If count
+ * is non-NULL, this is unused.
* @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.
+ * @min_width: The minimum width of the digits in the output string.
+ * Output will be zero-padded on the left to fill.
* @grouping: see definition in localeconv().
* @thousands_sep: see definition in localeconv().
*
+ * There are 2 modes: counting and filling. If @buffer is NULL,
+ * we are in counting mode, else filling mode.
+ * If counting, the required buffer size is returned.
+ * If filling, we know the buffer will be large enough, so we don't
+ * need to pass in the buffer size.
* Inserts thousand grouping characters (as defined by grouping and
* thousands_sep) 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.
+ *
+ * As closely as possible, this code mimics the logic in decimal.py's
+ _insert_thousands_sep().
**/
-int
+Py_ssize_t
_Py_InsertThousandsGrouping(STRINGLIB_CHAR *buffer,
Py_ssize_t n_buffer,
+ STRINGLIB_CHAR *digits,
Py_ssize_t n_digits,
- Py_ssize_t buf_size,
- Py_ssize_t *count,
- int append_zero_char,
+ Py_ssize_t min_width,
const char *grouping,
const char *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 */
+ Py_ssize_t count = 0;
+ Py_ssize_t n_zeros;
+ int loop_broken = 0;
+ int use_separator = 0; /* First time through, don't append the
+ separator. They only go between
+ groups. */
+ STRINGLIB_CHAR *buffer_end = NULL;
+ STRINGLIB_CHAR *digits_end = NULL;
+ Py_ssize_t l;
+ Py_ssize_t n_chars;
+ Py_ssize_t thousands_sep_len = strlen(thousands_sep);
+ Py_ssize_t remaining = n_digits; /* Number of chars remaining to
+ be looked at */
+ /* A generator that returns all of the grouping widths, until it
+ returns 0. */
+ GroupGenerator groupgen;
+ _GroupGenerator_init(&groupgen, grouping);
- /* 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;
+ if (buffer) {
+ buffer_end = buffer + n_buffer;
+ digits_end = digits + n_digits;
+ }
+
+ while ((l = _GroupGenerator_next(&groupgen)) > 0) {
+ l = MIN(l, MAX(MAX(remaining, min_width), 1));
+ n_zeros = MAX(0, l - remaining);
+ n_chars = MAX(0, MIN(remaining, l));
+
+ /* Use n_zero zero's and n_chars chars */
+
+ /* Count only, don't do anything. */
+ count += (use_separator ? thousands_sep_len : 0) + n_zeros + n_chars;
+
+ if (buffer) {
+ /* Copy into the output buffer. */
+ fill(&digits_end, &buffer_end, n_chars, n_zeros,
+ use_separator ? thousands_sep : NULL, thousands_sep_len);
}
- /* Starting at the end and working right-to-left, keep track of
- what grouping needs to be added and insert that. */
- current_grouping = *grouping++;
+ /* Use a separator next time. */
+ use_separator = 1;
- /* If the first character is 0, perform no grouping at all. */
- if (current_grouping == 0)
- return 1;
+ remaining -= n_chars;
+ min_width -= l;
- 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 (remaining <= 0 && min_width <= 0) {
+ loop_broken = 1;
+ 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;
+ min_width -= thousands_sep_len;
+ }
+ if (!loop_broken) {
+ /* We left the loop without using a break statement. */
+
+ l = MAX(MAX(remaining, min_width), 1);
+ n_zeros = MAX(0, l - remaining);
+ n_chars = MAX(0, MIN(remaining, l));
+
+ /* Use n_zero zero's and n_chars chars */
+ count += (use_separator ? thousands_sep_len : 0) + n_zeros + n_chars;
+ if (buffer) {
+ /* Copy into the output buffer. */
+ fill(&digits_end, &buffer_end, n_chars, n_zeros,
+ use_separator ? thousands_sep : NULL, thousands_sep_len);
}
- return 1;
+ }
+ return count;
}
/**
* _Py_InsertThousandsGroupingLocale:
* @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.
*
* Reads thee current locale and calls _Py_InsertThousandsGrouping().
**/
-int
+Py_ssize_t
_Py_InsertThousandsGroupingLocale(STRINGLIB_CHAR *buffer,
Py_ssize_t n_buffer,
+ STRINGLIB_CHAR *digits,
Py_ssize_t n_digits,
- Py_ssize_t buf_size,
- Py_ssize_t *count,
- int append_zero_char)
+ Py_ssize_t min_width)
{
struct lconv *locale_data = localeconv();
const char *grouping = locale_data->grouping;
const char *thousands_sep = locale_data->thousands_sep;
- return _Py_InsertThousandsGrouping(buffer, n_buffer, n_digits,
- buf_size, count,
- append_zero_char, grouping,
- thousands_sep);
+ return _Py_InsertThousandsGrouping(buffer, n_buffer, digits, n_digits,
+ min_width, grouping, thousands_sep);
}
#endif /* STRINGLIB_LOCALEUTIL_H */