summaryrefslogtreecommitdiffstats
path: root/Objects/stringlib/localeutil.h
blob: f5481338757fdc6c3b58c9fabdddf4e60c7b49c1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
/* stringlib: locale related helpers implementation */

#ifndef STRINGLIB_LOCALEUTIL_H
#define STRINGLIB_LOCALEUTIL_H

#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: 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.
 * @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.
 *
 * 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().
 **/
Py_ssize_t
_Py_InsertThousandsGrouping(STRINGLIB_CHAR *buffer,
                            Py_ssize_t n_buffer,
                            STRINGLIB_CHAR *digits,
                            Py_ssize_t n_digits,
                            Py_ssize_t min_width,
                            const char *grouping,
                            const char *thousands_sep)
{
    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);

    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);
        }

        /* Use a separator next time. */
        use_separator = 1;

        remaining -= n_chars;
        min_width -= l;

        if (remaining <= 0 && min_width <= 0) {
            loop_broken = 1;
            break;
        }
        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 count;
}

/**
 * _Py_InsertThousandsGroupingLocale:
 * @buffer: A pointer to the start of a string.
 * @n_digits: The number of digits in the string, in which we want
 *            to put the grouping chars.
 *
 * Reads thee current locale and calls _Py_InsertThousandsGrouping().
 **/
Py_ssize_t
_Py_InsertThousandsGroupingLocale(STRINGLIB_CHAR *buffer,
                                  Py_ssize_t n_buffer,
                                  STRINGLIB_CHAR *digits,
                                  Py_ssize_t n_digits,
                                  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, digits, n_digits,
                                           min_width, grouping, thousands_sep);
}
#endif /* STRINGLIB_LOCALEUTIL_H */