printf.c 7.46 KB
Newer Older
Damien's avatar
Damien committed
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
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
#include <stdarg.h>
#include "std.h"

#define PF_FLAG_LEFT_ADJUST (0x01)
#define PF_FLAG_SHOW_SIGN   (0x02)
#define PF_FLAG_SPACE_SIGN  (0x04)
#define PF_FLAG_NO_TRAILZ   (0x08)
#define PF_FLAG_ZERO_PAD    (0x10)

// tricky; we compute pad string by: pad_chars + (flags & PF_FLAG_ZERO_PAD)
#define PF_PAD_SIZE PF_FLAG_ZERO_PAD
static const char *pad_chars = "                0000000000000000";

typedef struct _pfenv_t {
    void *data;
    void (*print_strn)(void *, const char *str, unsigned int len);
} pfenv_t;

static void print_str_dummy(void *data, const char *str, unsigned int len) {
}

pfenv_t pfenv_dummy = {0, print_str_dummy};

static int pfenv_print_strn(pfenv_t *pfenv, const char *str, unsigned int len, int flags, int width) {
    int pad = width - len;
    if (pad > 0 && (flags & PF_FLAG_LEFT_ADJUST) == 0) {
        while (pad > 0) {
            int p = pad;
            if (p > PF_PAD_SIZE)
                p = PF_PAD_SIZE;
            pfenv->print_strn(pfenv->data, pad_chars + (flags & PF_FLAG_ZERO_PAD), p);
            pad -= p;
        }
    }
    pfenv->print_strn(pfenv->data, str, len);
    while (pad > 0) {
        int p = pad;
        if (p > PF_PAD_SIZE)
            p = PF_PAD_SIZE;
        pfenv->print_strn(pfenv->data, pad_chars, p);
        pad -= p;
    }
    return len;
}

// enough room for 32 signed number
#define INT_BUF_SIZE (12)

static int pfenv_print_int(pfenv_t *pfenv, unsigned int x, int sgn, int base, int base_char, int flags, int width) {
    char sign = 0;
    if (sgn) {
        if ((int)x < 0) {
            sign = '-';
            x = -x;
        } else if (flags & PF_FLAG_SHOW_SIGN) {
            sign = '+';
        } else if (flags & PF_FLAG_SPACE_SIGN) {
            sign = ' ';
        }
    }

    char buf[INT_BUF_SIZE];
    char *b = buf + INT_BUF_SIZE;

    if (x == 0) {
        *(--b) = '0';
    } else {
        do {
            int c = x % base;
            x /= base;
            if (c >= 10) {
                c += base_char - 10;
            } else {
                c += '0';
            }
            *(--b) = c;
        } while (b > buf && x != 0);
    }

    if (b > buf && sign != 0) {
        *(--b) = sign;
    }

    return pfenv_print_strn(pfenv, b, buf + INT_BUF_SIZE - b, flags, width);
}

void pfenv_prints(pfenv_t *pfenv, const char *str) {
    pfenv->print_strn(pfenv->data, str, strlen(str));
}

int pfenv_printf(pfenv_t *pfenv, const char *fmt, va_list args) {
    int chrs = 0;
    for (;;) {
        {
            const char *f = fmt;
            while (*f != '\0' && *f != '%') {
                ++f; // XXX UTF8 advance char
            }
            if (f > fmt) {
                pfenv->print_strn(pfenv->data, fmt, f - fmt);
                chrs += f - fmt;
                fmt = f;
            }
        }

        if (*fmt == '\0') {
            break;
        }

        // move past % character
        ++fmt;

        // parse flags, if they exist
        int flags = 0;
        while (*fmt != '\0') {
            if (*fmt == '-') flags |= PF_FLAG_LEFT_ADJUST;
            else if (*fmt == '+') flags |= PF_FLAG_SHOW_SIGN;
            else if (*fmt == ' ') flags |= PF_FLAG_SPACE_SIGN;
            else if (*fmt == '!') flags |= PF_FLAG_NO_TRAILZ;
            else if (*fmt == '0') flags |= PF_FLAG_ZERO_PAD;
            else break;
            ++fmt;
        }

        // parse width, if it exists
        int width = 0;
        for (; '0' <= *fmt && *fmt <= '9'; ++fmt) {
            width = width * 10 + *fmt - '0';
        }

        // parse precision, if it exists
        int prec = -1;
        if (*fmt == '.') {
            ++fmt;
            if (*fmt == '*') {
                ++fmt;
                prec = va_arg(args, int);
            } else {
                prec = 0;
                for (; '0' <= *fmt && *fmt <= '9'; ++fmt) {
                    prec = prec * 10 + *fmt - '0';
                }
            }
            if (prec < 0) {
                prec = 0;
            }
        }

        // parse long specifiers (current not used)
        //bool long_arg = false;
        if (*fmt == 'l') {
            ++fmt;
            //long_arg = true;
        }

        if (*fmt == '\0') {
            break;
        }

        switch (*fmt) {
            case 'b':
                if (va_arg(args, int)) {
                    chrs += pfenv_print_strn(pfenv, "true", 4, flags, width);
                } else {
                    chrs += pfenv_print_strn(pfenv, "false", 5, flags, width);
                }
                break;
            case 'c':
            {
                char str = va_arg(args, int);
                chrs += pfenv_print_strn(pfenv, &str, 1, flags, width);
                break;
            }
            case 's':
            {
                const char *str = va_arg(args, const char*);
                if (str) {
                    if (prec < 0) {
                        prec = strlen(str);
                    }
                    chrs += pfenv_print_strn(pfenv, str, prec, flags, width);
                } else {
                    chrs += pfenv_print_strn(pfenv, "(null)", 6, flags, width);
                }
                break;
            }
            case 'u':
                chrs += pfenv_print_int(pfenv, va_arg(args, int), 0, 10, 'a', flags, width);
                break;
            case 'd':
                chrs += pfenv_print_int(pfenv, va_arg(args, int), 1, 10, 'a', flags, width);
                break;
            case 'x':
            case 'p': // ?
                chrs += pfenv_print_int(pfenv, va_arg(args, int), 0, 16, 'a', flags, width);
                break;
            case 'X':
            case 'P': // ?
                chrs += pfenv_print_int(pfenv, va_arg(args, int), 0, 16, 'A', flags, width);
                break;
            default:
                pfenv->print_strn(pfenv->data, fmt, 1);
                chrs += 1;
                break;
        }
        ++fmt;
    }
    return chrs;
}

void lcd_print_strn(const char *str, unsigned int len);

void xxx(void *data, const char *str, unsigned int len) {
    lcd_print_strn(str, len);
}

pfenv_t pfenv_stdout = {0, xxx};

int printf(const char *fmt, ...) {
    //pfenv_t pfenv;
    //pfenv.data = 0;
    //pfenv.print_strn = xxx;
    va_list args;
    va_start(args, fmt);
    return pfenv_printf(&pfenv_stdout, fmt, args);
}

// need this because gcc optimises printf("%c", c) -> putchar(c), and printf("a") -> putchar('a')
int putchar(int c) {
    char chr = c;
    xxx(0, &chr, 1);
    return chr;
}

// need this because gcc optimises printf("string\n") -> puts("string")
int puts(const char *s) {
    xxx(0, s, strlen(s));
    char chr = '\n';
    xxx(0, &chr, 1);
    return 1;
}

typedef struct _strn_pfenv_t {
    char *cur;
    size_t remain;
} strn_pfenv_t;

void strn_print_strn(void *data, const char *str, unsigned int len) {
    strn_pfenv_t *strn_pfenv = data;
    if (len > strn_pfenv->remain) {
        len = strn_pfenv->remain;
    }
    memcpy(strn_pfenv->cur, str, len);
    strn_pfenv->cur += len;
    strn_pfenv->remain -= len;
}

int snprintf(char *str, size_t size, const char *fmt, ...) {
    strn_pfenv_t strn_pfenv;
    strn_pfenv.cur = str;
    strn_pfenv.remain = size;
    pfenv_t pfenv;
    pfenv.data = &strn_pfenv;
    pfenv.print_strn = strn_print_strn;
    va_list args;
    va_start(args, fmt);
    int len = pfenv_printf(&pfenv, fmt, args);
    // add terminating null byte
    if (size > 0) {
        if (strn_pfenv.remain == 0) {
            strn_pfenv.cur[-1] = 0;
        } else {
            strn_pfenv.cur[0] = 0;
        }
    }
    return len;
}