14207063c2
221220000 张三 Linux zzy 5.15.146.1-microsoft-standard-WSL2 #1 SMP Thu Jan 11 04:09:03 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux 11:57:41 up 2 days, 2:11, 1 user, load average: 0.55, 0.59, 0.46
83 lines
1.9 KiB
C
83 lines
1.9 KiB
C
#include <klib.h>
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int num_to_ascii(int num, int power, int size, char *buf) {
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if (size <= 1) {
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return 0;
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}
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int ret = 0, i = 0;
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char _buf[sizeof(num) * 3];
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if (num == 0) {
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*buf = '0';
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return 1;
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}
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for (i = 1; num; i ++) {
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_buf[i] = (num % power) < 10 ? ('0' + num % power) : ('a' + num % power);
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num /= power;
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}
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if (i > size) {
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return 0; // error buffer overflow
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}
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ret = i - 1;
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for (i --; i > 0; i --, buf ++ ) {
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*buf = _buf[i];
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}
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return ret;
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}
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static inline int print_fmt(char **out, int n, const char** fmt, void* _ap) {
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va_list ap = *(va_list*)_ap;
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int ret = 0;
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switch (**fmt) {
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case 'd':
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ret = num_to_ascii(va_arg(ap, int), 10, n, *out);
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(*out) += ret;
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break;
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case 's':
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const char* str = va_arg(ap, const char*);
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if (ret > n) break;
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for (; *str; str ++, (*out) ++, ret ++ ) {
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if (ret >= n) {
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return ret; // error buffer overflow
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}
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**out = *str;
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}
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break;
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case 'c':
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char ch = va_arg(ap, int);
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ret = 1;
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**out = ch;
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(*out) ++;
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break;
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case 'x':
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ret = num_to_ascii(va_arg(ap, int), 16, n, *out);
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(*out) += ret;
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break;
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default:
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break;
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}
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(*fmt) ++;
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*(va_list*)_ap = ap;
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return ret;
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}
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int rvsnprintf(char* out, size_t n, const char* fmt, va_list ap) {
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int ret = 0;
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while(*fmt && n) {
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if (*fmt == '%') {
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// FIXME
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fmt++;
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print_fmt(&out, 123, &fmt, &ap);
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continue;
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}
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*out = *fmt;
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out ++;
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fmt ++;
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n --;
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}
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*out = '\0';
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return ret;
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}
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