84 lines
2.0 KiB
C
84 lines
2.0 KiB
C
/*
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* vsnprintf() is borrowed from pk.
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*/
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//#include <stdint.h>
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//#include <stdarg.h>
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//#include <stdbool.h>
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#include "util/snprintf.h"
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int32 vsnprintf(char* out, size_t n, const char* s, va_list vl) {
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bool format = FALSE;
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bool longarg = FALSE;
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size_t pos = 0;
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for (; *s; s++) {
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if (format) {
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switch (*s) {
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case 'l':
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longarg = TRUE;
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break;
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case 'p':
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longarg = TRUE;
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if (++pos < n) out[pos - 1] = '0';
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if (++pos < n) out[pos - 1] = 'x';
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case 'x': {
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long num = longarg ? va_arg(vl, long) : va_arg(vl, int);
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for (int i = 2 * (longarg ? sizeof(long) : sizeof(int)) - 1; i >= 0; i--) {
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int d = (num >> (4 * i)) & 0xF;
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if (++pos < n) out[pos - 1] = (d < 10 ? '0' + d : 'a' + d - 10);
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}
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longarg = FALSE;
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format = FALSE;
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break;
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}
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case 'd': {
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long num = longarg ? va_arg(vl, long) : va_arg(vl, int);
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if (num < 0) {
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num = -num;
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if (++pos < n) out[pos - 1] = '-';
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}
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long digits = 1;
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for (long nn = num; nn /= 10; digits++)
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;
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for (int i = digits - 1; i >= 0; i--) {
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if (pos + i + 1 < n) out[pos + i] = '0' + (num % 10);
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num /= 10;
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}
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pos += digits;
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longarg = FALSE;
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format = FALSE;
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break;
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}
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case 's': {
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const char* s2 = va_arg(vl, const char*);
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while (*s2) {
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if (++pos < n) out[pos - 1] = *s2;
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s2++;
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}
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longarg = FALSE;
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format = FALSE;
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break;
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}
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case 'c': {
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if (++pos < n) out[pos - 1] = (char)va_arg(vl, int);
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longarg = FALSE;
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format = FALSE;
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break;
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}
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default:
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break;
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}
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} else if (*s == '%')
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format = TRUE;
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else if (++pos < n)
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out[pos - 1] = *s;
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}
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if (pos < n)
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out[pos] = 0;
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else if (n)
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out[n - 1] = 0;
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return pos;
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}
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