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string.c
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77 lines (66 loc) · 1.4 KB
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#include "string.h"
#include "../cpu/type.h"
/**
* K&R implementation
*/
void int_to_ascii(int n, char str[]) {
int i, sign;
if ((sign = n) < 0) n = -n;
i = 0;
do {
str[i++] = n % 10 + '0';
} while ((n /= 10) > 0);
if (sign < 0) str[i++] = '-';
str[i] = '\0';
reverse(str);
}
void hex_to_ascii(int n, char str[]) {
append(str, '0');
append(str, 'x');
char zeros = 0;
s32 tmp;
int i;
for (i = 28; i > 0; i -= 4) {
tmp = (n >> i) & 0xF;
if (tmp == 0 && zeros == 0) continue;
zeros = 1;
if (tmp > 0xA) append(str, tmp - 0xA + 'a');
else append(str, tmp + '0');
}
tmp = n & 0xF;
if (tmp >= 0xA) append(str, tmp - 0xA + 'a');
else append(str, tmp + '0');
}
/* K&R */
void reverse(char s[]) {
int c, i, j;
for (i = 0, j = strlen(s)-1; i < j; i++, j--) {
c = s[i];
s[i] = s[j];
s[j] = c;
}
}
/* K&R */
int strlen(char s[]) {
int i = 0;
while (s[i] != '\0') ++i;
return i;
}
void append(char s[], char n) {
int len = strlen(s);
s[len] = n;
s[len+1] = '\0';
}
void backspace(char s[]) {
int len = strlen(s);
s[len-1] = '\0';
}
/* K&R
* Returns <0 if s1<s2, 0 if s1==s2, >0 if s1>s2 */
int strcmp(char s1[], char s2[]) {
int i;
for (i = 0; s1[i] == s2[i]; i++) {
if (s1[i] == '\0') return 0;
}
return s1[i] - s2[i];
}