152 lines
2.9 KiB
C
152 lines
2.9 KiB
C
#include <stddef.h>
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#include <stdint.h>
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void *memset(void *p, int c, size_t n) {
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char *cp = p;
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for (size_t i = 0; i < n; i++) cp[i] = c;
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return p;
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}
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void *memcpy(void *dst, const void *src, size_t n) {
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char *a = dst;
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const char *b = src;
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for (size_t i = 0; i < n; i++) a[i] = b[i];
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return dst;
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}
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size_t strlen(char *s) {
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char *s2;
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for (s2 = s; *s2; ++s2);
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return (s2 - s);
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}
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// https://aticleworld.com/memcmp-in-c/
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int memcmp(const void *s1, const void *s2, int len)
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{
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unsigned char *p = (unsigned char *)s1;
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unsigned char *q = (unsigned char *)s2;
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int charCompareStatus = 0;
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//If both pointer pointing same memory block
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if (s1 == s2)
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{
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return charCompareStatus;
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}
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while (len > 0)
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{
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if (*p != *q)
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{ //compare the mismatching character
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charCompareStatus = (*p >*q)?1:-1;
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break;
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}
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len--;
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p++;
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q++;
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}
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return charCompareStatus;
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}
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int strcmp(const char *a, const char *b) {
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while (*a && (*a == *b)) {
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a++, b++;
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}
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return (unsigned char)*a - (unsigned char)*b;
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}
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size_t strcspn(const char *s, const char *reject) {
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size_t count = 0;
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for (; *s != '\0'; ++s) {
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const char *r = reject;
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while (*r != '\0') {
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if (*s == *r) {
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return count;
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}
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r++;
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}
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count++;
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}
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return count;
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}
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size_t strspn(const char *s, const char *accept) {
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size_t count = 0;
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for (; *s != '\0'; ++s) {
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const char *a = accept;
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int matched = 0;
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while (*a != '\0') {
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if (*s == *a) {
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matched = 1;
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break;
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}
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a++;
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}
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if (!matched) {
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return count;
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}
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count++;
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}
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return count;
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}
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char *strcpy(char *dest, const char *src) {
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char *d = dest;
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while ((*d++ = *src++) != '\0') {
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;
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}
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return dest;
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}
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char *strchr(const char *s, int c) {
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char ch = (char)c;
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while (*s != '\0') {
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if (*s == ch) {
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return (char *)s;
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}
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s++;
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}
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if (ch == '\0') {
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return (char *)s;
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}
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return NULL;
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}
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char *strstr(const char *str, const char *substring)
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{
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const char *a;
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const char *b;
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b = substring;
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if (*b == 0) {
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return (char *) str;
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}
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for ( ; *str != 0; str += 1) {
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if (*str != *b) {
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continue;
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}
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a = str;
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while (1) {
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if (*b == 0) {
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return (char *) str;
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}
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if (*a++ != *b++) {
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break;
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}
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}
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b = substring;
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}
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return NULL;
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}
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char *strcat(char *dest, const char *src) {
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size_t i, j;
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for(i = 0; dest[i] != '\0'; i++);
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for(j = 0; src[j] != '\0'; j++) {
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dest[i+j] = src[j];
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}
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dest[i+j] = '\0';
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return dest;
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}
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