Implemented some basic libc functions and a text console

libc/string/strtok.c

@@ -0,0 +1,144 @@
+#include <limits.h>
+#include <socks/libc/string.h>
+
+#define ALIGN (sizeof(size_t))
+#define ONES ((size_t)-1 / UCHAR_MAX)
+#define HIGHS (ONES * (UCHAR_MAX / 2 + 1))
+#define HASZERO(X) (((X)-ONES) & ~(X)&HIGHS)
+#define BITOP(A, B, OP)                                                        \
+    ((A)[(size_t)(B) / (8 * sizeof *(A))] OP(size_t) 1                         \
+     << ((size_t)(B) % (8 * sizeof *(A))))
+
+char *strchrnul(const char *s, int c) {
+    size_t *w;
+    size_t k;
+
+    c = (unsigned char)c;
+    if (!c) {
+        return (char *)s + strlen(s);
+    }
+
+    for (; (uintptr_t)s % ALIGN; s++) {
+        if (!*s || *(unsigned char *)s == c) {
+            return (char *)s;
+        }
+    }
+
+    k = ONES * c;
+    for (w = (void *)s; !HASZERO(*w) && !HASZERO(*w ^ k); w++)
+        ;
+    for (s = (void *)w; *s && *(unsigned char *)s != c; s++)
+        ;
+    return (char *)s;
+}
+
+char *strchr(const char *s, int c) {
+    char *r = strchrnul(s, c);
+    return *(unsigned char *)r == (unsigned char)c ? r : 0;
+}
+
+size_t lfind(const char *str, const char accept) {
+    return (size_t)strchr(str, accept);
+}
+
+size_t strspn(const char *s, const char *c) {
+    const char *a                       = s;
+    size_t byteset[32 / sizeof(size_t)] = {0};
+
+    if (!c[0]) {
+        return 0;
+    }
+
+    if (!c[1]) {
+        for (; *s == *c; s++) {
+            return s - a;
+        }
+    }
+
+    for (; *c && BITOP(byteset, *(unsigned char *)c, |=); c++)
+        ;
+    for (; *s && BITOP(byteset, *(unsigned char *)s, &); s++)
+        ;
+    return s - a;
+}
+
+size_t strcspn(const char *s, const char *c) {
+    const char *a = s;
+
+    if (c[0] && c[1]) {
+        size_t byteset[32 / sizeof(size_t)] = {0};
+        for (; *c && BITOP(byteset, *(unsigned char *)c, |=); c++)
+            ;
+        for (; *s && !BITOP(byteset, *(unsigned char *)s, &); s++)
+            ;
+        return s - a;
+    }
+
+    return strchrnul(s, *c) - a;
+}
+
+char *strpbrk(const char *s, const char *b) {
+    s += strcspn(s, b);
+    return *s ? (char *)s : 0;
+}
+
+char *strtok_r(char *str, const char *delim, char **sp) {
+    int i   = 0;
+    int len = strlen(delim);
+
+    /* Were we given any delimiters? */
+    if (len == 0) {
+        return NULL;
+    }
+
+    /* If we weren't given a string, and save pointer is NULL, return. */
+    if (!str && !sp) {
+        return NULL;
+    }
+
+    /* If we were given a string, initialise sp for subsequent calls. */
+    if (str) {
+        *sp = str;
+    }
+
+    /* Go to the start of the substring, skipping any delimiters. */
+    char *p_start = *sp;
+    while (1) {
+        for (i = 0; i < len; i++) {
+            if (*p_start == delim[i]) {
+                p_start++;
+                break;
+            }
+        }
+
+        if (i == len) {
+            *sp = p_start;
+            break;
+        }
+    }
+
+    /* Are we at the end of the string? */
+    if (**sp == '\0') {
+        *sp = NULL;
+        return *sp;
+    }
+
+    /* Find the end of the substring, and
+       replace the delimiter with null */
+    while (**sp != '\0') {
+        for (i = 0; i < len; i++) {
+            if (**sp == delim[i]) {
+                **sp = '\0';
+                break;
+            }
+        }
+
+        (*sp)++;
+        if (i < len) {
+            break;
+        }
+    }
+
+    return p_start;
+}
+