Implement storedevs, prepare to port littlefs

kernel/hal/hal.h

@@ -13,7 +13,11 @@ void *hal_memset(void *p, int c, size_t n);
 void *hal_memcpy(void *dst, const void *src, size_t n);
 size_t hal_strlen(char *s);
 int hal_memcmp(const void *s1, const void *s2, int len);
-
+int hal_strcmp(const char *a, const char *b);
+size_t hal_strcspn(const char *s, const char *reject);
+size_t hal_strspn(const char *s, const char *accept);
+char *hal_strcpy(char *dest, const char *src);
+char *hal_strchr(const char *s, int c);
 
 #if defined(__x86_64__)
 # define HAL_PAGE_SIZE 0x1000

kernel/hal/util.c

@@ -45,3 +45,67 @@ int hal_memcmp(const void *s1, const void *s2, int len)
     }
     return charCompareStatus;
 }
+
+int hal_strcmp(const char *a, const char *b) {
+  while (*a && (*a == *b)) {
+    a++, b++;
+  }
+  return (unsigned char)*a - (unsigned char)*b;
+}
+
+size_t hal_strcspn(const char *s, const char *reject) {
+    size_t count = 0;
+    for (; *s != '\0'; ++s) {
+        const char *r = reject;
+        while (*r != '\0') {
+            if (*s == *r) {
+                return count;
+            }
+            r++;
+        }
+        count++;
+    }
+    return count;
+}
+
+size_t hal_strspn(const char *s, const char *accept) {
+    size_t count = 0;
+    for (; *s != '\0'; ++s) {
+        const char *a = accept;
+        int matched = 0;
+        while (*a != '\0') {
+            if (*s == *a) {
+                matched = 1;
+                break;
+            }
+            a++;
+        }
+        if (!matched) {
+            return count;
+        }
+        count++;
+    }
+    return count;
+}
+
+char *hal_strcpy(char *dest, const char *src) {
+    char *d = dest;
+    while ((*d++ = *src++) != '\0') {
+        ;
+    }
+    return dest;
+}
+
+char *hal_strchr(const char *s, int c) {
+    char ch = (char)c;
+    while (*s != '\0') {
+        if (*s == ch) {
+            return (char *)s;
+        }
+        s++;
+    }
+    if (ch == '\0') {
+        return (char *)s;
+    }
+    return NULL;
+}