libluna+libc: Add strncmp, strncat and strncpy

libc/include/string.h

@@ -32,12 +32,21 @@ extern "C"
     /* Compare two null-terminated strings. */
     int strcmp(const char* a, const char* b);
 
+    /* Compare two fixed-size null-terminated strings. */
+    int strncmp(const char* a, const char* b, size_t max);
+
     /* Copy the null-terminated string src into dest. Should be avoided to prevent buffer overflow attacks. */
     __deprecated char* strcpy(char* dest, const char* src);
 
+    /* Copy the fixed-size null-terminated string src into dest. */
+    char* strncpy(char* dest, const char* src, size_t max);
+
     /* Concatenate the null-terminated string src onto dest. Should be avoided to prevent buffer overflow attacks. */
     __deprecated char* strcat(char* dest, const char* src);
 
+    /* Concatenate the fixed-size null-terminated string src onto dest. */
+    char* strncat(char* dest, const char* src, size_t max);
+
     /* Return a pointer to the first occurrence of the character c in str, or NULL if it could not be found. */
     char* strchr(const char* str, int c);
 

libluna/include/luna/CString.h

@@ -12,6 +12,7 @@ extern "C"
     usize strnlen(const char* str, usize max);
 
     int strcmp(const char* a, const char* b);
+    int strncmp(const char* a, const char* b, usize max);
 
     usize strspn(const char* str, const char* accept);
     usize strcspn(const char* str, const char* reject);
@@ -28,6 +29,9 @@ extern "C"
     [[deprecated]] char* strcpy(char* dst, const char* src);
     [[deprecated]] char* strcat(char* dst, const char* src);
 
+    char* strncpy(char* dest, const char* src, size_t max);
+    char* strncat(char* dest, const char* src, size_t max);
+
     char* strchr(const char* str, int c);
     char* strrchr(const char* str, int c);
 }

libluna/src/CString.cpp

@@ -64,6 +64,17 @@ extern "C"
         return *(const u8*)a - *(const u8*)b;
     }
 
+    int strncmp(const char* a, const char* b, usize max)
+    {
+        const char* s = a;
+        while (*a && (*a == *b) && (size_t)(a - s) < (max - 1))
+        {
+            a++;
+            b++;
+        }
+        return *(const u8*)a - *(const u8*)b;
+    }
+
     usize wcslen(const wchar_t* str)
     {
         const wchar_t* i = str;
@@ -113,6 +124,26 @@ extern "C"
         return s;
     }
 
+    char* strncpy(char* dest, const char* src, size_t max)
+    {
+        size_t i;
+        for (i = 0; i < max && src[i] != 0; i++) dest[i] = src[i];
+        for (; i < max; i++) dest[i] = 0;
+        return dest;
+    }
+
+    char* strncat(char* dest, const char* src, size_t max)
+    {
+        size_t len = strlen(dest);
+        size_t i;
+
+        for (i = 0; i < max && *(src + i); i++) *(dest + len + i) = *(src + i);
+
+        *(dest + len + i) = '\0';
+
+        return dest;
+    }
+
     char* strchr(const char* str, int c)
     {
         while (*str && *str != c) str++;