Better axl_strchr + handle finding '\0'

axl_string.c

@@ -82,12 +82,12 @@ i8* axl_strncat(i8* dst, const i8* src, u32 n) //n actually means "not more than
 
 i32 axl_strcmp(const i8* s1, const i8* s2)
 {
-    if (!s1 || !s2) 
+    if(!s1 || !s2) 
     {
         return (s1 == s2) ? 0 : (!s1 ? -1 : 1);
     }
 
-    for (;; s1++, s2++) 
+    for(;; s1++, s2++) 
     {
         u8 c1 = *(const u8*)s1;
         u8 c2 = *(const u8*)s2;
@@ -103,17 +103,17 @@ i32 axl_strcmp(const i8* s1, const i8* s2)
 
 i32 axl_strncmp(const i8* s1, const i8* s2, u32 n)
 {
-    if (!s1 || !s2) 
+    if(!s1 || !s2) 
     {
         return (s1 == s2) ? 0 : (!s1 ? -1 : 1);
     }
 
-    for (u32 i = 0; i < n; s1++, s2++) 
+    for(u32 i = 0; i < n; s1++, s2++, i++) 
     {
         u8 c1 = *(const u8*)s1;
         u8 c2 = *(const u8*)s2;
 
-        if (c1 != c2 || c1 == '\0' || c2 == '\0') 
+        if(c1 != c2 || c1 == '\0' || c2 == '\0') 
         {
             return c1 - c2;
         }
@@ -124,16 +124,18 @@ i32 axl_strncmp(const i8* s1, const i8* s2, u32 n)
 
 const i8* axl_strchr(const i8* str, i8 c)
 {
-    u32 i = 0;
-
-    while(str[i] != '\0')
+    if(!str) 
     {
-        if(str[i] == c)
-        {
-            return str + i;
-        }
-        i++;
+        return NULL;
     }
     
-    return NULL;
+    for(; *str != '\0'; ++str) 
+    {
+        if(*str == c) 
+        {
+            return str;
+        }
+    }
+    
+    return (c == '\0') ? str : NULL;
 }

axl_string.h

@@ -9,6 +9,7 @@ i8* axl_strncpy(i8* dst, const i8* src, u32 n);
 i8* axl_strcat(i8* dst, const i8* src);
 i8* axl_strncat(i8* dst, const i8* src, u32 n);
 i32 axl_strcmp(const i8* s1, const i8* s2);
+i32 axl_strncmp(const i8* s1, const i8* s2, u32 n);
 const i8* axl_strchr(const i8* str, i8 c);
 
 #endif // AXL_STRING

axl_string_test.c

@@ -24,6 +24,11 @@ KOAN(strlen_with_special_chars)
     ASSERT_UINT_EQ(12, axl_strlen(s));
 }
 
+KOAN(strlen_null)
+{
+    ASSERT_UINT_EQ(0, axl_strlen(NULL));
+}
+
 KOAN(strcpy_basic)
 {
     i8* src = (i8*)"test";
@@ -51,6 +56,17 @@ KOAN(strcpy_empty)
     axl_free(dst);
 }
 
+KOAN(strcpy_null_dst)
+{
+    i8 buf[10];
+    ASSERT_PTR_EQ(buf, axl_strcpy(buf, NULL));
+}
+
+KOAN(strcpy_null_src)
+{
+    ASSERT_NULL(axl_strcpy(NULL, (const i8*)"test"));
+}
+
 KOAN(strncpy_exact)
 {
     i8* src = (i8*)"hello";
@@ -91,6 +107,22 @@ KOAN(strncpy_pads_with_nulls)
     axl_free(dst);
 }
 
+KOAN(strncpy_zero_n)
+{
+    i8 dst[10] = {'w'};
+    axl_strncpy(dst, (const i8*)"test", 0);
+    ASSERT_INT_EQ('w', dst[0]);
+}
+
+KOAN(strncpy_embedded_null)
+{
+    i8* dst = (i8*)axl_malloc(10);
+    i8* src = (i8*)"ab\0cde";
+    axl_strncpy(dst, src, 5);
+    ASSERT_TRUE(memcmp(dst, "ab\0\0\0", 5) == 0);
+    axl_free(dst);
+}
+
 KOAN(strcat_basic)
 {
     i8* dst = (i8*)axl_malloc(20);
@@ -152,11 +184,18 @@ KOAN(strncat_always_null_terminates)
     i8* result = axl_strncat(dst, (i8*)"123456789", 3);
     ASSERT_PTR_EQ(dst, result);
     ASSERT_STR_EQ("test123", (const char*)dst);
-    ASSERT_INT_EQ(0, (int)dst[7]);  // Ensure null at position 7
+    ASSERT_INT_EQ(0, (int)dst[7]);
     
     axl_free(dst);
 }
 
+KOAN(strncat_zero_n)
+{
+    i8 dst[10] = "hi";
+    axl_strncat(dst, (const i8*)"world", 0);
+    ASSERT_STR_EQ("hi", (char*)dst);
+}
+
 KOAN(strcmp_equal)
 {
     i8* s1 = (i8*)"hello";
@@ -199,40 +238,79 @@ KOAN(strcmp_first_empty)
     ASSERT_TRUE(axl_strcmp(s1, s2) < 0);
 }
 
-KOAN(strlen_null) 
-{ 
-    ASSERT_UINT_EQ(0, axl_strlen(NULL)); 
-}
-
-KOAN(strcpy_null_dst) 
-{ 
-    i8 buf[10]; 
-    ASSERT_PTR_EQ(buf, axl_strcpy(buf, NULL));
-}
-
-KOAN(strcpy_null_src) 
-{ 
-    ASSERT_NULL(axl_strcpy(NULL, (const i8*)"test")); 
-}
-
-KOAN(strncpy_zero_n) 
+KOAN(strncmp_equal_shorter_n)
 {
-    i8 dst[10] = {'w'};
-    axl_strncpy(dst, (const i8*)"test", 0);
-    ASSERT_INT_EQ('w', dst[0]);
+    i8* s1 = (i8*)"hello";
+    i8* s2 = (i8*)"help!";
+    ASSERT_INT_EQ(0, axl_strncmp(s1, s2, 3));
 }
 
-KOAN(strncat_zero_n) 
+KOAN(strncmp_equal_longer_n)
 {
-    i8 dst[10] = "hi";
-    axl_strncat(dst, (const i8*)"world", 0);
-    ASSERT_STR_EQ("hi", (char*)dst);
+    i8* s1 = (i8*)"test";
+    i8* s2 = (i8*)"test";
+    ASSERT_INT_EQ(0, axl_strncmp(s1, s2, 10));
+}
+
+KOAN(strncmp_differs_at_n)
+{
+    i8* s1 = (i8*)"hello";
+    i8* s2 = (i8*)"helma";
+    ASSERT_TRUE(axl_strncmp(s1, s2, 5) < 0);
+}
+
+KOAN(strncmp_zero_n)
+{
+    i8* s1 = (i8*)"hello";
+    i8* s2 = (i8*)"world";
+    ASSERT_INT_EQ(0, axl_strncmp(s1, s2, 0));
+}
+
+KOAN(strncmp_null_ptrs)
+{
+    ASSERT_INT_EQ(0, axl_strncmp(NULL, NULL, 5));
+    ASSERT_TRUE(axl_strncmp(NULL, (i8*)"test", 5) < 0);
+    ASSERT_TRUE(axl_strncmp((i8*)"test", NULL, 5) > 0);
+}
+
+KOAN(strchr_null)
+{
+    ASSERT_NULL(axl_strchr(NULL, 'a'));
+}
+
+KOAN(strchr_empty)
+{
+    i8 str[] = "";
+    ASSERT_NULL(axl_strchr(str, 'a'));
+}
+
+KOAN(strchr_not_found)
+{
+    i8 str[] = "hello";
+    ASSERT_NULL(axl_strchr(str, 'x'));
+}
+
+KOAN(strchr_first_char)
+{
+    i8 str[] = "hello";
+    ASSERT_PTR_EQ(str, axl_strchr(str, 'h'));
+}
+
+KOAN(strchr_last_char)
+{
+    i8 str[] = "hello";
+    ASSERT_PTR_EQ(str + 4, axl_strchr(str, 'o'));
+}
+
+KOAN(strchr_null_terminator)
+{
+    i8 str[] = "hello";
+    ASSERT_PTR_EQ(str + 5, axl_strchr(str, '\0'));
 }
 
 KOAN(strchr_returns_proper_ptr)
 {
     i8 str[] = "hi Mark";
-
     ASSERT_PTR_EQ(str + 0, axl_strchr(str, 'h'));
     ASSERT_PTR_EQ(str + 1, axl_strchr(str, 'i'));
     ASSERT_PTR_EQ(str + 2, axl_strchr(str, ' '));
@@ -240,9 +318,8 @@ KOAN(strchr_returns_proper_ptr)
     ASSERT_PTR_EQ(str + 4, axl_strchr(str, 'a'));
     ASSERT_PTR_EQ(str + 5, axl_strchr(str, 'r'));
     ASSERT_PTR_EQ(str + 6, axl_strchr(str, 'k'));
-
-    ASSERT_NULL(axl_strchr(str, '\0'));
     ASSERT_NULL(axl_strchr(str, 'm'));
+    ASSERT_PTR_EQ(str + 7, axl_strchr(str, '\0'));
 }
 
 int main(void)