started working on parser

src/cstr.c

@@ -50,3 +50,43 @@ char* NULLABLE(vsprintf_malloc)(size_t buffer_size, cstr format, va_list argv){
     }
     return buf;
 }
+
+i32 cstr_seek(const char* src, const char* fragment, u32 startIndex, u32 seekLength){
+    char sc = *src, fc = *fragment;
+    if(sc == 0 || fc == 0)
+        return -1;
+    u32 fr_start = startIndex;
+    for(u32 si = startIndex; si-startIndex < seekLength && sc != 0; si++){
+        sc = src[si];
+        fc = fragment[si-fr_start];
+        if(fc == 0)
+            return fr_start;
+        if(sc != fc)
+            fr_start++;
+    }
+    return -1;
+}
+
+i32 cstr_seekReverse(const char* src, const char* fragment, u32 startIndex, u32 seekLength){
+    char sc = *src, fc = *fragment;
+    if(sc == 0 || fc == 0)
+        return -1;
+    i32 len = strlen(src);
+    if(startIndex == (u32)-1)
+        startIndex = len-1;
+    u32 fr_len = strlen(fragment);
+    for(u32 si = startIndex; si < (u32)-1 && si != (len - seekLength - 1); si--){
+        if(si + 1 < fr_len)
+            return -1;
+        sc = src[si];
+        fc = fragment[0];
+        u32 fr_start = si;
+        for(u32 fi = 0; fc == sc ; fi++){
+            if(fi == fr_len)
+                return fr_start;
+            fc = fragment[fi];
+            sc = src[si--];
+        }
+    }
+    return -1;
+}