diff --git a/crossfire/codegen.template b/crossfire/codegen.template
index 79831fd..4f3240e 100644
--- a/crossfire/codegen.template
+++ b/crossfire/codegen.template
@@ -34,12 +34,15 @@ typedef struct {
 
 int main() {
     char buf [ @(* 20 (vector-length pattern)) ];
-    @(for/list ([num (in-naturals)] [cset (in-vector pattern)])
-      @list{size_t @(format "i~a" num) ;
-            vartype @(format "v~a" num) ;
+    @(for/list ([num (in-naturals)] [iset-pos (in-vector pp-start)])
+      @list{size_t @(format "i~a" num) = @(car iset-pos) ;
+            vartype @(format "v~a" num) = @(cdr iset-pos) ;
 
       })
-    @(for/list ([num (in-naturals)] [cset (in-vector pattern)])
+
+    goto l_inner;
+
+    @(for/list ([num (in-naturals)] [iset (in-vector pattern)])
       (define iter (format "i~a" num))
       (define viter (format "v~a" num))
       (define iset (format "iset~a" num))
@@ -55,10 +58,22 @@ int main() {
       (string-join (for/list ([i (in-range (vector-length pattern))]) c-type-fmt) " "))
 l_inner:
 
+    @(define (end-conditionals)
+      (add-between
+        (for/list ([num (in-naturals)] [iset-pos (in-vector pp-end)])
+          (define iter (format "i~a" num))
+          (define viter (format "v~a" num))
+          @list{ @iter >= @(car iset-pos) && @viter >= @(cdr iset-pos) })
+        " && "))
+
+    if ( @end-conditionals[] ) {
+        goto l_end;
+    }
+
     ssize_t res = snprintf(buf, sizeof(buf), @(format "\"~a\\n\"" fmt), @vs );
     fwrite(buf, res, 1, stdout);
 
-    @(for/list ([cset (in-vector pattern)]) "}}")
+    @(for/list ([iset (in-vector pattern)]) "}}")
 l_end:
     return 0;
 }
diff --git a/crossfire/main.rkt b/crossfire/main.rkt
index cf1c9fe..2232d79 100644
--- a/crossfire/main.rkt
+++ b/crossfire/main.rkt
@@ -37,6 +37,9 @@
 
 ;; manifest.rkt processing
 
+;; Iset is a listof Interval
+;; Interval is a (cons start end) and represents [start, end)
+
 (define (make-iset) '())
 
 (define (iset-add iset start end)
@@ -71,18 +74,30 @@
   (for/sum ([ival (in-list iset)])
     (- (cdr ival) (car ival))))
 
+;; IsetPos is a (cons inum ival)
+;; inum - the interval number within the iset
+;; ival - the actual input value
+
 ;; converts a position of [0, iset-count) to 2 values
 ;; - iset interval number
 ;; - actual value within the interval
+;; allows going up to iset-count to support upper exclusive bounds of intervals
 (define (pos->iset-pos iset pos)
-  (when (empty? iset)
-    (error "iset-pos out of range"))
-  (match-define (cons (cons fs fe) r) iset)
-  (define delta (- fe fs))
-  (if (< pos delta)
-    (values 0 (+ fs pos))
-    (let-values ([(inum val) (pos->iset-pos r (- pos delta))])
-      (values (add1 inum) val))))
+  (define (helper iset pos)
+    (match-define (cons (cons fs fe) r) iset)
+    (define delta (- fe fs))
+    (if (< pos delta)
+      (cons 0 (+ fs pos))
+      (match-let ([(cons inum val) (helper r (- pos delta))])
+        (cons (add1 inum) val))))
+  (define cnt (iset-count iset))
+  (cond
+    [(> pos cnt) (error "iset-pos out of range" iset pos)]
+    [(= pos cnt)
+     ;; support interval exclusive upper bound
+     (match-define (cons inum ival) (helper iset (sub1 pos)))
+     (cons inum (add1 ival))]
+    [else (helper iset pos)]))
 
 (define (char->iset ch)
   (define cp (char->integer ch))
@@ -145,31 +160,32 @@
 
 ;; pattern processing
 
+;; a PatternPos is a vector of IsetPos
+
 (define (pattern-count pattern)
   (for/fold ([sum 1]) ([p (in-vector pattern)])
     (* sum (iset-count p))))
 
-;; design recipe violations follow
-;; (sorry)
-;; (i wanted this to be fast so i try to avoid spamming the heap)
-; (define (pattern-generate pattern out-port)
-;   (define len (vector-length pattern))
-;   (define gen (make-bytes len))
-;   (define (output gen)
-;     (write-bytes gen out-port)
-;     (printf "\n"))
-;   (define (permute i gen)
-;     (cond [(= i len) (output gen)]
-;           [else
-;             (for ([chr (in-set (vector-ref pattern i))])
-;               (bytes-set! gen i chr)
-;               (permute (add1 i) gen))]))
-;   (permute 0 gen))
+(define (pattern-start pattern)
+  (for/vector ([iset (in-vector pattern)])
+    (pos->iset-pos iset 0)))
+
+(define (pattern-end pattern)
+  (for/vector ([iset (in-vector pattern)])
+    (pos->iset-pos iset (iset-count iset))))
+
+;; there used to be a racket implementation of the input generator but it majorly violated the
+;; design recipe and got obsoleted by the template C version (which is intended to be more portable
+;; and faster)
 
 ;; ok gamer move time
 (define-runtime-path codegen-template "codegen.template")
-(define (pattern-codegen pattern)
-  (eval-template `(file ,(path->string codegen-template)) (hash 'pattern pattern)))
+(define (pattern-codegen pattern pp-start pp-end)
+  (eval-template
+    `(file ,(path->string codegen-template))
+    (hash 'pattern pattern
+          'pp-start pp-start
+          'pp-end pp-end)))
 
 (define-values [name mode command pattern]
   (parse-manifest
@@ -178,6 +194,5 @@
       (command ("meme"))
       (pattern "test?d?a?a?s"))))
 
-; (pattern-generate pattern (current-output-port))
-; (displayln (pattern-count pattern))
-(pattern-codegen pattern)
+(pattern-codegen pattern (pattern-start pattern) (pattern-end pattern))
+(printf "// total: ~a\n" (pattern-count pattern))