From 80d7c54dd58bcc0f71aea45c93c38e6216a84c04 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Fri, 16 May 2025 07:20:15 -0700
Subject: buf: move pattern preparation to function.

* buf.c (prepare_pattern): New static function.
(buf_xor_pattern): Use prepare_pattern to
classify the pat parameter and prepare the
pattern.
---
 buf.c | 104 +++++++++++++++++++++++++++++++++++++-----------------------------
 1 file changed, 59 insertions(+), 45 deletions(-)

diff --git a/buf.c b/buf.c
index 94cccaa7..17bdde4b 100644
--- a/buf.c
+++ b/buf.c
@@ -50,6 +50,8 @@
 #include "txr.h"
 #include "buf.h"
 
+static struct buf *buf_handle(val buf, val ctx);
+
 static cnum buf_check_len(val len, val self)
 {
   cnum l = c_num(len, self);
@@ -84,6 +86,62 @@ static void err_oflow(val self)
   uw_throwf(error_s, lit("~a: array size overflow"), self, nao);
 }
 
+static void prepare_pattern(mem_t **ppat, mem_t **pfree, mem_t pbuf[SIZEOF_PTR],
+                            ucnum *plen, int *left_p, val pat, val self)
+{
+  *left_p = 0;
+  *pfree = 0;
+
+  switch (type(pat)) {
+  case CHR:
+  case NUM:
+    {
+      cnum pn = c_num(pat, self);
+      unsigned char *fill = pbuf + SIZEOF_PTR;
+
+      if (pn < 0) {
+        *left_p = 1;
+        pn = -pn;
+      }
+
+      do {
+        *--fill = pn & 0xff;
+        pn >>= 8;
+      } while (fill > pbuf && pn);
+
+      *plen = pbuf + SIZEOF_PTR - fill;
+      *ppat = fill;
+    }
+    break;
+  case BGNUM:
+    {
+      if (minusp(pat)) {
+        *left_p = 1;
+        pat = neg(pat);
+      }
+
+      {
+        mp_int *m = mp(pat);
+        ucnum pl = mp_unsigned_bin_size(m);
+        mem_t *p = chk_malloc(pl);
+        mp_to_unsigned_bin(m, p);
+        *ppat = *pfree = p;
+        *plen = pl;
+      }
+    }
+    break;
+  case BUF:
+    {
+      struct buf *pb = buf_handle(pat, self);
+      *ppat = pb->data;
+      *plen = c_unum(pb->len, self);
+    }
+    break;
+  default:
+    unsup_obj(self, pat);
+  }
+}
+
 val make_buf(val len, val init_val, val alloc_size)
 {
   val self = lit("make-buf");
@@ -1985,51 +2043,7 @@ val buf_xor_pattern(val buf, val pat)
   unsigned char pbuf[SIZEOF_PTR] = { 0 };
   int left = 0;
 
-  switch (type(pat)) {
-  case NUM:
-    {
-      cnum pn = c_num(pat, self);
-      unsigned char *fill = pbuf + sizeof (pbuf);
-
-      if (pn < 0) {
-        left = 1;
-        pn = -pn;
-      }
-
-      do {
-        *--fill = pn & 0xff;
-        pn >>= 8;
-      } while (fill > pbuf && pn);
-
-      pl = pbuf + sizeof(pbuf) - fill;
-      p = fill;;
-    }
-    break;
-  case BGNUM:
-    {
-      if (minusp(pat)) {
-        left = 1;
-        pat = neg(pat);
-      }
-
-      {
-        mp_int *m = mp(pat);
-        pl = mp_unsigned_bin_size(m);
-        p = fr = chk_malloc(pl);
-        mp_to_unsigned_bin(m, p);
-      }
-    }
-    break;
-  case BUF:
-    {
-      struct buf *pb = buf_handle(pat, self);
-      p = pb->data;
-      pl = c_unum(pb->len, self);
-    }
-    break;
-  default:
-    unsup_obj(self, pat);
-  }
+  prepare_pattern(&p, &fr, pbuf, &pl, &left, pat, self);
 
   {
     val nbuf = make_ubuf(l);
-- 
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