diff --git a/internal/cgen/var.go b/internal/cgen/var.go
index 1181ec0..68384c1 100644
--- a/internal/cgen/var.go
+++ b/internal/cgen/var.go
@@ -125,7 +125,7 @@
 	b.printf("%s%s* %s%s WUFFS_BASE__POTENTIALLY_UNUSED = NULL;\n", c, elem, io1Prefix, preName)
 	b.printf("%s%s* %s%s WUFFS_BASE__POTENTIALLY_UNUSED = NULL;\n", c, elem, io2Prefix, preName)
 
-	b.printf("if (%s) {\n", preName)
+	b.printf("if (%s && %s->data.ptr) {\n", preName, preName)
 
 	b.printf("%s%s = %s->data.ptr;\n", io0Prefix, preName, preName)
 	b.printf("%s%s = %s%s + %s->%s;\n", io1Prefix, preName, io0Prefix, preName, preName, i1)
@@ -149,8 +149,8 @@
 	}
 	preName := aPrefix + n.Name().Str(g.tm)
 
-	b.printf("if (%s) {\n%s->%s = ((size_t)(%s%s - %s->data.ptr));\n}\n",
-		preName, preName, i1, iopPrefix, preName, preName)
+	b.printf("if (%s && %s->data.ptr) {\n%s->%s = ((size_t)(%s%s - %s->data.ptr));\n}\n",
+		preName, preName, preName, i1, iopPrefix, preName, preName)
 	return nil
 }
 
diff --git a/release/c/wuffs-unsupported-snapshot.c b/release/c/wuffs-unsupported-snapshot.c
index 4b8b3c5..0517639 100644
--- a/release/c/wuffs-unsupported-snapshot.c
+++ b/release/c/wuffs-unsupported-snapshot.c
@@ -22698,7 +22698,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -23573,7 +23573,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -23615,7 +23615,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -23682,7 +23682,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -23729,7 +23729,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -23866,7 +23866,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -23899,7 +23899,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -23969,7 +23969,7 @@
   ok:
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -24006,7 +24006,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -24231,7 +24231,7 @@
   ok:
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -24268,7 +24268,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -24371,7 +24371,7 @@
   ok:
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -24404,7 +24404,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -24539,7 +24539,7 @@
   ok:
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -24742,7 +24742,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -24856,7 +24856,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -25174,7 +25174,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -25388,7 +25388,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -25418,7 +25418,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -25712,7 +25712,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -25735,7 +25735,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -25840,7 +25840,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -26013,7 +26013,7 @@
   uint8_t* io0_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io1_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io2_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     io0_a_dst = a_dst->data.ptr;
     io1_a_dst = io0_a_dst + a_dst->meta.wi;
     iop_a_dst = io1_a_dst;
@@ -26066,7 +26066,7 @@
   if (v_block_size <= 900000) {
     self->private_impl.f_block_size = v_block_size;
   }
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     a_dst->meta.wi = ((size_t)(iop_a_dst - a_dst->data.ptr));
   }
 
@@ -26093,7 +26093,7 @@
   uint8_t* io0_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io1_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io2_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     io0_a_dst = a_dst->data.ptr;
     io1_a_dst = io0_a_dst + a_dst->meta.wi;
     iop_a_dst = io1_a_dst;
@@ -26187,7 +26187,7 @@
 
   goto exit;
   exit:
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     a_dst->meta.wi = ((size_t)(iop_a_dst - a_dst->data.ptr));
   }
 
@@ -26222,7 +26222,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -26317,7 +26317,7 @@
   ok:
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -26346,7 +26346,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -26450,7 +26450,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -26647,7 +26647,7 @@
   wuffs_base__token* io0_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   wuffs_base__token* io1_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   wuffs_base__token* io2_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     io0_a_dst = a_dst->data.ptr;
     io1_a_dst = io0_a_dst + a_dst->meta.wi;
     iop_a_dst = io1_a_dst;
@@ -26660,7 +26660,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -27184,10 +27184,10 @@
 
   goto exit;
   exit:
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     a_dst->meta.wi = ((size_t)(iop_a_dst - a_dst->data.ptr));
   }
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -28681,7 +28681,7 @@
   uint8_t* io0_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io1_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io2_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     io0_a_dst = a_dst->data.ptr;
     io1_a_dst = io0_a_dst + a_dst->meta.wi;
     iop_a_dst = io1_a_dst;
@@ -28740,7 +28740,7 @@
 
   goto exit;
   exit:
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     a_dst->meta.wi = ((size_t)(iop_a_dst - a_dst->data.ptr));
   }
 
@@ -28768,7 +28768,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -28897,7 +28897,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -28920,7 +28920,7 @@
   uint8_t* io0_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io1_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io2_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     io0_a_dst = a_dst->data.ptr;
     io1_a_dst = io0_a_dst + a_dst->meta.wi;
     iop_a_dst = io1_a_dst;
@@ -28933,7 +28933,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -29016,10 +29016,10 @@
 
   goto exit;
   exit:
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     a_dst->meta.wi = ((size_t)(iop_a_dst - a_dst->data.ptr));
   }
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -29103,7 +29103,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -29324,7 +29324,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -29617,7 +29617,7 @@
   uint8_t* io0_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io1_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io2_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     io0_a_dst = a_dst->data.ptr;
     io1_a_dst = io0_a_dst + a_dst->meta.wi;
     iop_a_dst = io1_a_dst;
@@ -29630,7 +29630,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -29791,10 +29791,10 @@
   }
   goto exit;
   exit:
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     a_dst->meta.wi = ((size_t)(iop_a_dst - a_dst->data.ptr));
   }
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -29830,7 +29830,7 @@
   uint8_t* io0_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io1_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io2_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     io0_a_dst = a_dst->data.ptr;
     io1_a_dst = io0_a_dst + a_dst->meta.wi;
     iop_a_dst = io1_a_dst;
@@ -29843,7 +29843,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -30049,10 +30049,10 @@
   }
   goto exit;
   exit:
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     a_dst->meta.wi = ((size_t)(iop_a_dst - a_dst->data.ptr));
   }
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -30094,7 +30094,7 @@
   uint8_t* io0_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io1_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io2_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     io0_a_dst = a_dst->data.ptr;
     io1_a_dst = io0_a_dst + a_dst->meta.wi;
     iop_a_dst = io1_a_dst;
@@ -30107,7 +30107,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -30268,10 +30268,10 @@
   }
   goto exit;
   exit:
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     a_dst->meta.wi = ((size_t)(iop_a_dst - a_dst->data.ptr));
   }
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -30311,7 +30311,7 @@
   uint8_t* io0_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io1_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io2_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     io0_a_dst = a_dst->data.ptr;
     io1_a_dst = io0_a_dst + a_dst->meta.wi;
     iop_a_dst = io1_a_dst;
@@ -30324,7 +30324,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -30603,10 +30603,10 @@
 
   goto exit;
   exit:
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     a_dst->meta.wi = ((size_t)(iop_a_dst - a_dst->data.ptr));
   }
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -30895,7 +30895,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -31037,7 +31037,7 @@
   self->private_impl.f_bits = v_bits;
   self->private_impl.f_n_bits = v_n_bits;
   self->private_impl.f_output_wi = v_output_wi;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -31059,7 +31059,7 @@
   uint8_t* io0_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io1_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io2_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     io0_a_dst = a_dst->data.ptr;
     io1_a_dst = io0_a_dst + a_dst->meta.wi;
     iop_a_dst = io1_a_dst;
@@ -31104,7 +31104,7 @@
 
   goto exit;
   exit:
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     a_dst->meta.wi = ((size_t)(iop_a_dst - a_dst->data.ptr));
   }
 
@@ -31562,7 +31562,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -31662,7 +31662,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -31828,7 +31828,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -31947,7 +31947,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -31972,7 +31972,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -32047,7 +32047,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -32162,7 +32162,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -32238,7 +32238,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -32260,7 +32260,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -32311,7 +32311,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -32337,7 +32337,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -32513,7 +32513,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -32534,7 +32534,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -32606,7 +32606,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -32627,7 +32627,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -32674,7 +32674,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -32700,7 +32700,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -32897,7 +32897,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -32920,7 +32920,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -33027,7 +33027,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -33046,7 +33046,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -33194,7 +33194,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -33223,7 +33223,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -33365,7 +33365,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -33403,7 +33403,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -33593,7 +33593,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -33920,7 +33920,7 @@
   uint8_t* io0_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io1_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io2_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     io0_a_dst = a_dst->data.ptr;
     io1_a_dst = io0_a_dst + a_dst->meta.wi;
     iop_a_dst = io1_a_dst;
@@ -33933,7 +33933,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -34204,10 +34204,10 @@
 
   goto exit;
   exit:
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     a_dst->meta.wi = ((size_t)(iop_a_dst - a_dst->data.ptr));
   }
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -34697,7 +34697,7 @@
   wuffs_base__token* io0_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   wuffs_base__token* io1_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   wuffs_base__token* io2_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     io0_a_dst = a_dst->data.ptr;
     io1_a_dst = io0_a_dst + a_dst->meta.wi;
     iop_a_dst = io1_a_dst;
@@ -34710,7 +34710,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -35640,10 +35640,10 @@
 
   goto exit;
   exit:
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     a_dst->meta.wi = ((size_t)(iop_a_dst - a_dst->data.ptr));
   }
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -35667,7 +35667,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -35782,7 +35782,7 @@
     goto label__goto_done__break;
   }
   label__goto_done__break:;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
   return (v_n | v_floating_point);
@@ -35802,7 +35802,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -35832,7 +35832,7 @@
   if (v_n == a_n) {
     v_n |= 256;
   }
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
   return v_n;
@@ -35854,7 +35854,7 @@
   wuffs_base__token* io0_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   wuffs_base__token* io1_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   wuffs_base__token* io2_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     io0_a_dst = a_dst->data.ptr;
     io1_a_dst = io0_a_dst + a_dst->meta.wi;
     iop_a_dst = io1_a_dst;
@@ -35867,7 +35867,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -35937,10 +35937,10 @@
 
   goto exit;
   exit:
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     a_dst->meta.wi = ((size_t)(iop_a_dst - a_dst->data.ptr));
   }
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -35964,7 +35964,7 @@
   wuffs_base__token* io0_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   wuffs_base__token* io1_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   wuffs_base__token* io2_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     io0_a_dst = a_dst->data.ptr;
     io1_a_dst = io0_a_dst + a_dst->meta.wi;
     iop_a_dst = io1_a_dst;
@@ -35977,7 +35977,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -36119,10 +36119,10 @@
 
   goto exit;
   exit:
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     a_dst->meta.wi = ((size_t)(iop_a_dst - a_dst->data.ptr));
   }
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -36145,7 +36145,7 @@
   wuffs_base__token* io0_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   wuffs_base__token* io1_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   wuffs_base__token* io2_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     io0_a_dst = a_dst->data.ptr;
     io1_a_dst = io0_a_dst + a_dst->meta.wi;
     iop_a_dst = io1_a_dst;
@@ -36158,7 +36158,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -36276,10 +36276,10 @@
 
   goto exit;
   exit:
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     a_dst->meta.wi = ((size_t)(iop_a_dst - a_dst->data.ptr));
   }
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -36302,7 +36302,7 @@
   wuffs_base__token* io0_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   wuffs_base__token* io1_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   wuffs_base__token* io2_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     io0_a_dst = a_dst->data.ptr;
     io1_a_dst = io0_a_dst + a_dst->meta.wi;
     iop_a_dst = io1_a_dst;
@@ -36315,7 +36315,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -36414,10 +36414,10 @@
 
   goto exit;
   exit:
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     a_dst->meta.wi = ((size_t)(iop_a_dst - a_dst->data.ptr));
   }
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -36597,7 +36597,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -36781,7 +36781,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -36823,7 +36823,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -36890,7 +36890,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -37026,7 +37026,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -37078,7 +37078,7 @@
   ok:
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -37504,7 +37504,7 @@
   uint8_t* io0_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io1_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io2_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     io0_a_dst = a_dst->data.ptr;
     io1_a_dst = io0_a_dst + a_dst->meta.wi;
     iop_a_dst = io1_a_dst;
@@ -37517,7 +37517,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -37701,10 +37701,10 @@
 
   goto exit;
   exit:
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     a_dst->meta.wi = ((size_t)(iop_a_dst - a_dst->data.ptr));
   }
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -39636,7 +39636,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -39928,7 +39928,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -39953,7 +39953,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -40132,7 +40132,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -40301,7 +40301,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -40521,7 +40521,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -40540,7 +40540,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -40634,7 +40634,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -40655,7 +40655,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -40931,7 +40931,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -40950,7 +40950,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -40972,7 +40972,7 @@
   ok:
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -40996,7 +40996,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -41309,7 +41309,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -41328,7 +41328,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -41390,7 +41390,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -41411,7 +41411,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -41479,7 +41479,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -41502,7 +41502,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -41582,7 +41582,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -41601,7 +41601,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -41643,7 +41643,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -41666,7 +41666,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -41828,7 +41828,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -41869,7 +41869,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -42119,7 +42119,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -42143,7 +42143,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -42274,7 +42274,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -42321,7 +42321,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -42544,7 +42544,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -42580,7 +42580,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -42886,7 +42886,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -43069,7 +43069,7 @@
   uint8_t* io0_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io1_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   uint8_t* io2_a_dst WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     io0_a_dst = a_dst->data.ptr;
     io1_a_dst = io0_a_dst + a_dst->meta.wi;
     iop_a_dst = io1_a_dst;
@@ -43082,7 +43082,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -43533,10 +43533,10 @@
 
   goto exit;
   exit:
-  if (a_dst) {
+  if (a_dst && a_dst->data.ptr) {
     a_dst->meta.wi = ((size_t)(iop_a_dst - a_dst->data.ptr));
   }
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -44094,7 +44094,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -44523,7 +44523,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -44565,7 +44565,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -44632,7 +44632,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -44698,7 +44698,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -44980,7 +44980,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -45328,7 +45328,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -45424,7 +45424,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -45466,7 +45466,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -45533,7 +45533,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }
 
@@ -45590,7 +45590,7 @@
   const uint8_t* io0_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io1_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
   const uint8_t* io2_a_src WUFFS_BASE__POTENTIALLY_UNUSED = NULL;
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     io0_a_src = a_src->data.ptr;
     io1_a_src = io0_a_src + a_src->meta.ri;
     iop_a_src = io1_a_src;
@@ -45702,7 +45702,7 @@
 
   goto exit;
   exit:
-  if (a_src) {
+  if (a_src && a_src->data.ptr) {
     a_src->meta.ri = ((size_t)(iop_a_src - a_src->data.ptr));
   }