utf8: move duplicated code from parser and stream.

* stream.c (struct byte_input_ungetch): Removed.
(byte_in_unget_char_callback): Removed.
(byte_in_unget_char): Use struct utf8_tiny_buf instead
of struct byte_input_ungetch, and use utf8_tiny_buf_putc
instead of byte_in_unget_char_callback.

* parser.c (struct shadow_ungetch): Removed.
(shadow_unget_char_callback): Removed.
(shadow_unget_char): Use struct utf8_tiny_buf instead
of struct shadow_ungetch, and use utf8_tiny_buf_putc
instead of shadow_unget_char_callback.

* utf8.c (utf8_tiny_buf_putc): New function, identical to
shadow_unget_char_callback and byte_in_unget_char_callback.

* utf8.h (struct utf8_tiny_buf): New struct type,
identical to removed struct shadow_ungetch and
struct byte_input_ungetch.
(utf8_tiny_buf_putc): Declared.

4 files changed, 21 insertions, 31 deletions

diff --git a/parser.c b/parser.c
index cc910d83..79be046f 100644
--- a/parser.c
+++ b/parser.c
@@ -98,11 +98,6 @@ static struct shadow_ops_map {
   struct strm_ops *from, *to;
 } shadow_tab[SHADOW_TAB_SIZE];
 
-struct shadow_ungetch {
-  unsigned char buf[8];
-  unsigned char *ptr;
-};
-
 static void yy_tok_mark(struct yy_token *tok)
 {
   gc_conservative_mark(tok->yy_lval.val);
@@ -2180,31 +2175,25 @@ static val shadow_get_char(val stream)
   return (wch != WEOF) ? chr(wch) : nil;
 }
 
-static int shadow_unget_char_callback(int ch, mem_t *ctx)
-{
-  struct shadow_ungetch *su = coerce(struct shadow_ungetch *, ctx);
-  return (su->ptr > su->buf) ? *--su->ptr = ch, 1 : 0;
-}
-
 static val shadow_unget_char(val stream, val ch)
 
 {
   struct strm_base *s = coerce(struct strm_base *, stream->co.handle);
   struct shadow_context *sc = coerce(struct shadow_context *, s->shadow_obj);
-  struct shadow_ungetch su;
-  unsigned char *bend = su.buf + sizeof su.buf;
+  struct utf8_tiny_buf bu;
+  unsigned char *bend = bu.buf + sizeof bu.buf;
 
-  su.ptr = bend;
+  bu.ptr = bend;
 
-  (void) utf8_encode(c_chr(ch), shadow_unget_char_callback, coerce(mem_t *, &su));
+  (void) utf8_encode(c_chr(ch), utf8_tiny_buf_putc, coerce(mem_t *, &bu));
 
-  if (convert(size_t, bend - su.ptr) > sc->index)
+  if (convert(size_t, bend - bu.ptr) > sc->index)
     uw_throwf(file_error_s,
               lit("unget-char: cannot push past beginning of byte stream"),
               nao);
 
-  while (su.ptr < bend)
-    sc->buf[--sc->index] = *su.ptr++;
+  while (bu.ptr < bend)
+    sc->buf[--sc->index] = *bu.ptr++;
 
   return ch;
 }
diff --git a/stream.c b/stream.c
index e58ead71..182d5696 100644
--- a/stream.c
+++ b/stream.c
@@ -2162,11 +2162,6 @@ struct byte_input {
   size_t index;
 };
 
-struct byte_input_ungetch {
-  unsigned char buf[8];
-  unsigned char *ptr;
-};
-
 static void byte_in_stream_destroy(val stream)
 {
   struct byte_input *bi = coerce(struct byte_input *, stream->co.handle);
@@ -2196,21 +2191,15 @@ static val byte_in_get_char(val stream)
   return (wch != WEOF) ? chr(wch) : nil;
 }
 
-static int byte_in_unget_char_callback(int ch, mem_t *ctx)
-{
-  struct byte_input_ungetch *bu = coerce(struct byte_input_ungetch *, ctx);
-  return (bu->ptr > bu->buf) ? *--bu->ptr = ch, 1 : 0;
-}
-
 static val byte_in_unget_char(val stream, val ch)
 {
   struct byte_input *bi = coerce(struct byte_input *, stream->co.handle);
-  struct byte_input_ungetch bu;
+  struct utf8_tiny_buf bu;
   unsigned char *bend = bu.buf + sizeof bu.buf;
 
   bu.ptr = bend;
 
-  (void) utf8_encode(c_chr(ch), byte_in_unget_char_callback, coerce(mem_t *, &bu));
+  (void) utf8_encode(c_chr(ch), utf8_tiny_buf_putc, coerce(mem_t *, &bu));
 
   if (convert(size_t, bend - bu.ptr) > bi->index)
     uw_throwf(file_error_s,
diff --git a/utf8.c b/utf8.c
index 0bdb70a8..4ce7742d 100644
--- a/utf8.c
+++ b/utf8.c
@@ -275,6 +275,12 @@ int utf8_encode(wchar_t wch, int (*put)(int ch, mem_t *ctx), mem_t *ctx)
             num(wch), nao);
 }
 
+int utf8_tiny_buf_putc(int ch, mem_t *ctx)
+{
+  struct utf8_tiny_buf *bu = coerce(struct utf8_tiny_buf *, ctx);
+  return (bu->ptr > bu->buf) ? *--bu->ptr = ch, 1 : 0;
+}
+
 void utf8_decoder_init(utf8_decoder_t *ud)
 {
   ud->state = utf8_init;
diff --git a/utf8.h b/utf8.h
index b0985613..69d7e13d 100644
--- a/utf8.h
+++ b/utf8.h
@@ -49,7 +49,13 @@ typedef struct utf8_decoder {
 
 #define utf8_decoder_initializer { utf8_init, 0, 0, 0, 0, 0, 0, { 0 } }
 
+struct utf8_tiny_buf {
+  unsigned char buf[8];
+  unsigned char *ptr;
+};
+
 int utf8_encode(wchar_t, int (*put)(int ch, mem_t *ctx), mem_t *ctx);
+int utf8_tiny_buf_putc(int ch, mem_t *ctx);
 void utf8_decoder_init(utf8_decoder_t *);
 wint_t utf8_decode(utf8_decoder_t *,int (*get)(mem_t *ctx), mem_t *ctx);
 int utf8_getc(utf8_decoder_t *);