* src/lread.c (skip_dyn_bytes): New function.

(read1): Use it.  Use getc instead of READCHAR to read bytes.
(load_each_byte): Remove.  Update users.

Fixes: debbugs:12598

3 files changed, 54 insertions, 33 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 420cb5aed63..46f872ba29d 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,9 @@
+2013-02-08  Stefan Monnier  <monnier@iro.umontreal.ca>
+
+        * lread.c (skip_dyn_bytes): New function (bug#12598).
+        (read1): Use it.  Use getc instead of READCHAR to read bytes.
+        (load_each_byte): Remove.  Update users.
+
 2013-02-08  Dmitry Antipov  <dmantipov@yandex.ru>
 
         * search.c (scan_buffer): Calculate end byte position just once.
diff --git a/src/doc.c b/src/doc.c
index 16c0d4090a0..fa2eca66a1d 100644
--- a/src/doc.c
+++ b/src/doc.c
@@ -176,9 +176,9 @@ get_doc_string (Lisp_Object filepos, bool unibyte, bool definition)
       if (space_left <= 0)
         {
           ptrdiff_t in_buffer = p - get_doc_string_buffer;
-          get_doc_string_buffer =
-            xpalloc (get_doc_string_buffer, &get_doc_string_buffer_size,
-                     16 * 1024, -1, 1);
+          get_doc_string_buffer
+            = xpalloc (get_doc_string_buffer, &get_doc_string_buffer_size,
+                       16 * 1024, -1, 1);
           p = get_doc_string_buffer + in_buffer;
           space_left = (get_doc_string_buffer_size - 1
                         - (p - get_doc_string_buffer));
@@ -279,10 +279,10 @@ Invalid data in documentation file -- %c followed by code %03o",
   else
     {
       /* The data determines whether the string is multibyte.  */
-      ptrdiff_t nchars =
-        multibyte_chars_in_text (((unsigned char *) get_doc_string_buffer
-                                  + offset),
-                                 to - (get_doc_string_buffer + offset));
+      ptrdiff_t nchars
+        = multibyte_chars_in_text (((unsigned char *) get_doc_string_buffer
+                                    + offset),
+                                   to - (get_doc_string_buffer + offset));
       return make_string_from_bytes (get_doc_string_buffer + offset,
                                      nchars,
                                      to - (get_doc_string_buffer + offset));
diff --git a/src/lread.c b/src/lread.c
index 09eccb0fb30..c62c62a5e5a 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -96,11 +96,6 @@ static Lisp_Object Qload_in_progress;
    It must be set to nil before all top-level calls to read0.  */
 static Lisp_Object read_objects;
 
-/* True means READCHAR should read bytes one by one (not character)
-   when READCHARFUN is Qget_file_char or Qget_emacs_mule_file_char.
-   This is set by read1 temporarily while handling #@NUMBER.  */
-static bool load_each_byte;
-
 /* List of descriptors now open for Fload.  */
 static Lisp_Object load_descriptor_list;
 
@@ -328,7 +323,7 @@ readchar (Lisp_Object readcharfun, bool *multibyte)
       return c;
     }
   c = (*readbyte) (-1, readcharfun);
-  if (c < 0 || load_each_byte)
+  if (c < 0)
     return c;
   if (multibyte)
     *multibyte = 1;
@@ -353,6 +348,30 @@ readchar (Lisp_Object readcharfun, bool *multibyte)
   return STRING_CHAR (buf);
 }
 
+static void
+skip_dyn_bytes (Lisp_Object readcharfun, ptrdiff_t n)
+{
+  if (EQ (readcharfun, Qget_file_char)
+      || EQ (readcharfun, Qget_emacs_mule_file_char))
+    {
+      block_input ();           /* FIXME: Not sure if it's needed.  */
+      fseek (instream, n, SEEK_CUR);
+      unblock_input ();
+    }
+  else
+    { /* We're not reading directly from a file.  In that case, it's difficult
+         to reliably count bytes, since these are usually meant for the file's
+         encoding, whereas we're now typically in the internal encoding.
+         But luckily, skip_dyn_bytes is used to skip over a single
+         dynamic-docstring (or dynamic byte-code) which is always quoted such
+         that \037 is the final char.  */
+      int c;
+      do {
+        c = READCHAR;
+      } while (c >= 0 && c != '\037');
+    }
+}
+
 /* Unread the character C in the way appropriate for the stream READCHARFUN.
    If the stream is a user function, call it with the char as argument.  */
 
@@ -407,14 +426,7 @@ unreadchar (Lisp_Object readcharfun, int c)
   else if (EQ (readcharfun, Qget_file_char)
            || EQ (readcharfun, Qget_emacs_mule_file_char))
     {
-      if (load_each_byte)
-        {
-          block_input ();
-          ungetc (c, instream);
-          unblock_input ();
-        }
-      else
-        unread_char = c;
+      unread_char = c;
     }
   else
     call1 (readcharfun, make_number (c));
@@ -2388,7 +2400,6 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
   bool multibyte;
 
   *pch = 0;
-  load_each_byte = 0;
 
  retry:
 
@@ -2598,7 +2609,7 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
           return tmp;
         }
 
-      /* #@NUMBER is used to skip NUMBER following characters.
+      /* #@NUMBER is used to skip NUMBER following bytes.
          That's used in .elc files to skip over doc strings
          and function definitions.  */
       if (c == '@')
@@ -2606,7 +2617,6 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
           enum { extra = 100 };
           ptrdiff_t i, nskip = 0;
 
-          load_each_byte = 1;
           /* Read a decimal integer.  */
           while ((c = READCHAR) >= 0
                  && c >= '0' && c <= '9')
@@ -2616,8 +2626,15 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
               nskip *= 10;
               nskip += c - '0';
             }
-          UNREAD (c);
-
+          if (nskip > 0)
+            /* We can't use UNREAD here, because in the code below we side-step
+               READCHAR.  Instead, assume the first char after #@NNN occupies
+               a single byte, which is the case normally since it's just
+               a space.  */
+            nskip--;
+          else
+            UNREAD (c);
+            
           if (load_force_doc_strings
               && (EQ (readcharfun, Qget_file_char)
                   || EQ (readcharfun, Qget_emacs_mule_file_char)))
@@ -2659,19 +2676,17 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
               saved_doc_string_position = file_tell (instream);
 
               /* Copy that many characters into saved_doc_string.  */
+              block_input ();
               for (i = 0; i < nskip && c >= 0; i++)
-                saved_doc_string[i] = c = READCHAR;
+                saved_doc_string[i] = c = getc (instream);
+              unblock_input ();
 
               saved_doc_string_length = i;
             }
           else
-            {
-              /* Skip that many characters.  */
-              for (i = 0; i < nskip && c >= 0; i++)
-                c = READCHAR;
-            }
+            /* Skip that many bytes.  */
+            skip_dyn_bytes (readcharfun, nskip);
 
-          load_each_byte = 0;
           goto retry;
         }
       if (c == '!')