* cmds.c, coding.c: Use bool for booleans.

* cmds.c (move_point, Fself_insert_command):
* coding.h (struct composition status, struct coding_system):
* coding.c (detect_coding_utf_8, encode_coding_utf_8)
(detect_coding_utf_16, encode_coding_utf_16, detect_coding_emacs_mule)
(emacs_mule_char, decode_coding_emacs_mule)
(encode_coding_emacs_mule, detect_coding_iso_2022)
(decode_coding_iso_2022, encode_invocation_designation)
(encode_designation_at_bol, encode_coding_iso_2022)
(detect_coding_sjis, detect_coding_big5, decode_coding_sjis)
(decode_coding_big5, encode_coding_sjis, encode_coding_big5)
(detect_coding_ccl, encode_coding_ccl, decode_coding_raw_text)
(encode_coding_raw_text, detect_coding_charset)
(decode_coding_charset, encode_coding_charset, detect_eol)
(detect_coding, get_translation_table, produce_chars)
(consume_chars, reused_workbuf_in_use)
(make_conversion_work_buffer, code_conversion_save)
(decode_coding_object, encode_coding_object)
(detect_coding_system, char_encodable_p)
(Funencodable_char_position, code_convert_region)
(code_convert_string, code_convert_string_norecord)
(Fset_coding_system_priority):
* fileio.c (Finsert_file_contents):
Use bool for booleans.
* coding.h, lisp.h: Reflect above API changes.
* coding.c: Remove unnecessary static function decls.
(detect_coding): Use unsigned, not signed, to copy an unsigned field.
(decode_coding, encode_coding, decode_coding_gap): Return 'void',
not a boolean 'int', since callers never look at the return value.
(ALLOC_CONVERSION_WORK_AREA): Assume caller returns 'void', not 'int'.
* coding.h (decoding_buffer_size, encoding_buffer_size)
(emacs_mule_string_char): Remove unused extern decls.
(struct iso_2022_spec, struct coding_system):
Use 'unsigned int : 1' for boolean fields, since there's more than one.
(struct emacs_mule_spec): Remove unused field 'full_support'.
All initializations removed.
* cmds.c (internal_self_insert): Don't assume EMACS_INT fits in 'int'.

7 files changed, 208 insertions, 266 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 2a5afcaa310..7be88c568e2 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,6 +1,46 @@
+2012-08-27  Paul Eggert  <eggert@cs.ucla.edu>
+
+        * cmds.c, coding.c: Use bool for booleans.
+        * cmds.c (move_point, Fself_insert_command):
+        * coding.h (struct composition status, struct coding_system):
+        * coding.c (detect_coding_utf_8, encode_coding_utf_8)
+        (detect_coding_utf_16, encode_coding_utf_16, detect_coding_emacs_mule)
+        (emacs_mule_char, decode_coding_emacs_mule)
+        (encode_coding_emacs_mule, detect_coding_iso_2022)
+        (decode_coding_iso_2022, encode_invocation_designation)
+        (encode_designation_at_bol, encode_coding_iso_2022)
+        (detect_coding_sjis, detect_coding_big5, decode_coding_sjis)
+        (decode_coding_big5, encode_coding_sjis, encode_coding_big5)
+        (detect_coding_ccl, encode_coding_ccl, decode_coding_raw_text)
+        (encode_coding_raw_text, detect_coding_charset)
+        (decode_coding_charset, encode_coding_charset, detect_eol)
+        (detect_coding, get_translation_table, produce_chars)
+        (consume_chars, reused_workbuf_in_use)
+        (make_conversion_work_buffer, code_conversion_save)
+        (decode_coding_object, encode_coding_object)
+        (detect_coding_system, char_encodable_p)
+        (Funencodable_char_position, code_convert_region)
+        (code_convert_string, code_convert_string_norecord)
+        (Fset_coding_system_priority):
+        * fileio.c (Finsert_file_contents):
+        Use bool for booleans.
+        * coding.h, lisp.h: Reflect above API changes.
+        * coding.c: Remove unnecessary static function decls.
+        (detect_coding): Use unsigned, not signed, to copy an unsigned field.
+        (decode_coding, encode_coding, decode_coding_gap): Return 'void',
+        not a boolean 'int', since callers never look at the return value.
+        (ALLOC_CONVERSION_WORK_AREA): Assume caller returns 'void', not 'int'.
+        * coding.h (decoding_buffer_size, encoding_buffer_size)
+        (emacs_mule_string_char): Remove unused extern decls.
+        (struct iso_2022_spec, struct coding_system):
+        Use 'unsigned int : 1' for boolean fields, since there's more than one.
+        (struct emacs_mule_spec): Remove unused field 'full_support'.
+        All initializations removed.
+        * cmds.c (internal_self_insert): Don't assume EMACS_INT fits in 'int'.
+
 2012-08-27  Dmitry Antipov  <dmantipov@yandex.ru>
 
-        Fix spare memory change.
+        Fix spare memory change (Bug#12286).
         * alloc.c (mark_maybe_pointer): Handle MEM_TYPE_SPARE.
         (valid_lisp_object_p): Likewise.
 
diff --git a/src/charset.h b/src/charset.h
index 6e6d0ec2701..50d230489fe 100644
--- a/src/charset.h
+++ b/src/charset.h
@@ -496,7 +496,7 @@ extern int iso_charset_table[ISO_MAX_DIMENSION][ISO_MAX_CHARS][ISO_MAX_FINAL];
 
 
 
-/* 1 if CHARSET may contain the character C.  */
+/* True if CHARSET may contain the character C.  */
 #define CHAR_CHARSET_P(c, charset)                                       \
   ((ASCII_CHAR_P (c) && (charset)->ascii_compatible_p)                   \
    || ((CHARSET_UNIFIED_P (charset)                                      \
diff --git a/src/cmds.c b/src/cmds.c
index b416135ee9e..90d3cd6dced 100644
--- a/src/cmds.c
+++ b/src/cmds.c
@@ -47,10 +47,10 @@ DEFUN ("forward-point", Fforward_point, Sforward_point, 1, 1, 0,
   return make_number (PT + XINT (n));
 }
 
-/* Add N to point; or subtract N if FORWARD is zero.  N defaults to 1.
+/* Add N to point; or subtract N if FORWARD is false.  N defaults to 1.
    Validate the new location.  Return nil.  */
 static Lisp_Object
-move_point (Lisp_Object n, int forward)
+move_point (Lisp_Object n, bool forward)
 {
   /* This used to just set point to point + XINT (n), and then check
      to see if it was within boundaries.  But now that SET_PT can
@@ -277,7 +277,7 @@ After insertion, the value of `auto-fill-function' is called if the
 At the end, it runs `post-self-insert-hook'.  */)
   (Lisp_Object n)
 {
-  int remove_boundary = 1;
+  bool remove_boundary = 1;
   CHECK_NATNUM (n);
 
   if (!EQ (Vthis_command, KVAR (current_kboard, Vlast_command)))
@@ -438,7 +438,7 @@ internal_self_insert (int c, EMACS_INT n)
                   : UNIBYTE_TO_CHAR (XFASTINT (Fprevious_char ())))
           == Sword))
     {
-      int modiff = MODIFF;
+      EMACS_INT modiff = MODIFF;
       Lisp_Object sym;
 
       sym = call0 (Qexpand_abbrev);
diff --git a/src/coding.c b/src/coding.c
index 971686dc180..5bfd42c7272 100644
--- a/src/coding.c
+++ b/src/coding.c
@@ -147,18 +147,18 @@ STRUCT CODING_SYSTEM
   CODING conforms to the format of XXX, and update the members of
   DETECT_INFO.
 
-  Return 1 if the byte sequence conforms to XXX, otherwise return 0.
+  Return true if the byte sequence conforms to XXX.
 
   Below is the template of these functions.  */
 
 #if 0
-static int
+static bool
 detect_coding_XXX (struct coding_system *coding,
                    struct coding_detection_info *detect_info)
 {
   const unsigned char *src = coding->source;
   const unsigned char *src_end = coding->source + coding->src_bytes;
-  int multibytep = coding->src_multibyte;
+  bool multibytep = coding->src_multibyte;
   ptrdiff_t consumed_chars = 0;
   int found = 0;
   ...;
@@ -212,7 +212,7 @@ decode_coding_XXXX (struct coding_system *coding)
   /* A buffer to produce decoded characters.  */
   int *charbuf = coding->charbuf + coding->charbuf_used;
   int *charbuf_end = coding->charbuf + coding->charbuf_size;
-  int multibytep = coding->src_multibyte;
+  bool multibytep = coding->src_multibyte;
 
   while (1)
     {
@@ -260,7 +260,7 @@ decode_coding_XXXX (struct coding_system *coding)
 static void
 encode_coding_XXX (struct coding_system *coding)
 {
-  int multibytep = coding->dst_multibyte;
+  bool multibytep = coding->dst_multibyte;
   int *charbuf = coding->charbuf;
   int *charbuf_end = charbuf->charbuf + coding->charbuf_used;
   unsigned char *dst = coding->destination + coding->produced;
@@ -651,8 +651,8 @@ static struct coding_system coding_categories[coding_category_max];
 
 /* Safely get one byte from the source text pointed by SRC which ends
    at SRC_END, and set C to that byte.  If there are not enough bytes
-   in the source, it jumps to `no_more_source'.  If multibytep is
-   nonzero, and a multibyte character is found at SRC, set C to the
+   in the source, it jumps to 'no_more_source'.  If MULTIBYTEP,
+   and a multibyte character is found at SRC, set C to the
    negative value of the character code.  The caller should declare
    and set these variables appropriately in advance:
         src, src_end, multibytep */
@@ -685,7 +685,7 @@ static struct coding_system coding_categories[coding_category_max];
 /* Safely get two bytes from the source text pointed by SRC which ends
    at SRC_END, and set C1 and C2 to those bytes while skipping the
    heading multibyte characters.  If there are not enough bytes in the
-   source, it jumps to `no_more_source'.  If multibytep is nonzero and
+   source, it jumps to 'no_more_source'.  If MULTIBYTEP and
    a multibyte character is found for C2, set C2 to the negative value
    of the character code.  The caller should declare and set these
    variables appropriately in advance:
@@ -746,8 +746,8 @@ static struct coding_system coding_categories[coding_category_max];
 
 
 /* Store a byte C in the place pointed by DST and increment DST to the
-   next free point, and increment PRODUCED_CHARS.  If MULTIBYTEP is
-   nonzero, store in an appropriate multibyte from.  The caller should
+   next free point, and increment PRODUCED_CHARS.  If MULTIBYTEP,
+   store in an appropriate multibyte form.  The caller should
    declare and set the variables `dst' and `multibytep' appropriately
    in advance.  */
 
@@ -806,83 +806,6 @@ static struct coding_system coding_categories[coding_category_max];
   } while (0)
 
 
-/* Prototypes for static functions.  */
-static void record_conversion_result (struct coding_system *coding,
-                                      enum coding_result_code result);
-static int detect_coding_utf_8 (struct coding_system *,
-                                struct coding_detection_info *info);
-static void decode_coding_utf_8 (struct coding_system *);
-static int encode_coding_utf_8 (struct coding_system *);
-
-static int detect_coding_utf_16 (struct coding_system *,
-                                 struct coding_detection_info *info);
-static void decode_coding_utf_16 (struct coding_system *);
-static int encode_coding_utf_16 (struct coding_system *);
-
-static int detect_coding_iso_2022 (struct coding_system *,
-                                   struct coding_detection_info *info);
-static void decode_coding_iso_2022 (struct coding_system *);
-static int encode_coding_iso_2022 (struct coding_system *);
-
-static int detect_coding_emacs_mule (struct coding_system *,
-                                     struct coding_detection_info *info);
-static void decode_coding_emacs_mule (struct coding_system *);
-static int encode_coding_emacs_mule (struct coding_system *);
-
-static int detect_coding_sjis (struct coding_system *,
-                               struct coding_detection_info *info);
-static void decode_coding_sjis (struct coding_system *);
-static int encode_coding_sjis (struct coding_system *);
-
-static int detect_coding_big5 (struct coding_system *,
-                               struct coding_detection_info *info);
-static void decode_coding_big5 (struct coding_system *);
-static int encode_coding_big5 (struct coding_system *);
-
-static int detect_coding_ccl (struct coding_system *,
-                              struct coding_detection_info *info);
-static void decode_coding_ccl (struct coding_system *);
-static int encode_coding_ccl (struct coding_system *);
-
-static void decode_coding_raw_text (struct coding_system *);
-static int encode_coding_raw_text (struct coding_system *);
-
-static void coding_set_source (struct coding_system *);
-static ptrdiff_t coding_change_source (struct coding_system *);
-static void coding_set_destination (struct coding_system *);
-static ptrdiff_t coding_change_destination (struct coding_system *);
-static void coding_alloc_by_realloc (struct coding_system *, ptrdiff_t);
-static void coding_alloc_by_making_gap (struct coding_system *,
-                                        ptrdiff_t, ptrdiff_t);
-static unsigned char *alloc_destination (struct coding_system *,
-                                         ptrdiff_t, unsigned char *);
-static void setup_iso_safe_charsets (Lisp_Object);
-static ptrdiff_t encode_designation_at_bol (struct coding_system *,
-                                      int *, int *, unsigned char *);
-static int detect_eol (const unsigned char *,
-                       ptrdiff_t, enum coding_category);
-static Lisp_Object adjust_coding_eol_type (struct coding_system *, int);
-static void decode_eol (struct coding_system *);
-static Lisp_Object get_translation_table (Lisp_Object, int, int *);
-static Lisp_Object get_translation (Lisp_Object, int *, int *);
-static int produce_chars (struct coding_system *, Lisp_Object, int);
-static inline void produce_charset (struct coding_system *, int *,
-                                    ptrdiff_t);
-static void produce_annotation (struct coding_system *, ptrdiff_t);
-static int decode_coding (struct coding_system *);
-static inline int *handle_composition_annotation (ptrdiff_t, ptrdiff_t,
-                                                  struct coding_system *,
-                                                  int *, ptrdiff_t *);
-static inline int *handle_charset_annotation (ptrdiff_t, ptrdiff_t,
-                                              struct coding_system *,
-                                              int *, ptrdiff_t *);
-static void consume_chars (struct coding_system *, Lisp_Object, int);
-static int encode_coding (struct coding_system *);
-static Lisp_Object make_conversion_work_buffer (int);
-static Lisp_Object code_conversion_restore (Lisp_Object);
-static inline int char_encodable_p (int, Lisp_Object);
-static Lisp_Object make_subsidiaries (Lisp_Object);
-
 static void
 record_conversion_result (struct coding_system *coding,
                           enum coding_result_code result)
@@ -1264,8 +1187,7 @@ alloc_destination (struct coding_system *coding, ptrdiff_t nbytes,
 /*** 3. UTF-8 ***/
 
 /* See the above "GENERAL NOTES on `detect_coding_XXX ()' functions".
-   Check if a text is encoded in UTF-8.  If it is, return 1, else
-   return 0.  */
+   Return true if a text is encoded in UTF-8.  */
 
 #define UTF_8_1_OCTET_P(c)         ((c) < 0x80)
 #define UTF_8_EXTRA_OCTET_P(c)     (((c) & 0xC0) == 0x80)
@@ -1278,16 +1200,16 @@ alloc_destination (struct coding_system *coding, ptrdiff_t nbytes,
 #define UTF_8_BOM_2 0xBB
 #define UTF_8_BOM_3 0xBF
 
-static int
+static bool
 detect_coding_utf_8 (struct coding_system *coding,
                      struct coding_detection_info *detect_info)
 {
   const unsigned char *src = coding->source, *src_base;
   const unsigned char *src_end = coding->source + coding->src_bytes;
-  int multibytep = coding->src_multibyte;
+  bool multibytep = coding->src_multibyte;
   ptrdiff_t consumed_chars = 0;
-  int bom_found = 0;
-  int found = 0;
+  bool bom_found = 0;
+  bool found = 0;
 
   detect_info->checked |= CATEGORY_MASK_UTF_8;
   /* A coding system of this category is always ASCII compatible.  */
@@ -1371,10 +1293,10 @@ decode_coding_utf_8 (struct coding_system *coding)
   int *charbuf = coding->charbuf + coding->charbuf_used;
   int *charbuf_end = coding->charbuf + coding->charbuf_size;
   ptrdiff_t consumed_chars = 0, consumed_chars_base = 0;
-  int multibytep = coding->src_multibyte;
+  bool multibytep = coding->src_multibyte;
   enum utf_bom_type bom = CODING_UTF_8_BOM (coding);
-  int eol_dos =
-    !inhibit_eol_conversion && EQ (CODING_ID_EOL_TYPE (coding->id), Qdos);
+  bool eol_dos
+    = !inhibit_eol_conversion && EQ (CODING_ID_EOL_TYPE (coding->id), Qdos);
   int byte_after_cr = -1;
 
   if (bom != utf_without_bom)
@@ -1513,10 +1435,10 @@ decode_coding_utf_8 (struct coding_system *coding)
 }
 
 
-static int
+static bool
 encode_coding_utf_8 (struct coding_system *coding)
 {
-  int multibytep = coding->dst_multibyte;
+  bool multibytep = coding->dst_multibyte;
   int *charbuf = coding->charbuf;
   int *charbuf_end = charbuf + coding->charbuf_used;
   unsigned char *dst = coding->destination + coding->produced;
@@ -1577,8 +1499,7 @@ encode_coding_utf_8 (struct coding_system *coding)
 
 
 /* See the above "GENERAL NOTES on `detect_coding_XXX ()' functions".
-   Check if a text is encoded in one of UTF-16 based coding systems.
-   If it is, return 1, else return 0.  */
+   Return true if a text is encoded in one of UTF-16 based coding systems.  */
 
 #define UTF_16_HIGH_SURROGATE_P(val) \
   (((val) & 0xFC00) == 0xD800)
@@ -1587,13 +1508,13 @@ encode_coding_utf_8 (struct coding_system *coding)
   (((val) & 0xFC00) == 0xDC00)
 
 
-static int
+static bool
 detect_coding_utf_16 (struct coding_system *coding,
                       struct coding_detection_info *detect_info)
 {
   const unsigned char *src = coding->source;
   const unsigned char *src_end = coding->source + coding->src_bytes;
-  int multibytep = coding->src_multibyte;
+  bool multibytep = coding->src_multibyte;
   int c1, c2;
 
   detect_info->checked |= CATEGORY_MASK_UTF_16;
@@ -1680,12 +1601,12 @@ decode_coding_utf_16 (struct coding_system *coding)
   /* We may produces at most 3 chars in one loop.  */
   int *charbuf_end = coding->charbuf + coding->charbuf_size - 2;
   ptrdiff_t consumed_chars = 0, consumed_chars_base = 0;
-  int multibytep = coding->src_multibyte;
+  bool multibytep = coding->src_multibyte;
   enum utf_bom_type bom = CODING_UTF_16_BOM (coding);
   enum utf_16_endian_type endian = CODING_UTF_16_ENDIAN (coding);
   int surrogate = CODING_UTF_16_SURROGATE (coding);
-  int eol_dos =
-    !inhibit_eol_conversion && EQ (CODING_ID_EOL_TYPE (coding->id), Qdos);
+  bool eol_dos
+    = !inhibit_eol_conversion && EQ (CODING_ID_EOL_TYPE (coding->id), Qdos);
   int byte_after_cr1 = -1, byte_after_cr2 = -1;
 
   if (bom == utf_with_bom)
@@ -1795,17 +1716,17 @@ decode_coding_utf_16 (struct coding_system *coding)
   coding->charbuf_used = charbuf - coding->charbuf;
 }
 
-static int
+static bool
 encode_coding_utf_16 (struct coding_system *coding)
 {
-  int multibytep = coding->dst_multibyte;
+  bool multibytep = coding->dst_multibyte;
   int *charbuf = coding->charbuf;
   int *charbuf_end = charbuf + coding->charbuf_used;
   unsigned char *dst = coding->destination + coding->produced;
   unsigned char *dst_end = coding->destination + coding->dst_bytes;
   int safe_room = 8;
   enum utf_bom_type bom = CODING_UTF_16_BOM (coding);
-  int big_endian = CODING_UTF_16_ENDIAN (coding) == utf_16_big_endian;
+  bool big_endian = CODING_UTF_16_ENDIAN (coding) == utf_16_big_endian;
   ptrdiff_t produced_chars = 0;
   int c;
 
@@ -1930,16 +1851,15 @@ char emacs_mule_bytes[256];
 
 
 /* See the above "GENERAL NOTES on `detect_coding_XXX ()' functions".
-   Check if a text is encoded in `emacs-mule'.  If it is, return 1,
-   else return 0.  */
+   Return true if a text is encoded in 'emacs-mule'.  */
 
-static int
+static bool
 detect_coding_emacs_mule (struct coding_system *coding,
                           struct coding_detection_info *detect_info)
 {
   const unsigned char *src = coding->source, *src_base;
   const unsigned char *src_end = coding->source + coding->src_bytes;
-  int multibytep = coding->src_multibyte;
+  bool multibytep = coding->src_multibyte;
   ptrdiff_t consumed_chars = 0;
   int c;
   int found = 0;
@@ -2029,12 +1949,12 @@ emacs_mule_char (struct coding_system *coding, const unsigned char *src,
 {
   const unsigned char *src_end = coding->source + coding->src_bytes;
   const unsigned char *src_base = src;
-  int multibytep = coding->src_multibyte;
+  bool multibytep = coding->src_multibyte;
   int charset_ID;
   unsigned code;
   int c;
   int consumed_chars = 0;
-  int mseq_found = 0;
+  bool mseq_found = 0;
 
   ONE_MORE_BYTE (c);
   if (c < 0)
@@ -2411,12 +2331,12 @@ decode_coding_emacs_mule (struct coding_system *coding)
       /* We can produce up to 2 characters in a loop.  */
       - 1;
   ptrdiff_t consumed_chars = 0, consumed_chars_base;
-  int multibytep = coding->src_multibyte;
+  bool multibytep = coding->src_multibyte;
   ptrdiff_t char_offset = coding->produced_char;
   ptrdiff_t last_offset = char_offset;
   int last_id = charset_ascii;
-  int eol_dos =
-    !inhibit_eol_conversion && EQ (CODING_ID_EOL_TYPE (coding->id), Qdos);
+  bool eol_dos
+    = !inhibit_eol_conversion && EQ (CODING_ID_EOL_TYPE (coding->id), Qdos);
   int byte_after_cr = -1;
   struct composition_status *cmp_status = &coding->spec.emacs_mule.cmp_status;
 
@@ -2657,10 +2577,10 @@ decode_coding_emacs_mule (struct coding_system *coding)
   } while (0);
 
 
-static int
+static bool
 encode_coding_emacs_mule (struct coding_system *coding)
 {
-  int multibytep = coding->dst_multibyte;
+  bool multibytep = coding->dst_multibyte;
   int *charbuf = coding->charbuf;
   int *charbuf_end = charbuf + coding->charbuf_used;
   unsigned char *dst = coding->destination + coding->produced;
@@ -2722,7 +2642,7 @@ encode_coding_emacs_mule (struct coding_system *coding)
 
           if (preferred_charset_id >= 0)
             {
-              int result;
+              bool result;
 
               charset = CHARSET_FROM_ID (preferred_charset_id);
               CODING_CHAR_CHARSET_P (coding, dst, dst_end, c, charset, result);
@@ -3017,17 +2937,17 @@ setup_iso_safe_charsets (Lisp_Object attrs)
 
 
 /* See the above "GENERAL NOTES on `detect_coding_XXX ()' functions".
-   Check if a text is encoded in one of ISO-2022 based coding systems.
-   If it is, return 1, else return 0.  */
+   Return true if a text is encoded in one of ISO-2022 based coding
+   systems.  */
 
-static int
+static bool
 detect_coding_iso_2022 (struct coding_system *coding,
                         struct coding_detection_info *detect_info)
 {
   const unsigned char *src = coding->source, *src_base = src;
   const unsigned char *src_end = coding->source + coding->src_bytes;
-  int multibytep = coding->src_multibyte;
-  int single_shifting = 0;
+  bool multibytep = coding->src_multibyte;
+  bool single_shifting = 0;
   int id;
   int c, c1;
   ptrdiff_t consumed_chars = 0;
@@ -3390,8 +3310,6 @@ detect_coding_iso_2022 (struct coding_system *coding,
 
 /* Finish the current composition as invalid.  */
 
-static int finish_composition (int *, struct composition_status *);
-
 static int
 finish_composition (int *charbuf, struct composition_status *cmp_status)
 {
@@ -3541,7 +3459,7 @@ decode_coding_iso_2022 (struct coding_system *coding)
   int *charbuf_end
     = coding->charbuf + coding->charbuf_size - (MAX_ANNOTATION_LENGTH * 3);
   ptrdiff_t consumed_chars = 0, consumed_chars_base;
-  int multibytep = coding->src_multibyte;
+  bool multibytep = coding->src_multibyte;
   /* Charsets invoked to graphic plane 0 and 1 respectively.  */
   int charset_id_0 = CODING_ISO_INVOKED_CHARSET (coding, 0);
   int charset_id_1 = CODING_ISO_INVOKED_CHARSET (coding, 1);
@@ -3553,8 +3471,8 @@ decode_coding_iso_2022 (struct coding_system *coding)
   ptrdiff_t char_offset = coding->produced_char;
   ptrdiff_t last_offset = char_offset;
   int last_id = charset_ascii;
-  int eol_dos =
-    !inhibit_eol_conversion && EQ (CODING_ID_EOL_TYPE (coding->id), Qdos);
+  bool eol_dos
+    = !inhibit_eol_conversion && EQ (CODING_ID_EOL_TYPE (coding->id), Qdos);
   int byte_after_cr = -1;
   int i;
 
@@ -4282,7 +4200,7 @@ encode_invocation_designation (struct charset *charset,
                                struct coding_system *coding,
                                unsigned char *dst, ptrdiff_t *p_nchars)
 {
-  int multibytep = coding->dst_multibyte;
+  bool multibytep = coding->dst_multibyte;
   ptrdiff_t produced_chars = *p_nchars;
   int reg;                      /* graphic register number */
   int id = CHARSET_ID (charset);
@@ -4380,7 +4298,7 @@ encode_designation_at_bol (struct coding_system *coding,
   int r[4];
   int c, found = 0, reg;
   ptrdiff_t produced_chars = 0;
-  int multibytep = coding->dst_multibyte;
+  bool multibytep = coding->dst_multibyte;
   Lisp_Object attrs;
   Lisp_Object charset_list;
 
@@ -4422,21 +4340,21 @@ encode_designation_at_bol (struct coding_system *coding,
 
 /* See the above "GENERAL NOTES on `encode_coding_XXX ()' functions".  */
 
-static int
+static bool
 encode_coding_iso_2022 (struct coding_system *coding)
 {
-  int multibytep = coding->dst_multibyte;
+  bool multibytep = coding->dst_multibyte;
   int *charbuf = coding->charbuf;
   int *charbuf_end = charbuf + coding->charbuf_used;
   unsigned char *dst = coding->destination + coding->produced;
   unsigned char *dst_end = coding->destination + coding->dst_bytes;
   int safe_room = 16;
-  int bol_designation
+  bool bol_designation
     = (CODING_ISO_FLAGS (coding) & CODING_ISO_FLAG_DESIGNATE_AT_BOL
        && CODING_ISO_BOL (coding));
   ptrdiff_t produced_chars = 0;
   Lisp_Object attrs, eol_type, charset_list;
-  int ascii_compatible;
+  bool ascii_compatible;
   int c;
   int preferred_charset_id = -1;
 
@@ -4523,8 +4441,9 @@ encode_coding_iso_2022 (struct coding_system *coding)
                     CODING_ISO_DESIGNATION (coding, i)
                       = CODING_ISO_INITIAL (coding, i);
                 }
-              bol_designation
-                = CODING_ISO_FLAGS (coding) & CODING_ISO_FLAG_DESIGNATE_AT_BOL;
+              bol_designation = ((CODING_ISO_FLAGS (coding)
+                                  & CODING_ISO_FLAG_DESIGNATE_AT_BOL)
+                                 != 0);
             }
           else if (CODING_ISO_FLAGS (coding) & CODING_ISO_FLAG_RESET_AT_CNTL)
             ENCODE_RESET_PLANE_AND_REGISTER ();
@@ -4551,7 +4470,7 @@ encode_coding_iso_2022 (struct coding_system *coding)
 
           if (preferred_charset_id >= 0)
             {
-              int result;
+              bool result;
 
               charset = CHARSET_FROM_ID (preferred_charset_id);
               CODING_CHAR_CHARSET_P (coding, dst, dst_end, c, charset, result);
@@ -4631,16 +4550,15 @@ encode_coding_iso_2022 (struct coding_system *coding)
   */
 
 /* See the above "GENERAL NOTES on `detect_coding_XXX ()' functions".
-   Check if a text is encoded in SJIS.  If it is, return
-   CATEGORY_MASK_SJIS, else return 0.  */
+   Return true if a text is encoded in SJIS.  */
 
-static int
+static bool
 detect_coding_sjis (struct coding_system *coding,
                     struct coding_detection_info *detect_info)
 {
   const unsigned char *src = coding->source, *src_base;
   const unsigned char *src_end = coding->source + coding->src_bytes;
-  int multibytep = coding->src_multibyte;
+  bool multibytep = coding->src_multibyte;
   ptrdiff_t consumed_chars = 0;
   int found = 0;
   int c;
@@ -4688,16 +4606,15 @@ detect_coding_sjis (struct coding_system *coding,
 }
 
 /* See the above "GENERAL NOTES on `detect_coding_XXX ()' functions".
-   Check if a text is encoded in BIG5.  If it is, return
-   CATEGORY_MASK_BIG5, else return 0.  */
+   Return true if a text is encoded in BIG5.  */
 
-static int
+static bool
 detect_coding_big5 (struct coding_system *coding,
                     struct coding_detection_info *detect_info)
 {
   const unsigned char *src = coding->source, *src_base;
   const unsigned char *src_end = coding->source + coding->src_bytes;
-  int multibytep = coding->src_multibyte;
+  bool multibytep = coding->src_multibyte;
   ptrdiff_t consumed_chars = 0;
   int found = 0;
   int c;
@@ -4735,8 +4652,7 @@ detect_coding_big5 (struct coding_system *coding,
   return 1;
 }
 
-/* See the above "GENERAL NOTES on `decode_coding_XXX ()' functions".
-   If SJIS_P is 1, decode SJIS text, else decode BIG5 test.  */
+/* See the above "GENERAL NOTES on `decode_coding_XXX ()' functions".  */
 
 static void
 decode_coding_sjis (struct coding_system *coding)
@@ -4750,15 +4666,15 @@ decode_coding_sjis (struct coding_system *coding)
   int *charbuf_end
     = coding->charbuf + coding->charbuf_size - (MAX_ANNOTATION_LENGTH * 2);
   ptrdiff_t consumed_chars = 0, consumed_chars_base;
-  int multibytep = coding->src_multibyte;
+  bool multibytep = coding->src_multibyte;
   struct charset *charset_roman, *charset_kanji, *charset_kana;
   struct charset *charset_kanji2;
   Lisp_Object attrs, charset_list, val;
   ptrdiff_t char_offset = coding->produced_char;
   ptrdiff_t last_offset = char_offset;
   int last_id = charset_ascii;
-  int eol_dos =
-    !inhibit_eol_conversion && EQ (CODING_ID_EOL_TYPE (coding->id), Qdos);
+  bool eol_dos
+    = !inhibit_eol_conversion && EQ (CODING_ID_EOL_TYPE (coding->id), Qdos);
   int byte_after_cr = -1;
 
   CODING_GET_INFO (coding, attrs, charset_list);
@@ -4868,14 +4784,14 @@ decode_coding_big5 (struct coding_system *coding)
   int *charbuf_end
     = coding->charbuf + coding->charbuf_size - (MAX_ANNOTATION_LENGTH * 2);
   ptrdiff_t consumed_chars = 0, consumed_chars_base;
-  int multibytep = coding->src_multibyte;
+  bool multibytep = coding->src_multibyte;
   struct charset *charset_roman, *charset_big5;
   Lisp_Object attrs, charset_list, val;
   ptrdiff_t char_offset = coding->produced_char;
   ptrdiff_t last_offset = char_offset;
   int last_id = charset_ascii;
-  int eol_dos =
-    !inhibit_eol_conversion && EQ (CODING_ID_EOL_TYPE (coding->id), Qdos);
+  bool eol_dos
+    = !inhibit_eol_conversion && EQ (CODING_ID_EOL_TYPE (coding->id), Qdos);
   int byte_after_cr = -1;
 
   CODING_GET_INFO (coding, attrs, charset_list);
@@ -4957,13 +4873,12 @@ decode_coding_big5 (struct coding_system *coding)
    `japanese-jisx0208', `chinese-big5-1', and `chinese-big5-2'.  We
    are sure that all these charsets are registered as official charset
    (i.e. do not have extended leading-codes).  Characters of other
-   charsets are produced without any encoding.  If SJIS_P is 1, encode
-   SJIS text, else encode BIG5 text.  */
+   charsets are produced without any encoding.  */
 
-static int
+static bool
 encode_coding_sjis (struct coding_system *coding)
 {
-  int multibytep = coding->dst_multibyte;
+  bool multibytep = coding->dst_multibyte;
   int *charbuf = coding->charbuf;
   int *charbuf_end = charbuf + coding->charbuf_used;
   unsigned char *dst = coding->destination + coding->produced;
@@ -4971,7 +4886,7 @@ encode_coding_sjis (struct coding_system *coding)
   int safe_room = 4;
   ptrdiff_t produced_chars = 0;
   Lisp_Object attrs, charset_list, val;
-  int ascii_compatible;
+  bool ascii_compatible;
   struct charset *charset_kanji, *charset_kana;
   struct charset *charset_kanji2;
   int c;
@@ -5054,10 +4969,10 @@ encode_coding_sjis (struct coding_system *coding)
   return 0;
 }
 
-static int
+static bool
 encode_coding_big5 (struct coding_system *coding)
 {
-  int multibytep = coding->dst_multibyte;
+  bool multibytep = coding->dst_multibyte;
   int *charbuf = coding->charbuf;
   int *charbuf_end = charbuf + coding->charbuf_used;
   unsigned char *dst = coding->destination + coding->produced;
@@ -5065,7 +4980,7 @@ encode_coding_big5 (struct coding_system *coding)
   int safe_room = 4;
   ptrdiff_t produced_chars = 0;
   Lisp_Object attrs, charset_list, val;
-  int ascii_compatible;
+  bool ascii_compatible;
   struct charset *charset_big5;
   int c;
 
@@ -5130,17 +5045,16 @@ encode_coding_big5 (struct coding_system *coding)
 /*** 10. CCL handlers ***/
 
 /* See the above "GENERAL NOTES on `detect_coding_XXX ()' functions".
-   Check if a text is encoded in a coding system of which
-   encoder/decoder are written in CCL program.  If it is, return
-   CATEGORY_MASK_CCL, else return 0.  */
+   Return true if a text is encoded in a coding system of which
+   encoder/decoder are written in CCL program.  */
 
-static int
+static bool
 detect_coding_ccl (struct coding_system *coding,
                    struct coding_detection_info *detect_info)
 {
   const unsigned char *src = coding->source, *src_base;
   const unsigned char *src_end = coding->source + coding->src_bytes;
-  int multibytep = coding->src_multibyte;
+  bool multibytep = coding->src_multibyte;
   ptrdiff_t consumed_chars = 0;
   int found = 0;
   unsigned char *valids;
@@ -5182,7 +5096,7 @@ decode_coding_ccl (struct coding_system *coding)
   int *charbuf = coding->charbuf + coding->charbuf_used;
   int *charbuf_end = coding->charbuf + coding->charbuf_size;
   ptrdiff_t consumed_chars = 0;
-  int multibytep = coding->src_multibyte;
+  bool multibytep = coding->src_multibyte;
   struct ccl_program *ccl = &coding->spec.ccl->ccl;
   int source_charbuf[1024];
   int source_byteidx[1025];
@@ -5243,11 +5157,11 @@ decode_coding_ccl (struct coding_system *coding)
   coding->charbuf_used = charbuf - coding->charbuf;
 }
 
-static int
+static bool
 encode_coding_ccl (struct coding_system *coding)
 {
   struct ccl_program *ccl = &coding->spec.ccl->ccl;
-  int multibytep = coding->dst_multibyte;
+  bool multibytep = coding->dst_multibyte;
   int *charbuf = coding->charbuf;
   int *charbuf_end = charbuf + coding->charbuf_used;
   unsigned char *dst = coding->destination + coding->produced;
@@ -5308,7 +5222,6 @@ encode_coding_ccl (struct coding_system *coding)
   return 0;
 }
 
-
 
 /*** 10, 11. no-conversion handlers ***/
 
@@ -5317,8 +5230,8 @@ encode_coding_ccl (struct coding_system *coding)
 static void
 decode_coding_raw_text (struct coding_system *coding)
 {
-  int eol_dos =
-    !inhibit_eol_conversion && EQ (CODING_ID_EOL_TYPE (coding->id), Qdos);
+  bool eol_dos
+    = !inhibit_eol_conversion && EQ (CODING_ID_EOL_TYPE (coding->id), Qdos);
 
   coding->chars_at_source = 1;
   coding->consumed_char = coding->src_chars;
@@ -5333,10 +5246,10 @@ decode_coding_raw_text (struct coding_system *coding)
     record_conversion_result (coding, CODING_RESULT_SUCCESS);
 }
 
-static int
+static bool
 encode_coding_raw_text (struct coding_system *coding)
 {
-  int multibytep = coding->dst_multibyte;
+  bool multibytep = coding->dst_multibyte;
   int *charbuf = coding->charbuf;
   int *charbuf_end = coding->charbuf + coding->charbuf_used;
   unsigned char *dst = coding->destination + coding->produced;
@@ -5414,21 +5327,20 @@ encode_coding_raw_text (struct coding_system *coding)
 }
 
 /* See the above "GENERAL NOTES on `detect_coding_XXX ()' functions".
-   Check if a text is encoded in a charset-based coding system.  If it
-   is, return 1, else return 0.  */
+   Return true if a text is encoded in a charset-based coding system.  */
 
-static int
+static bool
 detect_coding_charset (struct coding_system *coding,
                        struct coding_detection_info *detect_info)
 {
   const unsigned char *src = coding->source, *src_base;
   const unsigned char *src_end = coding->source + coding->src_bytes;
-  int multibytep = coding->src_multibyte;
+  bool multibytep = coding->src_multibyte;
   ptrdiff_t consumed_chars = 0;
   Lisp_Object attrs, valids, name;
   int found = 0;
   ptrdiff_t head_ascii = coding->head_ascii;
-  int check_latin_extra = 0;
+  bool check_latin_extra = 0;
 
   detect_info->checked |= CATEGORY_MASK_CHARSET;
 
@@ -5532,14 +5444,14 @@ decode_coding_charset (struct coding_system *coding)
   int *charbuf_end
     = coding->charbuf + coding->charbuf_size - (MAX_ANNOTATION_LENGTH * 2);
   ptrdiff_t consumed_chars = 0, consumed_chars_base;
-  int multibytep = coding->src_multibyte;
+  bool multibytep = coding->src_multibyte;
   Lisp_Object attrs = CODING_ID_ATTRS (coding->id);
   Lisp_Object valids;
   ptrdiff_t char_offset = coding->produced_char;
   ptrdiff_t last_offset = char_offset;
   int last_id = charset_ascii;
-  int eol_dos =
-    !inhibit_eol_conversion && EQ (CODING_ID_EOL_TYPE (coding->id), Qdos);
+  bool eol_dos
+    = !inhibit_eol_conversion && EQ (CODING_ID_EOL_TYPE (coding->id), Qdos);
   int byte_after_cr = -1;
 
   valids = AREF (attrs, coding_attr_charset_valids);
@@ -5648,10 +5560,10 @@ decode_coding_charset (struct coding_system *coding)
   coding->charbuf_used = charbuf - coding->charbuf;
 }
 
-static int
+static bool
 encode_coding_charset (struct coding_system *coding)
 {
-  int multibytep = coding->dst_multibyte;
+  bool multibytep = coding->dst_multibyte;
   int *charbuf = coding->charbuf;
   int *charbuf_end = charbuf + coding->charbuf_used;
   unsigned char *dst = coding->destination + coding->produced;
@@ -5659,7 +5571,7 @@ encode_coding_charset (struct coding_system *coding)
   int safe_room = MAX_MULTIBYTE_LENGTH;
   ptrdiff_t produced_chars = 0;
   Lisp_Object attrs, charset_list;
-  int ascii_compatible;
+  bool ascii_compatible;
   int c;
 
   CODING_GET_INFO (coding, attrs, charset_list);
@@ -5865,7 +5777,6 @@ setup_coding_system (Lisp_Object coding_system, struct coding_system *coding)
       coding->encoder = encode_coding_emacs_mule;
       coding->common_flags
         |= (CODING_REQUIRE_DECODING_MASK | CODING_REQUIRE_ENCODING_MASK);
-      coding->spec.emacs_mule.full_support = 1;
       if (! NILP (AREF (attrs, coding_attr_emacs_mule_full))
           && ! EQ (CODING_ATTR_CHARSET_LIST (attrs), Vemacs_mule_charset_list))
         {
@@ -5883,7 +5794,6 @@ setup_coding_system (Lisp_Object coding_system, struct coding_system *coding)
             SSET (safe_charsets, XFASTINT (XCAR (tail)), 0);
           coding->max_charset_id = max_charset_id;
           coding->safe_charsets = SDATA (safe_charsets);
-          coding->spec.emacs_mule.full_support = 1;
         }
       coding->spec.emacs_mule.cmp_status.state = COMPOSING_NO;
       coding->spec.emacs_mule.cmp_status.method = COMPOSITION_NO;
@@ -6216,11 +6126,9 @@ detect_eol (const unsigned char *source, ptrdiff_t src_bytes,
 
   if ((1 << category) & CATEGORY_MASK_UTF_16)
     {
-      int msb, lsb;
-
-      msb = category == (coding_category_utf_16_le
-                         | coding_category_utf_16_le_nosig);
-      lsb = 1 - msb;
+      bool msb = category == (coding_category_utf_16_le
+                              | coding_category_utf_16_le_nosig);
+      bool lsb = !msb;
 
       while (src + 1 < src_end)
         {
@@ -6335,7 +6243,7 @@ static void
 detect_coding (struct coding_system *coding)
 {
   const unsigned char *src, *src_end;
-  int saved_mode = coding->mode;
+  unsigned int saved_mode = coding->mode;
 
   coding->consumed = coding->consumed_char = 0;
   coding->produced = coding->produced_char = 0;
@@ -6350,7 +6258,7 @@ detect_coding (struct coding_system *coding)
     {
       int c, i;
       struct coding_detection_info detect_info;
-      int null_byte_found = 0, eight_bit_found = 0;
+      bool null_byte_found = 0, eight_bit_found = 0;
 
       detect_info.checked = detect_info.found = detect_info.rejected = 0;
       for (src = coding->source; src < src_end; src++)
@@ -6609,11 +6517,11 @@ decode_eol (struct coding_system *coding)
 
 
 /* Return a translation table (or list of them) from coding system
-   attribute vector ATTRS for encoding (ENCODEP is nonzero) or
-   decoding (ENCODEP is zero). */
+   attribute vector ATTRS for encoding (if ENCODEP) or decoding (if
+   not ENCODEP). */
 
 static Lisp_Object
-get_translation_table (Lisp_Object attrs, int encodep, int *max_lookup)
+get_translation_table (Lisp_Object attrs, bool encodep, int *max_lookup)
 {
   Lisp_Object standard, translation_table;
   Lisp_Object val;
@@ -6743,7 +6651,7 @@ get_translation (Lisp_Object trans, int *buf, int *buf_end)
 
 static int
 produce_chars (struct coding_system *coding, Lisp_Object translation_table,
-               int last_block)
+               bool last_block)
 {
   unsigned char *dst = coding->destination + coding->produced;
   unsigned char *dst_end = coding->destination + coding->dst_bytes;
@@ -6846,7 +6754,7 @@ produce_chars (struct coding_system *coding, Lisp_Object translation_table,
         {
           if (coding->src_multibyte)
             {
-              int multibytep = 1;
+              bool multibytep = 1;
               ptrdiff_t consumed_chars = 0;
 
               while (1)
@@ -6882,7 +6790,7 @@ produce_chars (struct coding_system *coding, Lisp_Object translation_table,
           else
             while (src < src_end)
               {
-                int multibytep = 1;
+                bool multibytep = 1;
                 int c = *src++;
 
                 if (dst >= dst_end - 1)
@@ -7018,7 +6926,7 @@ produce_charset (struct coding_system *coding, int *charbuf, ptrdiff_t pos)
     if (! coding->charbuf)                                              \
       {                                                                 \
         record_conversion_result (coding, CODING_RESULT_INSUFFICIENT_MEM); \
-        return coding->result;                                          \
+        return;                                                         \
       }                                                                 \
     coding->charbuf_size = size;                                        \
   } while (0)
@@ -7079,7 +6987,7 @@ produce_annotation (struct coding_system *coding, ptrdiff_t pos)
    CODING->dst_object.
 */
 
-static int
+static void
 decode_coding (struct coding_system *coding)
 {
   Lisp_Object attrs;
@@ -7212,7 +7120,6 @@ decode_coding (struct coding_system *coding)
       bset_undo_list (current_buffer, undo_list);
       record_insert (coding->dst_pos, coding->produced_char);
     }
-  return coding->result;
 }
 
 
@@ -7341,7 +7248,7 @@ consume_chars (struct coding_system *coding, Lisp_Object translation_table,
   const unsigned char *src_end = coding->source + coding->src_bytes;
   ptrdiff_t pos = coding->src_pos + coding->consumed_char;
   ptrdiff_t end_pos = coding->src_pos + coding->src_chars;
-  int multibytep = coding->src_multibyte;
+  bool multibytep = coding->src_multibyte;
   Lisp_Object eol_type;
   int c;
   ptrdiff_t stop, stop_composition, stop_charset;
@@ -7488,7 +7395,7 @@ consume_chars (struct coding_system *coding, Lisp_Object translation_table,
    If CODING->dst_object is nil, the encoded data is placed at the
    memory area specified by CODING->destination.  */
 
-static int
+static void
 encode_coding (struct coding_system *coding)
 {
   Lisp_Object attrs;
@@ -7530,8 +7437,6 @@ encode_coding (struct coding_system *coding)
 
   if (BUFFERP (coding->dst_object) && coding->produced_char > 0)
     insert_from_gap (coding->produced_char, coding->produced);
-
-  return (coding->result);
 }
 
 
@@ -7545,26 +7450,27 @@ static Lisp_Object Vcode_conversion_workbuf_name;
    versions of Vcode_conversion_workbuf_name.  */
 static Lisp_Object Vcode_conversion_reused_workbuf;
 
-/* 1 iff Vcode_conversion_reused_workbuf is already in use.  */
-static int reused_workbuf_in_use;
+/* True iff Vcode_conversion_reused_workbuf is already in use.  */
+static bool reused_workbuf_in_use;
 
 
 /* Return a working buffer of code conversion.  MULTIBYTE specifies the
    multibyteness of returning buffer.  */
 
 static Lisp_Object
-make_conversion_work_buffer (int multibyte)
+make_conversion_work_buffer (bool multibyte)
 {
   Lisp_Object name, workbuf;
   struct buffer *current;
 
-  if (reused_workbuf_in_use++)
+  if (reused_workbuf_in_use)
     {
       name = Fgenerate_new_buffer_name (Vcode_conversion_workbuf_name, Qnil);
       workbuf = Fget_buffer_create (name);
     }
   else
     {
+      reused_workbuf_in_use = 1;
       if (NILP (Fbuffer_live_p (Vcode_conversion_reused_workbuf)))
         Vcode_conversion_reused_workbuf
           = Fget_buffer_create (Vcode_conversion_workbuf_name);
@@ -7606,7 +7512,7 @@ code_conversion_restore (Lisp_Object arg)
 }
 
 Lisp_Object
-code_conversion_save (int with_work_buf, int multibyte)
+code_conversion_save (bool with_work_buf, bool multibyte)
 {
   Lisp_Object workbuf = Qnil;
 
@@ -7617,7 +7523,7 @@ code_conversion_save (int with_work_buf, int multibyte)
   return workbuf;
 }
 
-int
+void
 decode_coding_gap (struct coding_system *coding,
                    ptrdiff_t chars, ptrdiff_t bytes)
 {
@@ -7660,7 +7566,6 @@ decode_coding_gap (struct coding_system *coding,
     }
 
   unbind_to (count, Qnil);
-  return coding->result;
 }
 
 
@@ -7706,8 +7611,8 @@ decode_coding_object (struct coding_system *coding,
   ptrdiff_t chars = to - from;
   ptrdiff_t bytes = to_byte - from_byte;
   Lisp_Object attrs;
-  int saved_pt = -1, saved_pt_byte IF_LINT (= 0);
-  int need_marker_adjustment = 0;
+  ptrdiff_t saved_pt = -1, saved_pt_byte IF_LINT (= 0);
+  bool need_marker_adjustment = 0;
   Lisp_Object old_deactivate_mark;
 
   old_deactivate_mark = Vdeactivate_mark;
@@ -7894,9 +7799,9 @@ encode_coding_object (struct coding_system *coding,
   ptrdiff_t chars = to - from;
   ptrdiff_t bytes = to_byte - from_byte;
   Lisp_Object attrs;
-  int saved_pt = -1, saved_pt_byte IF_LINT (= 0);
-  int need_marker_adjustment = 0;
-  int kill_src_buffer = 0;
+  ptrdiff_t saved_pt = -1, saved_pt_byte IF_LINT (= 0);
+  bool need_marker_adjustment = 0;
+  bool kill_src_buffer = 0;
   Lisp_Object old_deactivate_mark;
 
   old_deactivate_mark = Vdeactivate_mark;
@@ -8172,10 +8077,10 @@ function `define-coding-system'.  */)
 
 
 /* Detect how the bytes at SRC of length SRC_BYTES are encoded.  If
-   HIGHEST is nonzero, return the coding system of the highest
+   HIGHEST, return the coding system of the highest
    priority among the detected coding systems.  Otherwise return a
    list of detected coding systems sorted by their priorities.  If
-   MULTIBYTEP is nonzero, it is assumed that the bytes are in correct
+   MULTIBYTEP, it is assumed that the bytes are in correct
    multibyte form but contains only ASCII and eight-bit chars.
    Otherwise, the bytes are raw bytes.
 
@@ -8190,7 +8095,7 @@ function `define-coding-system'.  */)
 Lisp_Object
 detect_coding_system (const unsigned char *src,
                       ptrdiff_t src_chars, ptrdiff_t src_bytes,
-                      int highest, int multibytep,
+                      bool highest, bool multibytep,
                       Lisp_Object coding_system)
 {
   const unsigned char *src_end = src + src_bytes;
@@ -8200,7 +8105,7 @@ detect_coding_system (const unsigned char *src,
   ptrdiff_t id;
   struct coding_detection_info detect_info;
   enum coding_category base_category;
-  int null_byte_found = 0, eight_bit_found = 0;
+  bool null_byte_found = 0, eight_bit_found = 0;
 
   if (NILP (coding_system))
     coding_system = Qundecided;
@@ -8556,7 +8461,7 @@ highest priority.  */)
 }
 
 
-static inline int
+static inline bool
 char_encodable_p (int c, Lisp_Object attrs)
 {
   Lisp_Object tail;
@@ -8728,7 +8633,7 @@ to the string.  */)
   Lisp_Object positions;
   ptrdiff_t from, to;
   const unsigned char *p, *stop, *pend;
-  int ascii_compatible;
+  bool ascii_compatible;
 
   setup_coding_system (Fcheck_coding_system (coding_system), &coding);
   attrs = CODING_ID_ATTRS (coding.id);
@@ -8952,7 +8857,7 @@ is nil.  */)
 static Lisp_Object
 code_convert_region (Lisp_Object start, Lisp_Object end,
                      Lisp_Object coding_system, Lisp_Object dst_object,
-                     int encodep, int norecord)
+                     bool encodep, bool norecord)
 {
   struct coding_system coding;
   ptrdiff_t from, from_byte, to, to_byte;
@@ -9040,7 +8945,8 @@ not fully specified.)  */)
 
 Lisp_Object
 code_convert_string (Lisp_Object string, Lisp_Object coding_system,
-                     Lisp_Object dst_object, int encodep, int nocopy, int norecord)
+                     Lisp_Object dst_object, bool encodep, bool nocopy,
+                     bool norecord)
 {
   struct coding_system coding;
   ptrdiff_t chars, bytes;
@@ -9088,7 +8994,7 @@ code_convert_string (Lisp_Object string, Lisp_Object coding_system,
 
 Lisp_Object
 code_convert_string_norecord (Lisp_Object string, Lisp_Object coding_system,
-                              int encodep)
+                              bool encodep)
 {
   return code_convert_string (string, coding_system, Qt, encodep, 0, 1);
 }
@@ -9489,7 +9395,7 @@ usage: (set-coding-system-priority &rest coding-systems)  */)
   (ptrdiff_t nargs, Lisp_Object *args)
 {
   ptrdiff_t i, j;
-  int changed[coding_category_max];
+  bool changed[coding_category_max];
   enum coding_category priorities[coding_category_max];
 
   memset (changed, 0, sizeof changed);
diff --git a/src/coding.h b/src/coding.h
index 2987f19607b..c45d2ef86e2 100644
--- a/src/coding.h
+++ b/src/coding.h
@@ -321,7 +321,7 @@ struct composition_status
 {
   enum composition_state state;
   enum composition_method method;
-  int old_form;           /* 0:pre-21 form, 1:post-21 form */
+  bool old_form;          /* true if pre-21 form */
   int length;             /* number of elements produced in charbuf */
   int nchars;             /* number of characters composed */
   int ncomps;             /* number of composition components */
@@ -350,18 +350,18 @@ struct iso_2022_spec
      there was an invalid designation previously.  */
   int current_designation[4];
 
-  /* Set to 1 temporarily only when graphic register 2 or 3 is invoked
-     by single-shift while encoding.  */
-  int single_shifting;
-
-  /* Set to 1 temporarily only when processing at beginning of line.  */
-  int bol;
-
   /* If positive, we are now scanning CTEXT extended segment.  */
   int ctext_extended_segment_len;
 
-  /* If nonzero, we are now scanning embedded UTF-8 sequence.  */
-  int embedded_utf_8;
+  /* True temporarily only when graphic register 2 or 3 is invoked by
+     single-shift while encoding.  */
+  unsigned single_shifting : 1;
+
+  /* True temporarily only when processing at beginning of line.  */
+  unsigned bol : 1;
+
+  /* If true, we are now scanning embedded UTF-8 sequence.  */
+  unsigned embedded_utf_8 : 1;
 
   /* The current composition.  */
   struct composition_status cmp_status;
@@ -369,7 +369,6 @@ struct iso_2022_spec
 
 struct emacs_mule_spec
 {
-  int full_support;
   struct composition_status cmp_status;
 };
 
@@ -470,10 +469,6 @@ struct coding_system
   Lisp_Object dst_object;
   unsigned char *destination;
 
-  /* Set to 1 if the source of conversion is not in the member
-     `charbuf', but at `src_object'.  */
-  int chars_at_source;
-
   /* If an element is non-negative, it is a character code.
 
      If it is in the range -128..-1, it is a 8-bit character code
@@ -489,18 +484,21 @@ struct coding_system
   int *charbuf;
   int charbuf_size, charbuf_used;
 
+  /* True if the source of conversion is not in the member
+     `charbuf', but at `src_object'.  */
+  unsigned chars_at_source : 1;
+
   /* Set to 1 if charbuf contains an annotation.  */
-  int annotated;
+  unsigned annotated : 1;
 
   unsigned char carryover[64];
   int carryover_bytes;
 
   int default_char;
 
-  int (*detector) (struct coding_system *,
-                   struct coding_detection_info *);
+  bool (*detector) (struct coding_system *, struct coding_detection_info *);
   void (*decoder) (struct coding_system *);
-  int (*encoder) (struct coding_system *);
+  bool (*encoder) (struct coding_system *);
 };
 
 /* Meanings of bits in the member `common_flags' of the structure
@@ -688,22 +686,20 @@ struct coding_system
 #define ENCODE_UTF_8(str) code_convert_string_norecord (str, Qutf_8, 1)
 
 /* Extern declarations.  */
-extern Lisp_Object code_conversion_save (int, int);
-extern int decoding_buffer_size (struct coding_system *, int);
-extern int encoding_buffer_size (struct coding_system *, int);
+extern Lisp_Object code_conversion_save (bool, bool);
 extern void setup_coding_system (Lisp_Object, struct coding_system *);
 extern Lisp_Object coding_charset_list (struct coding_system *);
 extern Lisp_Object coding_system_charset_list (Lisp_Object);
 extern Lisp_Object code_convert_string (Lisp_Object, Lisp_Object,
-                                        Lisp_Object, int, int, int);
+                                        Lisp_Object, bool, bool, bool);
 extern Lisp_Object code_convert_string_norecord (Lisp_Object, Lisp_Object,
-                                                 int);
+                                                 bool);
 extern Lisp_Object raw_text_coding_system (Lisp_Object);
 extern Lisp_Object coding_inherit_eol_type (Lisp_Object, Lisp_Object);
 extern Lisp_Object complement_process_encoding_system (Lisp_Object);
 
-extern int decode_coding_gap (struct coding_system *,
-                              ptrdiff_t, ptrdiff_t);
+extern void decode_coding_gap (struct coding_system *,
+                               ptrdiff_t, ptrdiff_t);
 extern void decode_coding_object (struct coding_system *,
                                   Lisp_Object, ptrdiff_t, ptrdiff_t,
                                   ptrdiff_t, ptrdiff_t, Lisp_Object);
@@ -778,6 +774,5 @@ extern struct coding_system safe_terminal_coding;
 extern Lisp_Object Qcoding_system_error;
 
 extern char emacs_mule_bytes[256];
-extern int emacs_mule_string_char (unsigned char *);
 
 #endif /* EMACS_CODING_H */
diff --git a/src/fileio.c b/src/fileio.c
index 6deca0bf1e1..6906af7e74f 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -3760,7 +3760,8 @@ variable `last-coding-system-used' to the coding system actually used.  */)
       ptrdiff_t temp;
       ptrdiff_t this = 0;
       ptrdiff_t this_count = SPECPDL_INDEX ();
-      int multibyte = ! NILP (BVAR (current_buffer, enable_multibyte_characters));
+      bool multibyte
+        = ! NILP (BVAR (current_buffer, enable_multibyte_characters));
       Lisp_Object conversion_buffer;
       struct gcpro gcpro1;
 
diff --git a/src/lisp.h b/src/lisp.h
index 5b842d371a2..9ae24998aa2 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -2632,7 +2632,7 @@ extern void keys_of_cmds (void);
 /* Defined in coding.c */
 extern Lisp_Object Qcharset;
 extern Lisp_Object detect_coding_system (const unsigned char *, ptrdiff_t,
-                                         ptrdiff_t, int, int, Lisp_Object);
+                                         ptrdiff_t, bool, bool, Lisp_Object);
 extern void init_coding (void);
 extern void init_coding_once (void);
 extern void syms_of_coding (void);