Remove many -Wcast-qual warnings

This addresses only those cases that are easy to fix by adding or
moving a const qualifier or removing an unnecessary cast.  There are
many more complicated cases remaining.

src/backend/commands/analyze.c

@@ -1362,8 +1362,8 @@ get_next_S(double t, int n, double *stateptr)
 static int
 compare_rows(const void *a, const void *b)
 {
-	HeapTuple	ha = *(HeapTuple *) a;
-	HeapTuple	hb = *(HeapTuple *) b;
+	HeapTuple	ha = *(const HeapTuple *) a;
+	HeapTuple	hb = *(const HeapTuple *) b;
 	BlockNumber ba = ItemPointerGetBlockNumber(&ha->t_self);
 	OffsetNumber oa = ItemPointerGetOffsetNumber(&ha->t_self);
 	BlockNumber bb = ItemPointerGetBlockNumber(&hb->t_self);
@@ -2700,10 +2700,10 @@ compute_scalar_stats(VacAttrStatsP stats,
 static int
 compare_scalars(const void *a, const void *b, void *arg)
 {
-	Datum		da = ((ScalarItem *) a)->value;
-	int			ta = ((ScalarItem *) a)->tupno;
-	Datum		db = ((ScalarItem *) b)->value;
-	int			tb = ((ScalarItem *) b)->tupno;
+	Datum		da = ((const ScalarItem *) a)->value;
+	int			ta = ((const ScalarItem *) a)->tupno;
+	Datum		db = ((const ScalarItem *) b)->value;
+	int			tb = ((const ScalarItem *) b)->tupno;
 	CompareScalarsContext *cxt = (CompareScalarsContext *) arg;
 	int32		compare;
 
@@ -2734,8 +2734,8 @@ compare_scalars(const void *a, const void *b, void *arg)
 static int
 compare_mcvs(const void *a, const void *b)
 {
-	int			da = ((ScalarMCVItem *) a)->first;
-	int			db = ((ScalarMCVItem *) b)->first;
+	int			da = ((const ScalarMCVItem *) a)->first;
+	int			db = ((const ScalarMCVItem *) b)->first;
 
 	return da - db;
 }

src/backend/commands/copy.c

@@ -296,7 +296,7 @@ static char *limit_printout_length(const char *str);
 static void SendCopyBegin(CopyState cstate);
 static void ReceiveCopyBegin(CopyState cstate);
 static void SendCopyEnd(CopyState cstate);
-static void CopySendData(CopyState cstate, void *databuf, int datasize);
+static void CopySendData(CopyState cstate, const void *databuf, int datasize);
 static void CopySendString(CopyState cstate, const char *str);
 static void CopySendChar(CopyState cstate, char c);
 static void CopySendEndOfRow(CopyState cstate);
@@ -431,9 +431,9 @@ SendCopyEnd(CopyState cstate)
  *----------
  */
 static void
-CopySendData(CopyState cstate, void *databuf, int datasize)
+CopySendData(CopyState cstate, const void *databuf, int datasize)
 {
-	appendBinaryStringInfo(cstate->fe_msgbuf, (char *) databuf, datasize);
+	appendBinaryStringInfo(cstate->fe_msgbuf, databuf, datasize);
 }
 
 static void
@@ -1535,7 +1535,7 @@ CopyTo(CopyState cstate)
 		int32		tmp;
 
 		/* Signature */
-		CopySendData(cstate, (char *) BinarySignature, 11);
+		CopySendData(cstate, BinarySignature, 11);
 		/* Flags field */
 		tmp = 0;
 		if (cstate->oids)

src/backend/libpq/ip.c

@@ -283,14 +283,14 @@ pg_range_sockaddr(const struct sockaddr_storage * addr,
 				  const struct sockaddr_storage * netmask)
 {
 	if (addr->ss_family == AF_INET)
-		return range_sockaddr_AF_INET((struct sockaddr_in *) addr,
-									  (struct sockaddr_in *) netaddr,
-									  (struct sockaddr_in *) netmask);
+		return range_sockaddr_AF_INET((const struct sockaddr_in *) addr,
+									  (const struct sockaddr_in *) netaddr,
+									  (const struct sockaddr_in *) netmask);
 #ifdef HAVE_IPV6
 	else if (addr->ss_family == AF_INET6)
-		return range_sockaddr_AF_INET6((struct sockaddr_in6 *) addr,
-									   (struct sockaddr_in6 *) netaddr,
-									   (struct sockaddr_in6 *) netmask);
+		return range_sockaddr_AF_INET6((const struct sockaddr_in6 *) addr,
+									   (const struct sockaddr_in6 *) netaddr,
+									   (const struct sockaddr_in6 *) netmask);
 #endif
 	else
 		return 0;

src/backend/libpq/md5.c

@@ -33,7 +33,7 @@
  *	when it is no longer needed.
  */
 static uint8 *
-createPaddedCopyWithLength(uint8 *b, uint32 *l)
+createPaddedCopyWithLength(const uint8 *b, uint32 *l)
 {
 	uint8	   *ret;
 	uint32		q;
@@ -182,7 +182,7 @@ doTheRounds(uint32 X[16], uint32 state[4])
 }
 
 static int
-calculateDigestFromBuffer(uint8 *b, uint32 len, uint8 sum[16])
+calculateDigestFromBuffer(const uint8 *b, uint32 len, uint8 sum[16])
 {
 	register uint32 i,
 				j,
@@ -291,7 +291,7 @@ pg_md5_hash(const void *buff, size_t len, char *hexsum)
 {
 	uint8		sum[16];
 
-	if (!calculateDigestFromBuffer((uint8 *) buff, len, sum))
+	if (!calculateDigestFromBuffer(buff, len, sum))
 		return false;
 
 	bytesToHex(sum, hexsum);
@@ -301,7 +301,7 @@ pg_md5_hash(const void *buff, size_t len, char *hexsum)
 bool
 pg_md5_binary(const void *buff, size_t len, void *outbuf)
 {
-	if (!calculateDigestFromBuffer((uint8 *) buff, len, outbuf))
+	if (!calculateDigestFromBuffer(buff, len, outbuf))
 		return false;
 	return true;
 }

src/backend/nodes/makefuncs.c

@@ -45,7 +45,7 @@ makeA_Expr(A_Expr_Kind kind, List *name,
  *		As above, given a simple (unqualified) operator name
  */
 A_Expr *
-makeSimpleA_Expr(A_Expr_Kind kind, const char *name,
+makeSimpleA_Expr(A_Expr_Kind kind, char *name,
 				 Node *lexpr, Node *rexpr, int location)
 {
 	A_Expr	   *a = makeNode(A_Expr);

src/backend/nodes/tidbitmap.c

@@ -1011,8 +1011,8 @@ tbm_lossify(TIDBitmap *tbm)
 static int
 tbm_comparator(const void *left, const void *right)
 {
-	BlockNumber l = (*((const PagetableEntry **) left))->blockno;
-	BlockNumber r = (*((const PagetableEntry **) right))->blockno;
+	BlockNumber l = (*((PagetableEntry * const *) left))->blockno;
+	BlockNumber r = (*((PagetableEntry * const *) right))->blockno;
 
 	if (l < r)
 		return -1;

src/backend/postmaster/autovacuum.c

@@ -1028,10 +1028,10 @@ rebuild_database_list(Oid newdb)
 static int
 db_comparator(const void *a, const void *b)
 {
-	if (((avl_dbase *) a)->adl_score == ((avl_dbase *) b)->adl_score)
+	if (((const avl_dbase *) a)->adl_score == ((const avl_dbase *) b)->adl_score)
 		return 0;
 	else
-		return (((avl_dbase *) a)->adl_score < ((avl_dbase *) b)->adl_score) ? 1 : -1;
+		return (((const avl_dbase *) a)->adl_score < ((const avl_dbase *) b)->adl_score) ? 1 : -1;
 }
 
 /*

src/backend/storage/lmgr/lock.c

@@ -937,7 +937,7 @@ SetupLockInTable(LockMethod lockMethodTable, PGPROC *proc,
 	 * anytime.
 	 */
 	lock = (LOCK *) hash_search_with_hash_value(LockMethodLockHash,
-												(void *) locktag,
+												(const void *) locktag,
 												hashcode,
 												HASH_ENTER_NULL,
 												&found);
@@ -1673,7 +1673,7 @@ LockRelease(const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock)
 
 		Assert(FastPathTag(locktag) && FastPathWeakMode(lockmode));
 		lock = (LOCK *) hash_search_with_hash_value(LockMethodLockHash,
-													(void *) locktag,
+													(const void *) locktag,
 													locallock->hashcode,
 													HASH_FIND,
 													&found);
@@ -2505,7 +2505,7 @@ GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode)
 	LWLockAcquire(partitionLock, LW_SHARED);
 
 	lock = (LOCK *) hash_search_with_hash_value(LockMethodLockHash,
-												(void *) locktag,
+												(const void *) locktag,
 												hashcode,
 												HASH_FIND,
 												NULL);

src/backend/tsearch/dict_synonym.c

@@ -83,7 +83,7 @@ findwrd(char *in, char **end, uint16 *flags)
 static int
 compareSyn(const void *a, const void *b)
 {
-	return strcmp(((Syn *) a)->in, ((Syn *) b)->in);
+	return strcmp(((const Syn *) a)->in, ((const Syn *) b)->in);
 }
 
 

src/backend/tsearch/dict_thesaurus.c

@@ -348,7 +348,7 @@ cmpLexemeInfo(LexemeInfo *a, LexemeInfo *b)
 }
 
 static int
-cmpLexeme(TheLexeme *a, TheLexeme *b)
+cmpLexeme(const TheLexeme *a, const TheLexeme *b)
 {
 	if (a->lexeme == NULL)
 	{
@@ -366,14 +366,14 @@ cmpLexeme(TheLexeme *a, TheLexeme *b)
 static int
 cmpLexemeQ(const void *a, const void *b)
 {
-	return cmpLexeme((TheLexeme *) a, (TheLexeme *) b);
+	return cmpLexeme((const TheLexeme *) a, (const TheLexeme *) b);
 }
 
 static int
 cmpTheLexeme(const void *a, const void *b)
 {
-	TheLexeme  *la = (TheLexeme *) a;
-	TheLexeme  *lb = (TheLexeme *) b;
+	const TheLexeme  *la = (const TheLexeme *) a;
+	const TheLexeme  *lb = (const TheLexeme *) b;
 	int			res;
 
 	if ((res = cmpLexeme(la, lb)) != 0)

src/backend/tsearch/spell.c

@@ -140,7 +140,7 @@ lowerstr_ctx(IspellDict *Conf, const char *src)
 #define MAXNORMLEN 256
 
 #define STRNCMP(s,p)	strncmp( (s), (p), strlen(p) )
-#define GETWCHAR(W,L,N,T) ( ((uint8*)(W))[ ((T)==FF_PREFIX) ? (N) : ( (L) - 1 - (N) ) ] )
+#define GETWCHAR(W,L,N,T) ( ((const uint8*)(W))[ ((T)==FF_PREFIX) ? (N) : ( (L) - 1 - (N) ) ] )
 #define GETCHAR(A,N,T)	  GETWCHAR( (A)->repl, (A)->replen, N, T )
 
 static char *VoidString = "";
@@ -148,12 +148,12 @@ static char *VoidString = "";
 static int
 cmpspell(const void *s1, const void *s2)
 {
-	return (strcmp((*(const SPELL **) s1)->word, (*(const SPELL **) s2)->word));
+	return (strcmp((*(SPELL * const *) s1)->word, (*(SPELL * const *) s2)->word));
 }
 static int
 cmpspellaffix(const void *s1, const void *s2)
 {
-	return (strncmp((*(const SPELL **) s1)->p.flag, (*(const SPELL **) s2)->p.flag, MAXFLAGLEN));
+	return (strncmp((*(SPELL * const *) s1)->p.flag, (*(SPELL * const *) s2)->p.flag, MAXFLAGLEN));
 }
 
 static char *
@@ -332,7 +332,7 @@ FindWord(IspellDict *Conf, const char *word, int affixflag, int flag)
 	SPNodeData *StopLow,
 			   *StopHigh,
 			   *StopMiddle;
-	uint8	   *ptr = (uint8 *) word;
+	const uint8 *ptr = (const uint8 *) word;
 
 	flag &= FF_DICTFLAGMASK;
 

src/backend/tsearch/to_tsany.c

@@ -33,16 +33,16 @@ compareWORD(const void *a, const void *b)
 	int			res;
 
 	res = tsCompareString(
-						  ((ParsedWord *) a)->word, ((ParsedWord *) a)->len,
-						  ((ParsedWord *) b)->word, ((ParsedWord *) b)->len,
+						  ((const ParsedWord *) a)->word, ((const ParsedWord *) a)->len,
+						  ((const ParsedWord *) b)->word, ((const ParsedWord *) b)->len,
 						  false);
 
 	if (res == 0)
 	{
-		if (((ParsedWord *) a)->pos.pos == ((ParsedWord *) b)->pos.pos)
+		if (((const ParsedWord *) a)->pos.pos == ((const ParsedWord *) b)->pos.pos)
 			return 0;
 
-		res = (((ParsedWord *) a)->pos.pos > ((ParsedWord *) b)->pos.pos) ? 1 : -1;
+		res = (((const ParsedWord *) a)->pos.pos > ((const ParsedWord *) b)->pos.pos) ? 1 : -1;
 	}
 
 	return res;

src/backend/tsearch/ts_utils.c

@@ -62,7 +62,7 @@ get_tsearch_config_filename(const char *basename,
 static int
 comparestr(const void *a, const void *b)
 {
-	return strcmp(*(char **) a, *(char **) b);
+	return strcmp(*(char * const *) a, *(char * const *) b);
 }
 
 /*

src/backend/utils/adt/tsgistidx.c

@@ -131,8 +131,8 @@ gtsvectorout(PG_FUNCTION_ARGS)
 static int
 compareint(const void *va, const void *vb)
 {
-	int4		a = *((int4 *) va);
-	int4		b = *((int4 *) vb);
+	int4		a = *((const int4 *) va);
+	int4		b = *((const int4 *) vb);
 
 	if (a == b)
 		return 0;
@@ -593,8 +593,8 @@ typedef struct
 static int
 comparecost(const void *va, const void *vb)
 {
-	SPLITCOST  *a = (SPLITCOST *) va;
-	SPLITCOST  *b = (SPLITCOST *) vb;
+	const SPLITCOST  *a = (const SPLITCOST *) va;
+	const SPLITCOST  *b = (const SPLITCOST *) vb;
 
 	if (a->cost == b->cost)
 		return 0;

src/backend/utils/adt/tsquery_gist.c

@@ -156,10 +156,10 @@ typedef struct
 static int
 comparecost(const void *a, const void *b)
 {
-	if (((SPLITCOST *) a)->cost == ((SPLITCOST *) b)->cost)
+	if (((const SPLITCOST *) a)->cost == ((const SPLITCOST *) b)->cost)
 		return 0;
 	else
-		return (((SPLITCOST *) a)->cost > ((SPLITCOST *) b)->cost) ? 1 : -1;
+		return (((const SPLITCOST *) a)->cost > ((const SPLITCOST *) b)->cost) ? 1 : -1;
 }
 
 #define WISH_F(a,b,c) (double)( -(double)(((a)-(b))*((a)-(b))*((a)-(b)))*(c) )

src/backend/utils/adt/tsrank.c

@@ -134,8 +134,8 @@ static int
 compareQueryOperand(const void *a, const void *b, void *arg)
 {
 	char	   *operand = (char *) arg;
-	QueryOperand *qa = (*(QueryOperand **) a);
-	QueryOperand *qb = (*(QueryOperand **) b);
+	QueryOperand *qa = (*(QueryOperand * const *) a);
+	QueryOperand *qb = (*(QueryOperand * const *) b);
 
 	return tsCompareString(operand + qa->distance, qa->length,
 						   operand + qb->distance, qb->length,
@@ -498,8 +498,8 @@ typedef struct
 static int
 compareDocR(const void *va, const void *vb)
 {
-	DocRepresentation *a = (DocRepresentation *) va;
-	DocRepresentation *b = (DocRepresentation *) vb;
+	const DocRepresentation *a = (const DocRepresentation *) va;
+	const DocRepresentation *b = (const DocRepresentation *) vb;
 
 	if (a->pos == b->pos)
 		return 0;

src/backend/utils/adt/xml.c

@@ -396,7 +396,7 @@ cstring_to_xmltype(const char *string)
 static xmltype *
 xmlBuffer_to_xmltype(xmlBufferPtr buf)
 {
-	return (xmltype *) cstring_to_text_with_len((char *) xmlBufferContent(buf),
+	return (xmltype *) cstring_to_text_with_len((const char *) xmlBufferContent(buf),
 												xmlBufferLength(buf));
 }
 #endif
@@ -1267,7 +1267,7 @@ static bool
 print_xml_decl(StringInfo buf, const xmlChar *version,
 			   pg_enc encoding, int standalone)
 {
-	if ((version && strcmp((char *) version, PG_XML_DEFAULT_VERSION) != 0)
+	if ((version && strcmp((const char *) version, PG_XML_DEFAULT_VERSION) != 0)
 		|| (encoding && encoding != PG_UTF8)
 		|| standalone != -1)
 	{

src/backend/utils/mb/conv.c

@@ -247,8 +247,8 @@ compare1(const void *p1, const void *p2)
 	uint32		v1,
 				v2;
 
-	v1 = *(uint32 *) p1;
-	v2 = ((pg_utf_to_local *) p2)->utf;
+	v1 = *(const uint32 *) p1;
+	v2 = ((const pg_utf_to_local *) p2)->utf;
 	return (v1 > v2) ? 1 : ((v1 == v2) ? 0 : -1);
 }
 
@@ -262,8 +262,8 @@ compare2(const void *p1, const void *p2)
 	uint32		v1,
 				v2;
 
-	v1 = *(uint32 *) p1;
-	v2 = ((pg_local_to_utf *) p2)->code;
+	v1 = *(const uint32 *) p1;
+	v2 = ((const pg_local_to_utf *) p2)->code;
 	return (v1 > v2) ? 1 : ((v1 == v2) ? 0 : -1);
 }
 
@@ -279,10 +279,10 @@ compare3(const void *p1, const void *p2)
 				d1,
 				d2;
 
-	s1 = *(uint32 *) p1;
-	s2 = *((uint32 *) p1 + 1);
-	d1 = ((pg_utf_to_local_combined *) p2)->utf1;
-	d2 = ((pg_utf_to_local_combined *) p2)->utf2;
+	s1 = *(const uint32 *) p1;
+	s2 = *((const uint32 *) p1 + 1);
+	d1 = ((const pg_utf_to_local_combined *) p2)->utf1;
+	d2 = ((const pg_utf_to_local_combined *) p2)->utf2;
 	return (s1 > d1 || (s1 == d1 && s2 > d2)) ? 1 : ((s1 == d1 && s2 == d2) ? 0 : -1);
 }
 
@@ -296,8 +296,8 @@ compare4(const void *p1, const void *p2)
 	uint32		v1,
 				v2;
 
-	v1 = *(uint32 *) p1;
-	v2 = ((pg_local_to_utf_combined *) p2)->code;
+	v1 = *(const uint32 *) p1;
+	v2 = ((const pg_local_to_utf_combined *) p2)->code;
 	return (v1 > v2) ? 1 : ((v1 == v2) ? 0 : -1);
 }