gdb: const-ify unpack_* functions in remote.c

Const-ify the unpack_* functions, and then adjust the callers
accordingly.

gdb/ChangeLog:

	* remote.c (class remote_target)
	<remote_unpack_thread_info_response,
	parse_threadlist_response>: Constify parameter and/or return
	value and or local variable.
	(stub_unpack_int): Likewise.
	(unpack_nibble): Likewise.
	(unpack_byte): Likewise.
	(unpack_int): Likewise.
	(unpack_string): Likewise.
	(unpack_threadid): Likewise.
	(remote_target::remote_unpack_thread_info_response): Likewise.
	(remote_target::parse_threadlist_response): Likewise.

Change-Id: Ibda75f664d6e3452df00f85af7134533049171b7

2 files changed, 39 insertions, 25 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 9ac7b46..e1bf156 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,18 @@
+2021-01-18  Simon Marchi  <simon.marchi@polymtl.ca>
+
+	* remote.c (class remote_target)
+	<remote_unpack_thread_info_response,
+	parse_threadlist_response>: Constify parameter and/or return
+	value and or local variable.
+	(stub_unpack_int): Likewise.
+	(unpack_nibble): Likewise.
+	(unpack_byte): Likewise.
+	(unpack_int): Likewise.
+	(unpack_string): Likewise.
+	(unpack_threadid): Likewise.
+	(remote_target::remote_unpack_thread_info_response): Likewise.
+	(remote_target::parse_threadlist_response): Likewise.
+
 2021-01-15  Andrew Burgess  <andrew.burgess@embecosm.com>
 
 	* tui/tui.c (tui_is_window_visible): Compare to nullptr, not 0.
diff --git a/gdb/remote.c b/gdb/remote.c
index 74ebbf9..1df05e6 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -793,12 +793,12 @@ public: /* Remote specific methods.  */
 
   char *write_ptid (char *buf, const char *endbuf, ptid_t ptid);
 
-  int remote_unpack_thread_info_response (char *pkt, threadref *expectedref,
+  int remote_unpack_thread_info_response (const char *pkt, threadref *expectedref,
 					  gdb_ext_thread_info *info);
   int remote_get_threadinfo (threadref *threadid, int fieldset,
 			     gdb_ext_thread_info *info);
 
-  int parse_threadlist_response (char *pkt, int result_limit,
+  int parse_threadlist_response (const char *pkt, int result_limit,
 				 threadref *original_echo,
 				 threadref *resultlist,
 				 int *doneflag);
@@ -1017,7 +1017,7 @@ static CORE_ADDR remote_address_masked (CORE_ADDR);
 
 static void print_packet (const char *);
 
-static int stub_unpack_int (char *buff, int fieldlength);
+static int stub_unpack_int (const char *buff, int fieldlength);
 
 struct packet_config;
 
@@ -2999,19 +2999,19 @@ struct gdb_ext_thread_info
 
 #define BUF_THREAD_ID_SIZE (OPAQUETHREADBYTES * 2)
 
-static char *unpack_nibble (char *buf, int *val);
+static const char *unpack_nibble (const char *buf, int *val);
 
-static char *unpack_byte (char *buf, int *value);
+static const char *unpack_byte (const char *buf, int *value);
 
 static char *pack_int (char *buf, int value);
 
-static char *unpack_int (char *buf, int *value);
+static const char *unpack_int (const char *buf, int *value);
 
-static char *unpack_string (char *src, char *dest, int length);
+static const char *unpack_string (const char *src, char *dest, int length);
 
 static char *pack_threadid (char *pkt, threadref *id);
 
-static char *unpack_threadid (char *inbuf, threadref *id);
+static const char *unpack_threadid (const char *inbuf, threadref *id);
 
 void int_to_threadref (threadref *id, int value);
 
@@ -3121,7 +3121,7 @@ stubhex (int ch)
 }
 
 static int
-stub_unpack_int (char *buff, int fieldlength)
+stub_unpack_int (const char *buff, int fieldlength)
 {
   int nibble;
   int retval = 0;
@@ -3137,15 +3137,15 @@ stub_unpack_int (char *buff, int fieldlength)
   return retval;
 }
 
-static char *
-unpack_nibble (char *buf, int *val)
+static const char *
+unpack_nibble (const char *buf, int *val)
 {
   *val = fromhex (*buf++);
   return buf;
 }
 
-static char *
-unpack_byte (char *buf, int *value)
+static const char *
+unpack_byte (const char *buf, int *value)
 {
   *value = stub_unpack_int (buf, 2);
   return buf + 2;
@@ -3161,8 +3161,8 @@ pack_int (char *buf, int value)
   return buf;
 }
 
-static char *
-unpack_int (char *buf, int *value)
+static const char *
+unpack_int (const char *buf, int *value)
 {
   *value = stub_unpack_int (buf, 8);
   return buf + 8;
@@ -3192,8 +3192,8 @@ pack_string (char *pkt, char *string)
 }
 #endif /* 0 (unused) */
 
-static char *
-unpack_string (char *src, char *dest, int length)
+static const char *
+unpack_string (const char *src, char *dest, int length)
 {
   while (length--)
     *dest++ = *src++;
@@ -3215,11 +3215,11 @@ pack_threadid (char *pkt, threadref *id)
 }
 
 
-static char *
-unpack_threadid (char *inbuf, threadref *id)
+static const char *
+unpack_threadid (const char *inbuf, threadref *id)
 {
   char *altref;
-  char *limit = inbuf + BUF_THREAD_ID_SIZE;
+  const char *limit = inbuf + BUF_THREAD_ID_SIZE;
   int x, y;
 
   altref = (char *) id;
@@ -3334,7 +3334,7 @@ pack_threadinfo_request (char *pkt, int mode, threadref *id)
 				   the process.  */
 
 int
-remote_target::remote_unpack_thread_info_response (char *pkt,
+remote_target::remote_unpack_thread_info_response (const char *pkt,
 						   threadref *expectedref,
 						   gdb_ext_thread_info *info)
 {
@@ -3342,7 +3342,7 @@ remote_target::remote_unpack_thread_info_response (char *pkt,
   int mask, length;
   int tag;
   threadref ref;
-  char *limit = pkt + rs->buf.size (); /* Plausible parsing limit.  */
+  const char *limit = pkt + rs->buf.size (); /* Plausible parsing limit.  */
   int retval = 1;
 
   /* info->threadid = 0; FIXME: implement zero_threadref.  */
@@ -3465,18 +3465,17 @@ pack_threadlist_request (char *pkt, int startflag, int threadcount,
 /* Encoding:   'q':8,'M':8,count:16,done:8,argthreadid:64,(threadid:64)* */
 
 int
-remote_target::parse_threadlist_response (char *pkt, int result_limit,
+remote_target::parse_threadlist_response (const char *pkt, int result_limit,
 					  threadref *original_echo,
 					  threadref *resultlist,
 					  int *doneflag)
 {
   struct remote_state *rs = get_remote_state ();
-  char *limit;
   int count, resultcount, done;
 
   resultcount = 0;
   /* Assume the 'q' and 'M chars have been stripped.  */
-  limit = pkt + (rs->buf.size () - BUF_THREAD_ID_SIZE);
+  const char *limit = pkt + (rs->buf.size () - BUF_THREAD_ID_SIZE);
   /* done parse past here */
   pkt = unpack_byte (pkt, &count);	/* count field */
   pkt = unpack_nibble (pkt, &done);