move some rsp bits into rsp-low.h

This moves various low-level remote serial protocol bits into
common/rsp-low.[ch].

This is as close to a pure move as possible.  There are some
redundancies remaining but those will be dealt with in a subsequent
patch.

Note that the two variants of remote_escape_output disagreed on the
treatment of "*".  On the theory that quoting cannot hurt but the
absence possibly can, I chose the gdbserver variant to be the
canonical one.

2014-02-12  Tom Tromey  <tromey@redhat.com>

	* tracepoint.c: Include rsp-low.h.
	* remote.h (hex2bin, bin2hex, unpack_varlen_hex): Don't declare.
	* remote.c: Include rsp-low.h.
	(hexchars, ishex, unpack_varlen_hex, pack_nibble, pack_hex_byte)
	(fromhex, hex2bin, tohex, bin2hex, remote_escape_output)
	(remote_unescape_input): Move to common/rsp-low.c.
	* common/rsp-low.h: New file.
	* common/rsp-low.c: New file.
	* Makefile.in (SFILES): Add common/rsp-low.c.
	(HFILES_NO_SRCDIR): Add common/rsp-low.h.
	(COMMON_OBS): Add rsp-low.o.
	(rsp-low.o): New target.

2014-02-12  Tom Tromey  <tromey@redhat.com>

	* tracepoint.c: Include rsp-low.h.
	* server.c: Include rsp-low.h.
	* remote-utils.h (convert_ascii_to_int, convert_int_to_ascii)
	(unhexify, hexify, remote_escape_output, unpack_varlen_hex): Don't
	declare.
	* remote-utils.c: Include rsp-low.h.
	(fromhex, hexchars, ishex, unhexify, tohex, hexify)
	(remote_escape_output, remote_unescape_input, unpack_varlen_hex)
	(convert_int_to_ascii, convert_ascii_to_int): Move to
	common/rsp-low.c.
	* regcache.c: Include rsp-low.h.
	* ax.c: Include rsp-low.h.
	* Makefile.in (SFILES): Add common/rsp-low.c.
	(OBS): Add rsp-low.o.
	(rsp-low.o): New target.

2 files changed, 347 insertions, 0 deletions

diff --git a/gdb/common/rsp-low.c b/gdb/common/rsp-low.c
new file mode 100644
index 0000000..07e7ddb
--- /dev/null
+++ b/gdb/common/rsp-low.c
@@ -0,0 +1,277 @@
+/* Low-level RSP routines for GDB, the GNU debugger.
+
+   Copyright (C) 1988-2014 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef GDBSERVER
+#include "server.h"
+#else
+#include "defs.h"
+#endif
+
+#include <string.h>
+
+#include "rsp-low.h"
+
+/* Convert hex digit A to a number.  */
+
+int
+fromhex (int a)
+{
+  if (a >= '0' && a <= '9')
+    return a - '0';
+  else if (a >= 'a' && a <= 'f')
+    return a - 'a' + 10;
+  else if (a >= 'A' && a <= 'F')
+    return a - 'A' + 10;
+  else
+    error (_("Reply contains invalid hex digit %d"), a);
+}
+
+int
+tohex (int nib)
+{
+  if (nib < 10)
+    return '0' + nib;
+  else
+    return 'a' + nib - 10;
+}
+
+/* Encode 64 bits in 16 chars of hex.  */
+
+static const char hexchars[] = "0123456789abcdef";
+
+static int
+ishex (int ch, int *val)
+{
+  if ((ch >= 'a') && (ch <= 'f'))
+    {
+      *val = ch - 'a' + 10;
+      return 1;
+    }
+  if ((ch >= 'A') && (ch <= 'F'))
+    {
+      *val = ch - 'A' + 10;
+      return 1;
+    }
+  if ((ch >= '0') && (ch <= '9'))
+    {
+      *val = ch - '0';
+      return 1;
+    }
+  return 0;
+}
+
+char *
+pack_nibble (char *buf, int nibble)
+{
+  *buf++ = hexchars[(nibble & 0x0f)];
+  return buf;
+}
+
+char *
+pack_hex_byte (char *pkt, int byte)
+{
+  *pkt++ = hexchars[(byte >> 4) & 0xf];
+  *pkt++ = hexchars[(byte & 0xf)];
+  return pkt;
+}
+
+char *
+unpack_varlen_hex (char *buff,	/* packet to parse */
+		   ULONGEST *result)
+{
+  int nibble;
+  ULONGEST retval = 0;
+
+  while (ishex (*buff, &nibble))
+    {
+      buff++;
+      retval = retval << 4;
+      retval |= nibble & 0x0f;
+    }
+  *result = retval;
+  return buff;
+}
+
+int
+hex2bin (const char *hex, gdb_byte *bin, int count)
+{
+  int i;
+
+  for (i = 0; i < count; i++)
+    {
+      if (hex[0] == 0 || hex[1] == 0)
+	{
+	  /* Hex string is short, or of uneven length.
+	     Return the count that has been converted so far.  */
+	  return i;
+	}
+      *bin++ = fromhex (hex[0]) * 16 + fromhex (hex[1]);
+      hex += 2;
+    }
+  return i;
+}
+
+int
+unhexify (char *bin, const char *hex, int count)
+{
+  int i;
+
+  for (i = 0; i < count; i++)
+    {
+      if (hex[0] == 0 || hex[1] == 0)
+	{
+	  /* Hex string is short, or of uneven length.
+	     Return the count that has been converted so far. */
+	  return i;
+	}
+      *bin++ = fromhex (hex[0]) * 16 + fromhex (hex[1]);
+      hex += 2;
+    }
+  return i;
+}
+
+void
+convert_ascii_to_int (const char *from, unsigned char *to, int n)
+{
+  int nib1, nib2;
+  while (n--)
+    {
+      nib1 = fromhex (*from++);
+      nib2 = fromhex (*from++);
+      *to++ = (((nib1 & 0x0f) << 4) & 0xf0) | (nib2 & 0x0f);
+    }
+}
+
+int
+bin2hex (const gdb_byte *bin, char *hex, int count)
+{
+  int i;
+
+  /* May use a length, or a nul-terminated string as input.  */
+  if (count == 0)
+    count = strlen ((char *) bin);
+
+  for (i = 0; i < count; i++)
+    {
+      *hex++ = tohex ((*bin >> 4) & 0xf);
+      *hex++ = tohex (*bin++ & 0xf);
+    }
+  *hex = 0;
+  return i;
+}
+
+int
+hexify (char *hex, const char *bin, int count)
+{
+  int i;
+
+  /* May use a length, or a nul-terminated string as input. */
+  if (count == 0)
+    count = strlen (bin);
+
+  for (i = 0; i < count; i++)
+    {
+      *hex++ = tohex ((*bin >> 4) & 0xf);
+      *hex++ = tohex (*bin++ & 0xf);
+    }
+  *hex = 0;
+  return i;
+}
+
+void
+convert_int_to_ascii (const unsigned char *from, char *to, int n)
+{
+  int nib;
+  int ch;
+  while (n--)
+    {
+      ch = *from++;
+      nib = ((ch & 0xf0) >> 4) & 0x0f;
+      *to++ = tohex (nib);
+      nib = ch & 0x0f;
+      *to++ = tohex (nib);
+    }
+  *to++ = 0;
+}
+
+int
+remote_escape_output (const gdb_byte *buffer, int len,
+		      gdb_byte *out_buf, int *out_len,
+		      int out_maxlen)
+{
+  int input_index, output_index;
+
+  output_index = 0;
+  for (input_index = 0; input_index < len; input_index++)
+    {
+      gdb_byte b = buffer[input_index];
+
+      if (b == '$' || b == '#' || b == '}' || b == '*')
+	{
+	  /* These must be escaped.  */
+	  if (output_index + 2 > out_maxlen)
+	    break;
+	  out_buf[output_index++] = '}';
+	  out_buf[output_index++] = b ^ 0x20;
+	}
+      else
+	{
+	  if (output_index + 1 > out_maxlen)
+	    break;
+	  out_buf[output_index++] = b;
+	}
+    }
+
+  *out_len = input_index;
+  return output_index;
+}
+
+int
+remote_unescape_input (const gdb_byte *buffer, int len,
+		       gdb_byte *out_buf, int out_maxlen)
+{
+  int input_index, output_index;
+  int escaped;
+
+  output_index = 0;
+  escaped = 0;
+  for (input_index = 0; input_index < len; input_index++)
+    {
+      gdb_byte b = buffer[input_index];
+
+      if (output_index + 1 > out_maxlen)
+	error (_("Received too much data from the target."));
+
+      if (escaped)
+	{
+	  out_buf[output_index++] = b ^ 0x20;
+	  escaped = 0;
+	}
+      else if (b == '}')
+	escaped = 1;
+      else
+	out_buf[output_index++] = b;
+    }
+
+  if (escaped)
+    error (_("Unmatched escape character in target response."));
+
+  return output_index;
+}
+
diff --git a/gdb/common/rsp-low.h b/gdb/common/rsp-low.h
new file mode 100644
index 0000000..161c4a2
--- /dev/null
+++ b/gdb/common/rsp-low.h
@@ -0,0 +1,70 @@
+/* Low-level RSP routines for GDB, the GNU debugger.
+
+   Copyright (C) 1988-2014 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef COMMON_RSP_LOW_H
+#define COMMON_RSP_LOW_H
+
+/* Convert hex digit A to a number, or throw an exception.  */
+
+extern int fromhex (int a);
+
+/* Convert number NIB to a hex digit.  */
+
+extern int tohex (int nib);
+
+extern char *pack_nibble (char *buf, int nibble);
+
+extern char *pack_hex_byte (char *pkt, int byte);
+
+extern char *unpack_varlen_hex (char *buff, ULONGEST *result);
+
+extern int hex2bin (const char *hex, gdb_byte *bin, int count);
+
+extern int unhexify (char *bin, const char *hex, int count);
+
+extern void convert_ascii_to_int (const char *from, unsigned char *to, int n);
+
+extern int bin2hex (const gdb_byte *bin, char *hex, int count);
+
+extern int hexify (char *hex, const char *bin, int count);
+
+extern void convert_int_to_ascii (const unsigned char *from, char *to, int n);
+
+/* Convert BUFFER, binary data at least LEN bytes long, into escaped
+   binary data in OUT_BUF.  Set *OUT_LEN to the length of the data
+   encoded in OUT_BUF, and return the number of bytes in OUT_BUF
+   (which may be more than *OUT_LEN due to escape characters).  The
+   total number of bytes in the output buffer will be at most
+   OUT_MAXLEN.  This function properly escapes '*', and so is suitable
+   for the server side as well as the client.  */
+
+extern int remote_escape_output (const gdb_byte *buffer, int len,
+				 gdb_byte *out_buf, int *out_len,
+				 int out_maxlen);
+
+/* Convert BUFFER, escaped data LEN bytes long, into binary data
+   in OUT_BUF.  Return the number of bytes written to OUT_BUF.
+   Raise an error if the total number of bytes exceeds OUT_MAXLEN.
+
+   This function reverses remote_escape_output.  */
+
+extern int remote_unescape_input (const gdb_byte *buffer, int len,
+				  gdb_byte *out_buf, int out_maxlen);
+
+#endif /* COMMON_RSP_LOW_H */