utils.c

早期freebsd实现

  else
    {
      fatal ("virtual memory exhausted.");
    }
}

/* Like mmalloc but get error if no storage available, and protect against
   the caller wanting to allocate zero bytes.  Whether to return NULL for
   a zero byte request, or translate the request into a request for one
   byte of zero'd storage, is a religious issue. */

PTR
xmmalloc (md, size)
     PTR md;
     long size;
{
  register PTR val;

  if (size == 0)
    {
      val = NULL;
    }
  else if ((val = mmalloc (md, size)) == NULL)
    {
      nomem (size);
    }
  return (val);
}

/* Like mrealloc but get error if no storage available.  */

PTR
xmrealloc (md, ptr, size)
     PTR md;
     PTR ptr;
     long size;
{
  register PTR val;

  if (ptr != NULL)
    {
      val = mrealloc (md, ptr, size);
    }
  else
    {
      val = mmalloc (md, size);
    }
  if (val == NULL)
    {
      nomem (size);
    }
  return (val);
}

/* Like malloc but get error if no storage available, and protect against
   the caller wanting to allocate zero bytes.  */

PTR
xmalloc (size)
     long size;
{
  return (xmmalloc ((void *) NULL, size));
}

/* Like mrealloc but get error if no storage available.  */

PTR
xrealloc (ptr, size)
     PTR ptr;
     long size;
{
  return (xmrealloc ((void *) NULL, ptr, size));
}


/* My replacement for the read system call.
   Used like `read' but keeps going if `read' returns too soon.  */

int
myread (desc, addr, len)
     int desc;
     char *addr;
     int len;
{
  register int val;
  int orglen = len;

  while (len > 0)
    {
      val = read (desc, addr, len);
      if (val < 0)
	return val;
      if (val == 0)
	return orglen - len;
      len -= val;
      addr += val;
    }
  return orglen;
}

/* Make a copy of the string at PTR with SIZE characters
   (and add a null character at the end in the copy).
   Uses malloc to get the space.  Returns the address of the copy.  */

char *
savestring (ptr, size)
     const char *ptr;
     int size;
{
  register char *p = (char *) xmalloc (size + 1);
  memcpy (p, ptr, size);
  p[size] = 0;
  return p;
}

char *
msavestring (md, ptr, size)
     void *md;
     const char *ptr;
     int size;
{
  register char *p = (char *) xmmalloc (md, size + 1);
  memcpy (p, ptr, size);
  p[size] = 0;
  return p;
}

/* The "const" is so it compiles under DGUX (which prototypes strsave
   in <string.h>.  FIXME: This should be named "xstrsave", shouldn't it?
   Doesn't real strsave return NULL if out of memory?  */
char *
strsave (ptr)
     const char *ptr;
{
  return savestring (ptr, strlen (ptr));
}

char *
mstrsave (md, ptr)
     void *md;
     const char *ptr;
{
  return (msavestring (md, ptr, strlen (ptr)));
}

void
print_spaces (n, file)
     register int n;
     register FILE *file;
{
  while (n-- > 0)
    fputc (' ', file);
}

/* Ask user a y-or-n question and return 1 iff answer is yes.
   Takes three args which are given to printf to print the question.
   The first, a control string, should end in "? ".
   It should not say how to answer, because we do that.  */

/* VARARGS */
int
query (va_alist)
     va_dcl
{
  va_list args;
  char *ctlstr;
  register int answer;
  register int ans2;

  /* Automatically answer "yes" if input is not from a terminal.  */
  if (!input_from_terminal_p ())
    return 1;

  while (1)
    {
      wrap_here ("");		/* Flush any buffered output */
      fflush (stdout);
      va_start (args);
      ctlstr = va_arg (args, char *);
      vfprintf_filtered (stdout, ctlstr, args);
      va_end (args);
      printf_filtered ("(y or n) ");
      fflush (stdout);
      answer = fgetc (stdin);
      clearerr (stdin);		/* in case of C-d */
      if (answer == EOF)	/* C-d */
        return 1;
      if (answer != '\n')	/* Eat rest of input line, to EOF or newline */
	do 
	  {
	    ans2 = fgetc (stdin);
	    clearerr (stdin);
	  }
        while (ans2 != EOF && ans2 != '\n');
      if (answer >= 'a')
	answer -= 040;
      if (answer == 'Y')
	return 1;
      if (answer == 'N')
	return 0;
      printf_filtered ("Please answer y or n.\n");
    }
}


/* Parse a C escape sequence.  STRING_PTR points to a variable
   containing a pointer to the string to parse.  That pointer
   should point to the character after the \.  That pointer
   is updated past the characters we use.  The value of the
   escape sequence is returned.

   A negative value means the sequence \ newline was seen,
   which is supposed to be equivalent to nothing at all.

   If \ is followed by a null character, we return a negative
   value and leave the string pointer pointing at the null character.

   If \ is followed by 000, we return 0 and leave the string pointer
   after the zeros.  A value of 0 does not mean end of string.  */

int
parse_escape (string_ptr)
     char **string_ptr;
{
  register int c = *(*string_ptr)++;
  switch (c)
    {
    case 'a':
      return 007;		/* Bell (alert) char */
    case 'b':
      return '\b';
    case 'e':			/* Escape character */
      return 033;
    case 'f':
      return '\f';
    case 'n':
      return '\n';
    case 'r':
      return '\r';
    case 't':
      return '\t';
    case 'v':
      return '\v';
    case '\n':
      return -2;
    case 0:
      (*string_ptr)--;
      return 0;
    case '^':
      c = *(*string_ptr)++;
      if (c == '\\')
	c = parse_escape (string_ptr);
      if (c == '?')
	return 0177;
      return (c & 0200) | (c & 037);
      
    case '0':
    case '1':
    case '2':
    case '3':
    case '4':
    case '5':
    case '6':
    case '7':
      {
	register int i = c - '0';
	register int count = 0;
	while (++count < 3)
	  {
	    if ((c = *(*string_ptr)++) >= '0' && c <= '7')
	      {
		i *= 8;
		i += c - '0';
	      }
	    else
	      {
		(*string_ptr)--;
		break;
	      }
	  }
	return i;
      }
    default:
      return c;
    }
}

/* Print the character C on STREAM as part of the contents
   of a literal string whose delimiter is QUOTER.  */

void
printchar (c, stream, quoter)
     register int c;
     FILE *stream;
     int quoter;
{

  c &= 0xFF;			/* Avoid sign bit follies */

  if (              c < 0x20  ||		/* Low control chars */	
      (c >= 0x7F && c < 0xA0) ||		/* DEL, High controls */
      (sevenbit_strings && c >= 0x80)) {	/* high order bit set */
    switch (c)
      {
      case '\n':
	fputs_filtered ("\\n", stream);
	break;
      case '\b':
	fputs_filtered ("\\b", stream);
	break;
      case '\t':
	fputs_filtered ("\\t", stream);
	break;
      case '\f':
	fputs_filtered ("\\f", stream);
	break;
      case '\r':
	fputs_filtered ("\\r", stream);
	break;
      case '\033':
	fputs_filtered ("\\e", stream);
	break;
      case '\007':
	fputs_filtered ("\\a", stream);
	break;
      default:
	fprintf_filtered (stream, "\\%X", (unsigned int) c);
	break;
      }
  } else {
    if (c == '\\' || c == quoter)
      fputs_filtered ("\\", stream);
    fprintf_filtered (stream, "%c", c);
  }
}

/* Number of lines per page or UINT_MAX if paging is disabled.  */
static unsigned int lines_per_page;
/* Number of chars per line or UNIT_MAX is line folding is disabled.  */
static unsigned int chars_per_line;
/* Current count of lines printed on this page, chars on this line.  */
static unsigned int lines_printed, chars_printed;

/* Buffer and start column of buffered text, for doing smarter word-
   wrapping.  When someone calls wrap_here(), we start buffering output
   that comes through fputs_filtered().  If we see a newline, we just
   spit it out and forget about the wrap_here().  If we see another
   wrap_here(), we spit it out and remember the newer one.  If we see
   the end of the line, we spit out a newline, the indent, and then
   the buffered output.

   wrap_column is the column number on the screen where wrap_buffer begins.
     When wrap_column is zero, wrapping is not in effect.
   wrap_buffer is malloc'd with chars_per_line+2 bytes. 
     When wrap_buffer[0] is null, the buffer is empty.
   wrap_pointer points into it at the next character to fill.
   wrap_indent is the string that should be used as indentation if the
     wrap occurs.  */

static char *wrap_buffer, *wrap_pointer, *wrap_indent;
static int wrap_column;

/* ARGSUSED */
static void 
set_width_command (args, from_tty, c)
     char *args;
     int from_tty;
     struct cmd_list_element *c;
{
  if (!wrap_buffer)
    {
      wrap_buffer = (char *) xmalloc (chars_per_line + 2);
      wrap_buffer[0] = '\0';
    }
  else
    wrap_buffer = (char *) xrealloc (wrap_buffer, chars_per_line + 2);
  wrap_pointer = wrap_buffer;	/* Start it at the beginning */
}

extern FILE *instream;

static void
instream_cleanup(stream)
    FILE *stream;
{
  instream = stream;
}

static void
prompt_for_continue ()
{
  if (ISATTY(stdin) && ISATTY(stdout))
    {
      struct cleanup *old_chain = make_cleanup(instream_cleanup, instream);
      char *cp;

      instream = stdin;
      immediate_quit++;
      cp = gdb_readline ("---Type <return> to continue---");
      if (cp)
        free (cp);
      chars_printed = lines_printed = 0;
      immediate_quit--;
      do_cleanups(old_chain);
      dont_repeat ();		/* Forget prev cmd -- CR won't repeat it. */
    }
}

/* Reinitialize filter; ie. tell it to reset to original values.  */

void
reinitialize_more_filter ()
{
  lines_printed = 0;
  chars_printed = 0;
}

/* Indicate that if the next sequence of characters overflows the line,
   a newline should be inserted here rather than when it hits the end. 
   If INDENT is nonzero, it is a string to be printed to indent the
   wrapped part on the next line.  INDENT must remain accessible until
   the next call to wrap_here() or until a newline is printed through
   fputs_filtered().

   If the line is already overfull, we immediately print a newline and
   the indentation, and disable further wrapping.

   If we don't know the width of lines, but we know the page height,
   we must not wrap words, but should still keep track of newlines
   that were explicitly printed.

   INDENT should not contain tabs, as that
   will mess up the char count on the next line.  FIXME.  */

void
wrap_here(indent)
  char *indent;
{
  if (wrap_buffer[0])
    {
      *wrap_pointer = '\0';
      fputs (wrap_buffer, stdout);
    }
  wrap_pointer = wrap_buffer;
  wrap_buffer[0] = '\0';
  if (chars_per_line == UINT_MAX)		/* No line overflow checking */
    {
      wrap_column = 0;
    }
  else if (chars_printed >= chars_per_line)
    {
      puts_filtered ("\n");
      puts_filtered (indent);
      wrap_column = 0;
    }
  else
    {
      wrap_column = chars_printed;
      wrap_indent = indent;
    }
}

/* Like fputs but pause after every screenful, and can wrap at points
   other than the final character of a line.
   Unlike fputs, fputs_filtered does not return a value.
   It is OK for LINEBUFFER to be NULL, in which case just don't print
   anything.

   Note that a longjmp to top level may occur in this routine
   (since prompt_for_continue may do so) so this routine should not be
   called when cleanups are not in place.  */

void
fputs_filtered (linebuffer, stream)
     const char *linebuffer;
     FILE *stream;
{
  const char *lineptr;

  if (linebuffer == 0)
    return;
  
  /* Don't do any filtering if it is disabled.  */
  if (stream != stdout
   || (lines_per_page == UINT_MAX && chars_per_line == UINT_MAX))
    {
      fputs (linebuffer, stream);
      return;
    }

  /* Go through and output each character.  Show line extension
     when this is necessary; prompt user for new page when this is
     necessary.  */
  
  lineptr = linebuffer;
  while (*lineptr)
    {
      /* Possible new page.  */
      if (lines_printed >= lines_per_page - 1)
	prompt_for_continue ();

      while (*lineptr && *lineptr != '\n')
	{
	  /* Print a single line.  */
	  if (*lineptr == '\t')
	    {
	      if (wrap_column)
		*wrap_pointer++ = '\t';
	      else
		putc ('\t', stream);
	      /* Shifting right by 3 produces the number of tab stops
	         we have already passed, and then adding one and
		 shifting left 3 advances to the next tab stop.  */
	      chars_printed = ((chars_printed >> 3) + 1) << 3;
	      lineptr++;
	    }
	  else
	    {
	      if (wrap_column)
		*wrap_pointer++ = *lineptr;
	      else
	        putc (*lineptr, stream);
	      chars_printed++;