(doprnt1): Add support for '+' flag. Fix overflow checking.

1 files changed, 13 insertions, 14 deletions

diff --git a/src/doprnt.c b/src/doprnt.c
index 326fb5743e2..799f38d8f5d 100644
--- a/src/doprnt.c
+++ b/src/doprnt.c
@@ -106,7 +106,7 @@ doprnt1 (lispstrings, buffer, bufsize, format, format_end, nargs, args)
   char tembuf[DBL_MAX_10_EXP + 100];
 
   /* Size of sprintf_buffer.  */
-  int size_allocated = sizeof (tembuf);
+  unsigned size_allocated = sizeof (tembuf);
 
   /* Buffer to use for sprintf.  Either tembuf or same as BIG_BUFFER.  */
   char *sprintf_buffer = tembuf;
@@ -136,12 +136,12 @@ doprnt1 (lispstrings, buffer, bufsize, format, format_end, nargs, args)
     {
       if (*fmt == '%')  /* Check for a '%' character */
         {
-          int size_bound = 0;
+          unsigned size_bound = 0;
           int width;            /* Columns occupied by STRING.  */
 
           fmt++;
           /* Copy this one %-spec into fmtcpy.  */
-          string = (unsigned char *)fmtcpy;
+          string = (unsigned char *) fmtcpy;
           *string++ = '%';
           while (1)
             {
@@ -152,11 +152,11 @@ doprnt1 (lispstrings, buffer, bufsize, format, format_end, nargs, args)
                      This might be a field width or a precision; e.g.
                      %1.1000f and %1000.1f both might need 1000+ bytes.
                      Parse the width or precision, checking for overflow.  */
-                  int n = *fmt - '0';
+                  unsigned n = *fmt - '0';
                   while ('0' <= fmt[1] && fmt[1] <= '9')
                     {
                       if (n * 10 / 10 != n
-                          || (n = n * 10 + (fmt[1] - '0')) < 0)
+                          || (n = n * 10 + (fmt[1] - '0')) < n)
                         error ("Format width or precision too large");
                       *string++ = *++fmt;
                     }
@@ -164,7 +164,7 @@ doprnt1 (lispstrings, buffer, bufsize, format, format_end, nargs, args)
                   if (size_bound < n)
                     size_bound = n;
                 }
-              else if (*fmt == '-' || *fmt == ' ' || *fmt == '.')
+              else if (*fmt == '-' || *fmt == ' ' || *fmt == '.' || *fmt == '+')
                 ;
               else
                 break;
@@ -174,10 +174,9 @@ doprnt1 (lispstrings, buffer, bufsize, format, format_end, nargs, args)
 
           /* Make the size bound large enough to handle floating point formats
              with large numbers.  */
-          size_bound += DBL_MAX_10_EXP + 50;
-
-          if (size_bound < 0)
+          if (size_bound + DBL_MAX_10_EXP + 50 < size_bound)
             error ("Format width or precision too large");
+          size_bound += DBL_MAX_10_EXP + 50;
 
           /* Make sure we have that much.  */
           if (size_bound > size_allocated)
@@ -213,7 +212,7 @@ doprnt1 (lispstrings, buffer, bufsize, format, format_end, nargs, args)
                 abort ();
               sprintf (sprintf_buffer, fmtcpy, args[cnt++]);
               /* Now copy into final output, truncating as nec.  */
-              string = (unsigned char *)sprintf_buffer;
+              string = (unsigned char *) sprintf_buffer;
               goto doit;
 
             case 'f':
@@ -227,7 +226,7 @@ doprnt1 (lispstrings, buffer, bufsize, format, format_end, nargs, args)
                 u.half[1] = args[cnt++];
                 sprintf (sprintf_buffer, fmtcpy, u.d);
                 /* Now copy into final output, truncating as nec.  */
-                string = (unsigned char *)sprintf_buffer;
+                string = (unsigned char *) sprintf_buffer;
                 goto doit;
               }
 
@@ -240,13 +239,13 @@ doprnt1 (lispstrings, buffer, bufsize, format, format_end, nargs, args)
                 minlen = atoi (&fmtcpy[1]);
               if (lispstrings)
                 {
-                  string = ((struct Lisp_String *)args[cnt])->data;
-                  tem = STRING_BYTES ((struct Lisp_String *)args[cnt]);
+                  string = ((struct Lisp_String *) args[cnt])->data;
+                  tem = STRING_BYTES ((struct Lisp_String *) args[cnt]);
                   cnt++;
                 }
               else
                 {
-                  string = (unsigned char *)args[cnt++];
+                  string = (unsigned char *) args[cnt++];
                   tem = strlen (string);
                 }
               width = strwidth (string, tem);