Add the -k option to keep horizontal whitespace

directive.c

@@ -342,6 +342,7 @@ void    directive( void)
 ret:
     in_directive = FALSE;
     keep_comments = option_flags.c && compiling && !no_output;
+    keep_spaces = option_flags.k && compiling;
        /* keep_spaces is on for #define line even if no_output is TRUE  */
     if (! wrong_line)
         newlines++;

internal.H

@@ -324,6 +324,7 @@ extern struct std_limits_ {
 /* The boolean flags specified by the execution options.    */
 extern struct option_flags_ {
         int     c;                  /* -C option (keep comments)    */
+        int     k;                  /* -k option (keep white spaces)*/
 } option_flags;
 
 extern int      stdc_val;           /* Value of __STDC__            */
@@ -335,6 +336,7 @@ extern long     src_line;           /* Current source line number   */
 extern int      wrong_line;         /* Force #line to compiler      */
 extern int      newlines;           /* Count of blank lines         */
 extern int      keep_comments;      /* Don't remove comments        */
+extern int      keep_spaces;        /* Don't remove white spaces    */
 extern int      include_nest;       /* Nesting level of #include    */
 extern const char *     null;       /* "" string for convenience    */
 extern const char **    inc_dirp;   /* Directory of #includer       */

mcpp_main.c

@@ -45,6 +45,7 @@
     /* The boolean flags specified by the execution options.    */
     struct option_flags_    option_flags = {
         FALSE,          /* c:   -C (keep comments)                  */
+        FALSE,          /* k:   -k (keep white spaces)              */
     };
 
     int     mcpp_mode = STD;        /* Mode of preprocessing        */
@@ -263,7 +264,7 @@ static void     init_main( void)
     std_limits.str_len = NBUFF;
     std_limits.id_len = IDMAX;
     std_limits.n_mac_pars =  NMACPARS;
-    option_flags.c = FALSE;
+    option_flags.c = option_flags.k = FALSE;
     sh_file = NULL;
     sh_line = 0;
 }
@@ -455,6 +456,7 @@ static void mcpp_main( void)
     LINE_COL    line_col;   /* Location of macro call in source     */
 
     keep_comments = option_flags.c && !no_output;
+    keep_spaces = option_flags.k;       /* Will be turned off if !compiling */
     line_col.col = line_col.line = 0L;
 
     /*

support.c

@@ -1108,6 +1108,21 @@ static char *   parse_line( void)
                     free( temp);            /* End of file with un- */
                     return  NULL;           /*   terminated comment */
                 }
+                if (keep_spaces) {
+                    /*
+                     * Truncate a comment too long for the rest of the buffer.
+                     * The buffer may already be full: an earlier comment of
+                     * this line was truncated to end at 'limit - 1', and a
+                     * token after it moved 'tp' to 'limit'.  'limit - tp - 1'
+                     * is then negative, and would become a huge 'com_size',
+                     * so the comment gets no padding instead.
+                     */
+                    if (tp + com_size >= limit - 1)     /* Too long comment */
+                        com_size = (tp < limit - 1) ? limit - tp - 1 : 0;
+                    while (com_size--)
+                        *tp++ = ' ';        /* Spaces of the comment length */
+                    break;
+                }
                 if (temp == tp ||
                         ! (char_type[ *(tp - 1) & UCHARMAX] & HSP))
                     *tp++ = ' ';        /* Squeeze white spaces */
@@ -1141,7 +1156,12 @@ static char *   parse_line( void)
                     , NULL, (long) c, NULL);
         case '\t':                          /* Horizontal space     */
         case ' ':
-            if (! (char_type[ *(tp - 1) & UCHARMAX] & HSP)) {
+            if (keep_spaces) {
+                if (c == '\t')
+                    *tp++ = '\t';
+                else
+                    *tp++ = ' ';            /* Convert to ' '       */
+            } else if (! (char_type[ *(tp - 1) & UCHARMAX] & HSP)) {
                 *tp++ = ' ';                /* Squeeze white spaces */
             }
             break;
@@ -1206,6 +1226,10 @@ static char *   read_a_comment(
     char *      saved_sp;
     int         cat_line = 0;       /* Number of catenated lines    */
 
+    if (keep_spaces) {
+        saved_sp = sp - 2;          /* '-2' for beginning / and *   */
+        *sizp = 0;
+    }
     if (keep_comments)                      /* If writing comments  */
         mcpp_fputs( "/*", OUT);             /* Write the initializer*/
     c = *sp++;
@@ -1232,6 +1256,8 @@ static char *   read_a_comment(
                     /*  trouble on some other tools such as rpcgen. */
                 wrong_line = TRUE;
             }
+            if (keep_spaces)                /* Save the length      */
+                *sizp = *sizp + (sp - saved_sp);
             if ((mcpp_debug & MACRO_CALL) && compiling) {
                 if (cat_line) {
                     cat_line++;
@@ -1244,6 +1270,8 @@ static char *   read_a_comment(
             }
             return  sp;                     /* End of comment       */
         case '\n':                          /* Line-crossing comment*/
+            if (keep_spaces)                /* Save the length      */
+                *sizp = *sizp + (sp - saved_sp) - 1;    /* '-1' for '\n'    */
             if ((mcpp_debug & MACRO_CALL) && compiling) {
                                     /* Save location informations   */
                 if (cat_line == 0)  /* First line of catenation     */

system.c

@@ -377,6 +377,9 @@ opt_search: ;
             }
             break;
 
+        case 'k':                           /* Keep white spaces    */
+            option_flags.k = TRUE;
+            break;
 
         case 'M':           /* Output source file dependency line   */
             if (argv[ mcpp_optind - 1] == mcpp_optarg) {     /* -M   */
@@ -488,6 +491,8 @@ static void usage(
 
 "-I-         Unset system or site specific include directories.\n",
 
+"-k          Keep white spaces of input lines as they are.\n",
+
 "-M file\n",
 "            Output source file dependency line for makefile.\n",
 "-U <macro>  Undefine <macro>.\n",
@@ -532,7 +537,7 @@ static void set_opt_list(
 
     const char * const *    lp = & list[ 0];
 
-    strcpy( optlist, "e:CD:I:M:U:");
+    strcpy( optlist, "e:kCD:I:M:U:");
                                                 /* Default options  */
     while (*lp)
         strcat( optlist, *lp++);