A patch to add builtin read

[culliton@srg.af.mil (Tom Culliton x2278)]

OK, here it is.  I've hacked up Alan's read to support readline and make
my earlier realloc patch unnecessary, and made context diff's of all the
affected files.  The diffs assume you've been keeping up with the bug
fix patches posted here.  (If anyone wants a complete set of diffs
against a virgin copy of 1.4 let me know and I'll mail it to you.)
You'll also have to create the addon directory before applying the patch
and fiddle your makefile appropriately to enable this.  

It trips clean and an hour of poking at it hasn't turned up any obvious
stupidity.  Please let me know if you turn anything up.

Tom
------------------------------------------------------------------------------
*** addon.h.old	Mon Sep 20 20:41:32 1993
--- addon.h	Mon Sep 20 18:55:16 1993
***************
*** 36,38 ****
--- 36,55 ----
  extern void b_test(char **av);
  
  #endif
+ 
+ #ifdef	READ
+ 
+ #undef	ADDONS
+ #ifndef DWS
+ #define ADDONS	{ b_read,	"read" },
+ #else
+ #define ADDONS	{ b_read,	"read" },\
+ 		{ b_access,	"access" },\
+ 		{ b_test, 	"test" },\
+ 		{ b_test,	"[" },
+ #endif
+ 
+ 
+ extern void b_read(char **av);
+ 
+ #endif
*** addon.c.old	Mon Sep 20 20:41:24 1993
--- addon.c	Mon Sep 20 18:29:21 1993
***************
*** 20,22 ****
--- 20,35 ----
  #include "addon/test.c"
  
  #endif
+ 
+ #ifdef	READ
+ #ifndef	DWS
+ #include <sys/types.h>
+ 
+ #include "rc.h"		/* for bool TRUE, FALSE */
+ #include "addon.h"
+ #endif
+ 
+ 
+ #include "addon/read.c"
+ 
+ #endif
*** input.c.old	Mon Sep 20 20:54:42 1993
--- input.c	Tue Sep 21 15:29:11 1993
***************
*** 85,91 ****
  
  #ifdef READLINE
  #ifndef SVSIGS
! static char *rc_readline(char *prompt) {
  	char *r;
  	interrupt_happened = FALSE;
  	if (!setjmp(slowbuf.j)) {
--- 85,91 ----
  
  #ifdef READLINE
  #ifndef SVSIGS
! char *rc_readline(char *prompt) {
  	char *r;
  	interrupt_happened = FALSE;
  	if (!setjmp(slowbuf.j)) {
*** addon/read.c.old	Tue Sep 21 16:32:09 1993
--- addon/read.c	Tue Sep 21 16:01:08 1993
***************
*** 0 ****
--- 1,80 ----
+ /*
+  b_reads -- read a single line, terminated by \n or EOF, from the standard
+  input, and assign the line without the terminator to av[1].
+  */
+ 
+ #ifdef READLINE
+ #ifndef SVSIGS
+ extern char *rc_readline(char *);
+ #else
+ extern char *readline(char *);
+ #define rc_readline readline
+ #endif /* SVSIGS */
+ extern void add_history(char *);
+ #endif
+ 
+ static int
+ readchar(int fd)
+ {
+ 	unsigned char c;
+ 
+ 	if (read(fd, &c, 1) == 1)
+ 		return c;
+ 	else
+ 		return EOF;
+ }
+ 
+ void
+ b_read(char **av)
+ {
+ 	char *name;
+ 	int c;
+ 	char *line;
+ 	SIZE_T len;
+ 	SIZE_T max_len;
+ 	SIZE_T max_len_quantum;
+ 
+ 	/* check usage is "read name" */
+ 	if (av[1] == NULL)
+ 		rc_error("missing variable name");
+ 	if (av[2] != NULL)
+ 		rc_error("too many arguments to read");
+ 	name = av[1];
+ 
+ #ifdef READLINE
+ 	if (isatty(0)) {
+ 		line = rc_readline(NULL);
+ 		if (line == NULL) {
+ 			line = ealloc(1);
+ 			*line = '\0';
+ 			c = EOF;
+ 		} else {
+ 			if (*line != '\0')
+ 				add_history(line);
+ 			c = '\n';
+ 		}
+ 	} else
+ #endif
+ 	{
+ 		/* read a single line from stdin */
+ 		len = 0;
+ 		max_len = max_len_quantum = 256;
+ 		line = ealloc(max_len);
+ 		do {
+ 			c = readchar(0);
+ 			if (len == max_len) 
+ 				line = erealloc(line, max_len += max_len_quantum);
+ 			if (c == '\n' || c == EOF)
+ 				line[len] = 0;
+ 			else
+ 				line[len] = c;
+ 			len++;
+ 		} while (c != '\n' && c != EOF);
+ 	}
+ 	/* assign whatever we read to the variable */
+ 	assign(word(name, NULL), word(line, NULL), FALSE);
+ 	efree(line);
+ 
+ 	/* return TRUE if we terminated with a \n, otherwise FALSE */
+ 	set(c == '\n');
+ }
*** addon/trip.read.old	Tue Sep 21 16:32:09 1993
--- addon/trip.read	Mon Sep 20 20:46:40 1993
***************
*** 0 ****
--- 1,53 ----
+ # trip.read -- check a read implementation performs like a true v7 sh read
+ 
+ fn check {
+    echo $1 $2
+    ./rc -c $2
+    if ( ! ~ $status $1 ) {
+       echo failed: $2
+    }
+ }
+ 
+ check 0 true
+ check 1 false
+ 
+ nl = '
+ '
+ ifs = $nl
+ 
+ file = /etc/passwd
+ first = `{ cat $file }
+ first = $first(1)
+ 
+ echo 'start of trip.read'
+ 
+ # check read X and read '*' return 0
+ check 0 'exec <$file ; read X'
+ check 0 'exec <$file ; read ''*'''
+ 
+ # check read, read 1, read '=', and read '' return 1
+ check 1 'exec <$file ; read'
+ check 1 'exec <$file ; read 1'
+ check 1 'exec <$file ; read ''='''
+ check 1 'exec <$file ; read '''''
+ 
+ # check read X correctly reads first line
+ check 0 'exec <$file; read X ; ~ $X $first'
+ check 0 'echo -n $first | { read X ; ~ $X $first }'
+ 
+ # check read '*' correctly reads first line, preserves $0
+ check 0 'exec <$file ; old0 = $0 ; read ''*'' ; ~ $0 $old0 && ~ $1 $first && ~ $#* 1'
+ 
+ # check read returns 1 on EOF and I/O error
+ check 1 'exec </dev/null ; read X'
+ check 1 'exec <[0=]      ; read X'
+ 
+ # check read sets variable to '' when line is empty and on EOF and I/O error.
+ check 0 '{ X = X ; echo | { read X ; ~ $X '''' } }'
+ check 0 '{ exec </dev/null ; X = X ; read X ; ~ $X '''' }'
+ check 0 '{ exec <[0=]      ; X = X ; read X ; ~ $X '''' }'
+ 
+ echo 'end of trip.read'
+ 
+ # end-of-file
+