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C/C++ Users Group Library 1996 July
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C-C++ Users Group Library July 1996.iso
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vol_200
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231_01
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lexcmd.c
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1987-06-15
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/*
Little Smalltalk
misc lexer related routines
timothy a. budd 12/84
*/
/*
The source code for the Little Smalltalk System may be freely
copied provided that the source of all files is acknowledged
and that this condition is copied with each file.
The Little Smalltalk System is distributed without responsibility
for the performance of the program and without any guarantee of
maintenance.
All questions concerning Little Smalltalk should be addressed to:
Professor Tim Budd
Department of Computer Science
Oregon State University
Corvallis, Oregon
97331
USA
*/
# include <stdio.h>
# include "env.h"
# include <ctype.h>
extern char toktext[];
/* dolexcommand - read a ) type directive, and process it */
dolexcommand(p)
char *p;
{ char *q, buffer[100];
/* replace trailing newline with end of string */
for (q = p; *q && *q != '\n'; q++);
if (*q == '\n') *q = '\0';
switch( *++p) {
case '!':
# ifndef NOSYSTEM
system(++p);
# endif
break;
case 'e': for (++p; isspace(*p); p++);
if (! lexedit(p)) lexinclude(p);
break;
case 'g': for (++p; isspace(*p); p++);
sprintf(buffer,"%s/%s", LIBLOC, p);
lexread(buffer);
break;
case 'i': for (++p; isspace(*p); p++);
lexinclude(p);
break;
case 'r': for (++p; isspace(*p); p++);
lexread(p);
break;
case 's': for(++p; isspace(*p); p++);
dosave(p);
break;
case 'l': for(++p; isspace(*p); p++);
doload(p);
break;
default: lexerr("unknown command %s", toktext);
}
}
/* doload/dosave routines written by nick buchholz */
/*
doload and dosave routines make the following assumptions
1. version is the first global variable declared in main.
2. main is the first procedure seen by the loader
3. the loader allocates memory in the order it sees the procedures
4. memory is laid out as on the vax 780 under 4.2
on other machines any or all of these might be false and the
doload/dosave routines will not work
*/
extern int version;
dosave(p) char *p;{
int fd;
char *start, *end, *sbrk();
unsigned int length, len;
int dlen;
# ifdef OPEN3ARG
if ((fd = open(p, O_WRONLY|O_CREAT|O_TRUNC, 0666)) == -1)
# endif
# ifndef OPEN3ARG
if ((fd = creat(p, 0666)) == -1)
# endif
fprintf(stderr,"can't open: %s\n",p);
start = (char *) &version;
end = sbrk(0);
length = end - start;
write(fd, &version, sizeof(int));
write(fd, &start, sizeof(char *));
write(fd, &length, sizeof(unsigned int));
for (len = 0; len < length; len += dlen) {
dlen = ((length - len) > 512) ? 512 : (length - len);
if (dlen != write(fd, start + len, dlen)) {
cant_happen(23);
}
}
fprintf(stderr,"%u bytes written\n",len);
close(fd);
}
# ifdef ENVSAVE
extern char **environ;
# endif
doload(p) char *p;{
int fd;
char *start, *end, *brk();
unsigned int length, len;
int dlen;
int test;
# ifdef ENVSAVE
char **evsave;
# endif
# ifdef OPEN3ARG
if ((fd = open(p, O_RDONLY, 0)) == -1)
# endif
# ifndef OPEN3ARG
if ((fd = open(p, 0 )) == -1)
# endif
fprintf(stderr,"no such context as: %s\n", p);
else {
read(fd, &test, sizeof(int));
read(fd, &start, sizeof(char *));
read(fd, &length, sizeof(unsigned int));
if ((test != version) || (start != (char *) &version))
fprintf(stderr,"%s: not a valid context file for version %d\n",
p, version);
else {
start = (char *) &version;
end = brk(start + length + 1);
# ifdef ENVSAVE
evsave = environ;
# endif
for (len = 0; len < length; len += dlen) {
dlen = ((length - len) > 512) ? 512 : (length - len);
if (dlen != read(fd, start + len, dlen)) {
cant_happen(23);
}
}
# ifdef ENVSAVE
environ = evsave;
# endif
fprintf(stderr,"%u bytes read\n",len);
}
close(fd);
}
}
/* lexread - read commands from a file */
lexread(name)
char *name;
{ FILE *fd;
fd = fopen(name, "r");
if (fd == NULL) {
fprintf(stderr,"can't open %s\n", name);
}
else {
set_file(fd);
}
}
/* lexinclude - parse a class and include the class description */
lexinclude(name)
char *name;
{ char template[60], cmdbuf[120];
int i;
# ifndef NOSYSTEM
gettemp(template);
sprintf(cmdbuf,"%s %s >%s", PARSER, name, template);
i = system(cmdbuf);
if (i == 0)
lexread(template);
# endif
# ifdef NOSYSTEM
fprintf(stderr,")i does not work on this system\n");
# endif
}
/* lexedit - edit a class description */
int lexedit(name)
char *name;
{ char *e, buffer[100], *getenv();
# ifndef NOSYSTEM
e = getenv("EDITOR");
if (!e) e = "ed";
sprintf(buffer,"%s %s", e, name);
return(system(buffer));
# endif
# ifdef NOSYSTEM
fprintf(stderr,")e does not work on this system\n");
return(1);
# endif
}