Category : C Source Code
Archive   : JPSRC2.ZIP
Filename : CONFIG.C

/*
* config.c
*
* Copyright (C) 1991, Thomas G. Lane.
* This file is part of the Independent JPEG Group's software.
* For conditions of distribution and use, see the accompanying README file.
*/

/*
* This program is intended to help you determine how to configure the JPEG
* software for installation on a particular system. The idea is to try to
* compile and execute this program. If your compiler fails to compile the
* program, make changes as indicated in the comments below. Once you can
* compile the program, run it, and it will tell you how to set the various
* switches in jconfig.h and in your Makefile.
*
* This could all be done automatically if we could assume we were on a Unix
* system, but we don't want to assume that, so you'll have to edit and
* recompile this program until it works.
*
* As a general rule, each time you try to compile this program,
* pay attention only to the *first* error message you get from the compiler.
* Many C compilers will issue lots of spurious error messages once they
* have gotten confused. Go to the line indicated in the first error message,
* and read the comments preceding that line to see what to change.
*
* Almost all of the edits you may need to make to this program consist of
* changing a line that reads "#define SOME_SYMBOL" to "#undef SOME_SYMBOL",
* or vice versa. This is called defining or undefining that symbol.
*/


/* First we must see if your system has the include files we need.
* We start out with the assumption that your system follows the ANSI
* conventions for include files. If you get any error in the next dozen
* lines, undefine INCLUDES_ARE_ANSI.
*/

#define INCLUDES_ARE_ANSI /* replace 'define' by 'undef' if error here */

#ifdef INCLUDES_ARE_ANSI /* this will be skipped if you undef... */
#include /* If you ain't got this, you ain't got C. */
#ifdef __SASC /* Amiga SAS C provides size_t in stddef.h. */
#include /* (They are wrong...) */
#endif
#include /* size_t might be here too. */
typedef size_t my_size_t; /* The payoff: do we have size_t now? */
#include /* Check other ANSI includes we use. */
#endif


/* If your system doesn't follow the ANSI conventions, we have to figure out
* what it does follow. If you didn't get an error before this line, you can
* ignore everything down to "#define HAVE_ANSI_DEFINITIONS".
*/

#ifndef INCLUDES_ARE_ANSI /* skip these tests if INCLUDES_ARE_ANSI */

#include /* If you ain't got this, you ain't got C. */

/* jinclude.h will try to include if you don't set
* INCLUDES_ARE_ANSI. We need to test whether that include file is provided.
* If you get an error here, undefine HAVE_TYPES_H.
*/

#define HAVE_TYPES_H

#ifdef HAVE_TYPES_H
#include
#endif

/* We have to see if your string functions are defined by
* strings.h (BSD convention) or string.h (everybody else).
* We try the non-BSD convention first; define BSD if the compiler
* says it can't find string.h.
*/

#undef BSD

#ifdef BSD
#include
#else
#include
#endif

/* Usually size_t is defined in stdio.h, sys/types.h, and/or string.h.
* If not, you'll get an error on the "typedef size_t my_size_t;" line below.
* In that case, you'll have to search through your system library to
* figure out which include file defines "size_t". Look for a line that
* says "typedef something-or-other size_t;" (stddef.h and stdlib.h are
* good places to look first). Then, change the line below that says
* "#include " to instead include the file
* you found size_t in, and define NEED_SPECIAL_INCLUDE.
*/

#undef NEED_SPECIAL_INCLUDE /* assume we DON'T need it, for starters */

#ifdef NEED_SPECIAL_INCLUDE
#include
#endif

typedef size_t my_size_t; /* The payoff: do we have size_t now? */


#endif /* INCLUDES_ARE_ANSI */



/* The next question is whether your compiler supports ANSI-style function
* definitions. You need to know this in order to choose between using
* makefile.ansi and using makefile.unix.
* The #define line below is set to assume you have ANSI function definitions.
* If you get an error in this group of lines, undefine HAVE_ANSI_DEFINITIONS.
*/

#define HAVE_ANSI_DEFINITIONS

#ifdef HAVE_ANSI_DEFINITIONS
int testfunction (int arg1, int * arg2); /* check prototypes */

struct methods_struct { /* check method-pointer declarations */
int (*error_exit) (char *msgtext);
int (*trace_message) (char *msgtext);
};

int testfunction (int arg1, int * arg2) /* check definitions */
{
return arg2[arg1];
}
#endif


/* Now we want to find out if your compiler knows what "unsigned char" means.
* If you get an error on the "unsigned char un_char;" line,
* then undefine HAVE_UNSIGNED_CHAR.
*/

#define HAVE_UNSIGNED_CHAR

#ifdef HAVE_UNSIGNED_CHAR
unsigned char un_char;
#endif


/* Now we want to find out if your compiler knows what "unsigned short" means.
* If you get an error on the "unsigned short un_short;" line,
* then undefine HAVE_UNSIGNED_SHORT.
*/

#define HAVE_UNSIGNED_SHORT

#ifdef HAVE_UNSIGNED_SHORT
unsigned short un_short;
#endif


/* Now we want to find out if your compiler understands type "void".
* If you get an error anywhere in here, undefine HAVE_VOID.
*/

#define HAVE_VOID

#ifdef HAVE_VOID
typedef void * void_ptr; /* check void * */
typedef void (*void_func) (); /* check ptr to function returning void */

void testfunction2 (arg1, arg2) /* check void function result */
void_ptr arg1;
void_func arg2;
{
char * locptr = (char *) arg1; /* check casting to and from void * */
arg1 = (void *) locptr;
(*arg2) (1, 2); /* check call of fcn returning void */
}
#endif


/* Now we want to find out if your compiler knows what "const" means.
* If you get an error here, undefine HAVE_CONST.
*/

#define HAVE_CONST

#ifdef HAVE_CONST
static const int carray[3] = {1, 2, 3};

int testfunction3 (arg1)
const int arg1;
{
return carray[arg1];
}
#endif



/************************************************************************
* OK, that's it. You should not have to change anything beyond this
* point in order to compile and execute this program. (You might get
* some warnings, but you can ignore them.)
* When you run the program, it will make a couple more tests that it
* can do automatically, and then it will print out a summary of the changes
* that you need to make to the makefile and jconfig.h.
************************************************************************
*/


static int any_changes = 0;

int new_change ()
{
if (! any_changes) {
printf("\nMost of the changes recommended by this program can be made either\n");
printf("by editing jconfig.h, or by adding -Dsymbol switches to the CFLAGS\n");
printf("line in your Makefile. (Some PC compilers expect /Dsymbol instead.)\n");
printf("The CFLAGS method is simpler, but if your system doesn't use makefiles,\n");
printf("or if your compiler doesn't support -D, then you must change jconfig.h.\n");
any_changes = 1;
}
printf("\n"); /* blank line before each problem report */
return 0;
}


int test_char_sign (arg)
int arg;
{
if (arg == 189) { /* expected result for unsigned char */
new_change();
printf("You should add -DCHAR_IS_UNSIGNED to CFLAGS,\n");
printf("or else remove the /* */ comment marks from the line\n");
printf("/* #define CHAR_IS_UNSIGNED */ in jconfig.h.\n");
printf("(Be sure to delete the space before the # character too.)\n");
}
else if (arg != -67) { /* expected result for signed char */
new_change();
printf("Hmm, it seems 'char' is less than eight bits wide on your machine.\n");
printf("I fear the JPEG software will not work at all.\n");
}
return 0;
}


int test_shifting (arg)
long arg;
/* See whether right-shift on a long is signed or not. */
{
long res = arg >> 4;

if (res == 0x80817F4L) { /* expected result for unsigned */
new_change();
printf("You must add -DRIGHT_SHIFT_IS_UNSIGNED to CFLAGS,\n");
printf("or else remove the /* */ comment marks from the line\n");
printf("/* #define RIGHT_SHIFT_IS_UNSIGNED */ in jconfig.h.\n");
}
else if (res != -0x7F7E80CL) { /* expected result for signed */
new_change();
printf("Right shift isn't acting as I expect it to.\n");
printf("I fear the JPEG software will not work at all.\n");
}
return 0;
}


int main (argc, argv)
int argc;
char ** argv;
{
char signed_char_check = (char) (-67);

printf("Results of configuration check for Independent JPEG Group's software:\n");
printf("\nIf there's not a specific makefile provided for your compiler,\n");
#ifdef HAVE_ANSI_DEFINITIONS
printf("you should use makefile.ansi as the starting point for your Makefile.\n");
#else
printf("you should use makefile.unix as the starting point for your Makefile.\n");
#endif

/* Check whether we have all the ANSI features, */
/* and whether this agrees with __STDC__ being predefined. */
#ifdef __STDC__
#define MY__STDC__ /* ANSI compilers won't allow redefining __STDC__ */
#endif

#ifdef HAVE_ANSI_DEFINITIONS
#ifdef HAVE_UNSIGNED_CHAR
#ifdef HAVE_UNSIGNED_SHORT
#ifdef HAVE_CONST
#define HAVE_ALL_ANSI_FEATURES
#endif
#endif
#endif
#endif

#ifdef HAVE_ALL_ANSI_FEATURES
#ifndef MY__STDC__
new_change();
printf("Your compiler doesn't claim to be ANSI-compliant, but it is close enough\n");
printf("for me. Either add -D__STDC__ to CFLAGS, or add #define __STDC__ at the\n");
printf("beginning of jinclude.h (NOT jconfig.h).\n");
printf("Some compilers will not let you do this: they will complain that __STDC__\n");
printf("is a reserved name. In that case you have a compiler that really is ANSI,\n");
printf("but you have to give it a special switch (often -ansi) to make it so.\n");
printf("Check your compiler documentation and add the proper switch to CFLAGS.\n");
#define MY__STDC__
#endif
#else /* !HAVE_ALL_ANSI_FEATURES */
#ifdef MY__STDC__
new_change();
printf("Your compiler claims to be ANSI-compliant, but it is lying!\n");
printf("Either add -U__STDC__ to CFLAGS, or add #undef __STDC__\n");
printf("at the beginning of jinclude.h (NOT jconfig.h).\n");
#undef MY__STDC__
#endif
#endif /* HAVE_ALL_ANSI_FEATURES */

#ifndef MY__STDC__

#ifdef HAVE_ANSI_DEFINITIONS
new_change();
printf("You should add -DPROTO to CFLAGS, or else take out the several\n");
printf("#ifdef/#else/#endif lines surrounding #define PROTO in jconfig.h.\n");
printf("(Leave only one #define PROTO line.)\n");
#endif

#ifdef HAVE_UNSIGNED_CHAR
#ifdef HAVE_UNSIGNED_SHORT
new_change();
printf("You should add -DHAVE_UNSIGNED_CHAR and -DHAVE_UNSIGNED_SHORT\n");
printf("to CFLAGS, or else take out the #ifdef __STDC__/#endif lines\n");
printf("surrounding #define HAVE_UNSIGNED_CHAR and #define HAVE_UNSIGNED_SHORT\n");
printf("in jconfig.h.\n");
#else /* only unsigned char */
new_change();
printf("You should add -DHAVE_UNSIGNED_CHAR to CFLAGS,\n");
printf("or else move #define HAVE_UNSIGNED_CHAR outside the\n");
printf("#ifdef __STDC__/#endif lines surrounding it in jconfig.h.\n");
#endif
#else /* !HAVE_UNSIGNED_CHAR */
#ifdef HAVE_UNSIGNED_SHORT
new_change();
printf("You should add -DHAVE_UNSIGNED_SHORT to CFLAGS,\n");
printf("or else move #define HAVE_UNSIGNED_SHORT outside the\n");
printf("#ifdef __STDC__/#endif lines surrounding it in jconfig.h.\n");
#endif
#endif /* HAVE_UNSIGNED_CHAR */

#ifdef HAVE_CONST
new_change();
printf("You can delete the #define const line from jconfig.h.\n");
printf("(But things should still work if you don't.)\n");
#endif

#endif /* MY__STDC__ */

test_char_sign((int) signed_char_check);

test_shifting(-0x7F7E80B1L);

#ifndef HAVE_VOID
new_change();
printf("You should add -Dvoid=char to CFLAGS,\n");
printf("or else remove the /* */ comment marks from the line\n");
printf("/* #define void char */ in jconfig.h.\n");
printf("(Be sure to delete the space before the # character too.)\n");
#endif

#ifdef INCLUDES_ARE_ANSI
#ifndef MY__STDC__
new_change();
printf("You should add -DINCLUDES_ARE_ANSI to CFLAGS, or else add\n");
printf("#define INCLUDES_ARE_ANSI at the beginning of jinclude.h (NOT jconfig.h).\n");
#endif
#else /* !INCLUDES_ARE_ANSI */
#ifdef MY__STDC__
new_change();
printf("You should add -DNONANSI_INCLUDES to CFLAGS, or else add\n");
printf("#define NONANSI_INCLUDES at the beginning of jinclude.h (NOT jconfig.h).\n");
#endif
#ifdef NEED_SPECIAL_INCLUDE
new_change();
printf("In jinclude.h, change the line reading #include \n");
printf("to instead include the file you found size_t in.\n");
#else /* !NEED_SPECIAL_INCLUDE */
#ifndef HAVE_TYPES_H
new_change();
printf("In jinclude.h, delete the line reading #include .\n");
#endif
#endif /* NEED_SPECIAL_INCLUDE */
#ifdef BSD
new_change();
printf("You should add -DBSD to CFLAGS, or else add\n");
printf("#define BSD at the beginning of jinclude.h (NOT jconfig.h).\n");
#endif
#endif /* INCLUDES_ARE_ANSI */

if (any_changes) {
printf("\nI think that's everything...\n");
} else {
printf("\nI think jconfig.h is OK as distributed.\n");
}

return any_changes;
}