root/ckconfig.c
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DEFINITIONS
This source file includes following definitions.
- testfunction
- test2function
- test3function
- test4function
- possibly_duplicate_function
- possibly_dupli_function
- is_char_signed
- is_shifting_signed
- main
/*
* ckconfig.c
*
* Copyright (C) 1991-1994, 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 produce a "jconfig.h" file for
* your system.
*
* 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 has all the ANSI-standard
* include files. If you get any error trying to include one of these files,
* undefine the corresponding HAVE_xxx symbol.
*/
#define HAVE_STDDEF_H /* replace 'define' by 'undef' if error here */
#ifdef HAVE_STDDEF_H /* next line will be skipped if you undef... */
#include <stddef.h>
#endif
#define HAVE_STDLIB_H /* same thing for stdlib.h */
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#include <stdio.h> /* If you ain't got this, you ain't got C. */
/* We have to see if your string functions are defined by
* strings.h (old BSD convention) or string.h (everybody else).
* We try the non-BSD convention first; define NEED_BSD_STRINGS
* if the compiler says it can't find string.h.
*/
#undef NEED_BSD_STRINGS
#ifdef NEED_BSD_STRINGS
#include <strings.h>
#else
#include <string.h>
#endif
/* On some systems (especially older Unix machines), type size_t is
* defined only in the include file <sys/types.h>. If you get a failure
* on the size_t test below, try defining NEED_SYS_TYPES_H.
*/
#undef NEED_SYS_TYPES_H /* start by assuming we don't need it */
#ifdef NEED_SYS_TYPES_H
#include <sys/types.h>
#endif
/* Usually type size_t is defined in one of the include files we've included
* above. If not, you'll get an error on the "typedef size_t my_size_t;" line.
* In that case, first try defining NEED_SYS_TYPES_H just above.
* If that doesn't work, 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;". Then, change the line below
* that says "#include <someincludefile.h>" to instead include the file
* you found size_t in, and define NEED_SPECIAL_INCLUDE. If you can't find
* type size_t anywhere, try replacing "#include <someincludefile.h>" with
* "typedef unsigned int size_t;".
*/
#undef NEED_SPECIAL_INCLUDE /* assume we DON'T need it, for starters */
#ifdef NEED_SPECIAL_INCLUDE
#include <someincludefile.h>
#endif
typedef size_t my_size_t; /* The payoff: do we have size_t now? */
/* The next question is whether your compiler supports ANSI-style function
* prototypes. 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 prototypes.
* If you get an error in this group of lines, undefine HAVE_PROTOTYPES.
*/
#define HAVE_PROTOTYPES
#ifdef HAVE_PROTOTYPES
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 (*another_method) (void);
};
int testfunction (int arg1, int * arg2) /* check definitions */
{
return arg2[arg1];
}
int test2function (void) /* check void arg list */
{
return 0;
}
#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
/* Caution: a C++ compiler will insist on complete prototypes */
typedef void * void_ptr; /* check void * */
#ifdef HAVE_PROTOTYPES /* check ptr to function returning void */
typedef void (*void_func) (int a, int b);
#else
typedef void (*void_func) ();
#endif
#ifdef HAVE_PROTOTYPES /* check void function result */
void test3function (void_ptr arg1, void_func arg2)
#else
void test3function (arg1, arg2)
void_ptr arg1;
void_func arg2;
#endif
{
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};
#ifdef HAVE_PROTOTYPES
int test4function (const int arg1)
#else
int test4function (arg1)
const int arg1;
#endif
{
return carray[arg1];
}
#endif
/* If you get an error or warning about this structure definition,
* define INCOMPLETE_TYPES_BROKEN.
*/
#undef INCOMPLETE_TYPES_BROKEN
#ifndef INCOMPLETE_TYPES_BROKEN
typedef struct undefined_structure * undef_struct_ptr;
#endif
/* If you get an error about duplicate names,
* define NEED_SHORT_EXTERNAL_NAMES.
*/
#undef NEED_SHORT_EXTERNAL_NAMES
#ifndef NEED_SHORT_EXTERNAL_NAMES
int possibly_duplicate_function ()
{
return 0;
}
int possibly_dupli_function ()
{
return 1;
}
#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 create jconfig.h and print out
* any additional suggestions it has.
************************************************************************
*/
#ifdef HAVE_PROTOTYPES
int is_char_signed (int arg)
#else
int is_char_signed (arg)
int arg;
#endif
{
if (arg == 189) { /* expected result for unsigned char */
return 0; /* type char is unsigned */
}
else if (arg != -67) { /* expected result for signed char */
printf("Hmm, it seems 'char' is not eight bits wide on your machine.\n");
printf("I fear the JPEG software will not work at all.\n\n");
}
return 1; /* assume char is signed otherwise */
}
#ifdef HAVE_PROTOTYPES
int is_shifting_signed (long arg)
#else
int is_shifting_signed (arg)
long arg;
#endif
/* See whether right-shift on a long is signed or not. */
{
long res = arg >> 4;
if (res == -0x7F7E80CL) { /* expected result for signed shift */
return 1; /* right shift is signed */
}
/* see if unsigned-shift hack will fix it. */
/* we can't just test exact value since it depends on width of long... */
res |= (~0L) << (32-4);
if (res == -0x7F7E80CL) { /* expected result now? */
return 0; /* right shift is unsigned */
}
printf("Right shift isn't acting as I expect it to.\n");
printf("I fear the JPEG software will not work at all.\n\n");
return 0; /* try it with unsigned anyway */
}
#ifdef HAVE_PROTOTYPES
int main (int argc, char ** argv)
#else
int main (argc, argv)
int argc;
char ** argv;
#endif
{
char signed_char_check = (char) (-67);
FILE *outfile;
/* Attempt to write jconfig.h */
if ((outfile = fopen("jconfig.h", "w")) == NULL) {
printf("Failed to write jconfig.h\n");
return 1;
}
/* Write out all the info */
fprintf(outfile, "/* jconfig.h --- generated by ckconfig.c */\n");
fprintf(outfile, "/* see jconfig.txt for explanations */\n\n");
#ifdef HAVE_PROTOTYPES
fprintf(outfile, "#define HAVE_PROTOTYPES\n");
#else
fprintf(outfile, "#undef HAVE_PROTOTYPES\n");
#endif
#ifdef HAVE_UNSIGNED_CHAR
fprintf(outfile, "#define HAVE_UNSIGNED_CHAR\n");
#else
fprintf(outfile, "#undef HAVE_UNSIGNED_CHAR\n");
#endif
#ifdef HAVE_UNSIGNED_SHORT
fprintf(outfile, "#define HAVE_UNSIGNED_SHORT\n");
#else
fprintf(outfile, "#undef HAVE_UNSIGNED_SHORT\n");
#endif
#ifdef HAVE_VOID
fprintf(outfile, "/* #define void char */\n");
#else
fprintf(outfile, "#define void char\n");
#endif
#ifdef HAVE_CONST
fprintf(outfile, "/* #define const */\n");
#else
fprintf(outfile, "#define const\n");
#endif
if (is_char_signed((int) signed_char_check))
fprintf(outfile, "#undef CHAR_IS_UNSIGNED\n");
else
fprintf(outfile, "#define CHAR_IS_UNSIGNED\n");
#ifdef HAVE_STDDEF_H
fprintf(outfile, "#define HAVE_STDDEF_H\n");
#else
fprintf(outfile, "#undef HAVE_STDDEF_H\n");
#endif
#ifdef HAVE_STDLIB_H
fprintf(outfile, "#define HAVE_STDLIB_H\n");
#else
fprintf(outfile, "#undef HAVE_STDLIB_H\n");
#endif
#ifdef NEED_BSD_STRINGS
fprintf(outfile, "#define NEED_BSD_STRINGS\n");
#else
fprintf(outfile, "#undef NEED_BSD_STRINGS\n");
#endif
#ifdef NEED_SYS_TYPES_H
fprintf(outfile, "#define NEED_SYS_TYPES_H\n");
#else
fprintf(outfile, "#undef NEED_SYS_TYPES_H\n");
#endif
fprintf(outfile, "#undef NEED_FAR_POINTERS\n");
#ifdef NEED_SHORT_EXTERNAL_NAMES
fprintf(outfile, "#define NEED_SHORT_EXTERNAL_NAMES\n");
#else
fprintf(outfile, "#undef NEED_SHORT_EXTERNAL_NAMES\n");
#endif
#ifdef INCOMPLETE_TYPES_BROKEN
fprintf(outfile, "#define INCOMPLETE_TYPES_BROKEN\n");
#else
fprintf(outfile, "#undef INCOMPLETE_TYPES_BROKEN\n");
#endif
fprintf(outfile, "\n#ifdef JPEG_INTERNALS\n\n");
if (is_shifting_signed(-0x7F7E80B1L))
fprintf(outfile, "#undef RIGHT_SHIFT_IS_UNSIGNED\n");
else
fprintf(outfile, "#define RIGHT_SHIFT_IS_UNSIGNED\n");
fprintf(outfile, "\n#endif /* JPEG_INTERNALS */\n");
fprintf(outfile, "\n#ifdef JPEG_CJPEG_DJPEG\n\n");
fprintf(outfile, "#define BMP_SUPPORTED /* BMP image file format */\n");
fprintf(outfile, "#define GIF_SUPPORTED /* GIF image file format */\n");
fprintf(outfile, "#define PPM_SUPPORTED /* PBMPLUS PPM/PGM image file format */\n");
fprintf(outfile, "#undef RLE_SUPPORTED /* Utah RLE image file format */\n");
fprintf(outfile, "#define TARGA_SUPPORTED /* Targa image file format */\n\n");
fprintf(outfile, "#undef TWO_FILE_COMMANDLINE /* You may need this on non-Unix systems */\n");
fprintf(outfile, "#undef NEED_SIGNAL_CATCHER /* Define this if you use jmemname.c */\n");
fprintf(outfile, "#undef DONT_USE_B_MODE\n");
fprintf(outfile, "/* #define PROGRESS_REPORT */ /* optional */\n");
fprintf(outfile, "\n#endif /* JPEG_CJPEG_DJPEG */\n");
/* Close the jconfig.h file */
fclose(outfile);
/* User report */
printf("Configuration check for Independent JPEG Group's software done.\n");
printf("\nI have written the jconfig.h file for you.\n\n");
#ifdef HAVE_PROTOTYPES
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
#ifdef NEED_SPECIAL_INCLUDE
printf("\nYou'll need to change jconfig.h to include the system include file\n");
printf("that you found type size_t in, or add a direct definition of type\n");
printf("size_t if that's what you used. Just add it to the end.\n");
#endif
return 0;
}