mirror of https://github.com/rfivet/uemacs.git
132 lines
3.1 KiB
C
132 lines
3.1 KiB
C
/* flook.c -- implements flook.h */
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#include "flook.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "defines.h"
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/* possible names and paths of help files under different OSes */
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const char *pathname[] = {
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#if BSD | USG
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".emacsrc",
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"emacs.hlp",
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# if PKCODE
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"/usr/global/lib/", "/usr/local/bin/", "/usr/local/lib/",
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# endif
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"/usr/local/", "/usr/lib/", ""
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#endif
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} ;
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#define PATHTABLE_SIZE (sizeof pathname / sizeof pathname[ 0])
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/* does <fname> exist on disk?
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*
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* char *fname; file to check for existance
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*/
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boolean fexist( const char *fname) {
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FILE *fp = fopen( fname, "r") ;
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if( fp == NULL)
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return FALSE ;
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else
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fclose( fp) ;
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return TRUE ;
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}
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/* Look up the existence of a file along the normal or PATH environment
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variable. Look first in the HOME directory if asked and possible.
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char *fname; base file name to search for
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boolean hflag; look in the HOME environment variable first?
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*/
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char *flook( const char *fname, boolean hflag) {
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static char fspec[ NSTRING] ; /* full path spec to search */
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int len = sizeof fspec - strlen( fname) - 1 ;
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if( len < 0)
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return NULL ;
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#if ENVFUNC
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if( hflag) {
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char *home = getenv( "HOME") ; /* path to home directory */
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if( home != NULL) {
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if( len > (int) strlen( home) + 1) {
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/* build home dir file spec */
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strcpy( fspec, home) ;
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strcat( fspec, "/") ;
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strcat( fspec, fname) ;
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/* and try it out */
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if( fexist( fspec))
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return fspec ;
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}
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}
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}
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#endif
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/* always try the current directory first */
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if( len >= 0) {
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strcpy( fspec, fname) ;
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if( fexist( fspec))
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return fspec ;
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}
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#if ENVFUNC
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# if USG | BSD
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# define PATHCHR ':'
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# else
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# define PATHCHR ';'
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# endif
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/* get the PATH variable */
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char *path = getenv( "PATH") ; /* environmental PATH variable */
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if( path != NULL)
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while( *path) {
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int cnt = len ;
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/* build next possible file spec */
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char *sp = fspec ; /* pointer into path spec */
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while( *path && (*path != PATHCHR)) {
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if( cnt-- > 0)
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*sp++ = *path ;
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path += 1 ;
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}
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if( cnt >= 0) {
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/* add a terminating dir separator if we need it */
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if (sp != fspec)
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*sp++ = '/';
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*sp = 0;
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strcat(fspec, fname);
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/* and try it out */
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if( fexist( fspec))
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return fspec ;
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}
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if( *path == PATHCHR)
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++path ;
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}
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#endif
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/* look it up via the old table method */
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for( unsigned i = 2 ; i < PATHTABLE_SIZE ; i++)
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if( len >= (int) strlen( pathname[ i])) {
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strcpy( fspec, pathname[ i]) ;
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strcat( fspec, fname);
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/* and try it out */
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if( fexist( fspec))
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return fspec ;
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}
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return NULL ; /* no such luck */
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}
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/* end of flook.c */
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