utils/src/more.c

136 lines
2.8 KiB
C

/* $Id$ */
/* Copyright (c) 2011-2020 Pierre Pronchery <khorben@defora.org> */
/* This file is part of DeforaOS Unix utils */
/* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 3 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <limits.h>
/* constants */
#ifndef PROGNAME
# define PROGNAME "more"
#endif
/* more */
/* private */
/* types */
typedef struct _Prefs
{
int lines;
} Prefs;
/* prototypes */
static int _more_error(char const * message, int ret);
/* functions */
/* more */
static int _more_do(Prefs * prefs, char const * filename);
static int _more(Prefs * prefs, int filec, char * filev[])
{
int ret = 0;
int i;
if(filec == 0)
return _more_do(prefs, NULL);
for(i = 0; i < filec; i++)
ret |= _more_do(prefs, filev[i]);
return ret;
}
static int _more_do(Prefs * prefs, char const * filename)
{
FILE * fp = stdin;
char buf[1024];
size_t len;
int n = 1;
int c;
if(filename != NULL && strcmp(filename, "-") != 0
&& (fp = fopen(filename, "r")) == NULL)
return _more_error(filename, 1);
while(fgets(buf, sizeof(buf), fp) != NULL)
{
len = strlen(buf);
if(fwrite(buf, 1, len, stdout) != len)
break; /* XXX report error */
if(prefs->lines <= 0)
continue;
if(len > 0 && buf[len - 1] != '\n')
continue;
if(++n % prefs->lines != 0)
continue;
n = 1;
fputs("--more--", stderr);
while((c = getchar()) != EOF && c != '\n');
}
if(filename != NULL && strcmp(filename, "-") != 0)
fclose(fp);
return 0;
}
/* more_error */
static int _more_error(char const * message, int ret)
{
fputs(PROGNAME ": ", stderr);
perror(message);
return ret;
}
/* usage */
static int _usage(void)
{
fputs("Usage: " PROGNAME " [file...]\n", stderr);
return 1;
}
/* public */
/* functions */
/* main */
int main(int argc, char * argv[])
{
Prefs prefs;
int o;
char * p;
memset(&prefs, 0, sizeof(prefs));
while((o = getopt(argc, argv, "n:")) != -1)
switch(o)
{
case 'n':
prefs.lines = strtol(optarg, &p, 10);
if(optarg[0] == '\0' || *p != '\0'
|| prefs.lines <= 0)
return _usage();
break;
default:
return _usage();
}
if(!isatty(0))
prefs.lines = 0;
else if(prefs.lines <= 0 && (p = getenv("LINES")) != NULL)
prefs.lines = strtol(p, NULL, 10);
return _more(&prefs, argc - optind, &argv[optind]);
}