cat.c

/* Copyright (c) 2008, Tim Post <tinkertim@gmail.com>
 * Copyright (c) 2011, Martin Sucha
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the original program's authors nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <getopt.h>
#include <str.h>
#include <fcntl.h>
#include <io/console.h>
#include <io/color.h>
#include <io/style.h>
#include <io/keycode.h>
#include <errno.h>
#include <vfs/vfs.h>
#include <assert.h>

#include "config.h"
#include "util.h"
#include "errors.h"
#include "entry.h"
#include "cat.h"
#include "cmds.h"

static const char *cmdname = "cat";
#define CAT_VERSION "0.0.1"
#define CAT_DEFAULT_BUFLEN 1024

static const char *cat_oops = "That option is not yet supported\n";
static const char *hexchars = "0123456789abcdef";

static bool paging_enabled = false;
static size_t chars_remaining = 0;
static size_t lines_remaining = 0;
static sysarg_t console_cols = 0;
static sysarg_t console_rows = 0;
static bool should_quit = false;

static struct option const long_options[] = {
        { "help", no_argument, 0, 'h' },
        { "version", no_argument, 0, 'v' },
        { "head", required_argument, 0, 'H' },
        { "tail", required_argument, 0, 't' },
        { "buffer", required_argument, 0, 'b' },
        { "more", no_argument, 0, 'm' },
        { "hex", no_argument, 0, 'x' },
        { 0, 0, 0, 0 }
};

/* Dispays help for cat in various levels */
void help_cmd_cat(unsigned int level)
{
        if (level == HELP_SHORT) {
                printf("`%s' shows the contents of files\n", cmdname);
        } else {
                help_cmd_cat(HELP_SHORT);
                printf(
                "Usage:  %s [options] <file1> [file2] [...]\n"
                "Options:\n"
                "  -h, --help       A short option summary\n"
                "  -v, --version    Print version information and exit\n"
                "  -H, --head ##    Print only the first ## bytes\n"
                "  -t, --tail ##    Print only the last ## bytes\n"
                "  -b, --buffer ##  Set the read buffer size to ##\n"
                "  -m, --more       Pause after each screen full\n"
                "  -x, --hex        Print bytes as hex values\n"
                "Currently, %s is under development, some options don't work.\n",
                cmdname, cmdname);
        }

        return;
}

static void waitprompt()
{
        console_set_pos(fphone(stdout), 0, console_rows-1);
        console_set_color(fphone(stdout), COLOR_BLUE, COLOR_WHITE, 0);
        printf("ENTER/SPACE/PAGE DOWN - next page, "
               "ESC/Q - quit, C - continue unpaged");
        fflush(stdout);
        console_set_style(fphone(stdout), STYLE_NORMAL);
}

static void waitkey()
{
        console_event_t ev;
        
        while (true) {
                if (!console_get_event(fphone(stdin), &ev)) {
                        return;
                }
                if (ev.type == KEY_PRESS) {
                        if (ev.key == KC_ESCAPE || ev.key == KC_Q) {
                                should_quit = true;
                                return;
                        }
                        if (ev.key == KC_C) {
                                paging_enabled = false;
                                return;
                        }
                        if (ev.key == KC_ENTER || ev.key == KC_SPACE ||
                            ev.key == KC_PAGE_DOWN) {
                                return;
                        }
                }
        }
        assert(false);
}

static void newpage()
{
        console_clear(fphone(stdout));
        chars_remaining = console_cols;
        lines_remaining = console_rows-1;
}

static void paged_char(wchar_t c)
{
        putchar(c);
        if (paging_enabled) {
                chars_remaining--;
                if (c == '\n' || chars_remaining == 0) {
                        chars_remaining = console_cols;
                        lines_remaining--;
                }
                if (lines_remaining == 0) {
                        fflush(stdout);
                        waitprompt();
                        waitkey();
                        newpage();
                }
        }
}

static unsigned int cat_file(const char *fname, size_t blen, bool hex)
{
        int fd, bytes = 0, count = 0, reads = 0;
        char *buff = NULL;
        int i;
        size_t offset = 0;

        fd = open(fname, O_RDONLY);
        if (fd < 0) {
                printf("Unable to open %s\n", fname);
                return 1;
        }

        if (NULL == (buff = (char *) malloc(blen + 1))) {
                close(fd);
                printf("Unable to allocate enough memory to read %s\n",
                        fname);
                return 1;
        }

        do {
                bytes = read(fd, buff, blen);
                if (bytes > 0) {
                        count += bytes;
                        buff[bytes] = '\0';
                        offset = 0;
                        for (i = 0; i < bytes && !should_quit; i++) {
                                if (hex) {
                                        paged_char(hexchars[((uint8_t)buff[i])/16]);
                                        paged_char(hexchars[((uint8_t)buff[i])%16]);
                                }
                                else {
                                        wchar_t c = str_decode(buff, &offset, bytes);
                                        if (c == 0) {
                                                /* Reached end of string */
                                                break;
                                        }
                                        paged_char(c);
                                }
                                
                        }
                        reads++;
                }
        } while (bytes > 0 && !should_quit);

        close(fd);
        if (bytes == -1) {
                printf("Error reading %s\n", fname);
                free(buff);
                return 1;
        }

        free(buff);

        return 0;
}

/* Main entry point for cat, accepts an array of arguments */
int cmd_cat(char **argv)
{
        unsigned int argc, i, ret = 0, buffer = 0;
        int c, opt_ind;
        bool hex = false;
        bool more = false;
        sysarg_t rows, cols;
        int rc;
        
        /*
         * reset global state
         * TODO: move to structure?
         */
        paging_enabled = false;
        chars_remaining = 0;
        lines_remaining = 0;
        console_cols = 0;
        console_rows = 0;
        should_quit = false;

        argc = cli_count_args(argv);

        for (c = 0, optind = 0, opt_ind = 0; c != -1;) {
                c = getopt_long(argc, argv, "xhvmH:t:b:", long_options, &opt_ind);
                switch (c) {
                case 'h':
                        help_cmd_cat(HELP_LONG);
                        return CMD_SUCCESS;
                case 'v':
                        printf("%s\n", CAT_VERSION);
                        return CMD_SUCCESS;
                case 'H':
                        printf("%s", cat_oops);
                        return CMD_FAILURE;
                case 't':
                        printf("%s", cat_oops);
                        return CMD_FAILURE;
                case 'b':
                        printf("%s", cat_oops);
                        break;
                case 'm':
                        more = true;
                        break;
                case 'x':
                        hex = true;
                        break;
                }
        }

        argc -= optind;

        if (argc < 1) {
                printf("%s - incorrect number of arguments. Try `%s --help'\n",
                        cmdname, cmdname);
                return CMD_FAILURE;
        }

        if (buffer <= 0)
                buffer = CAT_DEFAULT_BUFLEN;
        
        if (more) {
                rc = console_get_size(fphone(stdout), &cols, &rows);
                if (rc != EOK) {
                        printf("%s - cannot get console size\n", cmdname);
                        return CMD_FAILURE;
                }
                console_cols = cols;
                console_rows = rows;
                paging_enabled = true;
                newpage();
        }

        for (i = optind; argv[i] != NULL && !should_quit; i++)
                ret += cat_file(argv[i], buffer, hex);

        if (ret)
                return CMD_FAILURE;
        else
                return CMD_SUCCESS;
}

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