/* Copyright (C) 2004
 * Andy Goth <unununium@openverse.com>
 *
 * This code is available under the GNU General Public License; see COPYING. */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char** argv)
{
    int i, ret;
    int beg, end, pos, next;
    int seek, count;
    unsigned char buf[4096];

    if (argc != 3) {
        fprintf(stderr, "Usage: range START END\n");
        return EXIT_SUCCESS;
    } else {
        next = 0;
        beg = atoi(argv[1]);
        end = atoi(argv[2]);
        if (beg < 0) beg = 0;
    }

    while (1) {
        ret = read(0, buf, 4096);

        if (ret == -1) {
            perror("read");
            return EXIT_FAILURE;
        } else if (ret == 0) {
            return EXIT_SUCCESS;
        } else {
            pos = next;
            next += ret;
            /* Fall through. */
        }

        if (beg > pos) {
            /* Don't send beginning of block. */
            if (beg >= pos + ret) {
                /* Send nothing. */
                count = 0;
            } else {
                seek = beg - pos;
                if (end >= pos + ret) {
                    /* Send end of block. */
                    count = ret - seek;
                } else {
                    /* Send middle of block. */
                    count = end - beg + 1;
                }
            }
        } else if (end >= pos) {
            seek = 0;
            if (end >= pos + ret) {
                /* Send entire block. */
                count = ret;
            } else {
                /* Send beginning of block. */
                count = end - pos + 1;
            }
        } else {
            /* Send nothing. */
            count = 0;
        }

        while (count > 0) {
            ret = write(1, buf + seek, count);

            if (ret == -1) {
                perror("write");
                return EXIT_FAILURE;
            } else if (ret == 0) {
                fprintf(stderr, "write: stdout closed?\n");
                return EXIT_FAILURE;
            } else {
                seek  += ret;
                count -= ret;
            }
        }
    }

    return EXIT_SUCCESS;
}

/* vim: set ts=4 sts=4 sw=4 tw=80 et: */