src/streams.c

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *   2. 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.
 *
 * 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 HOLDER 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 "cx/streams.h"

#ifndef CX_STREAM_BCOPY_BUF_SIZE
#define CX_STREAM_BCOPY_BUF_SIZE 8192
#endif

#ifndef CX_STREAM_COPY_BUF_SIZE
#define CX_STREAM_COPY_BUF_SIZE 1024
#endif

size_t cx_stream_bncopy(
        void *src,
        void *dest,
        cx_read_func rfnc,
        cx_write_func wfnc,
        char *buf,
        size_t bufsize,
        size_t n
) {
    if (n == 0) {
        return 0;
    }

    char *lbuf;
    size_t ncp = 0;

    if (buf) {
        if (bufsize == 0) return 0;
        lbuf = buf;
    } else {
        if (bufsize == 0) bufsize = CX_STREAM_BCOPY_BUF_SIZE;
        lbuf = malloc(bufsize);
        if (lbuf == NULL) {
            return 0;
        }
    }

    size_t r;
    size_t rn = bufsize > n ? n : bufsize;
    while ((r = rfnc(lbuf, 1, rn, src)) != 0) {
        r = wfnc(lbuf, 1, r, dest);
        ncp += r;
        n -= r;
        rn = bufsize > n ? n : bufsize;
        if (r == 0 || n == 0) {
            break;
        }
    }

    if (lbuf != buf) {
        free(lbuf);
    }

    return ncp;
}

size_t cx_stream_ncopy(
        void *src,
        void *dest,
        cx_read_func rfnc,
        cx_write_func wfnc,
        size_t n
) {
    char buf[CX_STREAM_COPY_BUF_SIZE];
    return cx_stream_bncopy(src, dest, rfnc, wfnc,
                            buf, CX_STREAM_COPY_BUF_SIZE, n);
}