src/streams.c

Sun, 23 Nov 2025 13:15:19 +0100

author
Mike Becker <universe@uap-core.de>
date
Sun, 23 Nov 2025 13:15:19 +0100
changeset 1508
dfc0ddd9571e
parent 1319
aa1f580f8f59
permissions
-rw-r--r--

optimize sorted insertion by using the infimum instead of the supremum

The reason is that the supremum returns the equal element with the smallest index, and we want the largest.
Therefore, we use the infimum, which already gives us the largest index when there are equal elements, and increase the index by one. The infimum is also guaranteed to exist in that case.

/*
 * 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"
#include "cx/allocator.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 = cxMallocDefault(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) {
        cxFreeDefault(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);
}

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