Quelle sysstr.c Sprache: C

/****************************************************************************
**
**  This file is part of GAP, a system for computational discrete algebra.
**
**  Copyright of GAP belongs to its developers, whose names are too numerous
**  to list here. Please refer to the COPYRIGHT file for details.
**
**  SPDX-License-Identifier: GPL-2.0-or-later
**
**  This file implements low-level functions dealing with C strings and
**  characters.
*/

#include "sysstr.h"

size_t gap_strlcpy(char * dst, const char * src, size_t len)
{
    // Keep a copy of the original src.
    const char * const orig_src = src;

    // If a non-empty len was specified, we can actually copy some data.
    if (len > 0) {
        // Copy up to len-1 bytes (reserve one for the terminating zero).
        while (--len > 0) {
            // Copy from src to dst; if we reach the string end, we are
            // done and can simply return the total source string length
            if ((*dst++ = *src++) == 0) {
                // return length of source string without the zero byte
                return src - orig_src - 1;
            }
        }

        // If we got here, then we used up the whole buffer and len is zero.
        // We must make sure to terminate the destination string.
        *dst = 0;
    }

    // in the end, we must return the length of the source string, no
    // matter whether we completely copied or not; so advance src
    // till its terminator is reached
    while (*src++)
        ;

    // return length of source string without the zero byte
    return src - orig_src - 1;
}

size_t gap_strlcat(char * dst, const char * src, size_t len)
{
    // Keep a copy of the original dst.
    const char * const orig_dst = dst;

    // Find the end of the dst string, so that we can append after it.
    while (*dst != 0 && len > 0) {
        dst++;
        len--;
    }

    // We can only append anything if there is free space left in the
    // destination buffer.
    if (len > 0) {
        // One byte goes away for the terminating zero.
        len--;

        // Do the actual work and append from src to dst, until we either
        // appended everything, or reached the dst buffer's end.
        while (*src != 0 && len > 0) {
            *dst++ = *src++;
            len--;
        }

        // Terminate, terminate, terminate!
        *dst = 0;
    }

    // Compute the final result.
    return (dst - orig_dst) + strlen(src);
}

size_t strxcpy(char * dst, const char * src, size_t len)
{
    size_t res = gap_strlcpy(dst, src, len);
    assert(res < len);
    return res;
}

size_t strxcat(char * dst, const char * src, size_t len)
{
    size_t res = gap_strlcat(dst, src, len);
    assert(res < len);
    return res;
}

quality93%

¤ Dauer der Verarbeitung: 0.21 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.