source: mainline/uspace/lib/posix/src/string.c@ 09ab0a9a

/*
 * Copyright (c) 2011 Petr Koupy
 * Copyright (c) 2011 Jiri Zarevucky
 * Copyright (c) 2018 Jiri Svoboda
 * 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

/** @addtogroup libposix
 * @{
 */
/** @file String manipulation.
 */

#include "internal/common.h"
#include "posix/string.h"

#include <assert.h>

#include <errno.h>

#include "posix/limits.h"
#include "posix/stdlib.h"
#include "posix/signal.h"

#include "libc/str.h"
#include "libc/str_error.h"

/**
 * Copy a string.
 *
 * @param dest Destination pre-allocated buffer.
 * @param src Source string to be copied.
 * @return Pointer to the nul character in the destination string.
 */
char *stpcpy(char *restrict dest, const char *restrict src)
{
        assert(dest != NULL);
        assert(src != NULL);

        for (size_t i = 0; ; ++i) {
                dest[i] = src[i];

                if (src[i] == '\0') {
                        /* pointer to the terminating nul character */
                        return &dest[i];
                }
        }

        /* unreachable */
        return NULL;
}

/**
 * Copy fixed length string.
 *
 * @param dest Destination pre-allocated buffer.
 * @param src Source string to be copied.
 * @param n Number of bytes to be stored into destination buffer.
 * @return Pointer to the first written nul character or &dest[n].
 */
char *stpncpy(char *restrict dest, const char *restrict src, size_t n)
{
        assert(dest != NULL);
        assert(src != NULL);

        for (size_t i = 0; i < n; ++i) {
                dest[i] = src[i];

                /*
                 * the standard requires that nul characters
                 * are appended to the length of n, in case src is shorter
                 */
                if (src[i] == '\0') {
                        char *result = &dest[i];
                        for (++i; i < n; ++i) {
                                dest[i] = '\0';
                        }
                        return result;
                }
        }

        return &dest[n];
}

/**
 * Copy limited number of bytes in memory.
 *
 * @param dest Destination buffer.
 * @param src Source buffer.
 * @param c Character after which the copying shall stop.
 * @param n Number of bytes that shall be copied if not stopped earlier by c.
 * @return Pointer to the first byte after c in dest if found, NULL otherwise.
 */
void *memccpy(void *restrict dest, const void *restrict src, int c, size_t n)
{
        assert(dest != NULL);
        assert(src != NULL);

        unsigned char *bdest = dest;
        const unsigned char *bsrc = src;

        for (size_t i = 0; i < n; ++i) {
                bdest[i] = bsrc[i];

                if (bsrc[i] == (unsigned char) c) {
                        /* pointer to the next byte */
                        return &bdest[i + 1];
                }
        }

        return NULL;
}

/**
 * Duplicate a string.
 *
 * @param s String to be duplicated.
 * @return Newly allocated copy of the string.
 */
char *strdup(const char *s)
{
        return strndup(s, SIZE_MAX);
}

/**
 * Duplicate a specific number of bytes from a string.
 *
 * @param s String to be duplicated.
 * @param n Maximum length of the resulting string..
 * @return Newly allocated string copy of length at most n.
 */
char *strndup(const char *s, size_t n)
{
        assert(s != NULL);

        size_t len = strnlen(s, n);
        char *dup = malloc(len + 1);
        if (dup == NULL) {
                return NULL;
        }

        memcpy(dup, s, len);
        dup[len] = '\0';

        return dup;
}

/**
 * Scan string for a first occurence of a character.
 *
 * @param s String in which to look for the character.
 * @param c Character to look for.
 * @return Pointer to the specified character on success, pointer to the
 *     string terminator otherwise.
 */
char *gnu_strchrnul(const char *s, int c)
{
        assert(s != NULL);

        while (*s != c && *s != '\0') {
                s++;
        }

        return (char *) s;
}

/** Split string by delimiters.
 *
 * @param s             String to be tokenized. May not be NULL.
 * @param delim         String with the delimiters.
 * @param next          Variable which will receive the pointer to the
 *                      continuation of the string following the first
 *                      occurrence of any of the delimiter characters.
 *                      May be NULL.
 * @return              Pointer to the prefix of @a s before the first
 *                      delimiter character. NULL if no such prefix
 *                      exists.
 */
char *strtok_r(char *s, const char *delim, char **next)
{
        return __strtok_r(s, delim, next);
}

/**
 * Get error message string.
 *
 * @param errnum Error code for which to obtain human readable string.
 * @param buf Buffer to store a human readable string to.
 * @param bufsz Size of buffer pointed to by buf.
 * @return Zero on success, errno otherwise.
 */
int strerror_r(int errnum, char *buf, size_t bufsz)
{
        assert(buf != NULL);

        char *errstr = strerror(errnum);

        if (strlen(errstr) + 1 > bufsz) {
                return ERANGE;
        } else {
                strcpy(buf, errstr);
        }

        return EOK;
}

/**
 * Get limited length of the string.
 *
 * @param s String which length shall be determined.
 * @param n Maximum number of bytes that can be examined to determine length.
 * @return The lower of either string length or n limit.
 */
size_t strnlen(const char *s, size_t n)
{
        assert(s != NULL);

        for (size_t sz = 0; sz < n; ++sz) {

                if (s[sz] == '\0') {
                        return sz;
                }
        }

        return n;
}

/**
 * Get description of a signal.
 *
 * @param signum Signal number.
 * @return Human readable signal description.
 */
char *strsignal(int signum)
{
        static const char *const sigstrings[] = {
                [SIGABRT] = "SIGABRT (Process abort signal)",
                [SIGALRM] = "SIGALRM (Alarm clock)",
                [SIGBUS] = "SIGBUS (Access to an undefined portion of a memory object)",
                [SIGCHLD] = "SIGCHLD (Child process terminated, stopped, or continued)",
                [SIGCONT] = "SIGCONT (Continue executing, if stopped)",
                [SIGFPE] = "SIGFPE (Erroneous arithmetic operation)",
                [SIGHUP] = "SIGHUP (Hangup)",
                [SIGILL] = "SIGILL (Illegal instruction)",
                [SIGINT] = "SIGINT (Terminal interrupt signal)",
                [SIGKILL] = "SIGKILL (Kill process)",
                [SIGPIPE] = "SIGPIPE (Write on a pipe with no one to read it)",
                [SIGQUIT] = "SIGQUIT (Terminal quit signal)",
                [SIGSEGV] = "SIGSEGV (Invalid memory reference)",
                [SIGSTOP] = "SIGSTOP (Stop executing)",
                [SIGTERM] = "SIGTERM (Termination signal)",
                [SIGTSTP] = "SIGTSTP (Terminal stop signal)",
                [SIGTTIN] = "SIGTTIN (Background process attempting read)",
                [SIGTTOU] = "SIGTTOU (Background process attempting write)",
                [SIGUSR1] = "SIGUSR1 (User-defined signal 1)",
                [SIGUSR2] = "SIGUSR2 (User-defined signal 2)",
                [SIGPOLL] = "SIGPOLL (Pollable event)",
                [SIGPROF] = "SIGPROF (Profiling timer expired)",
                [SIGSYS] = "SIGSYS (Bad system call)",
                [SIGTRAP] = "SIGTRAP (Trace/breakpoint trap)",
                [SIGURG] = "SIGURG (High bandwidth data is available at a socket)",
                [SIGVTALRM] = "SIGVTALRM (Virtual timer expired)",
                [SIGXCPU] = "SIGXCPU (CPU time limit exceeded)",
                [SIGXFSZ] = "SIGXFSZ (File size limit exceeded)"
        };

        if (signum <= _TOP_SIGNAL) {
                return (char *) sigstrings[signum];
        }

        return (char *) "ERROR, Invalid signal number";
}

/** @}
 */