string.c

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/*-------------------------------------------------------------------------
 *
 * string.c
 *      string handling helpers
 *
 *
 * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    src/common/string.c
 *
 *-------------------------------------------------------------------------
 */


#ifndef FRONTEND
#include "postgres.h"
#else
#include "postgres_fe.h"
#endif

#include "common/string.h"


/*
 * Returns whether the string `str' has the postfix `end'.
 */
bool
pg_str_endswith(const char *str, const char *end)
{
    size_t      slen = strlen(str);
    size_t      elen = strlen(end);

    /* can't be a postfix if longer */
    if (elen > slen)
        return false;

    /* compare the end of the strings */
    str += slen - elen;
    return strcmp(str, end) == 0;
}


/*
 * strtoint --- just like strtol, but returns int not long
 */
int
strtoint(const char *pg_restrict str, char **pg_restrict endptr, int base)
{
    long        val;

    val = strtol(str, endptr, base);
    if (val != (int) val)
        errno = ERANGE;
    return (int) val;
}


/*
 * pg_clean_ascii -- Replace any non-ASCII chars with a '?' char
 *
 * Modifies the string passed in which must be '\0'-terminated.
 *
 * This function exists specifically to deal with filtering out
 * non-ASCII characters in a few places where the client can provide an almost
 * arbitrary string (and it isn't checked to ensure it's a valid username or
 * database name or similar) and we don't want to have control characters or other
 * things ending up in the log file where server admins might end up with a
 * messed up terminal when looking at them.
 *
 * In general, this function should NOT be used- instead, consider how to handle
 * the string without needing to filter out the non-ASCII characters.
 *
 * Ultimately, we'd like to improve the situation to not require stripping out
 * all non-ASCII but perform more intelligent filtering which would allow UTF or
 * similar, but it's unclear exactly what we should allow, so stick to ASCII only
 * for now.
 */
void
pg_clean_ascii(char *str)
{
    /* Only allow clean ASCII chars in the string */
    char       *p;

    for (p = str; *p != '\0'; p++)
    {
        if (*p < 32 || *p > 126)
            *p = '?';
    }
}


/*
 * pg_is_ascii -- Check if string is made only of ASCII characters
 */
bool
pg_is_ascii(const char *str)
{
    while (*str)
    {
        if (IS_HIGHBIT_SET(*str))
            return false;
        str++;
    }
    return true;
}


/*
 * pg_strip_crlf -- Remove any trailing newline and carriage return
 *
 * Removes any trailing newline and carriage return characters (\r on
 * Windows) in the input string, zero-terminating it.
 *
 * The passed in string must be zero-terminated.  This function returns
 * the new length of the string.
 */
int
pg_strip_crlf(char *str)
{
    int         len = strlen(str);

    while (len > 0 && (str[len - 1] == '\n' ||
                       str[len - 1] == '\r'))
        str[--len] = '\0';

    return len;
}