ucx/ucx/string.h

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2017 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.
 */
/**
 * Bounded string implementation.
 * 
 * The UCX strings (<code>sstr_t</code>) provide an alternative to C strings.
 * The main difference to C strings is, that <code>sstr_t</code> does <b>not
 * need to be <code>NULL</code>-terminated</b>. Instead the length is stored
 * within the structure.
 * 
 * When using <code>sstr_t</code>, developers must be full aware of what type
 * of string (<code>NULL</code>-terminated) or not) they are using, when 
 * accessing the <code>char* ptr</code> directly.
 * 
 * The UCX string module provides some common string functions, known from
 * standard libc, working with <code>sstr_t</code>.
 * 
 * @file   string.h
 * @author Mike Becker
 * @author Olaf Wintermann
 */

#ifndef UCX_STRING_H
#define	UCX_STRING_H

#include "ucx.h"
#include "allocator.h"
#include <stddef.h>

/*
 * Use this macro to disable the shortcuts if you experience macro collision.
 */
#ifndef UCX_NO_SSTR_SHORTCUTS
/**
 * Shortcut for a <code>sstr_t struct</code>
 * or <code>scstr_t struct</code> literal.
 */
#define ST(s) { s, sizeof(s)-1 }

/** Shortcut for the conversion of a C string to a <code>sstr_t</code>. */
#define S(s) sstrn(s, sizeof(s)-1)

/** Shortcut for the conversion of a C string to a <code>scstr_t</code>. */
#define SC(s) scstrn(s, sizeof(s)-1)
#endif /* UCX_NO_SSTR_SHORTCUTS */

/*
 * Use this macro to disable the format macros.
 */
#ifndef UCX_NO_SSTR_FORMAT_MACROS
/** Expands a sstr_t or scstr_t to printf arguments. */
#define SFMT(s) (int) (s).length, (s).ptr

/** Format specifier for a sstr_t or scstr_t. */
#define PRIsstr ".*s"
#endif /* UCX_NO_SSTR_FORMAT_MACROS */

#ifdef	__cplusplus
extern "C" {
#endif
/**
 * The UCX string structure.
 */
typedef struct {
   /** A pointer to the string
    * (<b>not necessarily <code>NULL</code>-terminated</b>) */
    char *ptr;
    /** The length of the string */
    size_t length;
} sstr_t;

/**
 * The UCX string structure for immutable (constant) strings.
 */
typedef struct {
    /** A constant pointer to the immutable string
     * (<b>not necessarily <code>NULL</code>-terminated</b>) */
    const char *ptr;
    /** The length of the string */
    size_t length;
} scstr_t;

#ifdef	__cplusplus
}
#endif


#ifdef __cplusplus
/**
 * One of two type adjustment functions that return a scstr_t.
 * 
 * Used <b>internally</b> to convert a UCX string to an immutable UCX string.
 * 
 * <b>Do not use this function manually.</b>
 * 
 * @param str some sstr_t
 * @return an immutable (scstr_t) version of the provided string.
 */
inline scstr_t s2scstr(sstr_t s) {
    scstr_t c;
    c.ptr = s.ptr;
    c.length = s.length;
    return c;
}

/**
 * One of two type adjustment functions that return a scstr_t.
 * 
 * Used <b>internally</b> to convert a UCX string to an immutable UCX string.
 * This variant is used, when the string is already immutable and no operation
 * needs to be performed.
 * 
 * <b>Do not use this function manually.</b>
 * 
 * @param str some scstr_t
 * @return the argument itself
 */
inline scstr_t s2scstr(scstr_t str) {
    return str;
}

/**
 * Converts a UCX string to an immutable UCX string (scstr_t).
 * @param str some UCX string
 * @return the an immutable version of the provided string
 */
#define SCSTR(s) s2scstr(s)
#else

/**
 * One of two type adjustment functions that return a scstr_t.
 * 
 * Used <b>internally</b> to convert a UCX string to an immutable UCX string.
 * This variant is used, when the string is already immutable and no operation
 * needs to be performed.
 * 
 * <b>Do not use this function manually.</b>
 * 
 * @param str some scstr_t
 * @return the argument itself
 */
scstr_t ucx_sc2sc(scstr_t str);

/**
 * One of two type adjustment functions that return a scstr_t.
 * 
 * Used <b>internally</b> to convert a UCX string to an immutable UCX string.
 * 
 * <b>Do not use this function manually.</b>
 * 
 * @param str some sstr_t
 * @return an immutable (scstr_t) version of the provided string.
 */
scstr_t ucx_ss2sc(sstr_t str);

#if __STDC_VERSION__ >= 201112L
/**
 * Converts a UCX string to an immutable UCX string (scstr_t).
 * @param str some UCX string
 * @return the an immutable version of the provided string
 */
#define SCSTR(str) _Generic(str, sstr_t: ucx_ss2sc, scstr_t: ucx_sc2sc)(str)

#elif defined(__GNUC__) || defined(__clang__)

/**
 * Converts a UCX string to an immutable UCX string (scstr_t).
 * @param str some UCX string
 * @return the an immutable version of the provided string
 */
#define SCSTR(str) __builtin_choose_expr( \
        __builtin_types_compatible_p(typeof(str), sstr_t), \
        ucx_ss2sc, \
        ucx_sc2sc)(str)

#elif defined(__sun)

/**
 * Converts a UCX string to an immutable UCX string (scstr_t).
 * @param str some UCX string
 * @return the an immutable version of the provided string
 */
#define SCSTR(str) ({typeof(str) ucx_tmp_var_str = str; \
	scstr_t ucx_tmp_var_c; \
	ucx_tmp_var_c.ptr = ucx_tmp_var_str.ptr;\
	ucx_tmp_var_c.length = ucx_tmp_var_str.length;\
	ucx_tmp_var_c; })
#else /* no generics and no builtins */

/**
 * Converts a UCX string to an immutable UCX string (scstr_t).
 * 
 * This <b>internal</b> function (ab)uses the C standard an expects one single
 * argument which is then implicitly converted to scstr_t without a warning.
 * 
 * <b>Do not use this function manually.</b>
 * 
 * @return the an immutable version of the provided string
 */
scstr_t ucx_ss2c_s();

/**
 * Converts a UCX string to an immutable UCX string (scstr_t).
 * @param str some UCX string
 * @return the an immutable version of the provided string
 */
#define SCSTR(str) ucx_ss2c_s(str)
#endif /* C11 feature test */

#endif /* C++ */

#ifdef	__cplusplus
extern "C" {
#endif


/**
 * Creates a new sstr_t based on a C string.
 * 
 * The length is implicitly inferred by using a call to <code>strlen()</code>.
 *
 * <b>Note:</b> the sstr_t will hold a <i>reference</i> to the C string. If you
 * do want a copy, use sstrdup() on the return value of this function.
 * 
 * If you need to wrap a constant string, use scstr().
 * 
 * @param cstring the C string to wrap
 * @return a new sstr_t containing the C string
 * 
 * @see sstrn()
 */
sstr_t sstr(char *cstring);

/**
 * Creates a new sstr_t of the specified length based on a C string.
 *
 * <b>Note:</b> the sstr_t will hold a <i>reference</i> to the C string. If you
 * do want a copy, use sstrdup() on the return value of this function.
 * 
 * If you need to wrap a constant string, use scstrn().
 * 
 * @param cstring  the C string to wrap
 * @param length   the length of the string
 * @return a new sstr_t containing the C string
 * 
 * @see sstr()
 * @see S()
 */
sstr_t sstrn(char *cstring, size_t length);

/**
 * Creates a new scstr_t based on a constant C string.
 * 
 * The length is implicitly inferred by using a call to <code>strlen()</code>.
 *
 * <b>Note:</b> the scstr_t will hold a <i>reference</i> to the C string. If you
 * do want a copy, use scstrdup() on the return value of this function.
 * 
 * @param cstring the C string to wrap
 * @return a new scstr_t containing the C string
 * 
 * @see scstrn()
 */
scstr_t scstr(const char *cstring);


/**
 * Creates a new scstr_t of the specified length based on a constant C string.
 *
 * <b>Note:</b> the scstr_t will hold a <i>reference</i> to the C string. If you
 * do want a copy, use scstrdup() on the return value of this function.
 * 
 * 
 * @param cstring  the C string to wrap
 * @param length   the length of the string
 * @return a new scstr_t containing the C string
 * 
 * @see scstr()
 */
scstr_t scstrn(const char *cstring, size_t length);

/**
 * Returns the cumulated length of all specified strings.
 * 
 * <b>Attention:</b> if the count argument does not match the count of the
 * specified strings, the behavior is undefined.
 *
 * @param count    the total number of specified strings (so at least 1)
 * @param ...      all strings
 * @return the cumulated length of all strings
 */
size_t scstrnlen(size_t count, ...);

/**
 * Alias for scstrnlen() which automatically converts the arguments.
 * 
 * @param count    the total number of specified strings (so at least 1)
 * @param ...      all strings
 * @return the cumulated length of all strings
 */
#define sstrnlen(count, ...) scstrnlen(count, __VA_ARGS__)

/**
 * Concatenates two or more strings.
 * 
 * The resulting string will be allocated by standard <code>malloc()</code>. 
 * So developers <b>MUST</b> pass the sstr_t.ptr to <code>free()</code>.
 * 
 * The sstr_t.ptr of the return value will <i>always</i> be <code>NULL</code>-
 * terminated.
 *
 * @param count   the total number of strings to concatenate
 * @param s1      first string
 * @param ...     all remaining strings
 * @return the concatenated string
 */
sstr_t scstrcat(size_t count, scstr_t s1, ...);

/**
 * Alias for scstrcat() which automatically converts the arguments.
 * 
 * @param count   the total number of strings to concatenate
 * @param s1      first string
 * @param ...     all remaining strings
 * @return the concatenated string
 */
#define sstrcat(count, s1, ...) scstrcat(count, SCSTR(s1), __VA_ARGS__)

/**
 * Concatenates two or more strings using a UcxAllocator.
 * 
 * See scstrcat() for details.
 *
 * @param a       the allocator to use
 * @param count   the total number of strings to concatenate
 * @param s1      first string
 * @param ...     all remaining strings
 * @return the concatenated string
 */
sstr_t scstrcat_a(UcxAllocator *a, size_t count, scstr_t s1, ...);

/**
 * Alias for scstrcat_a() which automatically converts the arguments.
 * 
 * See sstrcat() for details.
 *
 * @param a       the allocator to use
 * @param count   the total number of strings to concatenate
 * @param s1      first string
 * @param ...     all remaining strings
 * @return the concatenated string
 */
#define sstrcat_a(a, count, s1, ...) \
    scstrcat_a(a, count, SCSTR(s1), __VA_ARGS__)

/**
 * Returns a substring starting at the specified location.
 * 
 * <b>Attention:</b> the new string references the same memory area as the
 * input string and will <b>NOT</b> be <code>NULL</code>-terminated.
 * Use sstrdup() to get a copy.
 * 
 * @param string input string
 * @param start  start location of the substring
 * @return a substring of <code>string</code> starting at <code>start</code>
 * 
 * @see sstrsubsl()
 * @see sstrchr()
 */
sstr_t sstrsubs(sstr_t string, size_t start);

/**
 * Returns a substring with a maximum length starting at the specified location.
 * 
 * <b>Attention:</b> the new string references the same memory area as the
 * input string and will <b>NOT</b> be <code>NULL</code>-terminated.
 * Use sstrdup() to get a copy.
 * 
 * @param string input string
 * @param start  start location of the substring
 * @param length the maximum length of the substring
 * @return a substring of <code>string</code> starting at <code>start</code>
 * with a maximum length of <code>length</code>
 * 
 * @see sstrsubs()
 * @see sstrchr()
 */
sstr_t sstrsubsl(sstr_t string, size_t start, size_t length);

/**
 * Returns a substring of an immutable string starting at the specified
 * location.
 * 
 * <b>Attention:</b> the new string references the same memory area as the
 * input string and will <b>NOT</b> be <code>NULL</code>-terminated.
 * Use scstrdup() to get a copy.
 * 
 * @param string input string
 * @param start  start location of the substring
 * @return a substring of <code>string</code> starting at <code>start</code>
 * 
 * @see scstrsubsl()
 * @see scstrchr()
 */
scstr_t scstrsubs(scstr_t string, size_t start);

/**
 * Returns a substring of an immutable string with a maximum length starting
 * at the specified location.
 * 
 * <b>Attention:</b> the new string references the same memory area as the
 * input string and will <b>NOT</b> be <code>NULL</code>-terminated.
 * Use scstrdup() to get a copy.
 * 
 * @param string input string
 * @param start  start location of the substring
 * @param length the maximum length of the substring
 * @return a substring of <code>string</code> starting at <code>start</code>
 * with a maximum length of <code>length</code>
 * 
 * @see scstrsubs()
 * @see scstrchr()
 */
scstr_t scstrsubsl(scstr_t string, size_t start, size_t length);

/**
 * Returns a substring starting at the location of the first occurrence of the
 * specified character.
 * 
 * If the string does not contain the character, an empty string is returned.
 * 
 * @param string the string where to locate the character
 * @param chr    the character to locate
 * @return       a substring starting at the first location of <code>chr</code>
 * 
 * @see sstrsubs()
 */
sstr_t sstrchr(sstr_t string, int chr);

/**
 * Returns a substring starting at the location of the last occurrence of the
 * specified character.
 * 
 * If the string does not contain the character, an empty string is returned.
 * 
 * @param string the string where to locate the character
 * @param chr    the character to locate
 * @return       a substring starting at the last location of <code>chr</code>
 * 
 * @see sstrsubs()
 */
sstr_t sstrrchr(sstr_t string, int chr);

/**
 * Returns an immutable substring starting at the location of the first
 * occurrence of the specified character.
 * 
 * If the string does not contain the character, an empty string is returned.
 * 
 * @param string the string where to locate the character
 * @param chr    the character to locate
 * @return       a substring starting at the first location of <code>chr</code>
 * 
 * @see scstrsubs()
 */
scstr_t scstrchr(scstr_t string, int chr);

/**
 * Returns an immutable substring starting at the location of the last
 * occurrence of the specified character.
 * 
 * If the string does not contain the character, an empty string is returned.
 * 
 * @param string the string where to locate the character
 * @param chr    the character to locate
 * @return       a substring starting at the last location of <code>chr</code>
 * 
 * @see scstrsubs()
 */
scstr_t scstrrchr(scstr_t string, int chr);

/**
 * Returns a substring starting at the location of the first occurrence of the
 * specified string.
 * 
 * If the string does not contain the other string, an empty string is returned.
 * 
 * If <code>match</code> is an empty string, the complete <code>string</code> is
 * returned.
 * 
 * @param string the string to be scanned
 * @param match  string containing the sequence of characters to match
 * @return       a substring starting at the first occurrence of
 *               <code>match</code>, or an empty string, if the sequence is not
 *               present in <code>string</code>
 */
sstr_t scstrsstr(sstr_t string, scstr_t match);

/**
 * Alias for scstrsstr() which automatically converts the match string.
 * 
 * @param string the string to be scanned
 * @param match  string containing the sequence of characters to match
 * @return       a substring starting at the first occurrence of
 *               <code>match</code>, or an empty string, if the sequence is not
 *               present in <code>string</code>
 */
#define sstrstr(string, match) scstrsstr(string, SCSTR(match))

/**
 * Returns an immutable substring starting at the location of the
 * first occurrence of the specified immutable string.
 * 
 * If the string does not contain the other string, an empty string is returned.
 * 
 * If <code>match</code> is an empty string, the complete <code>string</code> is
 * returned.
 * 
 * @param string the string to be scanned
 * @param match  string containing the sequence of characters to match
 * @return       a substring starting at the first occurrence of
 *               <code>match</code>, or an empty string, if the sequence is not
 *               present in <code>string</code>
 */
scstr_t scstrscstr(scstr_t string, scstr_t match);

/**
 * Alias for scstrscstr() which automatically converts the match string.
 * 
 * @param string the string to be scanned
 * @param match  string containing the sequence of characters to match
 * @return       a substring starting at the first occurrence of
 *               <code>match</code>, or an empty string, if the sequence is not
 *               present in <code>string</code>
 */
#define sstrscstr(string, match) scstrscstr(string, SCSTR(match))

/**
 * Splits a string into parts by using a delimiter string.
 * 
 * This function will return <code>NULL</code>, if one of the following happens:
 * <ul>
 *   <li>the string length is zero</li>
 *   <li>the delimeter length is zero</li>
 *   <li>the string equals the delimeter</li>
 *   <li>memory allocation fails</li>
 * </ul>
 * 
 * The integer referenced by <code>count</code> is used as input and determines
 * the maximum size of the resulting array, i.e. the maximum count of splits to
 * perform + 1.
 * 
 * The integer referenced by <code>count</code> is also used as output and is
 * set to
 * <ul>
 *   <li>-2, on memory allocation errors</li>
 *   <li>-1, if either the string or the delimiter is an empty string</li>
 *   <li>0, if the string equals the delimiter</li>
 *   <li>1, if the string does not contain the delimiter</li>
 *   <li>the count of array items, otherwise</li>
 * </ul>
 * 
 * If the string starts with the delimiter, the first item of the resulting
 * array will be an empty string.
 * 
 * If the string ends with the delimiter and the maximum list size is not
 * exceeded, the last array item will be an empty string.
 * In case the list size would be exceeded, the last array item will be the
 * remaining string after the last split, <i>including</i> the terminating
 * delimiter.
 * 
 * <b>Attention:</b> The array pointer <b>AND</b> all sstr_t.ptr of the array
 * items must be manually passed to <code>free()</code>. Use sstrsplit_a() with
 * an allocator to managed memory, to avoid this.
 *
 * @param string the string to split
 * @param delim  the delimiter string
 * @param count  IN: the maximum size of the resulting array (0 = no limit),
 *               OUT: the actual size of the array
 * @return a sstr_t array containing the split strings or
 * <code>NULL</code> on error
 * 
 * @see scstrsplit_a()
 */
sstr_t* scstrsplit(scstr_t string, scstr_t delim, ssize_t *count);

/**
 * Alias for scstrsplit() which automatically converts the arguments.
 * 
 * @param string the string to split
 * @param delim  the delimiter string
 * @param count  IN: the maximum size of the resulting array (0 = no limit),
 *               OUT: the actual size of the array
 * @return a sstr_t array containing the split strings or
 * <code>NULL</code> on error
 * 
 * @see sstrsplit_a()
 */
#define sstrsplit(string, delim, count) \
    scstrsplit(SCSTR(string), SCSTR(delim), count)

/**
 * Performing scstrsplit() using a UcxAllocator.
 * 
 * <i>Read the description of scstrsplit() for details.</i>
 * 
 * The memory for the sstr_t.ptr pointers of the array items and the memory for
 * the sstr_t array itself are allocated by using the UcxAllocator.malloc()
 * function.
 * 
 * <b>Note:</b> the allocator is not used for memory that is freed within the
 * same call of this function (locally scoped variables).
 * 
 * @param allocator the UcxAllocator used for allocating memory
 * @param string the string to split
 * @param delim  the delimiter string
 * @param count  IN: the maximum size of the resulting array (0 = no limit),
 *               OUT: the actual size of the array
 * @return a sstr_t array containing the split strings or
 * <code>NULL</code> on error
 * 
 * @see scstrsplit()
 */
sstr_t* scstrsplit_a(UcxAllocator *allocator, scstr_t string, scstr_t delim,
        ssize_t *count);

/**
 * Alias for scstrsplit_a() which automatically converts the arguments.
 * 
 * @param allocator the UcxAllocator used for allocating memory
 * @param string the string to split
 * @param delim  the delimiter string
 * @param count  IN: the maximum size of the resulting array (0 = no limit),
 *               OUT: the actual size of the array
 * @return a sstr_t array containing the split strings or
 * <code>NULL</code> on error
 * 
 * @see sstrsplit()
 */
#define sstrsplit_a(allocator, string, delim, count) \
    scstrsplit_a(allocator, SCSTR(string), SCSTR(delim), count)

/**
 * Compares two UCX strings with standard <code>memcmp()</code>.
 * 
 * At first it compares the scstr_t.length attribute of the two strings. The
 * <code>memcmp()</code> function is called, if and only if the lengths match.
 * 
 * @param s1 the first string
 * @param s2 the second string
 * @return -1, if the length of s1 is less than the length of s2 or 1, if the 
 * length of s1 is greater than the length of s2 or the result of
 * <code>memcmp()</code> otherwise (i.e. 0 if the strings match)
 */
int scstrcmp(scstr_t s1, scstr_t s2);

/**
 * Alias for scstrcmp() which automatically converts its arguments.
 * 
 * @param s1 the first string
 * @param s2 the second string
 * @return -1, if the length of s1 is less than the length of s2 or 1, if the 
 * length of s1 is greater than the length of s2 or the result of
 * <code>memcmp()</code> otherwise (i.e. 0 if the strings match)
 */
#define sstrcmp(s1, s2) scstrcmp(SCSTR(s1), SCSTR(s2))

/**
 * Compares two UCX strings ignoring the case.
 * 
 * At first it compares the scstr_t.length attribute of the two strings. If and
 * only if the lengths match, both strings are compared char by char ignoring
 * the case.
 * 
 * @param s1 the first string
 * @param s2 the second string
 * @return -1, if the length of s1 is less than the length of s2 or 1, if the 
 * length of s1 is greater than the length of s2 or the result of the platform
 * specific string comparison function ignoring the case.
 */
int scstrcasecmp(scstr_t s1, scstr_t s2);

/**
 * Alias for scstrcasecmp() which automatically converts the arguments.
 * 
 * @param s1 the first string
 * @param s2 the second string
 * @return -1, if the length of s1 is less than the length of s2 or 1, if the 
 * length of s1 is greater than the length of s2 or the result of the platform
 * specific string comparison function ignoring the case.
 */
#define sstrcasecmp(s1, s2) scstrcasecmp(SCSTR(s1), SCSTR(s2))

/**
 * Creates a duplicate of the specified string.
 * 
 * The new sstr_t will contain a copy allocated by standard
 * <code>malloc()</code>. So developers <b>MUST</b> pass the sstr_t.ptr to
 * <code>free()</code>.
 * 
 * The sstr_t.ptr of the return value will <i>always</i> be <code>NULL</code>-
 * terminated and mutable, regardless of the argument.
 * 
 * @param string the string to duplicate
 * @return a duplicate of the string
 * @see scstrdup_a()
 */
sstr_t scstrdup(scstr_t string);

/**
 * Alias for scstrdup() which automatically converts the argument.
 * 
 * @param string the string to duplicate
 * @return a duplicate of the string
 * @see sstrdup_a()
 */
#define sstrdup(string) scstrdup(SCSTR(string))

/**
 * Creates a duplicate of the specified string using a UcxAllocator.
 * 
 * The new sstr_t will contain a copy allocated by the allocators
 * UcxAllocator.malloc() function. So it is implementation depended, whether the
 * returned sstr_t.ptr pointer must be passed to the allocators
 * UcxAllocator.free() function manually.
 * 
 * The sstr_t.ptr of the return value will <i>always</i> be <code>NULL</code>-
 * terminated and mutable, regardless of the argument.
 * 
 * @param allocator a valid instance of a UcxAllocator
 * @param string the string to duplicate
 * @return a duplicate of the string
 * @see scstrdup()
 */
sstr_t scstrdup_a(UcxAllocator *allocator, scstr_t string);

/**
 * Alias for scstrdup_a() which automatically converts the argument.
 * 
 * @param allocator a valid instance of a UcxAllocator
 * @param string the string to duplicate
 * @return a duplicate of the string
 * @see scstrdup()
 */
#define sstrdup_a(allocator, string) scstrdup_a(allocator, SCSTR(string))


/**
 * Omits leading and trailing spaces.
 * 
 * This function returns a new sstr_t containing a trimmed version of the
 * specified string.
 * 
 * <b>Note:</b> the new sstr_t references the same memory, thus you
 * <b>MUST NOT</b> pass the sstr_t.ptr of the return value to
 * <code>free()</code>. It is also highly recommended to avoid assignments like
 * <code>mystr = sstrtrim(mystr);</code> as you lose the reference to the
 * source string. Assignments of this type are only permitted, if the
 * sstr_t.ptr of the source string does not need to be freed or if another
 * reference to the source string exists.
 * 
 * @param string the string that shall be trimmed
 * @return a new sstr_t containing the trimmed string
 */
sstr_t sstrtrim(sstr_t string);

/**
 * Omits leading and trailing spaces.
 * 
 * This function returns a new scstr_t containing a trimmed version of the
 * specified string.
 * 
 * <b>Note:</b> the new scstr_t references the same memory, thus you
 * <b>MUST NOT</b> pass the scstr_t.ptr of the return value to
 * <code>free()</code>. It is also highly recommended to avoid assignments like
 * <code>mystr = scstrtrim(mystr);</code> as you lose the reference to the
 * source string. Assignments of this type are only permitted, if the
 * scstr_t.ptr of the source string does not need to be freed or if another
 * reference to the source string exists.
 * 
 * @param string the string that shall be trimmed
 * @return a new scstr_t containing the trimmed string
 */
scstr_t scstrtrim(scstr_t string);

/**
 * Checks, if a string has a specific prefix.
 * @param string the string to check
 * @param prefix the prefix the string should have
 * @return 1, if and only if the string has the specified prefix, 0 otherwise
 */
int scstrprefix(scstr_t string, scstr_t prefix);

/**
 * Alias for scstrprefix() which automatically converts the arguments.
 * 
 * @param string the string to check
 * @param prefix the prefix the string should have
 * @return 1, if and only if the string has the specified prefix, 0 otherwise
 */
#define sstrprefix(string, prefix) scstrprefix(SCSTR(string), SCSTR(prefix))

/**
 * Checks, if a string has a specific suffix.
 * @param string the string to check
 * @param suffix the suffix the string should have
 * @return 1, if and only if the string has the specified suffix, 0 otherwise
 */
int scstrsuffix(scstr_t string, scstr_t suffix);

/**
 * Alias for scstrsuffix() which automatically converts the arguments.
 *
 * @param string the string to check
 * @param suffix the suffix the string should have
 * @return 1, if and only if the string has the specified suffix, 0 otherwise
 */
#define sstrsuffix(string, suffix) scstrsuffix(SCSTR(string), SCSTR(suffix))

/**
 * Returns a lower case version of a string.
 * 
 * This function creates a duplicate of the input string, first. See the
 * documentation of scstrdup() for the implications.
 * 
 * @param string the input string
 * @return the resulting lower case string
 * @see scstrdup()
 */
sstr_t scstrlower(scstr_t string);

/**
 * Alias for scstrlower() which automatically converts the argument.
 * 
 * @param string the input string
 * @return the resulting lower case string
 */
#define sstrlower(string) scstrlower(SCSTR(string))

/**
 * Returns a lower case version of a string.
 * 
 * This function creates a duplicate of the input string, first. See the
 * documentation of scstrdup_a() for the implications.
 * 
 * @param allocator the allocator used for duplicating the string
 * @param string the input string
 * @return the resulting lower case string
 * @see scstrdup_a()
 */
sstr_t scstrlower_a(UcxAllocator *allocator, scstr_t string);


/**
 * Alias for scstrlower_a() which automatically converts the argument.
 * 
 * @param allocator the allocator used for duplicating the string
 * @param string the input string
 * @return the resulting lower case string
 */
#define sstrlower_a(allocator, string) scstrlower_a(allocator, SCSTR(string))

/**
 * Returns a upper case version of a string.
 * 
 * This function creates a duplicate of the input string, first. See the
 * documentation of scstrdup() for the implications.
 * 
 * @param string the input string
 * @return the resulting upper case string
 * @see scstrdup()
 */
sstr_t scstrupper(scstr_t string);

/**
 * Alias for scstrupper() which automatically converts the argument.
 * 
 * @param string the input string
 * @return the resulting upper case string
 */
#define sstrupper(string) scstrupper(SCSTR(string))

/**
 * Returns a upper case version of a string.
 * 
 * This function creates a duplicate of the input string, first. See the
 * documentation of scstrdup_a() for the implications.
 * 
 * @param allocator the allocator used for duplicating the string
 * @param string the input string
 * @return the resulting upper case string
 * @see scstrdup_a()
 */
sstr_t scstrupper_a(UcxAllocator *allocator, scstr_t string);

/**
 * Alias for scstrupper_a() which automatically converts the argument.
 * 
 * @param allocator the allocator used for duplicating the string
 * @param string the input string
 * @return the resulting upper case string
 */
#define sstrupper_a(allocator, string) scstrupper_a(allocator, string)

#ifdef	__cplusplus
}
#endif

#endif	/* UCX_STRING_H */