src/ucx/string.h

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2013 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>

/** Shortcut for a <code>sstr_t struct</code> literal. */
#define ST(s) { (char*)s, sizeof(s)-1 }

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

#ifdef	__cplusplus
extern "C" {
#endif

/**
 * The UCX string structure.
 */
typedef struct {
   /** A reference to the string (<b>not necessarily  <code>NULL</code>
    * -terminated</b>) */
    char   *ptr;
    /** The length of the string */
    size_t length;
} sstr_t;

/**
 * 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.
 * 
 * @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.
 * 
 * @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);


/**
 * Returns the cumulated length of all specified strings.
 *
 * At least one string must be specified.
 * 
 * <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 string   the first string
 * @param ...      all other strings
 * @return the cumulated length of all strings
 */
size_t sstrnlen(size_t count, sstr_t string, ...);


/**
 * Concatenates strings.
 * 
 * At least one string must be specified and there must be enough memory
 * available referenced by the destination sstr_t.ptr for this function to
 * successfully concatenate all specified strings.
 * 
 * The sstr_t.length of the destination string specifies the capacity and
 * should match the total memory available referenced by the destination
 * sstr_t.ptr. This function <i>never</i> copies data beyond the capacity and
 * does not modify any of the source strings.
 * 
 * <b>Attention:</b>
 * <ul>
 *   <li>Any content in the destination string will be overwritten</li>
 *   <li>The destination sstr_t.ptr is <b>NOT</b>
 *       <code>NULL</code>-terminated</li>
 *   <li>The destination sstr_t.length is set to the total length of the
 *       concatenated strings</li>
 *   <li><i>Hint:</i> get a <code>NULL</code>-terminated string by performing
 *       <code>mystring.ptr[mystring.length]='\0'</code> after calling this
 *       function</li>
 * </ul>
 *
 * @param dest    new sstr_t with capacity information and allocated memory
 * @param count   the total number of strings to concatenate
 * @param src     the first string
 * @param ...     all other strings
 * @return the argument for <code>dest</code> is returned
 */
sstr_t sstrncat(sstr_t dest, size_t count, sstr_t src, ...);


/**
 * 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 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);

/**
 * 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 list, 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 list items, otherwise</li>
 * </ul>
 * 
 * If the string starts with the delimiter, the first item of the resulting
 * list will be an empty string.
 * 
 * If the string ends with the delimiter and the maximum list size is not
 * exceeded, the last list item will be an empty string.
 * 
 * <b>Attention:</b> All list items <b>AND</b> all sstr_t.ptr of the list
 * 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 list (0 for an
 *               unbounded list), OUT: the actual size of the list
 * @return a list of the split strings as sstr_t array or
 *         <code>NULL</code> on error
 * 
 * @see sstrsplit_a()
 */
sstr_t* sstrsplit(sstr_t string, sstr_t delim, size_t *count);

/**
 * Performing sstrsplit() using an UcxAllocator.
 * 
 * <i>Read the description of sstrsplit() for details.</i>
 * 
 * The memory for the sstr_t.ptr pointers of the list 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 list (0 for an
 *               unbounded list), OUT: the actual size of the list
 * @return a list of the split strings as sstr_t array or
 *         <code>NULL</code> on error
 * 
 * @see sstrsplit()
 */
sstr_t* sstrsplit_a(UcxAllocator *allocator, sstr_t string, sstr_t delim,
        size_t *count);

/**
 * Compares two UCX strings with standard <code>memcmp()</code>.
 * 
 * At first it compares the sstr_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 sstrcmp(sstr_t s1, sstr_t s2);

/**
 * Compares two UCX strings ignoring the case.
 * 
 * At first it compares the sstr_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 difference between the
 * first two differing characters otherwise (i.e. 0 if the strings match and
 * no characters differ)
 */
int sstrcasecmp(sstr_t s1, sstr_t 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.
 * 
 * @param string the string to duplicate
 * @return a duplicate of the string
 * @see sstrdup_a()
 */
sstr_t sstrdup(sstr_t string);

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

/**
 * 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 sstrprefix(sstr_t string, sstr_t 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 sstrsuffix(sstr_t string, sstr_t suffix);

#ifdef	__cplusplus
}
#endif

#endif	/* UCX_STRING_H */