/*
* libZRTP SDK library, implements the ZRTP secure VoIP protocol.
* Copyright (c) 2006-2009 Philip R. Zimmermann. All rights reserved.
* Contact: http://philzimmermann.com
* For licensing and other legal details, see the file zrtp_legal.c.
*
* Viktor Krykun <v.krikun at zfoneproject.com>
*/
#ifndef __ZRTP_STRING_H__
#define __ZRTP_STRING_H__
#include "zrtp_config.h"
/**
* \file zrtp_strings.h
* \brief libzrtp safe strings
*/
/*============================================================================*/
/* Libzrtp Strings */
/*============================================================================*/
#define ZRTP_STRING8 12
#define ZRTP_STRING16 20
#define ZRTP_STRING32 36
#define ZRTP_STRING64 68
#define ZRTP_STRING128 132
#define ZRTP_STRING256 260
#define ZRTP_STRING1024 1028
#if ( ZRTP_PLATFORM != ZP_SYMBIAN )
#pragma pack(push, 1)
#endif
typedef struct zrtp_stringn
{
uint16_t length;
uint16_t max_length;
char buffer[0];
} zrtp_stringn_t;
typedef struct zrtp_string8
{
uint16_t length;
uint16_t max_length;
char buffer[ZRTP_STRING8];
} zrtp_string8_t;
typedef struct zrtp_string16
{
uint16_t length;
uint16_t max_length;
char buffer[ZRTP_STRING16];
} zrtp_string16_t;
typedef struct zrtp_string32
{
uint16_t length;
uint16_t max_length;
char buffer[ZRTP_STRING32];
} zrtp_string32_t;
typedef struct zrtp_string64
{
uint16_t length;
uint16_t max_length;
char buffer[ZRTP_STRING64];
} zrtp_string64_t;
typedef struct zrtp_string128
{
uint16_t length;
uint16_t max_length;
char buffer[ZRTP_STRING128];
} zrtp_string128_t;
typedef struct zrtp_string256
{
uint16_t length;
uint16_t max_length;
char buffer[ZRTP_STRING256];
} zrtp_string256_t;
typedef struct zrtp_string1024
{
uint16_t length;
uint16_t max_length;
char buffer[ZRTP_STRING1024];
} zrtp_string1024_t;
#if ( ZRTP_PLATFORM != ZP_SYMBIAN )
#pragma pack(pop)
#endif
/**
* \defgroup zrtp_strings Libzrtp Safe Strings
*
* Using standard C-like strings is potentially dangerous in any program. All standard functions for
* working with c-strings rely on zero-termination, since c-strings don't contain a representation
* of their length. This can cause many mistakes. Moreover, it is impossible to use these strings
* for storing binary data.
*
* To solve these problems libzrtp uses zstrings instead of normal c-strings. A zstring is just a
* wrapped c-string that stores its own length. Use the following data types, macros and utility
* functions for working with zstrings in your applications.
*
* zstrings are easy to use, and at the same time light-weight and flexible.
* We use two groups of zstring types:
* \li zrtp_stringn_t - base type for all operations with zstrings;
* \li zrtp_stringXX_t group - storage types.
*
* One can use any zrtp_stringXX_t type (big enough to store necessary data) esired and operate with
* it using global zstring functions. To cast zrtp_stringXX_t to zrtp_stringn_t, the \ref ZSTR_GV
* and \ref ZSTR_GVP macros can be used.
*
* The main principle of running zstrings is storing its current data size. So to avoid mistakes and
* mess it is advised to use preestablished initialization macros. The description of each follows.
* \{
*/
/**
* \brief Casts zrtp_stringXX_t to a pointer to zrtp_stringn_t.
*
* This macro prevents static casts caused by using zstring functions. Prevents mistakes and makes
* zstrings safer to use.
* \sa ZSTR_GVP
*/
#define ZSTR_GV(pstr) \
(zrtp_stringn_t*)((char*)pstr.buffer - sizeof(pstr.max_length) - sizeof(pstr.length))
/**
* \brief Casts zrtp_stringXX_t* to a pointer to zrtp_stringn_t.
*
* This macro prevents static casts from using zstring functions.
* \sa ZSTR_GV
*/
#define ZSTR_GVP(pstr) \
(zrtp_stringn_t*)((char*)pstr->buffer - sizeof(pstr->max_length) - sizeof(pstr->length))
/**
* \brief Macro for empty zstring initialization
* \warning Use this macro on every zrtp_string structure allocation.
* usage: \code zrtp_string_t zstr = ZSTR_INIT_EMPTY(zstr); \endcode
*/
#define ZSTR_INIT_EMPTY(a) { 0, sizeof(a.buffer) - 1, { 0 }}
/**
* \brief Macro for zstring initialization from a constant C-string
* usage: \code zrtp_string_t zstr = ZSTR_INIT_WITH_CONST_CSTRING("zstring use example"); \endcode
*/
#define ZSTR_INIT_WITH_CONST_CSTRING(s) {sizeof(s) - 1, 0, s}
/**
* \brief Macro for zstring clearing
*
* Use this macro for initializing already created zstrings
* usage: \code ZSTR_SET_EMPTY(zstr); \endcode
*/
#define ZSTR_SET_EMPTY(a)\
{ a.length = 0; a.max_length = sizeof(a.buffer) - 1; a.buffer[0] = 0; }
#if defined(__cplusplus)
extern "C"
{
#endif
/**
* \brief compare two zstrings
*
* Function compares the two strings left and right.
* \param left - one string for comparing;
* \param right - the other string for comparing.
* \return
* - -1 if left string less than right;
* - 0 if left string is equal to right;
* - 1 if left string greater than right.
*/
int zrtp_zstrcmp(const zrtp_stringn_t *left, const zrtp_stringn_t *right);
/**
* \brief Copy a zstring
*
* The zrtp_zstrcpy function copies the string pointed by src to the structure pointed to by dst.
* \param src source string;
* \param dst destination string.
*/
void zrtp_zstrcpy(zrtp_stringn_t *dst, const zrtp_stringn_t *src);
/**
* \brief Copy first N bytes of zstring
*
* The zrtp_zstrncpy function copies the first N bytes from the string pointed to by src to the
* structure pointed by dst.
* \param src - source string;
* \param dst - destination string;
* \param size - nuber of bytes to copy.
*/
void zrtp_zstrncpy(zrtp_stringn_t *dst, const zrtp_stringn_t *src, uint16_t size);
/**
* @brief Copy a c-string into a z-string
* \param dst - destination zsyring
* \param src - source c-string to be copied.
*/
void zrtp_zstrcpyc(zrtp_stringn_t *dst, const char *src);
/**
* \brief Copy first N bytes of a c-string into a z-string
* \param dst - destination zsyring
* \param src - source c-string to be copied.
* \param size - number of bytes to be copied from \c src to \c dst
*/
void zrtp_zstrncpyc(zrtp_stringn_t *dst, const char *src, uint16_t size);
/**
* \brief Concatenate two strings
*
* The zrtp_zstrcat function appends the src string to the dst string. If dst string doesn't have
* enough space it will be truncated.
* \param src source string;
* \param dst destination string.
*/
void zrtp_zstrcat(zrtp_stringn_t *dst, const zrtp_stringn_t *src);
/**
* \brief Clear a zstring
* \param zstr - string for clearing;
*/
void zrtp_wipe_zstring(zrtp_stringn_t *zstr);
/**
* \brief Compare two binary strings
*
* This function is used to prevent errors caused by other, non byte-to-byte comparison
* implementations. The secret sorting function is sensitive to such things.
*
* \param s1 - first string for comparison
* \param s2 - second string for comparison
* \param n - number of bytes to be compared
* \return - an integer less than, equal to, or greater than zero, if the first n bytes of s1
* is found, respectively, to be less than, to match, or to be greater than the first n bytes of s2.
*/
int zrtp_memcmp(const void* s1, const void* s2, uint32_t n);
/**
* \brief Converts binary data to the hex string representation
*
* \param bin - pointer to the binary buffer for converting;
* \param bin_size - binary data size;
* \param buff - destination buffer;
* \param buff_size - destination buffer size.
* \return
* - pointer to the buff with converted data;
* - "Buffer too small" in case of error.
*/
const char* hex2str(const char* bin, int bin_size, char* buff, int buff_size);
/**
* \brief Converts hex string to the binary representation
*
* \param buff - source buffer for converting;
* \param buff_size - source buffer size;
* \param bin - pointer to the destination binary buffer;
* \param bin_size - binary data size;
* \return
* - pointer to the buff with converted data, or NULL in case of error.
*/
char *str2hex(const char* buff, int buff_size, char* bin, int bin_size);
#if defined(__cplusplus)
}
#endif
/** \} */
#endif /* __ZRTP_STRING_H__ */