/////////////////////////////////////////////////////////////////////////////
// Name:        base64.h
// Purpose:     interface of global functions
// Author:      wxWidgets team
// RCS-ID:      $Id$
// Licence:     wxWindows license
/////////////////////////////////////////////////////////////////////////////


// ============================================================================
// Global functions/macros
// ============================================================================

/** @addtogroup group_funcmacro_misc */
//@{

/** 
    Elements of this enum specify the possible behaviours of wxBase64Decode
    when an invalid character is encountered.
*/
enum wxBase64DecodeMode
{
    wxBase64DecodeMode_Strict,  ///< Normal behaviour: stop at any invalid characters.
    wxBase64DecodeMode_SkipWS,  ///< Skip whitespace characters.
    wxBase64DecodeMode_Relaxed  ///< The most lenient behaviour: simply ignore all invalid characters.
};

/**
    This function encodes the given data using base64.

    To allocate the buffer of the correct size, use wxBase64EncodedSize() or
    call this function with @a dst set to @NULL -- it will then return the
    necessary buffer size.

    This raw encoding function overload writes the output string into the
    provided buffer; the other overloads return it as a wxString.

    @param dst
        The output buffer, may be @NULL to retrieve the needed buffer size.
    @param dstLen
        The output buffer size, ignored if dst is @NULL.
    @param src
        The input buffer, must not be @NULL.
    @param srcLen
        The length of the input data.

    @return @c wxCONV_FAILED if the output buffer is too small.

    @header{wx/base64.h}
*/
size_t wxBase64Encode(char* dst, size_t dstLen,
                      const void* src,
                      size_t srcLen);

/**
    This function encodes the given data using base64 and returns the output as
    a wxString.

    There is no error return.

    To allocate the buffer of the correct size, use wxBase64EncodedSize() or
    call this function with @a dst set to @NULL -- it will then return the
    necessary buffer size.

    @param src
        The input buffer, must not be @NULL.
    @param srcLen
        The length of the input data.

    @header{wx/base64.h}
*/
wxString wxBase64Encode(const void* src, size_t srcLen);

/**
    This function encodes the given data using base64 and returns the output as
    a wxString.

    There is no error return.

    @header{wx/base64.h}
*/
wxString wxBase64Encode(const wxMemoryBuffer& buf);


/**
    Returns the size of the buffer necessary to contain the data encoded in a
    base64 string of length @e srcLen. This can be useful for allocating a
    buffer to be passed to wxBase64Decode().

    @header{wx/base64.h}
*/
size_t wxBase64DecodedSize(size_t srcLen);

/**
    Returns the length of the string with base64 representation of a buffer of
    specified size @e len. This can be useful for allocating the buffer passed
    to wxBase64Encode().

    @header{wx/base64.h}
*/
size_t wxBase64EncodedSize(size_t len);

/**
    This function decodes a Base64-encoded string.

    This overload is a raw decoding function and decodes the data into the
    provided buffer @a dst of the given size @e dstLen. An error is returned if
    the buffer is not large enough -- that is not at least
    wxBase64DecodedSize(srcLen) bytes. Notice that the buffer will @e not be
    @NULL-terminated.

    This overload returns the number of bytes written to the buffer or the
    necessary buffer size if @a dst was @NULL or @c wxCONV_FAILED on error,
    e.g. if the output buffer is too small or invalid characters were
    encountered in the input string.

    @param dst
        Pointer to output buffer, may be @NULL to just compute the necessary
        buffer size.
    @param dstLen
        The size of the output buffer, ignored if dst is @NULL.
    @param src
        The input string, must not be @NULL. For the version using wxString,
        the input string should contain only ASCII characters.
    @param srcLen
        The length of the input string or special value wxNO_LEN if the string
        is @NULL-terminated and the length should be computed by this function
        itself.
    @param mode
        This parameter specifies the function behaviour when invalid characters
        are encountered in input. By default, any such character stops the
        decoding with error. If the mode is wxBase64DecodeMode_SkipWS, then the
        white space characters are silently skipped instead. And if it is
        wxBase64DecodeMode_Relaxed, then all invalid characters are skipped.
    @param posErr
        If this pointer is non-@NULL and an error occurs during decoding, it is
        filled with the index of the invalid character.

    @header{wx/base64.h}
*/
size_t wxBase64Decode(void* dst, size_t dstLen,
                      const char* src,
                      size_t srcLen = wxNO_LEN,
                      wxBase64DecodeMode mode = wxBase64DecodeMode_Strict,
                      size_t *posErr = NULL);

/**
    See the wxBase64Decode(void*,size_t,const char*,size_t,wxBase64DecodeMode,size_t*)
    overload for more info about the parameters of this function.

    This overload allocates memory internally and returns it as wxMemoryBuffer
    and is recommended for normal use.

    This overload returns a buffer with the base64 decoded binary equivalent
    of the input string. In neither case is the buffer @NULL-terminated.

    @header{wx/base64.h}
*/
wxMemoryBuffer wxBase64Decode(const char* src,
                              size_t srcLen = wxNO_LEN,
                              wxBase64DecodeMode mode = wxBase64DecodeMode_Strict,
                              size_t *posErr = NULL);

/**
    See the wxBase64Decode(void*,size_t,const char*,size_t,wxBase64DecodeMode,size_t*)
    overload for more info about the parameters of this function.

    This overload takes as input a wxString and returns the internally-allocated
    memory as a wxMemoryBuffer, containing the base64 decoded data.

    @header{wx/base64.h}
*/
wxMemoryBuffer wxBase64Decode(const wxString& src,
                              wxBase64DecodeMode mode = wxBase64DecodeMode_Strict,
                              size_t *posErr = NULL);

//@}