mdw@git.distorted.org.uk Git - mLib/blob - codec/codec.h

   1 /* -*-c-*-
   2  *
   3  * Abstract interface to codecs
   4  *
   5  * (c) 2009 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of the mLib utilities library.
  11  *
  12  * mLib is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * mLib is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with mLib; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 #ifndef MLIB_CODEC_H
  29 #define MLIB_CODEC_H
  30
  31 #ifdef __cplusplus
  32   extern "C" {
  33 #endif
  34
  35 /*----- Header files ------------------------------------------------------*/
  36
  37 #ifndef MLIB_DSTR_H
  38 #  include "dstr.h"
  39 #endif
  40
  41 /*----- Data structures ---------------------------------------------------*/
  42
  43 typedef struct codec {
  44   const struct codec_ops *ops;
  45 } codec;
  46
  47 typedef struct codec_class {
  48   const char *name;
  49   codec *(*encoder)(unsigned /*flags*/,
  50                     const char */*indent*/, unsigned /*maxline*/);
  51   codec *(*decoder)(unsigned /*flags*/);
  52
  53 #define CDCF_LOWERC 1u                  /* Prefer lower case */
  54 #define CDCF_IGNCASE 2u                 /* Ignore case on input */
  55 #define CDCF_NOEQPAD 4u                 /* No `=' padding */
  56 #define CDCF_IGNEQPAD 8u                /* Ignore `=' pad errors on input */
  57 #define CDCF_IGNEQMID 16u               /* Ignore pad chars on input */
  58 #define CDCF_IGNZPAD 32u                /* Ignore zero padding on input */
  59 #define CDCF_IGNNEWL 64u                /* Ignore newlines on input */
  60 #define CDCF_IGNINVCH 128u              /* Ignore invalid chars on input */
  61
  62 #define CDCF_IGNJUNK                    /* Ignore all bad things */     \
  63   (CDCF_IGNEQMID | CDCF_IGNZPAD |                                       \
  64    CDCF_IGNCASE | CDCF_IGNNEWL | CDCF_IGNINVCH)
  65
  66 } codec_class;
  67
  68 #define CODEC_ERRORS(_)                                                 \
  69   _(OK,         "No error")                                             \
  70   _(INVCH,      "Invalid character")                                    \
  71   _(INVEQPAD,   "Invalid padding character")                            \
  72   _(INVZPAD,    "Nonzero padding bits")
  73 enum {
  74 #define DECLERR(name, text) CDCERR_##name,
  75   CODEC_ERRORS(DECLERR)
  76 #undef DECLERR
  77   CDCERR__LIMIT
  78 };
  79
  80 typedef struct codec_ops {
  81   const codec_class *c;
  82   int (*code)(codec */*c*/, const void */*p*/, size_t /*sz*/, dstr */*d*/);
  83   void (*destroy)(codec */*c*/);
  84 } codec_ops;
  85
  86 /*----- Functions provided ------------------------------------------------*/
  87
  88 /* --- @codec_strerror@ --- *
  89  *
  90  * Arguments:   @int err@ = error code from codec
  91  *
  92  * Returns:     Pointer to error text.
  93  *
  94  * Use:         Converts error codes to human-readable strings.
  95  */
  96
  97 const char *codec_strerror(int /*err*/);
  98
  99 /*----- Null codec --------------------------------------------------------*/
 100
 101 extern const codec_class null_codec_class;
 102
 103 /*----- That's all, folks -------------------------------------------------*/
 104
 105 #ifdef __cplusplus
 106   }
 107 #endif
 108
 109 #endif