mdw@git.distorted.org.uk Git - disorder/blob - lib/sink.h

   1 /*
   2  * This file is part of DisOrder
   3  * Copyright (C) 2004, 2007, 2008, 2013 Richard Kettlewell
   4  *
   5  * This program is free software: you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation, either version 3 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18 /** @file lib/sink.h
  19  * @brief Abstract output sink type
  20  */
  21
  22 #ifndef SINK_H
  23 #define SINK_H
  24
  25 #include <stdarg.h>
  26
  27 struct dynstr;
  28
  29 /** @brief Sink type
  30  *
  31  * A sink is something you write bytes to; the opposite would be a
  32  * source.  We provide sink_stdio() and sink_dynstr() to create sinks
  33  * to write to stdio streams and dynamic strings.
  34  */
  35 struct sink {
  36   /** @brief Write callback
  37    * @param s Sink to write to
  38    * @param buffer First byte to write
  39    * @param nbytes Number of bytes to write
  40    * @return non-negative on success, -1 on error
  41    */
  42   int (*write)(struct sink *s, const void *buffer, int nbytes);
  43
  44   /** @brief Flush callback
  45    * @param s Sink to write to
  46    * @return non-negative on success, -1 on error
  47    */
  48   int (*flush)(struct sink *s);
  49
  50   /** @brief Error callback
  51    * @param s Sink
  52    * @return Last error code
  53    */
  54   int (*error)(struct sink *s);
  55
  56   enum error_class eclass;
  57 };
  58
  59 struct sink *sink_stdio(const char *name, FILE *fp);
  60 /* return a sink which writes to @fp@.  If @name@ is not a null
  61  * pointer, it will be used in (fatal) error messages; if it is a null
  62  * pointer then errors will be signalled by returning -1. */
  63
  64 struct sink *sink_dynstr(struct dynstr *output);
  65 /* return a sink which appends to @output@. */
  66
  67 struct sink *sink_discard(void);
  68 /* return a sink which junks everything */
  69
  70 struct sink *sink_error(void);
  71 /* return a sink which fails all writes */
  72
  73 int sink_vprintf(struct sink *s, const char *fmt, va_list ap);
  74 int sink_printf(struct sink *s, const char *fmt, ...)
  75   attribute((format (printf, 2, 3)));
  76 /* equivalent of vfprintf/fprintf for sink @s@ */
  77
  78 /** @brief Write bytes to a sink
  79  * @param s Sink to write to
  80  * @param buffer First byte to write
  81  * @param nbytes Number of bytes to write
  82  * @return non-negative on success, -1 on error
  83  */
  84 static inline int sink_write(struct sink *s, const void *buffer, int nbytes) {
  85   return s->write(s, buffer, nbytes);
  86 }
  87
  88 /** @brief Write string to a sink
  89  * @param s Sink to write to
  90  * @param str String to write
  91  * @return non-negative on success, -1 on error
  92  */
  93 static inline int sink_writes(struct sink *s, const char *str) {
  94   return s->write(s, str, strlen(str));
  95 }
  96
  97 static inline int sink_flush(struct sink *s) {
  98   return s->flush(s);
  99 }
 100
 101 /** @brief Write one byte to a sink
 102  * @param s Sink to write to
 103  * @param c Byte to write (as a @c char)
 104  * @return non-negative on success, -1 on error
 105  */
 106 static inline int sink_writec(struct sink *s, char c) {
 107   return s->write(s, &c, 1);
 108 }
 109
 110 static inline int sink_err(struct sink *s) {
 111   return s->error(s);
 112 }
 113
 114 #endif /* SINK_H */
 115
 116 /*
 117 Local Variables:
 118 c-basic-offset:2
 119 comment-column:40
 120 End:
 121 */