src/libstrongswan/chunk.h

   1 /**
   2  * @file chunk.h
   3  *
   4  * @brief Pointer/length abstraction and its functions.
   5  *
   6  */
   7
   8 /*
   9  * Copyright (C) 2005-2006 Martin Willi
  10  * Copyright (C) 2005 Jan Hutter
  11  * Hochschule fuer Technik Rapperswil
  12  *
  13  * This program is free software; you can redistribute it and/or modify it
  14  * under the terms of the GNU General Public License as published by the
  15  * Free Software Foundation; either version 2 of the License, or (at your
  16  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  17  *
  18  * This program is distributed in the hope that it will be useful, but
  19  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  20  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  21  * for more details.
  22  */
  23
  24 #ifndef CHUNK_H_
  25 #define CHUNK_H_
  26
  27 #include <string.h>
  28 #include <stdarg.h>
  29
  30 #include <library.h>
  31
  32 typedef struct chunk_t chunk_t;
  33
  34 /**
  35  * General purpose pointer/length abstraction.
  36  */
  37 struct chunk_t {
  38         /** Pointer to start of data */
  39         u_char *ptr;
  40         /** Length of data in bytes */
  41         size_t len;
  42 };
  43
  44 /**
  45  * A { NULL, 0 }-chunk handy for initialization.
  46  */
  47 extern chunk_t chunk_empty;
  48
  49 /**
  50  * Create a new chunk pointing to "ptr" with length "len"
  51  */
  52 chunk_t chunk_create(u_char *ptr, size_t len);
  53
  54 /**
  55  * Create a clone of a chunk pointing to "ptr"
  56  */
  57 chunk_t chunk_create_clone(u_char *ptr, chunk_t chunk);
  58
  59 /**
  60  * Calculate length of multiple chunks
  61  */
  62 size_t chunk_length(const char *mode, ...);
  63
  64 /**
  65  * Concatenate chunks into a chunk pointing to "ptr",
  66  * "mode" is a string of "c" (copy) and "m" (move), which says
  67  * how to handle to chunks in "..."
  68  */
  69 chunk_t chunk_create_cat(u_char *ptr, const char* mode, ...);
  70
  71 /**
  72  * Split up a chunk into parts, "mode" is a string of "a" (alloc),
  73  * "c" (copy) and "m" (move). Each letter say for the corresponding chunk if
  74  * it should get allocated on heap, copied into existing chunk, or the chunk
  75  * should point into "chunk". The length of each part is an argument before
  76  * each target chunk. E.g.:
  77  * chunk_split(chunk, "mcac", 3, &a, 7, &b, 5, &c, d.len, &d);
  78  */
  79 void chunk_split(chunk_t chunk, const char *mode, ...);
  80
  81 /**
  82  * Free contents of a chunk
  83  */
  84 void chunk_free(chunk_t *chunk);
  85
  86 /**
  87  * Initialize a chunk to point to buffer inspectable by sizeof()
  88  */
  89 #define chunk_from_buf(str) { str, sizeof(str) }
  90
  91 /**
  92  * Allocate a chunk on the heap
  93  */
  94 #define chunk_alloc(bytes) chunk_create(malloc(bytes), bytes)
  95
  96 /**
  97  * Allocate a chunk on the stack
  98  */
  99 #define chunk_alloca(bytes) chunk_create(alloca(bytes), bytes)
 100
 101 /**
 102  * Clone a chunk on heap
 103  */
 104 #define chunk_clone(chunk) chunk_create_clone(malloc(chunk.len), chunk)
 105
 106 /**
 107  * Clone a chunk on stack
 108  */
 109 #define chunk_clonea(chunk) chunk_create_clone(alloca(chunk.len), chunk)
 110
 111 /**
 112  * Concatenate chunks into a chunk on heap
 113  */
 114 #define chunk_cat(mode, ...) chunk_create_cat(malloc(chunk_length(mode, __VA_ARGS__)), mode, __VA_ARGS__)
 115
 116 /**
 117  * Concatenate chunks into a chunk on stack
 118  */
 119 #define chunk_cata(mode, ...) chunk_create_cat(alloca(chunk_length(mode, __VA_ARGS__)), mode, __VA_ARGS__)
 120
 121 /**
 122  * Skip n bytes in chunk (forward pointer, shorten length)
 123  */
 124 chunk_t chunk_skip(chunk_t chunk, size_t bytes);
 125
 126 /**
 127  *  Compare two chunks, returns zero if a equals b
 128  *  or negative/positive if a is small/greater than b
 129  */
 130 int chunk_compare(chunk_t a, chunk_t b);
 131
 132 /**
 133  * Compare two chunks for equality,
 134  * NULL chunks are never equal.
 135  */
 136 bool chunk_equals(chunk_t a, chunk_t b);
 137
 138 /**
 139  * Compare two chunks for equality,
 140  * NULL chunks are always equal.
 141  */
 142 bool chunk_equals_or_null(chunk_t a, chunk_t b);
 143
 144 #endif /* CHUNK_H_ */