+++ /dev/null
-/*
-
- silcbuffer.h
-
- Author: Pekka Riikonen <priikone@poseidon.pspt.fi>
-
- Copyright (C) 1998 - 2000 Pekka Riikonen
-
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
- (at your option) any later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
-*/
-
-#ifndef SILCBUFFER_H
-#define SILCBUFFER_H
-
-/*
- SILC Buffer object.
-
- SilcBuffer is very simple and easy to use, yet you can do to the
- buffer almost anything you want with its method functions. The buffer
- is constructed of four different data sections that in whole creates
- the allocated data area. Following short description of the fields
- of the buffer.
-
- unsigned int truelen;
-
- True length of the buffer. This is set at the allocation of the
- buffer and it should not be touched after that. This field should
- be considered read-only.
-
- unsigned int len;
-
- Length of the currently valid data area. Tells the length of the
- data at the buffer. This is set to zero at the allocation of the
- buffer and should not be updated by hand. Method functions of the
- buffer automatically updates this field. However, it is not
- read-only field and can be updated manually if necessary.
-
- unsiged char *head;
-
- Head of the allocated buffer. This is the start of the allocated
- data area and remains as same throughout the lifetime of the buffer.
- However, the end of the head area or the start of the currently valid
- data area is variable.
-
- --------------------------------
- | head | data | tail |
- --------------------------------
- ^ ^
-
- Current head section in the buffer is sb->data - sb->head.
-
- unsigned char *data;
-
- Currently valid data area. This is the start of the currently valid
- main data area. The data area is variable in all directions.
-
- --------------------------------
- | head | data | tail |
- --------------------------------
- ^ ^
-
- Current valid data area in the buffer is sb->tail - sb->data.
-
- unsigned char *tail;
-
- Tail of the buffer. This is the end of the currently valid data area
- or start of the tail area. The start of the tail area is variable.
-
- --------------------------------
- | head | data | tail |
- --------------------------------
- ^ ^
-
- Current tail section in the buffer is sb->end - sb->tail.
-
- unsigned char *end;
-
- End of the allocated buffer. This is the end of the allocated data
- area and remains as same throughout the lifetime of the buffer.
- Usually this field is not needed except when checking the size
- of the buffer.
-
- --------------------------------
- | head | data | tail |
- --------------------------------
- ^
-
- Length of the entire buffer is (ie. truelen) sb->end - sb->head.
-
- Currently valid data area is considered to be the main data area in
- the buffer. However, the entire buffer is of course valid data and can
- be used as such. Usually head section of the buffer includes different
- kind of headers or similiar. Data section includes the main data of
- the buffer. Tail section can be seen as a reserve space of the data
- section. Tail section can be pulled towards end thus the data section
- becomes larger.
-
- This buffer scheme is based on Linux kernel's Socket Buffer, the
- idea were taken directly from there and credits should go there.
-
-*/
-
-typedef struct SilcBufferStruct {
- unsigned int truelen;
- unsigned int len;
- unsigned char *head;
- unsigned char *data;
- unsigned char *tail;
- unsigned char *end;
-
- /* Method functions. */
- unsigned char *(*pull)(struct SilcBufferStruct *, unsigned int);
- unsigned char *(*push)(struct SilcBufferStruct *, unsigned int);
- unsigned char *(*pull_tail)(struct SilcBufferStruct *, unsigned int);
- unsigned char *(*push_tail)(struct SilcBufferStruct *, unsigned int);
- unsigned char *(*put)(struct SilcBufferStruct *, unsigned char *,
- unsigned int);
- unsigned char *(*put_head)(struct SilcBufferStruct *, unsigned char *,
- unsigned int);
- unsigned char *(*put_tail)(struct SilcBufferStruct *, unsigned char *,
- unsigned int);
-} SilcBufferObject;
-
-typedef SilcBufferObject *SilcBuffer;
-
-/* Macros */
-
-/* Returns the true length of the buffer. This is used to pull
- the buffer area to the end of the buffer. */
-#define SILC_BUFFER_END(x) ((x)->end - (x)->head)
-
-#ifndef SILC_DEBUG /* When we are not doing debugging we use
- optimized inline buffer functions. */
-/*
- * Optimized buffer managing routines. These are short inline
- * functions.
- */
-
-/* Pulls current data area towards end. The length of the currently
- valid data area is also decremented. Returns pointer to the data
- area before pulling.
-
- Example:
- ---------------------------------
- | head | data | tail |
- ---------------------------------
- ^
- Pulls the start of the data area.
-
- ---------------------------------
- | head | data | tail |
- ---------------------------------
- ^
-*/
-
-extern inline
-unsigned char *silc_buffer_pull(SilcBuffer sb, unsigned int len)
-{
- unsigned char *old_data = sb->data;
-
- assert(len <= (sb->tail - sb->data));
-
- sb->data += len;
- sb->len -= len;
-
- return old_data;
-}
-
-/* Pushes current data area towards beginning. Length of the currently
- valid data area is also incremented. Returns a pointer to the
- data area before pushing.
-
- Example:
- ---------------------------------
- | head | data | tail |
- ---------------------------------
- ^
- Pushes the start of the data area.
-
- ---------------------------------
- | head | data | tail |
- ---------------------------------
- ^
-*/
-
-extern inline
-unsigned char *silc_buffer_push(SilcBuffer sb, unsigned int len)
-{
- unsigned char *old_data = sb->data;
-
- assert((sb->data - len) >= sb->head);
-
- sb->data -= len;
- sb->len += len;
-
- return old_data;
-}
-
-/* Pulls current tail section towards end. Length of the current valid
- data area is also incremented. Returns a pointer to the data area
- before pulling.
-
- Example:
- ---------------------------------
- | head | data | tail |
- ---------------------------------
- ^
- Pulls the start of the tail section.
-
- ---------------------------------
- | head | data | tail |
- ---------------------------------
- ^
-*/
-
-extern inline
-unsigned char *silc_buffer_pull_tail(SilcBuffer sb, unsigned int len)
-{
- unsigned char *old_tail = sb->tail;
-
- assert((sb->end - sb->tail) >= len);
-
- sb->tail += len;
- sb->len += len;
-
- return old_tail;
-}
-
-/* Pushes current tail section towards beginning. Length of the current
- valid data area is also decremented. Returns a pointer to the
- tail section before pushing.
-
- Example:
- ---------------------------------
- | head | data | tail |
- ---------------------------------
- ^
- Pushes the start of the tail section.
-
- ---------------------------------
- | head | data | tail |
- ---------------------------------
- ^
-*/
-
-extern inline
-unsigned char *silc_buffer_push_tail(SilcBuffer sb, unsigned int len)
-{
- unsigned char *old_tail = sb->tail;
-
- assert((sb->tail - len) >= sb->data);
-
- sb->tail -= len;
- sb->len -= len;
-
- return old_tail;
-}
-
-/* Puts data at the head of the buffer. Returns pointer to the copied
- data area.
-
- Example:
- ---------------------------------
- | head | data | tail |
- ---------------------------------
- ^
- Puts data to the head section.
-*/
-
-extern inline
-unsigned char *silc_buffer_put_head(SilcBuffer sb,
- unsigned char *data,
- unsigned int len)
-{
- assert((sb->data - sb->head) >= len);
- return memcpy(sb->head, data, len);
-}
-
-/* Puts data at the start of the valid data area. Returns a pointer
- to the copied data area.
-
- Example:
- ---------------------------------
- | head | data | tail |
- ---------------------------------
- ^
- Puts data to the data section.
-*/
-
-extern inline
-unsigned char *silc_buffer_put(SilcBuffer sb,
- unsigned char *data,
- unsigned int len)
-{
- assert((sb->tail - sb->data) >= len);
- return memcpy(sb->data, data, len);
-}
-
-/* Puts data at the tail of the buffer. Returns pointer to the copied
- data area.
-
- Example:
- ---------------------------------
- | head | data | tail |
- ---------------------------------
- ^
- Puts data to the tail section.
-*/
-
-extern inline
-unsigned char *silc_buffer_put_tail(SilcBuffer sb,
- unsigned char *data,
- unsigned int len)
-{
- assert((sb->end - sb->tail) >= len);
- return memcpy(sb->tail, data, len);
-}
-
-#endif /* !SILC_DEBUG */
-
-/* Prototypes */
-SilcBuffer silc_buffer_alloc(unsigned int len);
-void silc_buffer_free(SilcBuffer sb);
-#ifdef SILC_DEBUG
-unsigned char *silc_buffer_pull(SilcBuffer sb, unsigned int len);
-unsigned char *silc_buffer_push(SilcBuffer sb, unsigned int len);
-unsigned char *silc_buffer_pull_tail(SilcBuffer sb, unsigned int len);
-unsigned char *silc_buffer_push_tail(SilcBuffer sb, unsigned int len);
-unsigned char *silc_buffer_put_head(SilcBuffer sb,
- unsigned char *data,
- unsigned int len);
-unsigned char *silc_buffer_put(SilcBuffer sb,
- unsigned char *data,
- unsigned int len);
-unsigned char *silc_buffer_put_tail(SilcBuffer sb,
- unsigned char *data,
- unsigned int len);
-#endif
-
-#endif
projects / silc.git / blobdiff