#ifndef _GSM0710_BUFFER_H_#define _GSM0710_BUFFER_H_/* * buffer.h -- buffer for the GSM 0710 protocol device driver *             and protocol frame definition * * Copyright (C) 2003 Tuukka Karvonen <tkarvone@iki.fi> * * Version 1.0 October 2003 * * 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. *  * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. * */#ifndef min#define min(a,b) ((a < b) ? a :b)#endif typedef struct GSM0710_Frame {  unsigned char channel;  unsigned char control;  int data_length;  unsigned char *data;} GSM0710_Frame;#define GSM0710_BUFFER_SIZE 2048typedef struct GSM0710_Buffer {  unsigned char data[GSM0710_BUFFER_SIZE];  unsigned char *readp;  unsigned char *writep;  unsigned char *endp;  int flag_found; // set if last character read was flag  unsigned long received_count;  unsigned long dropped_count;} GSM0710_Buffer;// increases buffer pointer by one and wraps around if necessary#define INC_BUF_POINTER(buf,p) p++; if (p == buf->endp) p = buf->data;/* Allocates memory for a new buffer and initializes it. * * RETURNS: * the pointer to a new buufer */GSM0710_Buffer *gsm0710_buffer_init();/* Destroys the buffer (i.e. frees up the memory * * PARAMS: * buf - buffer to be destroyed */void gsm0710_buffer_destroy(GSM0710_Buffer *buf);/* Tells, how many chars are saved into the buffer. * *///int gsm0710_buffer_length(GSM0710_Buffer *buf);#define gsm0710_buffer_length(buf) ((buf->readp > buf->writep) ? (GSM0710_BUFFER_SIZE - (buf->readp - buf->writep)) : (buf->writep-buf->readp))/* Tells, how much free space there is in the buffer *///int gsm0710_buffer_free(GSM0710_Buffer *buf);#define gsm0710_buffer_free(buf) ((buf->readp > buf->writep) ? (buf->readp - buf->writep) : (GSM0710_BUFFER_SIZE - (buf->writep-buf->readp)))/* Tries to read count number of chars from the buffer * * PARAMS: * buf    - pointer to the buffer * output - where to read the characters (in user memory) * count  - number of characters to be read * RETURNS: * number of characters read */int gsm0710_buffer_read(GSM0710_Buffer *buf, char *output, int count);/* Encapsulates data to a frame and writes it to the buffer * * PARAMS * buf     - pointer to the buffer * channel - logical channel where the frame is sent to * input   - input data (in user memory) * count   - how many characters should be written * RETURNS * number of characters written */int gsm0710_buffer_write2ch(GSM0710_Buffer *buf, int channel, 			    const char *input, int count);/* Writes data to the buffer * * PARAMS * buf     - pointer to the buffer * input   - input data (in user memory) * count   - how many characters should be written * RETURNS * number of characters written */int gsm0710_buffer_write(GSM0710_Buffer *buf, const char *input, int count);/* Gets a frame from buffer. You have to remember to free this frame * when it's not needed anymore * * PARAMS: * buf   - the buffer, where the frame is extracted * RETURNS: * frame or null, if there isn't ready frame with given index */GSM0710_Frame *gsm0710_buffer_get_frame(GSM0710_Buffer *buf);// destroys a framevoid destroy_frame(GSM0710_Frame *frame);/* Calculates frame check sequence from given characters. * * PARAMS: * input - character array * count - number of characters in array (that are included) * RETURNS: * frame check sequence */unsigned char make_fcs(const unsigned char *input, int count);#endif /* _GSM0710_BUFFER_H_ */