Yoji KURODA / RingBuffer

General purpose ring buffer library

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RingBuffer.cpp@2:ea6d02ba96ae, 2012-09-27 (annotated)

Committer:
ykuroda
Date:
Thu Sep 27 13:15:54 2012 +0000
Revision:
2:ea6d02ba96ae
Parent:
1:1c3a10f2eb04 
pointer edition

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ykuroda 1:1c3a10f2eb04 1 //
ykuroda 1:1c3a10f2eb04 2 // RingBuffer.cpp ... General purpose ring buffer library
ykuroda 1:1c3a10f2eb04 3 //
ykuroda 1:1c3a10f2eb04 4 // Copyright 2012 Yoji KURODA
ykuroda 1:1c3a10f2eb04 5 //
ykuroda 1:1c3a10f2eb04 6 // 2009.11.13 ... Originally written in C by Y.Kuroda for Renesas H83664
ykuroda 1:1c3a10f2eb04 7 // 2012.08.31 ... Code convert for mbed in C++
ykuroda 1:1c3a10f2eb04 8 //
ykuroda 1:1c3a10f2eb04 9
ykuroda 0:db7fa84ff50e 10 #include "string.h"
ykuroda 0:db7fa84ff50e 11 #include "RingBuffer.h"
ykuroda 0:db7fa84ff50e 12
ykuroda 0:db7fa84ff50e 13
ykuroda 0:db7fa84ff50e 14 /*
ykuroda 0:db7fa84ff50e 15 * Machine Independent Area
ykuroda 0:db7fa84ff50e 16 */
ykuroda 0:db7fa84ff50e 17 RingBuffer::RingBuffer(int _bufsize)
ykuroda 0:db7fa84ff50e 18 : bufsize(_bufsize)
ykuroda 0:db7fa84ff50e 19 {
ykuroda 0:db7fa84ff50e 20 buf = new unsigned char [bufsize+1];
ykuroda 2:ea6d02ba96ae 21 sp = ep = buf;
ykuroda 0:db7fa84ff50e 22 memset(buf,0,bufsize);
ykuroda 0:db7fa84ff50e 23 }
ykuroda 0:db7fa84ff50e 24
ykuroda 0:db7fa84ff50e 25 RingBuffer::~RingBuffer()
ykuroda 0:db7fa84ff50e 26 {
ykuroda 0:db7fa84ff50e 27 delete [] buf;
ykuroda 0:db7fa84ff50e 28 }
ykuroda 0:db7fa84ff50e 29
ykuroda 0:db7fa84ff50e 30 int
ykuroda 0:db7fa84ff50e 31 RingBuffer::save(unsigned char c)
ykuroda 0:db7fa84ff50e 32 {
ykuroda 0:db7fa84ff50e 33 if( (ep==sp-1)||
ykuroda 2:ea6d02ba96ae 34 ((sp==buf)&&
ykuroda 2:ea6d02ba96ae 35 (ep==buf+bufsize-1)) ) /* buffer full */
ykuroda 0:db7fa84ff50e 36 return 0;
ykuroda 0:db7fa84ff50e 37
ykuroda 2:ea6d02ba96ae 38 *ep = c;
ykuroda 0:db7fa84ff50e 39 ep++;
ykuroda 0:db7fa84ff50e 40
ykuroda 2:ea6d02ba96ae 41 if(ep > buf+bufsize)
ykuroda 2:ea6d02ba96ae 42 ep = buf;
ykuroda 2:ea6d02ba96ae 43
ykuroda 0:db7fa84ff50e 44 return 1;
ykuroda 0:db7fa84ff50e 45 }
ykuroda 0:db7fa84ff50e 46
ykuroda 0:db7fa84ff50e 47 unsigned char
ykuroda 0:db7fa84ff50e 48 RingBuffer::read(void)
ykuroda 0:db7fa84ff50e 49 {
ykuroda 0:db7fa84ff50e 50 unsigned char ret;
ykuroda 0:db7fa84ff50e 51
ykuroda 0:db7fa84ff50e 52 if(sp == ep)
ykuroda 0:db7fa84ff50e 53 return 0; /* buffer empty */
ykuroda 0:db7fa84ff50e 54
ykuroda 2:ea6d02ba96ae 55 ret = *sp;
ykuroda 2:ea6d02ba96ae 56 *sp = 0;
ykuroda 0:db7fa84ff50e 57 sp++;
ykuroda 0:db7fa84ff50e 58
ykuroda 2:ea6d02ba96ae 59 if(sp > buf+bufsize)
ykuroda 2:ea6d02ba96ae 60 sp = buf;
ykuroda 2:ea6d02ba96ae 61
ykuroda 0:db7fa84ff50e 62 return ret;
ykuroda 0:db7fa84ff50e 63 }
ykuroda 0:db7fa84ff50e 64
ykuroda 0:db7fa84ff50e 65 int
ykuroda 0:db7fa84ff50e 66 RingBuffer::check(void)
ykuroda 0:db7fa84ff50e 67 {
ykuroda 0:db7fa84ff50e 68 int n = ep-sp;
ykuroda 0:db7fa84ff50e 69 if(n<0)
ykuroda 0:db7fa84ff50e 70 n = bufsize-n;
ykuroda 0:db7fa84ff50e 71
ykuroda 0:db7fa84ff50e 72 return n;
ykuroda 0:db7fa84ff50e 73 }
ykuroda 0:db7fa84ff50e 74