xeye_ atsu / Mbed 2 deprecated I2S_AIC23B_RiceGolomb

パラメータを適応変化させる事により圧縮率を向上させた動的ライス・ゴロム符号を利用した可逆圧縮方式。圧縮ソフト、圧縮率のMATLABシミュレーションは詳細はInterface誌2011年8月号に掲載されるRX62Nマイコン連動特集にて掲載予定。

Dependencies:   mbed

Lossless_lib/_bitio.cpp

Committer:
lynxeyed_atsu
Date:
2011-03-30
Revision:
0:d920d64db582

File content as of revision 0:d920d64db582:

#include "mbed.h"
#include "string"
#include "_bitio.h"


//FILE *infp, *outfp;
int     getcount, putcount;
int     bitbuf;


void init_bit_o(void)
{
    putcount = 8; bitbuf = 0;
}

void init_bit_i(void)
{
    getcount = 0; bitbuf = 0;
}


Uint getbit(void)
{
    int flag;
    if (--getcount >= 0)  return (bitbuf >> getcount) & 1U;
    getcount = 7;
    if((flag = fgetc(infp))==EOF)return OVERRUN;
    else bitbuf = flag;
    return (bitbuf >> 7) & 1U;
}

Uint getbits(int n)
{
    Uint x = 0;
    if (n < 1 || 25 < n)  return 0;
    while (n > getcount) {
        n -= getcount;
        x |= rightbits(getcount, bitbuf) << n;
        bitbuf = fgetc(infp); 
        getcount = 8;
    }
    getcount -= n;
    return x | rightbits(n, bitbuf >> getcount);
}


void putbit(Uint bit)
{
    putcount--;
    if (bit != 0)  bitbuf |= (1 << putcount);
    if (putcount == 0) {
        if (fputc(bitbuf, outfp) == EOF)  error("can't write\r\n");
        bitbuf = 0; putcount = 8;
    }
}


void putbits(int n, Uint x)
{
    if (n < 1 || 25 < n)  return;
    while (n >= putcount) {
        n -= putcount;
        bitbuf |= rightbits(putcount, x >> n);
        if (fputc(bitbuf, outfp) == EOF)  error("cant write\r\n");
        bitbuf = 0U; 
        putcount = 8;
    }
    putcount -= n;
    bitbuf |= rightbits(n, x) << putcount;
}