codecy.cpp

介绍小波的函数

#include "stdafx.h"
#include "codecy.h"

#include "basefwt.h"
#include "mbior97.h"
#include "ezw.h"


/////////////////////////////////////////constructor/destructor//////////////////////////////////////////////////
CodecY::CodecY() : m_status(0), m_width(0), m_height(0)
{
        bior97 = new mBior97();
        ezw = new EZW();
}
CodecY::~CodecY()
{
        delete bior97;
        delete ezw;
}
/////////////////////////////////////////constructor/destructor//////////////////////////////////////////////////



/////////////////////////////////////////init////////////////////////////////////////////////////////////////////
void CodecY::initgray(unsigned int width, unsigned int height)
{
        m_width = width;
        m_height = height;
        bior97->init(m_width, m_height);
        m_status = 1;
}
/////////////////////////////////////////init////////////////////////////////////////////////////////////////////


/////////////////////////////////////////compress/decompress/////////////////////////////////////////////////////
unsigned char* CodecY::compressgray(const unsigned char* data, unsigned int& size, unsigned int TH)
{
        const char hdr[] = "YBior97EZW";
        if (m_status == 0) return 0;

        bior97->trans(data, 3, TH);
        size = ezw->compress(bior97->gettspec() + sizeof(CODECHDR), bior97->getspec(), m_width, m_height);      //0 - err
        //ezw size - OK
        if (size == 0)
                return 0;

        struct CODECHDR* phdr = (struct CODECHDR*) bior97->gettspec();
        memset(phdr, 0, sizeof(CODECHDR));
        memcpy(phdr->hdr, hdr, 10);
        phdr->size = size;
        phdr->width = m_width;
        phdr->height = m_height;
        phdr->crc = crc((unsigned char *)phdr, sizeof(CODECHDR) + size);

        size += sizeof(CODECHDR);
        return (unsigned char*)phdr;
}

int CodecY::decompressgray(unsigned char* dest, unsigned char* sour)
{
        const char hdr[] = "YBior97EZW";
        if (m_status == 0) return 0;

        struct CODECHDR* phdr = (struct CODECHDR*)sour;

        if (memcmp(phdr->hdr, hdr, 10) != 0)
                return -1;
        if (phdr->width != m_width || phdr->height != m_height)
                return -2;

        unsigned short c = phdr->crc;
        phdr->crc = 0;
        if (c != crc(sour, sizeof(CODECHDR) + phdr->size))
                return -3;

        unsigned int size = ezw->decompress(bior97->getspec(), (char *)(sour + sizeof(CODECHDR)), phdr->width, phdr->height);       //size = phdr->size
        if (size != phdr->size)
                return -4;
 
        bior97->setJ(3);
        bior97->synth(dest);

        return m_width * m_height;
}
/////////////////////////////////////////compress/decompress/////////////////////////////////////////////////////










unsigned short CodecY::crc(const unsigned char* addr, unsigned int len) const
{
        unsigned int nleft = len;
        unsigned int sum = 0;

        while (nleft > 1) {
                sum += *addr++;
                nleft -= 2;
        }
        /* mop up an odd byte, if necessary */
        if (nleft == 1) {
                unsigned short u = 0;
                *(unsigned char *)(&u) = *(unsigned char *)addr;
                sum += u;
        }

        sum = (sum >> 16) + (sum & 0xffff);
        return (unsigned short)~sum;
}