trpage_readbuf.cpp

来自「最新osg包」· C++ 代码 · 共 714 行 · 第 1/2 页

bool trpgMemReadBuffer::isEmpty()
{
    if (!data)  return true;

    if (pos >= len)
        return true;

    // Also test the limits
    for (unsigned int i=0;i<limits.size();i++)
        if (limits[i] == 0)  return true;

    return false;
}

// Set Length
// Allocate the given space
void trpgMemReadBuffer::SetLength(int newLen)
{
    if (newLen > totLen) {
        if (data)
            delete [] data;
        data = new char[newLen];
        totLen = newLen;
    }
    len = newLen;
    pos = 0;
}

// Get Data Ptr
// Return a pointer to our data so it can be written to
char *trpgMemReadBuffer::GetDataPtr()
{
    return data;
}

// Get Data
// Protected method for actually retrieving a piece of data
bool trpgMemReadBuffer::GetData(char *ret,int rlen)
{
    if (rlen < 0)
        return false;

    // Test against limits imposed from without
    if (!TestLimit(rlen))  throw 1;

    // See if we've actually got the data
    if (pos+rlen > len)  throw 1;

    // Copy into the return buffer
    memcpy(ret,&data[pos],rlen);

    // Update any limits we might have
    UpdateLimits(rlen);

    pos += rlen;

    return true;
}

// Get Reference to Data
// Protected method that retrieves a reference to the given amoutn of data
bool trpgMemReadBuffer::GetDataRef(char **ret,int rlen)
{
    if (rlen < 0)  return false;

    // Test against limits
    if (!TestLimit(rlen)) throw 1;
    if (pos + rlen > len)  throw 1;

    // Set up reference
    *ret = &data[pos];

    UpdateLimits(rlen);
    pos += rlen;

    return true;
}

// Skip
// Same as read except we're not, uh, reading
bool trpgMemReadBuffer::Skip(int rlen)
{
    if (rlen == 0)
        return true;

    if (rlen < 0)
        return false;

    // Test against limits
    if (!TestLimit(rlen))  return false;
    if (pos + rlen > len)  return false;

    UpdateLimits(rlen);

    pos += rlen;

    return true;
}

/* Appendable File read class
 */

trpgrAppFile::trpgrAppFile(trpgEndian inNess,const char *fileName)
{
    Init(inNess,fileName);
}

void trpgrAppFile::Init(trpgEndian inNess,const char *fileName)
{
    valid = false;
    ness = inNess;
    cpuNess = trpg_cpu_byte_order();

    if (!(fp = osgDB::fopen(fileName,"rb")))
        return;

    valid = true;
}

trpgrAppFile::~trpgrAppFile()
{
    if (fp)
        fclose(fp);

    valid = false;
}

bool trpgrAppFile::isValid(void) const
{
    return valid;
}

// Read a section of data from the given file
//  and dump it into the given buffer
bool trpgrAppFile::Read(trpgMemReadBuffer *buf,int32 offset)
{
    if (!valid)  return false;

    // Seek to the right location
    if (fseek(fp,offset,SEEK_SET))
        return false;

    // Read a length
    int32 len;
    if (fread(&len,sizeof(int32),1,fp) != 1) {
        valid = false;
        return false;
    }

    // Byteswap if necessary
    if (ness != cpuNess)
        len = trpg_byteswap_int(len);

    if (len < 0) {
        valid = false;
        return false;
    }

    buf->SetLength(len);
    char *data = buf->GetDataPtr();
    if (!data) {
        valid = false;
        return false;
    }

        if (fread(data,sizeof(char),len,fp) != (uint32)len) {
        valid = false;
        return false;
    }

    return true;
}

/* Read a section of data from the given file
   and dump it into the given memory.  Sanity
   check the length against the size of the memory
   passed into dataSize.
*/
bool trpgrAppFile::Read(char *data,int32 baseOffset,int32 objOffset,int32 dataSize)
{
    if (!valid)  return false;

    // Seek to the right place
    int result;
    if ((result = fseek(fp,baseOffset,SEEK_SET))) {
        valid = false;
        return false;
    }

    // Read the total object length
    int32 len;
    if (fread(&len,sizeof(int32),1,fp) != 1) {
        valid = false;
        return false;
    }

    // Byteswap if necessary
    if (ness != cpuNess)
        len = trpg_byteswap_int(len);

    if (len < 0) {
        valid = false;
        return false;
    }

    // It's all right to read less than the whole data block
    if (objOffset+dataSize > len)
        return false;

    // Skip to the object offset
    if (fseek(fp,objOffset,SEEK_CUR)) {
        valid = false;
        return false;
    }

    // Read the raw data
    // Note: What about byte swapping?
        if (fread(data,sizeof(char),dataSize,fp) != (uint32)dataSize) {
        valid = false;
        return false;
    }

    return true;
}

/* App File Cache
   This class manages a group of appendable files with
   the same base name and extension.  It will keep a certain
   number of them open to facilitate caching.
*/

trpgrAppFileCache::trpgrAppFileCache(const char *inPre,const char *inExt,int noFiles)
{
    Init(inPre,inExt,noFiles);
}

void trpgrAppFileCache::Init(const char *inPre,const char *inExt,int noFiles)
{
    strcpy(baseName,inPre);
    strcpy(ext,inExt);

    files.resize(noFiles);
    timeCount = 0;
}

trpgrAppFileCache::~trpgrAppFileCache()
{
    unsigned int len = files.size();
    for (unsigned int i=0;i<len;i++) {
        if (files[i].afile) {
            delete files[i].afile;
            files[i].afile = NULL;
        }
    }
}

trpgrAppFile *trpgrAppFileCache::GetNewRAppFile(trpgEndian ness, const char *fileName)
{
    return new trpgrAppFile(ness,fileName);
}

trpgrAppFile *trpgrAppFileCache::GetFile(trpgEndian ness,int id)
{
    return GetFile(ness,id,-1,-1);
}

/*
 */
trpgrAppFile *trpgrAppFileCache::GetFile(trpgEndian ness,int id,int col,int row)
{
    // Look for it already here
    int foundID = -1;
    unsigned int i;
    for (i=0;i<files.size();i++) {
        if ((files[i].id == id)&&
            (files[i].col == col) &&
            (files[i].row == row)) {
            foundID = i;
            break;
        }
    }

    // Found it in cache, just return
    if (foundID != -1) {
        OpenFile &of = files[foundID];

        if (of.afile->isValid())
        {
            of.lastUsed = timeCount;
            return of.afile;
        }
        else
        {
            if (of.afile)
                delete of.afile;
            of.afile = NULL;
        }
    }

    // Didn't find it.  Need to reclaim one
    // Look for the oldest used
    int oldTime=-1,oldID=-1;
    for (i=0;i<files.size();i++) {
        OpenFile &of = files[i];
        if (!of.afile || (oldTime == -1) || (of.lastUsed < oldTime)) {
            oldID = i;
            oldTime = of.lastUsed;
            if (!of.afile)
                break;
        }
    }


    // Reclaim this one
    OpenFile &of = files[oldID];
    if (of.afile)
        delete of.afile;
    char fileName[1024];
    if(col==-1) {
        sprintf(fileName,"%s_%d.%s",baseName,id,ext);
    }
    else {
        char dir[1024];
        char filebase[1024];
        //this is very ugly, but it avoids radical API changes
        // find the last PATHSEPERATOR in the baseName string
        int len = strlen(baseName);
        while(--len > 0) {
            if(baseName[len]==PATHSEPERATOR[0]) {
                strcpy(filebase,&baseName[len+1]);
                strcpy(dir,baseName);
                dir[len]='\0';
                break;
            }
        }
        sprintf(fileName,"%s" PATHSEPERATOR "%d" PATHSEPERATOR "%d" PATHSEPERATOR "%s_%d.%s",
                dir,col,row,filebase,id,ext);
    }
    of.afile = GetNewRAppFile(ness,fileName);
    of.id = id;
    of.row = row;
    of.col = col;
    of.lastUsed = timeCount;

    timeCount++;

    return of.afile;
}

// Constructor for OpenFile class
trpgrAppFileCache::OpenFile::OpenFile()
{
    afile = NULL;
    lastUsed = 0;
    id = -1;
}