0x0d is a carriage return. Someone is using character I/O somewhere. It’s
possible they are appearing after ‘nul’ characters 0x00 bytes or some such.
George Watson
Principal, Sierra Computing
wat...@sierracmp.com
> On Dec 14, 2015, at 10:52 AM, Jerry Tol <jerto...@gmail.com> wrote:
>
> Hello,
> I'm implementing a gdal raster driver for an internal file format and am
> getting results I do not understand. The output is a binary raster of 32-bit
> floating point data, but the resulting file contains single bytes of value
> 0x0D at seemingly random intervals throughout the data.
>
> Within my implementation of IWriteBlock, I see that the buffer pointed to by
> pImage does not contain these 0x0D's, however after calling VSIFWrite the
> output file does indeed have these individual bytes scattered throughout. In
> all cases, I am creating a new output file (not overwriting an existing
> file). Sometimes the 0D's occur in the middle of a 4-byte float, others are
> between two 4-byte float sequences. I cannot figure how/when/why these random
> 0D's are occurring in my output.
>
> Thank you for any help provided. Here is my implementation of IWriteBlock
> CPLErr RLYRRasterBand::IWriteBlock(int nBlockXOff, int nBlockYOff, void
> *pImage)
> {
> RLYRDataset *poGDS = (RLYRDataset *)poDS;
> if (poGDS->fp == 0) {
> CPLError(CE_Failure, CPLE_FileIO, "IWriteBlock: fp is NULL");
> return CE_Failure;
> }
> nBlockYOff = poDS->GetRasterYSize() - nBlockYOff - 1;
>
> size_t cdtSize = GDALGetDataTypeSize(GetRasterDataType()) / 8;
> size_t nSeek = RLYRMeta::offset_data +
> cdtSize * (nBlockXOff * nBlockYSize + nBlockYOff * nBlockXSize);
> int zeeksez = VSIFSeek(poGDS->fp, nSeek, SEEK_SET);
> if (zeeksez != 0) {
> CPLError(CE_Warning, CPLE_FileIO, "VSIFSeek returns %d",
> zeeksez);
> return CE_Failure;
> }
>
> size_t nBlockLen = nBlockXSize * nBlockYSize;
> size_t nWrit = VSIFWrite(pImage, cdtSize, nBlockLen, poGDS->fp);
> if (nWrit != nBlockLen) {
> CPLError(CE_Warning, CPLE_FileIO, "VSIFWrite returns %d",
> nWrit);
> return CE_Failure;
> }
>
> // test code - 'foo' does not exhibit bad data but the output file does
> //if (nBlockYOff == 1130) {
> // FILE *tfp = VSIFOpen("h:\\rasters\\o\\foo", "wb");
> // size_t nWrit2 = fwrite(pImage, cdtSize, nBlockLen, tfp);
> // VSIFClose(tfp);
> //}
>
> return CE_None;
> }
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