---
title: "BLOSC Support"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{BLOSC Support}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---

```{r, include = FALSE}
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)
```

Functions that access Copernicus Marine raster files stored in the
[ZARR format](https://zarr.dev/) (`cms_download_subset()` and
`cms_zarr_proxy()`) generally require
[BLOSC decompression](https://github.com/Blosc/c-blosc).
This package uses the features provided by the GDAL library as ported
by the [sf package](https://r-spatial.github.io/sf/).

Not all `sf` builds come with BLOSC support. If you receive an error
about missing BLOSC support, you need to reinstall `sf` with BLOSC.
Below you will find instructions to get BLOSC support on your OS.

## Windows

The tool chain for building R packages on Windows includes BLOSC
support by default. You just need to install the latest version of
[sf from CRAN](https://cran.r-project.org/package=sf). If this doesn't
work, you can build sf from source with RTools >= 4.5.

## MacOS

On MacOS you can build the `sf` package from source, but ensure
that you have the GDAL library installed first using the
homebrew formula (which contains BLOSC support)

```{bash, eval=FALSE}
brew install pkg-config
brew install gdal
```

```{r, eval=FALSE}
install.packages("sf", type = "source", configure.args = "--with-proj-lib=$(brew --prefix)/lib/")
```

## Debian (and alike)

First run:

```{bash, eval=FALSE}
sudo apt-get install libblosc-dev
```

Then reinstall `sf` to make sure it compiles with BLOSC support

## Fedora (and alike)

First run:

```{bash, eval=FALSE}
sudo yum install blosc-devel
```

Then reinstall `sf` to make sure it compiles with BLOSC support