lib: add fetch-picolib script

Author: bradjc

lib/fetch-picolib.sh

@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+
+PICOLIB_VERSION=$1
+
+if [ $PICOLIB_VERSION = "1.8.5" ]; then
+  PICOLIB_SHA="5168a7ea6522717ec5867e0105a224fe7e3779371b095deedc2cd58da369d8cc"
+fi
+
+# Name of the pre-created compiled directories.
+ZIP_FILE=libtock-picolib-$PICOLIB_VERSION.zip
+
+# List of mirrors we support.
+MIRRORS=(\
+  "https://www.cs.virginia.edu/~bjc8c/archive/tock"\
+  "https://alpha.mirror.svc.schuermann.io/files"\
+)
+
+let FOUND=0
+
+# Try from each mirror until we successfully download a .zip file.
+for MIRROR in ${MIRRORS[@]}; do
+  URL=$MIRROR/$ZIP_FILE
+  echo "Fetching picolib from ${MIRROR}..."
+  echo "  Fetching ${URL}..."
+  wget -q "$URL" && (echo "$PICOLIB_SHA $ZIP_FILE" | sha256sum -c)
+  if [ $? -ne 0 ]; then
+    echo "  WARNING: Fetching picolib from mirror $MIRROR failed!" >&2
+  else
+    let FOUND=1
+    break
+  fi
+done
+
+if [[ $FOUND -ne 0 ]]; then
+  unzip $ZIP_FILE
+else
+  echo "ERROR: Unable to find tock-picolib"
+  exit -1
+fi