add n64 sram filetype converter

sh/sram

@@ -0,0 +1,50 @@
+#!/usr/bin/env zsh
+
+sram() {
+    die() {
+        echo -E "$@">&2
+        exit 1
+    }
+
+    crop() {
+        tail -n +$((($1)/16+1))
+    }
+
+    revend() {
+        objcopy -I binary -O binary --reverse-bytes=4 "$@"
+    }
+
+    dump() {
+        xxd -ps -c 16 "$@"
+    }
+
+    zeros() {
+        # one row (16) of zeros
+        yes "00000000000000000000000000000000" | head -n $1
+    }
+
+    game="$1"
+    in="$2"
+    out="$3"
+
+    if [[ "$game" == "mm" ]]; then
+        headsize=$((0x20800))
+    elif [[ "$game" == "oot" ]]; then
+        headsize=$((0x40800))
+    else
+        echo "Unknown game." >&2
+        return 1
+    fi
+
+    [ -e "$2" ] || die "input save does not exist"
+
+    if [[ "${in##*.}" == "SaveRAM" ]] then
+        dump "$in" | crop $headsize | dump -r > "$out"
+    else
+        cat <(zeros $(($headsize/16))) <(dump "$in") | dump -r > "$out"
+    fi
+
+    revend "$out"
+}
+
+sram "$@"