Add support for the seekable format (#310)

Support the seekable format through bindings to the upstream
functionality in zstd-safe. The seekable format can be activated with
the `seekable` feature flag.

zstd-safe/Cargo.toml

@@ -34,8 +34,12 @@ arrays = []
 no_asm = ["zstd-sys/no_asm"]
 doc-cfg = []
 zdict_builder = ["zstd-sys/zdict_builder"]
+seekable = ["zstd-sys/seekable"]
 
 # These two are for cross-language LTO.
 # Will only work if `clang` is used to build the C library.
 fat-lto = ["zstd-sys/fat-lto"]
 thin-lto = ["zstd-sys/thin-lto"]
+
+[lints.rust]
+non_upper_case_globals = "allow"

zstd-safe/src/constants_seekable.rs

@@ -0,0 +1,6 @@
+// This file has been generated by ./update_consts.sh
+pub const SEEKABLE_FRAMEINDEX_TOOLARGE: u64 = zstd_sys::ZSTD_SEEKABLE_FRAMEINDEX_TOOLARGE as u64;
+pub const SEEKABLE_MAGICNUMBER: u32 = zstd_sys::ZSTD_SEEKABLE_MAGICNUMBER;
+pub const SEEKABLE_MAX_FRAME_DECOMPRESSED_SIZE: u32 = zstd_sys::ZSTD_SEEKABLE_MAX_FRAME_DECOMPRESSED_SIZE;
+pub const SEEKABLE_MAXFRAMES: u32 = zstd_sys::ZSTD_SEEKABLE_MAXFRAMES;
+pub const seekTableFooterSize: u32 = zstd_sys::ZSTD_seekTableFooterSize;

zstd-safe/src/lib.rs

@@ -27,6 +27,9 @@ extern crate std;
 #[cfg(test)]
 mod tests;
 
+#[cfg(feature = "seekable")]
+pub mod seekable;
+
 // Re-export zstd-sys
 pub use zstd_sys;
 
@@ -48,6 +51,9 @@ include!("constants.rs");
 #[cfg(feature = "experimental")]
 include!("constants_experimental.rs");
 
+#[cfg(feature = "seekable")]
+include!("constants_seekable.rs");
+
 /// Represents the compression level used by zstd.
 pub type CompressionLevel = i32;