[deflate] Add support for DEFLATE decompression

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 283 insertions, 0 deletions

diff --git a/src/include/ipxe/deflate.h b/src/include/ipxe/deflate.h
new file mode 100644
index 000000000..19c5125eb
--- /dev/null
+++ b/src/include/ipxe/deflate.h
@@ -0,0 +1,283 @@
+#ifndef _IPXE_DEFLATE_H
+#define _IPXE_DEFLATE_H
+
+/** @file
+ *
+ * DEFLATE decompression algorithm
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stdint.h>
+#include <string.h>
+#include <ipxe/uaccess.h>
+
+/** Compression formats */
+enum deflate_format {
+	/** Raw DEFLATE data (no header or footer) */
+	DEFLATE_RAW,
+	/** ZLIB header and footer */
+	DEFLATE_ZLIB,
+};
+
+/** Block header length (in bits) */
+#define DEFLATE_HEADER_BITS 3
+
+/** Block header final block flags bit */
+#define DEFLATE_HEADER_BFINAL_BIT 0
+
+/** Block header type LSB */
+#define DEFLATE_HEADER_BTYPE_LSB 1
+
+/** Block header type mask */
+#define DEFLATE_HEADER_BTYPE_MASK 0x03
+
+/** Block header type: literal data */
+#define DEFLATE_HEADER_BTYPE_LITERAL 0
+
+/** Block header type: static Huffman alphabet */
+#define DEFLATE_HEADER_BTYPE_STATIC 1
+
+/** Block header type: dynamic Huffman alphabet */
+#define DEFLATE_HEADER_BTYPE_DYNAMIC 2
+
+/** Literal header LEN/NLEN field length (in bits) */
+#define DEFLATE_LITERAL_LEN_BITS 16
+
+/** Dynamic header length (in bits) */
+#define DEFLATE_DYNAMIC_BITS 14
+
+/** Dynamic header HLIT field LSB */
+#define DEFLATE_DYNAMIC_HLIT_LSB 0
+
+/** Dynamic header HLIT field mask */
+#define DEFLATE_DYNAMIC_HLIT_MASK 0x1f
+
+/** Dynamic header HDIST field LSB */
+#define DEFLATE_DYNAMIC_HDIST_LSB 5
+
+/** Dynamic header HDIST field mask */
+#define DEFLATE_DYNAMIC_HDIST_MASK 0x1f
+
+/** Dynamic header HCLEN field LSB */
+#define DEFLATE_DYNAMIC_HCLEN_LSB 10
+
+/** Dynamic header HCLEN field mask */
+#define DEFLATE_DYNAMIC_HCLEN_MASK 0x0f
+
+/** Dynamic header code length length (in bits) */
+#define DEFLATE_CODELEN_BITS 3
+
+/** Maximum length of a Huffman symbol (in bits) */
+#define DEFLATE_HUFFMAN_BITS 15
+
+/** Quick lookup length for a Huffman symbol (in bits)
+ *
+ * This is a policy decision.
+ */
+#define DEFLATE_HUFFMAN_QL_BITS 7
+
+/** Quick lookup shift */
+#define DEFLATE_HUFFMAN_QL_SHIFT ( 16 - DEFLATE_HUFFMAN_QL_BITS )
+
+/** Literal/length end of block code */
+#define DEFLATE_LITLEN_END 256
+
+/** Maximum value of a literal/length code */
+#define DEFLATE_LITLEN_MAX_CODE 287
+
+/** Maximum value of a distance code */
+#define DEFLATE_DISTANCE_MAX_CODE 31
+
+/** Maximum value of a code length code */
+#define DEFLATE_CODELEN_MAX_CODE 18
+
+/** ZLIB header length (in bits) */
+#define ZLIB_HEADER_BITS 16
+
+/** ZLIB header compression method LSB */
+#define ZLIB_HEADER_CM_LSB 0
+
+/** ZLIB header compression method mask */
+#define ZLIB_HEADER_CM_MASK 0x0f
+
+/** ZLIB header compression method: DEFLATE */
+#define ZLIB_HEADER_CM_DEFLATE 8
+
+/** ZLIB header preset dictionary flag bit */
+#define ZLIB_HEADER_FDICT_BIT 13
+
+/** ZLIB ADLER32 length (in bits) */
+#define ZLIB_ADLER32_BITS 32
+
+/** A Huffman-coded set of symbols of a given length */
+struct deflate_huf_symbols {
+	/** Length of Huffman-coded symbols */
+	uint8_t bits;
+	/** Shift to normalise symbols of this length to 16 bits */
+	uint8_t shift;
+	/** Number of Huffman-coded symbols having this length */
+	uint16_t freq;
+	/** First symbol of this length (normalised to 16 bits)
+	 *
+	 * Stored as a 32-bit value to allow the value 0x10000 to be
+	 * used for empty sets of symbols longer than the maximum
+	 * utilised length.
+	 */
+	uint32_t start;
+	/** Raw symbols having this length */
+	uint16_t *raw;
+};
+
+/** A Huffman-coded alphabet */
+struct deflate_alphabet {
+	/** Huffman-coded symbol set for each length */
+	struct deflate_huf_symbols huf[DEFLATE_HUFFMAN_BITS];
+	/** Quick lookup table */
+	uint8_t lookup[ 1 << DEFLATE_HUFFMAN_QL_BITS ];
+	/** Raw symbols
+	 *
+	 * Ordered by Huffman-coded symbol length, then by symbol
+	 * value.  This field has a variable length.
+	 */
+	uint16_t raw[0];
+};
+
+/** A static Huffman alphabet length pattern */
+struct deflate_static_length_pattern {
+	/** Length pair */
+	uint8_t fill;
+	/** Repetition count */
+	uint8_t count;
+} __attribute__ (( packed ));
+
+/** Decompressor */
+struct deflate {
+	/** Resume point
+	 *
+	 * Used as the target of a computed goto to jump to the
+	 * appropriate point within the state machine.
+	 */
+	void *resume;
+	/** Format */
+	enum deflate_format format;
+
+	/** Accumulator */
+	uint32_t accumulator;
+	/** Bit-reversed accumulator
+	 *
+	 * Don't ask.
+	 */
+	uint32_t rotalumucca;
+	/** Number of bits within the accumulator */
+	unsigned int bits;
+
+	/** Current block header */
+	unsigned int header;
+	/** Remaining length of data (e.g. within a literal block) */
+	size_t remaining;
+	/** Current length index within a set of code lengths */
+	unsigned int length_index;
+	/** Target length index within a set of code lengths */
+	unsigned int length_target;
+	/** Current length within a set of code lengths */
+	unsigned int length;
+	/** Number of extra bits required */
+	unsigned int extra_bits;
+	/** Length of a duplicated string */
+	size_t dup_len;
+	/** Distance of a duplicated string */
+	size_t dup_distance;
+
+	/** Literal/length Huffman alphabet */
+	struct deflate_alphabet litlen;
+	/** Literal/length raw symbols
+	 *
+	 * Must immediately follow the literal/length Huffman alphabet.
+	 */
+	uint16_t litlen_raw[ DEFLATE_LITLEN_MAX_CODE + 1 ];
+	/** Number of symbols in the literal/length Huffman alphabet */
+	unsigned int litlen_count;
+
+	/** Distance and code length Huffman alphabet
+	 *
+	 * The code length Huffman alphabet has a maximum Huffman
+	 * symbol length of 7 and a maximum code value of 18, and is
+	 * thus strictly smaller than the distance Huffman alphabet.
+	 * Since we never need both alphabets simultaneously, we can
+	 * reuse the storage space for the distance alphabet to
+	 * temporarily hold the code length alphabet.
+	 */
+	struct deflate_alphabet distance_codelen;
+	/** Distance and code length raw symbols
+	 *
+	 * Must immediately follow the distance and code length
+	 * Huffman alphabet.
+	 */
+	uint16_t distance_codelen_raw[ DEFLATE_DISTANCE_MAX_CODE + 1 ];
+	/** Number of symbols in the distance Huffman alphabet */
+	unsigned int distance_count;
+
+	/** Huffman code lengths
+	 *
+	 * The literal/length and distance code lengths are
+	 * constructed as a single set of lengths.
+	 *
+	 * The code length Huffman alphabet has a maximum code value
+	 * of 18 and the set of lengths is thus strictly smaller than
+	 * the combined literal/length and distance set of lengths.
+	 * Since we never need both alphabets simultaneously, we can
+	 * reuse the storage space for the literal/length and distance
+	 * code lengths to temporarily hold the code length code
+	 * lengths.
+	 */
+	uint8_t lengths[ ( ( DEFLATE_LITLEN_MAX_CODE + 1 ) +
+			   ( DEFLATE_DISTANCE_MAX_CODE + 1 ) +
+			   1 /* round up */ ) / 2 ];
+};
+
+/** A chunk of data */
+struct deflate_chunk {
+	/** Data */
+	userptr_t data;
+	/** Current offset */
+	size_t offset;
+	/** Length of data */
+	size_t len;
+};
+
+/**
+ * Initialise chunk of data
+ *
+ * @v chunk		Chunk of data to initialise
+ * @v data		Data
+ * @v offset		Starting offset
+ * @v len		Length
+ */
+static inline __attribute__ (( always_inline )) void
+deflate_chunk_init ( struct deflate_chunk *chunk, userptr_t data,
+		     size_t offset, size_t len ) {
+
+	chunk->data = data;
+	chunk->offset = offset;
+	chunk->len = len;
+}
+
+/**
+ * Check if decompression has finished
+ *
+ * @v deflate		Decompressor
+ * @ret finished	Decompression has finished
+ */
+static inline int deflate_finished ( struct deflate *deflate ) {
+	return ( deflate->resume == NULL );
+}
+
+extern void deflate_init ( struct deflate *deflate,
+			   enum deflate_format format );
+extern int deflate_inflate ( struct deflate *deflate,
+			     struct deflate_chunk *in,
+			     struct deflate_chunk *out );
+
+#endif /* _IPXE_DEFLATE_H */