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+/*
+ * Copyright (C) 2013-2015 Willy Tarreau <w@1wt.eu>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef _SLZ_H
+#define _SLZ_H
+
+#include <inttypes.h>
+
+/* We have two macros UNALIGNED_LE_OK and UNALIGNED_FASTER. The latter indicates
+ * that using unaligned data is faster than a simple shift. On x86 32-bit at
+ * least it is not the case as the per-byte access is 30% faster. A core2-duo on
+ * x86_64 is 7% faster to read one byte + shifting by 8 than to read one word,
+ * but a core i5 is 7% faster doing the unaligned read, so we privilege more
+ * recent implementations here.
+ */
+#if defined(__x86_64__)
+#define UNALIGNED_LE_OK
+#define UNALIGNED_FASTER
+#define USE_64BIT_QUEUE
+#elif defined(__i386__) || defined(__i486__) || defined(__i586__) || defined(__i686__)
+#define UNALIGNED_LE_OK
+//#define UNALIGNED_FASTER
+#elif defined(__ARMEL__) && defined(__ARM_ARCH_7A__)
+#define UNALIGNED_LE_OK
+#define UNALIGNED_FASTER
+#elif defined(__ARM_ARCH_8A) || defined(__ARM_FEATURE_UNALIGNED)
+#define UNALIGNED_LE_OK
+#define UNALIGNED_FASTER
+#endif
+
+/* Log2 of the size of the hash table used for the references table. */
+#define HASH_BITS 13
+
+enum slz_state {
+ SLZ_ST_INIT, /* stream initialized */
+ SLZ_ST_EOB, /* header or end of block already sent */
+ SLZ_ST_FIXED, /* inside a fixed huffman sequence */
+ SLZ_ST_LAST, /* last block, BFINAL sent */
+ SLZ_ST_DONE, /* BFINAL+EOB sent BFINAL */
+ SLZ_ST_END /* end sent (BFINAL, EOB, CRC + len) */
+};
+
+enum {
+ SLZ_FMT_GZIP, /* RFC1952: gzip envelope and crc32 for CRC */
+ SLZ_FMT_ZLIB, /* RFC1950: zlib envelope and adler-32 for CRC */
+ SLZ_FMT_DEFLATE, /* RFC1951: raw deflate, and no crc */
+};
+
+struct slz_stream {
+#ifdef USE_64BIT_QUEUE
+ uint64_t queue; /* last pending bits, LSB first */
+#else
+ uint32_t queue; /* last pending bits, LSB first */
+#endif
+ uint32_t qbits; /* number of bits in queue, < 8 on 32-bit, < 32 on 64-bit */
+ unsigned char *outbuf; /* set by encode() */
+ uint16_t state; /* one of slz_state */
+ uint8_t level:1; /* 0 = no compression, 1 = compression */
+ uint8_t format:2; /* SLZ_FMT_* */
+ uint8_t unused1; /* unused for now */
+ uint32_t crc32;
+ uint32_t ilen;
+};
+
+/* Functions specific to rfc1951 (deflate) */
+long slz_rfc1951_encode(struct slz_stream *strm, unsigned char *out, const unsigned char *in, long ilen, int more);
+int slz_rfc1951_init(struct slz_stream *strm, int level);
+int slz_rfc1951_finish(struct slz_stream *strm, unsigned char *buf);
+
+/* Functions specific to rfc1952 (gzip) */
+uint32_t slz_crc32_by1(uint32_t crc, const unsigned char *buf, int len);
+uint32_t slz_crc32_by4(uint32_t crc, const unsigned char *buf, int len);
+long slz_rfc1952_encode(struct slz_stream *strm, unsigned char *out, const unsigned char *in, long ilen, int more);
+int slz_rfc1952_send_header(struct slz_stream *strm, unsigned char *buf);
+int slz_rfc1952_init(struct slz_stream *strm, int level);
+int slz_rfc1952_finish(struct slz_stream *strm, unsigned char *buf);
+
+/* Functions specific to rfc1950 (zlib) */
+uint32_t slz_adler32_by1(uint32_t crc, const unsigned char *buf, int len);
+uint32_t slz_adler32_block(uint32_t crc, const unsigned char *buf, long len);
+long slz_rfc1950_encode(struct slz_stream *strm, unsigned char *out, const unsigned char *in, long ilen, int more);
+int slz_rfc1950_send_header(struct slz_stream *strm, unsigned char *buf);
+int slz_rfc1950_init(struct slz_stream *strm, int level);
+int slz_rfc1950_finish(struct slz_stream *strm, unsigned char *buf);
+
+/* generic functions */
+
+/* Initializes stream <strm>. It will configure the stream to use format
+ * <format> for the data, which must be one of SLZ_FMT_*. The compression level
+ * passed in <level> is set. This value can only be 0 (no compression) or 1
+ * (compression) and other values will lead to unpredictable behaviour. The
+ * function should always return 0.
+ */
+static inline int slz_init(struct slz_stream *strm, int level, int format)
+{
+ int ret;
+
+ if (format == SLZ_FMT_GZIP)
+ ret = slz_rfc1952_init(strm, level);
+ else if (format == SLZ_FMT_ZLIB)
+ ret = slz_rfc1950_init(strm, level);
+ else { /* deflate for anything else */
+ ret = slz_rfc1951_init(strm, level);
+ strm->format = format;
+ }
+ return ret;
+}
+
+/* Encodes the block according to the format used by the stream. This means
+ * that the CRC of the input block may be computed according to the CRC32 or
+ * adler-32 algorithms. The number of output bytes is returned.
+ */
+static inline long slz_encode(struct slz_stream *strm, void *out,
+ const void *in, long ilen, int more)
+{
+ long ret;
+
+ if (strm->format == SLZ_FMT_GZIP)
+ ret = slz_rfc1952_encode(strm, (unsigned char *) out, (const unsigned char *) in, ilen, more);
+ else if (strm->format == SLZ_FMT_ZLIB)
+ ret = slz_rfc1950_encode(strm, (unsigned char *) out, (const unsigned char *) in, ilen, more);
+ else /* deflate for other ones */
+ ret = slz_rfc1951_encode(strm, (unsigned char *) out, (const unsigned char *) in, ilen, more);
+
+ return ret;
+}
+
+/* Flushes pending bits and sends the trailer for stream <strm> into buffer
+ * <buf> if needed. When it's done, the stream state is updated to SLZ_ST_END.
+ * It returns the number of bytes emitted. The trailer consists in flushing the
+ * possibly pending bits from the queue (up to 24 bits), rounding to the next
+ * byte, then 4 bytes for the CRC when doing zlib/gzip, then another 4 bytes
+ * for the input length for gzip. That may about to 4+4+4 = 12 bytes, that the
+ * caller must ensure are available before calling the function.
+ */
+static inline int slz_finish(struct slz_stream *strm, void *buf)
+{
+ int ret;
+
+ if (strm->format == SLZ_FMT_GZIP)
+ ret = slz_rfc1952_finish(strm, (unsigned char *) buf);
+ else if (strm->format == SLZ_FMT_ZLIB)
+ ret = slz_rfc1950_finish(strm, (unsigned char *) buf);
+ else /* deflate for other ones */
+ ret = slz_rfc1951_finish(strm, (unsigned char *) buf);
+
+ return ret;
+}
+
+#endif