| /**************************************************************************** |
| * libs/libc/lzf/lzf_c.c |
| * |
| * Copyright (c) 2000-2010 Marc Alexander Lehmann <schmorp@schmorp.de> |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPE- CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| * |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Included Files |
| ****************************************************************************/ |
| |
| #include "lzf/lzf.h" |
| |
| #ifdef CONFIG_LIBC_LZF |
| |
| /**************************************************************************** |
| * Pre-processor Definitions |
| ****************************************************************************/ |
| |
| #define HSIZE (1 << HLOG) |
| |
| /* Don't play with this unless you benchmark! The data format is not |
| * dependent on the hash function. The hash function might seem strange, just |
| * believe me, it works ;) |
| */ |
| |
| #ifndef FRST |
| # define FRST(p) (((p[0]) << 8) | p[1]) |
| # define NEXT(v,p) (((v) << 8) | p[2]) |
| # if defined(CONFIG_LIBC_LZF_FASTEST) |
| # define IDX(h) ((( h >> (3*8 - HLOG)) - h ) & (HSIZE - 1)) |
| # elif defined(CONFIG_LIBC_LZF_FAST) |
| # define IDX(h) ((( h >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) |
| # else |
| # define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) |
| # endif |
| #endif |
| |
| /* IDX works because it is very similar to a multiplicative hash, e.g. |
| * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1)) |
| * the latter is also quite fast on newer CPUs, and compresses similarly. |
| * |
| * the next one is also quite good, albeit slow ;) |
| * (int)(cos(h & 0xffffff) * 1e6) |
| */ |
| |
| #if 0 |
| /* original lzv-like hash function, much worse and thus slower */ |
| |
| # define FRST(p) (p[0] << 5) ^ p[1] |
| # define NEXT(v,p) ((v) << 5) ^ p[2] |
| # define IDX(h) ((h) & (HSIZE - 1)) |
| #endif |
| |
| #define MAX_LIT (1 << 5) |
| #define MAX_OFF (1 << HLOG) |
| #define MAX_REF ((1 << 8) + (1 << 3)) |
| |
| #if __GNUC__ >= 3 |
| # define expect(expr,value) __builtin_expect((expr),(value)) |
| # define inline inline |
| #else |
| # define expect(expr,value) (expr) |
| # define inline static |
| #endif |
| |
| #define expect_false(expr) expect((expr) != 0, 0) |
| #define expect_true(expr) expect((expr) != 0, 1) |
| |
| /**************************************************************************** |
| * Public Functions |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Name: lzf_compress |
| * |
| * Description: |
| * Compress in_len bytes stored at the memory block starting at |
| * in_data and write the result to out_data, up to a maximum length |
| * of out_len bytes. |
| * |
| * If the output buffer is not large enough or any error occurs return 0, |
| * otherwise return the number of bytes used, which might be considerably |
| * more than in_len (but less than 104% of the original size), so it |
| * makes sense to always use out_len == in_len - 1), to ensure _some_ |
| * compression, and store the data uncompressed otherwise (with a flag, of |
| * course. |
| * |
| * lzf_compress might use different algorithms on different systems and |
| * even different runs, thus might result in different compressed strings |
| * depending on the phase of the moon or similar factors. However, all |
| * these strings are architecture-independent and will result in the |
| * original data when decompressed using lzf_decompress. |
| * |
| * The buffers must not be overlapping. |
| * |
| * Compressed format: |
| * |
| * 000LLLLL <L+1> ; literal, L+1=1..33 octets |
| * LLLooooo oooooooo ; backref L+1=1..7 octets, o+1=1..4096 offset |
| * 111ooooo LLLLLLLL oooooooo ; backref L+8 octets, o+1=1..4096 offset |
| * |
| ****************************************************************************/ |
| |
| size_t lzf_compress(FAR const void *const in_data, |
| unsigned int in_len, FAR void *out_data, |
| unsigned int out_len, lzf_state_t htab, |
| FAR struct lzf_header_s **reshdr) |
| { |
| FAR const uint8_t *ip = (const uint8_t *)in_data; |
| FAR uint8_t *op = (uint8_t *)out_data; |
| FAR const uint8_t *in_end = ip + in_len; |
| FAR uint8_t *out_end = op + out_len; |
| FAR const uint8_t *ref; |
| ssize_t cs; |
| ssize_t retlen; |
| |
| /* off requires a type wide enough to hold a general pointer difference. |
| * ISO C doesn't have that (size_t might not be enough and ptrdiff_t only |
| * works for differences within a single object). We also assume that no |
| * no bit pattern traps. Since the only platform that is both non-POSIX |
| * and fails to support both assumptions is windows 64 bit, we make a |
| * special workaround for it. |
| */ |
| |
| #ifdef CONFIG_HAVE_LONG_LONG |
| uint64_t off; /* Workaround for missing POSIX compliance */ |
| #else |
| unsigned long off; |
| #endif |
| unsigned int hval; |
| int lit; |
| |
| if (!in_len || !out_len) |
| { |
| cs = 0; |
| goto genhdr; |
| } |
| |
| #if INIT_HTAB |
| memset(htab, 0, sizeof(htab)); |
| #endif |
| |
| lit = 0; /* start run */ |
| op++; |
| |
| hval = FRST(ip); |
| while (ip < in_end - 2) |
| { |
| lzf_hslot_t *hslot; |
| |
| hval = NEXT(hval, ip); |
| hslot = htab + IDX(hval); |
| ref = *hslot + LZF_HSLOT_BIAS; |
| *hslot = ip - LZF_HSLOT_BIAS; |
| |
| if (1 |
| #if INIT_HTAB |
| && ref < ip /* the next test will actually take care of this, but this is faster */ |
| #endif |
| && (off = ip - ref - 1) < MAX_OFF |
| && ref > (uint8_t *)in_data |
| && ref[2] == ip[2] |
| #ifdef CONFIG_LIBC_LZF_ALIGN |
| && ((ref[1] << 8) | ref[0]) == ((ip[1] << 8) | ip[0]) |
| #else |
| && *(FAR uint16_t *)ref == *(FAR uint16_t *)ip |
| #endif |
| ) |
| { |
| /* Match found at *ref++ */ |
| |
| unsigned int len = 2; |
| unsigned int maxlen = in_end - ip - len; |
| maxlen = maxlen > MAX_REF ? MAX_REF : maxlen; |
| |
| /* First a faster conservative test */ |
| |
| if (expect_false(op + 3 + 1 >= out_end)) |
| { |
| /* Second the exact but rare test */ |
| |
| if (op - !lit + 3 + 1 >= out_end) |
| { |
| cs = 0; |
| goto genhdr; |
| } |
| } |
| |
| op[(- lit) - 1] = lit - 1; /* Stop run */ |
| op -= !lit; /* Undo run if length is zero */ |
| |
| for (; ; ) |
| { |
| if (expect_true(maxlen > 16)) |
| { |
| len++; |
| if (ref[len] != ip[len]) |
| { |
| break; |
| } |
| |
| len++; |
| if (ref[len] != ip[len]) |
| { |
| break; |
| } |
| |
| len++; |
| if (ref[len] != ip[len]) |
| { |
| break; |
| } |
| |
| len++; |
| if (ref[len] != ip[len]) |
| { |
| break; |
| } |
| |
| len++; |
| if (ref[len] != ip[len]) |
| { |
| break; |
| } |
| |
| len++; |
| if (ref[len] != ip[len]) |
| { |
| break; |
| } |
| |
| len++; |
| if (ref[len] != ip[len]) |
| { |
| break; |
| } |
| |
| len++; |
| if (ref[len] != ip[len]) |
| { |
| break; |
| } |
| |
| len++; |
| if (ref[len] != ip[len]) |
| { |
| break; |
| } |
| |
| len++; |
| if (ref[len] != ip[len]) |
| { |
| break; |
| } |
| |
| len++; |
| if (ref[len] != ip[len]) |
| { |
| break; |
| } |
| |
| len++; |
| if (ref[len] != ip[len]) |
| { |
| break; |
| } |
| |
| len++; |
| if (ref[len] != ip[len]) |
| { |
| break; |
| } |
| |
| len++; |
| if (ref[len] != ip[len]) |
| { |
| break; |
| } |
| |
| len++; |
| if (ref[len] != ip[len]) |
| { |
| break; |
| } |
| |
| len++; |
| if (ref[len] != ip[len]) |
| { |
| break; |
| } |
| } |
| |
| do |
| { |
| len++; |
| } |
| while (len < maxlen && ref[len] == ip[len]); |
| |
| break; |
| } |
| |
| len -= 2; /* len is now #octets - 1 */ |
| ip++; |
| |
| if (len < 7) |
| { |
| *op++ = (off >> 8) + (len << 5); |
| } |
| else |
| { |
| *op++ = (off >> 8) + (7 << 5); |
| *op++ = len - 7; |
| } |
| |
| *op++ = off; |
| |
| lit = 0; op++; /* start run */ |
| |
| ip += len + 1; |
| |
| if (expect_false (ip >= in_end - 2)) |
| { |
| break; |
| } |
| |
| #if defined(CONFIG_LIBC_LZF_FASTEST) || defined(CONFIG_LIBC_LZF_FAST) |
| --ip; |
| # if defined(CONFIG_LIBC_LZF_FAST) && !defined(CONFIG_LIBC_LZF_FASTEST) |
| --ip; |
| # endif |
| hval = FRST(ip); |
| |
| hval = NEXT(hval, ip); |
| htab[IDX(hval)] = ip - LZF_HSLOT_BIAS; |
| ip++; |
| |
| # if defined(CONFIG_LIBC_LZF_FAST) && !defined(CONFIG_LIBC_LZF_FASTEST) |
| hval = NEXT(hval, ip); |
| htab[IDX(hval)] = ip - LZF_HSLOT_BIAS; |
| ip++; |
| # endif |
| #else |
| ip -= len + 1; |
| |
| do |
| { |
| hval = NEXT(hval, ip); |
| htab[IDX(hval)] = ip - LZF_HSLOT_BIAS; |
| ip++; |
| } |
| while (len--); |
| #endif |
| } |
| else |
| { |
| /* One more literal byte we must copy */ |
| |
| if (expect_false(op >= out_end)) |
| { |
| cs = 0; |
| goto genhdr; |
| } |
| |
| lit++; |
| *op++ = *ip++; |
| |
| if (expect_false(lit == MAX_LIT)) |
| { |
| op[(- lit) - 1] = lit - 1; /* Stop run */ |
| lit = 0; /* Start run */ |
| op++; |
| } |
| } |
| } |
| |
| /* At most 3 bytes can be missing here */ |
| |
| if (op + 3 > out_end) |
| { |
| cs = 0; |
| goto genhdr; |
| } |
| |
| while (ip < in_end) |
| { |
| lit++; *op++ = *ip++; |
| |
| if (expect_false(lit == MAX_LIT)) |
| { |
| op[(- lit) - 1] = lit - 1; /* Stop run */ |
| lit = 0; /* Start run */ |
| op++; |
| } |
| } |
| |
| op[(- lit) - 1] = lit - 1; /* End run */ |
| op -= !lit; /* Undo run if length is zero */ |
| |
| cs = op - (uint8_t *)out_data; |
| |
| genhdr: |
| if (cs) |
| { |
| FAR struct lzf_type1_header_s *header; |
| |
| /* Write compressed */ |
| |
| header = (FAR struct lzf_type1_header_s *) |
| ((uintptr_t)out_data - LZF_TYPE1_HDR_SIZE); |
| |
| header->lzf_magic[0] = 'Z'; |
| header->lzf_magic[1] = 'V'; |
| header->lzf_type = LZF_TYPE1_HDR; |
| header->lzf_clen[0] = cs >> 8; |
| header->lzf_clen[1] = cs & 0xff; |
| header->lzf_ulen[0] = in_len >> 8; |
| header->lzf_ulen[1] = in_len & 0xff; |
| |
| *reshdr = (FAR struct lzf_header_s *)header; |
| retlen = cs + LZF_TYPE1_HDR_SIZE; |
| } |
| else |
| { |
| FAR struct lzf_type0_header_s *header; |
| |
| /* Write uncompressed */ |
| |
| header = (FAR struct lzf_type0_header_s *) |
| ((uintptr_t)in_data - LZF_TYPE0_HDR_SIZE); |
| |
| header->lzf_magic[0] = 'Z'; |
| header->lzf_magic[1] = 'V'; |
| header->lzf_type = LZF_TYPE0_HDR; |
| header->lzf_len[0] = in_len >> 8; |
| header->lzf_len[1] = in_len & 0xff; |
| |
| *reshdr = (FAR struct lzf_header_s *)header; |
| retlen = in_len + LZF_TYPE0_HDR_SIZE; |
| } |
| |
| return retlen; |
| } |
| |
| #endif /* CONFIG_LIBC_LZF */ |
