lib_qlz.c

// Fast data compression library
// Copyright (C) 2006-2009 Lasse Mikkel Reinhold
// lar@quicklz.com
//
// QuickLZ can be used for free under the GPL-1 or GPL-2 license (where anything 
// released into public must be open source) or under a commercial license if such 
// has been acquired (see http://www.quicklz.com/order.html). The commercial license 
// does not cover derived or ported versions created by third parties under GPL.
// Version 1.4.1 final - april 2010
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <pthread.h>
#include "lib_safe.h"
#define QLZ_COMPRESSION_LEVEL 1
#define QLZ_STREAMING_BUFFER 0
#include "lib_qlz.h"
extern char *logname;
extern char *function;
extern int debug;
extern int BLKSIZE;

static pthread_mutex_t qlz_mutex = PTHREAD_MUTEX_INITIALIZER;

#if QLZ_VERSION_MAJOR != 1 || QLZ_VERSION_MINOR != 4 || QLZ_VERSION_REVISION != 1
#error quicklz.c and quicklz.h have different versions
#endif

#if (defined(x86_64) || defined(__X86__) || defined(__i386__) || defined(i386) || defined(_M_IX86) || defined(__386__) || defined(__x86_64__) || defined(_M_X64))
#define X86X64
#endif

#define MINOFFSET 2
#define UNCONDITIONAL_MATCHLEN 6
#define UNCOMPRESSED_END 4
#define CWORD_LEN 4

typedef unsigned int ui32;
typedef unsigned short int ui16;

// Return the decompressed block without the 
// leading byte that informs about the used compression
// First byte = 'Q' Indicates that the block is QLZ compressed
// First byte = 0 The block is not compressed
// First byte = 'L' Indicates that the block is LZO compressed
compr *clz_decompress(unsigned char *buf, int buflen)
{
    compr *retdata;
    char *scratch;
    if ( buflen <= 0 ) return NULL;
    pthread_mutex_lock(&qlz_mutex);
    retdata = s_zmalloc(sizeof(compr));
    if (buf[0] == 'Q') {
        retdata->size = qlz_size_decompressed((char *) &buf[1]);
        retdata->data = s_zmalloc(retdata->size);
        // SCRATCH_DECOMPRESS is defined in the beginning of the quicklz.c file
        scratch = (char *) s_malloc(QLZ_SCRATCH_COMPRESS);
        // decompress and write result
        retdata->size =
            qlz_decompress((char *) &buf[1], retdata->data, scratch);
        s_free(scratch);
    } else {
        retdata->size = buflen - 1;
        retdata->data = s_malloc(retdata->size);
        memcpy(retdata->data, &buf[1], buflen - 1);
    }
    pthread_mutex_unlock(&qlz_mutex);
    return retdata;
}

compr *clz_compress(unsigned char *buf, int buflen)
{
    compr *retdata;
    char *scratch;

    pthread_mutex_lock(&qlz_mutex);
    retdata = s_zmalloc(sizeof(compr));

    // allocate "uncompressed size" + 400 for the destination buffer
    retdata->data = s_zmalloc(buflen + 400 +1);

    // SCRATCH_COMPRESS is defined in the beginning of the lib_qlz.c file
    scratch = s_zmalloc(QLZ_SCRATCH_COMPRESS);
    retdata->size =
        qlz_compress(buf, (char *) &retdata->data[1], buflen, scratch);
    if (retdata->size < buflen) {
        retdata->size++;
        retdata->data[0] = 'Q';
    } else {
        retdata->size = buflen + 1;
        memcpy(&retdata->data[1], buf, buflen);
        retdata->data[0] = 0;
    }
    s_free(scratch);
    pthread_mutex_unlock(&qlz_mutex);
    return retdata;
}

int qlz_get_setting(int setting)
{
    switch (setting) {
    case 0:
        return QLZ_COMPRESSION_LEVEL;
    case 1:
        return QLZ_SCRATCH_COMPRESS;
    case 2:
        return QLZ_SCRATCH_DECOMPRESS;
    case 3:
        return QLZ_STREAMING_BUFFER;
#ifdef QLZ_MEMORY_SAFE
    case 6:
        return 1;
#else
    case 6:
        return 0;
#endif
    case 7:
        return QLZ_VERSION_MAJOR;
    case 8:
        return QLZ_VERSION_MINOR;
    case 9:
        return QLZ_VERSION_REVISION;
    }
    return -1;
}

static void reset_state(unsigned char hash_counter[QLZ_HASH_VALUES])
{
    memset(hash_counter, 0, QLZ_HASH_VALUES);
}

static __inline ui32 hash_func(ui32 i)
{
#if QLZ_COMPRESSION_LEVEL == 2
    return ((i >> 9) ^ (i >> 13) ^ i) & (QLZ_HASH_VALUES - 1);
#else
    return ((i >> 12) ^ i) & (QLZ_HASH_VALUES - 1);
#endif
}

static __inline ui32 fast_read(void const *src, ui32 bytes)
{
#ifndef X86X64
    unsigned char *p = (unsigned char *) src;
    switch (bytes) {
    case 4:
        return (*p | *(p + 1) << 8 | *(p + 2) << 16 | *(p + 3) << 24);
    case 3:
        return (*p | *(p + 1) << 8 | *(p + 2) << 16);
    case 2:
        return (*p | *(p + 1) << 8);
    case 1:
        return (*p);
    }
    return 0;
#else
    if (bytes >= 1 && bytes <= 4)
        return *((ui32 *) src);
    else
        return 0;
#endif
}

static __inline void fast_write(ui32 f, void *dst, size_t bytes)
{
#ifndef X86X64
    unsigned char *p = (unsigned char *) dst;

    switch (bytes) {
    case 4:
        *p = (unsigned char) f;
        *(p + 1) = (unsigned char) (f >> 8);
        *(p + 2) = (unsigned char) (f >> 16);
        *(p + 3) = (unsigned char) (f >> 24);
        return;
    case 3:
        *p = (unsigned char) f;
        *(p + 1) = (unsigned char) (f >> 8);
        *(p + 2) = (unsigned char) (f >> 16);
        return;
    case 2:
        *p = (unsigned char) f;
        *(p + 1) = (unsigned char) (f >> 8);
        return;
    case 1:
        *p = (unsigned char) f;
        return;
    }
#else
    switch (bytes) {
    case 4:
        *((ui32 *) dst) = f;
        return;
    case 3:
        *((ui32 *) dst) = f;
        return;
    case 2:
        *((ui16 *) dst) = (ui16) f;
        return;
    case 1:
        *((unsigned char *) dst) = (unsigned char) f;
        return;
    }
#endif
}

static __inline void memcpy_up(unsigned char *dst,
                               const unsigned char *src, ui32 n)
{
    // Caution if modifying memcpy_up! Overlap of dst and src must be special handled.
#ifndef X86X64
    unsigned char *end = dst + n;
    while (dst < end) {
        *dst = *src;
        dst++;
        src++;
    }
#else
    ui32 f = 0;
    do {
        *(ui32 *) (dst + f) = *(ui32 *) (src + f);
        f += MINOFFSET + 1;
    }
    while (f < n);
#endif
}


#if QLZ_COMPRESSION_LEVEL <= 2
static __inline void update_hash(qlz_hash_decompress h[QLZ_HASH_VALUES],
                                 unsigned char counter[QLZ_HASH_VALUES],
                                 const unsigned char *s)
{
#if QLZ_COMPRESSION_LEVEL == 1
    ui32 hash, fetch;
    fetch = fast_read(s, 3);
    hash = hash_func(fetch);
    h[hash].offset[0] = s;
    counter[hash] = 1;
#elif QLZ_COMPRESSION_LEVEL == 2
    ui32 hash, fetch;
    unsigned char c;
    fetch = fast_read(s, 3);
    hash = hash_func(fetch);
    c = counter[hash];
    h[hash].offset[c & (QLZ_POINTERS - 1)] = s;
    c++;
    counter[hash] = c;
#endif
}

static void update_hash_upto(qlz_hash_decompress h[QLZ_HASH_VALUES],
                             unsigned char counter[QLZ_HASH_VALUES],
                             unsigned char **lh, const unsigned char *max)
{
    while (*lh < max) {
        (*lh)++;
        update_hash(h, counter, *lh);
    }
}
#endif

static size_t qlz_compress_core(const unsigned char *source,
                                unsigned char *destination, size_t size,
                                qlz_hash_compress
                                hashtable[QLZ_HASH_VALUES],
                                unsigned char
                                hash_counter[QLZ_HASH_VALUES])
{
    const unsigned char *last_byte = source + size - 1;
    const unsigned char *src = source;
    unsigned char *cword_ptr = destination;
    unsigned char *dst = destination + CWORD_LEN;
    ui32 cword_val = 1U << 31;
    const unsigned char *last_matchstart =
        last_byte - UNCONDITIONAL_MATCHLEN - UNCOMPRESSED_END;
    ui32 fetch = 0;
    unsigned int lits = 0;

    (void) lits;

    if (src <= last_matchstart)
        fetch = fast_read(src, 3);

    while (src <= last_matchstart) {
        if ((cword_val & 1) == 1) {
            // store uncompressed if compression ratio is too low
            if (src > source + 3 * (size >> 2)
                && dst - destination >
                src - source - ((src - source) >> 5))
                return 0;

            fast_write((cword_val >> 1) | (1U << 31), cword_ptr,
                       CWORD_LEN);

            cword_ptr = dst;
            dst += CWORD_LEN;
            cword_val = 1U << 31;
            fetch = fast_read(src, 3);
        }
#if QLZ_COMPRESSION_LEVEL == 1
        {
            const unsigned char *o;
            ui32 hash, cached;

            hash = hash_func(fetch);

            cached = fetch ^ hashtable[hash].cache[0];
            hashtable[hash].cache[0] = fetch;

            o = hashtable[hash].offset[0];
            hashtable[hash].offset[0] = src;
#ifdef X86X64
            if ((cached & 0xffffff) == 0 && hash_counter[hash] != 0
                && (src - o > MINOFFSET
                    || (src == o + 1 && lits >= 3 && src > source + 3
                        && *src == *(src - 3) && *src == *(src - 2)
                        && *src == *(src - 1) && *src == *(src + 1)
                        && *src == *(src + 2))))
#else
            if (cached == 0 && hash_counter[hash] != 0
                && (src - o > MINOFFSET
                    || (src == o + 1 && lits >= 3 && src > source + 3
                        && *src == *(src - 3) && *src == *(src - 2)
                        && *src == *(src - 1) && *src == *(src + 1)
                        && *src == *(src + 2))))
#endif
            {
                if (*(o + 3) != *(src + 3)) {
                    cword_val = (cword_val >> 1) | (1U << 31);
                    fast_write((3 - 2) | (hash << 4), dst, 2);
                    src += 3;
                    dst += 2;
                } else {
                    const unsigned char *old_src = src;
                    size_t matchlen;

                    cword_val = (cword_val >> 1) | (1U << 31);
                    src += 4;

                    if (*(o + (src - old_src)) == *src) {
                        src++;
                        if (*(o + (src - old_src)) == *src) {
                            size_t q =
                                last_byte - UNCOMPRESSED_END - (src - 5) +
                                1;
                            size_t remaining = q > 255 ? 255 : q;
                            src++;
                            while (*(o + (src - old_src)) == *src
                                   && (size_t) (src - old_src) < remaining)
                                src++;
                        }
                    }

                    matchlen = src - old_src;
                    hash <<= 4;
                    if (matchlen < 18) {
                        fast_write((ui32) (matchlen - 2) | hash, dst, 2);
                        dst += 2;
                    } else {
                        fast_write((ui32) (matchlen << 16) | hash, dst, 3);
                        dst += 3;
                    }
                }
                fetch = fast_read(src, 3);
                lits = 0;
            } else {
                lits++;
                hash_counter[hash] = 1;
                *dst = *src;
                src++;
                dst++;
                cword_val = (cword_val >> 1);
#ifdef X86X64
                fetch = fast_read(src, 3);
#else
                fetch = fetch >> 8 & 0xffff | *(src + 2) << 16;
#endif
            }
        }
#elif QLZ_COMPRESSION_LEVEL >= 2
        {
            const unsigned char *o, *offset2;
            ui32 hash, matchlen, k, m, best_k = 0;
            unsigned char c;
            size_t remaining =
                (last_byte - UNCOMPRESSED_END - src + 1) >
                255 ? 255 : (last_byte - UNCOMPRESSED_END - src + 1);
            (void) best_k;

            fetch = fast_read(src, 3);
            hash = hash_func(fetch);

            c = hash_counter[hash];

            offset2 = hashtable[hash].offset[0];
            if (offset2 < src - MINOFFSET && c > 0
                && ((fast_read(offset2, 3) ^ fetch) & 0xffffff) == 0) {
                matchlen = 3;
                if (*(offset2 + matchlen) == *(src + matchlen)) {
                    matchlen = 4;
                    while (*(offset2 + matchlen) == *(src + matchlen)
                           && matchlen < remaining)
                        matchlen++;
                }
            } else
                matchlen = 0;
            for (k = 1; k < QLZ_POINTERS && c > k; k++) {
                o = hashtable[hash].offset[k];
#if QLZ_COMPRESSION_LEVEL == 3
                if (((fast_read(o, 3) ^ fetch) & 0xffffff) == 0
                    && o < src - MINOFFSET)
#elif QLZ_COMPRESSION_LEVEL == 2
                if (*(src + matchlen) == *(o + matchlen)
                    && ((fast_read(o, 3) ^ fetch) & 0xffffff) == 0
                    && o < src - MINOFFSET)
#endif
                {
                    m = 3;
                    while (*(o + m) == *(src + m) && m < remaining)
                        m++;
#if QLZ_COMPRESSION_LEVEL == 3
                    if ((m > matchlen) || (m == matchlen && o > offset2))
#elif QLZ_COMPRESSION_LEVEL == 2
                    if (m > matchlen)
#endif
                    {
                        offset2 = o;
                        matchlen = m;
                        best_k = k;
                    }
                }
            }
            o = offset2;
            hashtable[hash].offset[c & (QLZ_POINTERS - 1)] = src;
            c++;
            hash_counter[hash] = c;

#if QLZ_COMPRESSION_LEVEL == 3
            if (matchlen > 2 && src - o < 131071) {
                ui32 u;
                size_t offset = src - o;

                for (u = 1; u < matchlen; u++) {
                    fetch = fast_read(src + u, 3);
                    hash = hash_func(fetch);
                    c = hash_counter[hash]++;
                    hashtable[hash].offset[c & (QLZ_POINTERS - 1)] =
                        src + u;
                }

                cword_val = (cword_val >> 1) | (1U << 31);
                src += matchlen;

                if (matchlen == 3 && offset <= 63) {
                    *dst = (unsigned char) (offset << 2);
                    dst++;
                } else if (matchlen == 3 && offset <= 16383) {
                    ui32 f = (ui32) ((offset << 2) | 1);
                    fast_write(f, dst, 2);
                    dst += 2;
                } else if (matchlen <= 18 && offset <= 1023) {
                    ui32 f = ((matchlen - 3) << 2) | (offset << 6) | 2;
                    fast_write(f, dst, 2);
                    dst += 2;
                }

                else if (matchlen <= 33) {
                    ui32 f = ((matchlen - 2) << 2) | (offset << 7) | 3;
                    fast_write(f, dst, 3);
                    dst += 3;
                } else {
                    ui32 f = ((matchlen - 3) << 7) | (offset << 15) | 3;
                    fast_write(f, dst, 4);
                    dst += 4;
                }
            } else {
                *dst = *src;
                src++;
                dst++;
                cword_val = (cword_val >> 1);
            }

#elif QLZ_COMPRESSION_LEVEL == 2

            if (matchlen > 2) {
                cword_val = (cword_val >> 1) | (1U << 31);
                src += matchlen;

                if (matchlen < 10) {
                    ui32 f = best_k | ((matchlen - 2) << 2) | (hash << 5);
                    fast_write(f, dst, 2);
                    dst += 2;
                } else {
                    ui32 f = best_k | (matchlen << 16) | (hash << 5);
                    fast_write(f, dst, 3);
                    dst += 3;
                }
            } else {
                *dst = *src;
                src++;
                dst++;
                cword_val = (cword_val >> 1);
            }
#endif
        }
#endif

    }

    while (src <= last_byte) {
        if ((cword_val & 1) == 1) {
            fast_write((cword_val >> 1) | (1U << 31), cword_ptr,
                       CWORD_LEN);
            cword_ptr = dst;
            dst += CWORD_LEN;
            cword_val = 1U << 31;
        }
#if QLZ_COMPRESSION_LEVEL < 3
        if (src <= last_byte - 3) {
#if QLZ_COMPRESSION_LEVEL == 1
            ui32 hash;
            fetch = fast_read(src, 3);
            hash = hash_func(fetch);
            hashtable[hash].offset[0] = src;
            hashtable[hash].cache[0] = fetch;
            hash_counter[hash] = 1;
#elif QLZ_COMPRESSION_LEVEL == 2
            ui32 hash;
            unsigned char c;
            fetch = fast_read(src, 3);
            hash = hash_func(fetch);
            c = hash_counter[hash];
            hashtable[hash].offset[c & (QLZ_POINTERS - 1)] = src;
            c++;
            hash_counter[hash] = c;
#endif
        }
#endif
        *dst = *src;
        src++;
        dst++;

        cword_val = (cword_val >> 1);
    }

    while ((cword_val & 1) != 1)
        cword_val = (cword_val >> 1);

    fast_write((cword_val >> 1) | (1U << 31), cword_ptr, CWORD_LEN);

    // min. size must be 9 bytes so that the qlz_size functions can take 9 bytes as argument
    return dst - destination < 9 ? 9 : dst - destination;
}

static size_t qlz_decompress_core(const unsigned char *source,
                                  unsigned char *destination, size_t size,
                                  qlz_hash_decompress
                                  hashtable[QLZ_HASH_VALUES],
                                  unsigned char
                                  hash_counter[QLZ_HASH_VALUES],
                                  unsigned char *history,
                                  const char *source_2)
{
    const unsigned char *src = source;
    unsigned char *dst = destination;
    const unsigned char *last_destination_byte = destination + size - 1;
    ui32 cword_val = 1;
    const ui32 bitlut[16] =
        { 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0 };
    const unsigned char *last_matchstart =
        last_destination_byte - UNCONDITIONAL_MATCHLEN - UNCOMPRESSED_END;
    unsigned char *last_hashed = destination - 1;
    const unsigned char *last_source_byte =
        (const unsigned char *) source_2 + qlz_size_compressed(source_2) -
        1;

    (void) last_source_byte;
    (void) history;
    (void) last_hashed;
    (void) hash_counter;
    (void) hashtable;

    for (;;) {
        ui32 fetch;

        if (cword_val == 1) {
#ifdef QLZ_MEMORY_SAFE
            if (src + CWORD_LEN - 1 > last_source_byte)
                return 0;
#endif
            cword_val = fast_read(src, CWORD_LEN);
            src += CWORD_LEN;
        }
#ifdef QLZ_MEMORY_SAFE
        if (src + 4 - 1 > last_source_byte)
            return 0;
#endif

        fetch = fast_read(src, 4);

        if ((cword_val & 1) == 1) {
            ui32 matchlen;
            const unsigned char *offset2;

#if QLZ_COMPRESSION_LEVEL == 1
            ui32 hash;
            cword_val = cword_val >> 1;
            hash = (fetch >> 4) & 0xfff;
            offset2 = hashtable[hash].offset[0];

            if ((fetch & 0xf) != 0) {
                matchlen = (fetch & 0xf) + 2;
                src += 2;
            } else {
                matchlen = *(src + 2);
                src += 3;
            }

#elif QLZ_COMPRESSION_LEVEL == 2
            ui32 hash;
            unsigned char c;
            cword_val = cword_val >> 1;
            hash = (fetch >> 5) & 0x7ff;
            c = (unsigned char) (fetch & 0x3);
            offset2 = hashtable[hash].offset[c];

            if ((fetch & (28)) != 0) {
                matchlen = ((fetch >> 2) & 0x7) + 2;
                src += 2;
            } else {
                matchlen = *(src + 2);
                src += 3;
            }

#elif QLZ_COMPRESSION_LEVEL == 3
            ui32 offset;
            cword_val = cword_val >> 1;
            if ((fetch & 3) == 0) {
                offset = (fetch & 0xff) >> 2;
                matchlen = 3;
                src++;
            } else if ((fetch & 2) == 0) {
                offset = (fetch & 0xffff) >> 2;
                matchlen = 3;
                src += 2;
            } else if ((fetch & 1) == 0) {
                offset = (fetch & 0xffff) >> 6;
                matchlen = ((fetch >> 2) & 15) + 3;
                src += 2;
            } else if ((fetch & 127) != 3) {
                offset = (fetch >> 7) & 0x1ffff;
                matchlen = ((fetch >> 2) & 0x1f) + 2;
                src += 3;
            } else {
                offset = (fetch >> 15);
                matchlen = ((fetch >> 7) & 255) + 3;
                src += 4;
            }

            offset2 = dst - offset;
#endif

#ifdef QLZ_MEMORY_SAFE
            if (offset2 < history || offset2 > dst - MINOFFSET - 1)
                return 0;

            if (matchlen >
                (ui32) (last_destination_byte - dst - UNCOMPRESSED_END +
                        1))
                return 0;
#endif
            memcpy_up(dst, offset2, matchlen);
            dst += matchlen;

#if QLZ_COMPRESSION_LEVEL <= 2
            update_hash_upto(hashtable, hash_counter, &last_hashed,
                             dst - matchlen);
            last_hashed = dst - 1;
#endif
        }

        else {
            if (dst < last_matchstart) {
#ifdef X86X64
                *(ui32 *) dst = *(ui32 *) src;
#else
                memcpy_up(dst, src, 4);
#endif
                dst += bitlut[cword_val & 0xf];
                src += bitlut[cword_val & 0xf];
                cword_val = cword_val >> (bitlut[cword_val & 0xf]);
#if QLZ_COMPRESSION_LEVEL <= 2
                update_hash_upto(hashtable, hash_counter, &last_hashed,
                                 dst - 3);
#endif
            } else {
                while (dst <= last_destination_byte) {
                    if (cword_val == 1) {
                        src += CWORD_LEN;
                        cword_val = 1U << 31;
                    }
#ifdef QLZ_MEMORY_SAFE
                    if (src >= last_source_byte + 1)
                        return 0;
#endif
                    *dst = *src;
                    dst++;
                    src++;
                    cword_val = cword_val >> 1;
                }

#if QLZ_COMPRESSION_LEVEL <= 2
                update_hash_upto(hashtable, hash_counter, &last_hashed, last_destination_byte - 3);     // todo, use constant
#endif
                return size;
            }

        }
    }
}

size_t qlz_size_decompressed(const char *source)
{
    ui32 n, r;
    n = (((*source) & 2) == 2) ? 4 : 1;
    r = fast_read(source + 1 + n, n);
    r = r & (0xffffffff >> ((4 - n) * 8));
    return r;
}

size_t qlz_size_compressed(const char *source)
{
    ui32 n, r;
    n = (((*source) & 2) == 2) ? 4 : 1;
    r = fast_read(source + 1, n);
    r = r & (0xffffffff >> ((4 - n) * 8));
    return r;
}

size_t qlz_compress(const void *source, char *destination, size_t size,
                    char *scratch_compress)
{
    unsigned char *scratch_aligned =
        (unsigned char *) scratch_compress + QLZ_ALIGNMENT_PADD -
        (((size_t) scratch_compress) % QLZ_ALIGNMENT_PADD);
    size_t *buffersize = (size_t *) scratch_aligned;
    qlz_hash_compress *hashtable =
        (qlz_hash_compress *) (scratch_aligned + QLZ_BUFFER_COUNTER);
    unsigned char *hash_counter =
        (unsigned char *) hashtable +
        sizeof(qlz_hash_compress[QLZ_HASH_VALUES]);
#if QLZ_STREAMING_BUFFER > 0
    unsigned char *streambuffer = hash_counter + QLZ_HASH_VALUES;
#endif
    size_t r;
    ui32 compressed;
    size_t base;

    if (size == 0 || size > 0xffffffff - 400)
        return 0;

    if (size < 216)
        base = 3;
    else
        base = 9;

#if QLZ_STREAMING_BUFFER > 0
    if (*buffersize + size - 1 >= QLZ_STREAMING_BUFFER)
#endif
    {
        reset_state(hash_counter);
        r = base + qlz_compress_core((const unsigned char *) source,
                                     (unsigned char *) destination + base,
                                     size, hashtable, hash_counter);
#if QLZ_STREAMING_BUFFER > 0
        reset_state(hash_counter);
#endif
        if (r == base) {
            memcpy(destination + base, source, size);
            r = size + base;
            compressed = 0;
        } else {
            compressed = 1;
        }
        *buffersize = 0;
    }
#if QLZ_STREAMING_BUFFER > 0
    else {
        memcpy(streambuffer + *buffersize, source, size);
        r = base + qlz_compress_core((const unsigned char *) streambuffer +
                                     *buffersize,
                                     (unsigned char *) destination + base,
                                     size, hashtable, hash_counter);

        if (r == base) {
            memcpy(destination + base, streambuffer + *buffersize, size);
            r = size + base;
            compressed = 0;
            reset_state(hash_counter);
        } else {
            compressed = 1;
        }
        *buffersize += size;
    }
#endif
    if (base == 3) {
        *destination = (unsigned char) (0 | compressed);
        *(destination + 1) = (unsigned char) r;
        *(destination + 2) = (unsigned char) size;
    } else {
        *destination = (unsigned char) (2 | compressed);
        fast_write((ui32) r, destination + 1, 4);
        fast_write((ui32) size, destination + 5, 4);
    }

    *destination |= (QLZ_COMPRESSION_LEVEL << 2);
    *destination |= (1 << 6);
    *destination |=
        ((QLZ_STREAMING_BUFFER ==
          0 ? 0 : (QLZ_STREAMING_BUFFER ==
                   100000 ? 1 : (QLZ_STREAMING_BUFFER ==
                                 1000000 ? 2 : 3))) << 4);

// 76543210
// 01SSLLHC

    return r;
}

size_t qlz_decompress(const char *source, void *destination,
                      char *scratch_compress)
{
    unsigned char *scratch_aligned =
        (unsigned char *) scratch_compress + QLZ_ALIGNMENT_PADD -
        (((size_t) scratch_compress) % QLZ_ALIGNMENT_PADD);
    size_t *buffersize = (size_t *) scratch_aligned;
#if QLZ_COMPRESSION_LEVEL == 3
#if QLZ_STREAMING_BUFFER > 0
    unsigned char *streambuffer = scratch_aligned + QLZ_BUFFER_COUNTER;
#endif
    unsigned char *hash_counter = 0;
    qlz_hash_decompress *hashtable = 0;
#elif QLZ_COMPRESSION_LEVEL <= 2
    qlz_hash_decompress *hashtable =
        (qlz_hash_decompress *) (scratch_aligned + QLZ_BUFFER_COUNTER);
    unsigned char *hash_counter =
        (unsigned char *) hashtable +
        sizeof(qlz_hash_decompress[QLZ_HASH_VALUES]);
#if QLZ_STREAMING_BUFFER > 0
    unsigned char *streambuffer = hash_counter + QLZ_HASH_VALUES;
#endif
#endif
    ui32 headerlen = 2 * ((((*source) & 2) == 2) ? 4 : 1) + 1;
    size_t dsiz = qlz_size_decompressed(source);

#if QLZ_STREAMING_BUFFER > 0
    if (*buffersize + qlz_size_decompressed(source) - 1 >=
        QLZ_STREAMING_BUFFER)
#endif
    {
        if ((*source & 1) == 1) {
#if QLZ_COMPRESSION_LEVEL != 3
            reset_state(hash_counter);
#endif
            dsiz =
                qlz_decompress_core((const unsigned char *) source +
                                    headerlen,
                                    (unsigned char *) destination, dsiz,
                                    hashtable, hash_counter,
                                    (unsigned char *) destination, source);
        } else {
            memcpy(destination, source + headerlen, dsiz);
        }
        *buffersize = 0;
#if QLZ_COMPRESSION_LEVEL != 3
        reset_state(hash_counter);
#endif
    }
#if QLZ_STREAMING_BUFFER > 0
    else {
        if ((*source & 1) == 1) {
            dsiz =
                qlz_decompress_core((const unsigned char *) source +
                                    headerlen, streambuffer + *buffersize,
                                    dsiz, hashtable, hash_counter,
                                    streambuffer, source);
        } else {
            memcpy(streambuffer + *buffersize, source + headerlen, dsiz);
#if QLZ_COMPRESSION_LEVEL != 3
            reset_state(hash_counter);
#endif
        }
        memcpy(destination, streambuffer + *buffersize, dsiz);
        *buffersize += dsiz;
    }
#endif
    return dsiz;
}