lib_qlz15.c

// Fast data compression library
// Copyright (C) 2006-2011 Lasse Mikkel Reinhold
// lar@quicklz.com
//
// QuickLZ can be used for free under the GPL 1, 2 or 3 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.

// 1.5.0 final

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <pthread.h>
#include "lib_safe.h"
#include "lib_qlz15.h"

#if QLZ5_VERSION_MAJOR != 1 || QLZ5_VERSION_MINOR != 5 || QLZ5_VERSION_REVISION != 0
#error quicklz.c and quicklz.h have different versions
#endif

#if (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

#if QLZ5_COMPRESSION_LEVEL == 1 && defined QLZ5_PTR_64 && QLZ5_STREAMING_BUFFER == 0
#define OFFSET_BASE source
#define CAST (ui32)(size_t)
#else
#define OFFSET_BASE 0
#define CAST
#endif



// Return the decompressed block without the 
// leading byte that informs about the used compression
// First byte = 'Q' Indicates that the block is QLZ5 1.4.1 compressed
// First byte = 'R' Indicates that the block is QLZ5 1.5.1 compressed
// First byte = 0 The block is not compressed
// First byte = 'L' Indicates that the block is LZO compressed
compr *clz15_decompress(unsigned char *buf, int buflen)
{
    compr *retdata;
    qlz5_state_decompress *state_decompress =
        (qlz5_state_decompress *) malloc(sizeof(qlz5_state_decompress));

    if ( buflen <= 0 ) return NULL;
    retdata = s_zmalloc(sizeof(compr));
    if (buf[0] == 'R') {
        retdata->size = qlz5_size_decompressed((char *) &buf[1]);
        retdata->data = s_zmalloc(retdata->size);
        retdata->size =
            qlz5_decompress((char *) &buf[1], retdata->data,
                            state_decompress);
    } else {
        retdata->size = buflen - 1;
        retdata->data = s_malloc(retdata->size);
        memcpy(retdata->data, &buf[1], buflen - 1);
    }
    return retdata;
}

compr *clz15_compress(unsigned char *buf, int buflen)
{
    compr *retdata;
    qlz5_state_compress *state_compress =
        (qlz5_state_compress *) malloc(sizeof(qlz5_state_compress));

//    pthread_mutex_lock(&qlz5_mutex);
    retdata = s_zmalloc(sizeof(compr));

    // allocate "uncompressed size" + 400 for the destination buffer
    retdata->data = s_zmalloc(buflen + 400);
    retdata->size =
        qlz5_compress(buf, (char *) &retdata->data[1], buflen,
                      state_compress);
    if (retdata->size < buflen) {
        retdata->size++;
        retdata->data[0] = 'R';
    } else {
        retdata->size = buflen + 1;
        memcpy(&retdata->data[1], buf, buflen);
        retdata->data[0] = 0;
    }
//    pthread_mutex_unlock(&qlz5_mutex);
    return retdata;
}

int qlz5_get_setting(int setting)
{
    switch (setting) {
    case 0:
        return QLZ5_COMPRESSION_LEVEL;
    case 1:
        return sizeof(qlz5_state_compress);
    case 2:
        return sizeof(qlz5_state_decompress);
    case 3:
        return QLZ5_STREAMING_BUFFER;
#ifdef QLZ5_MEMORY_SAFE
    case 6:
        return 1;
#else
    case 6:
        return 0;
#endif
    case 7:
        return QLZ5_VERSION_MAJOR;
    case 8:
        return QLZ5_VERSION_MINOR;
    case 9:
        return QLZ5_VERSION_REVISION;
    }
    return -1;
}

#if QLZ5_COMPRESSION_LEVEL == 1
static int same(const unsigned char *src, size_t n)
{
    while (n > 0 && *(src + n) == *src)
        n--;
    return n == 0 ? 1 : 0;
}
#endif

static void reset_table_compress(qlz5_state_compress * state)
{
    int i;
    for (i = 0; i < QLZ5_HASH_VALUES; i++) {
#if QLZ5_COMPRESSION_LEVEL == 1
        state->hash[i].offset = 0;
#else
        state->hash_counter[i] = 0;
#endif
    }
}

static void reset_table_decompress(qlz5_state_decompress * state)
{
    int i;
    (void) state;
    (void) i;
#if QLZ5_COMPRESSION_LEVEL == 2
    for (i = 0; i < QLZ5_HASH_VALUES; i++) {
        state->hash_counter[i] = 0;
    }
#endif
}

static __inline ui32 hash_func(ui32 i)
{
#if QLZ5_COMPRESSION_LEVEL == 2
    return ((i >> 9) ^ (i >> 13) ^ i) & (QLZ5_HASH_VALUES - 1);
#else
    return ((i >> 12) ^ i) & (QLZ5_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 ui32 hashat(const unsigned char *src)
{
    ui32 fetch, hash;
    fetch = fast_read(src, 3);
    hash = hash_func(fetch);
    return hash;
}

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
}


size_t qlz5_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 qlz5_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 qlz5_size_header(const char *source)
{
    size_t n = 2 * ((((*source) & 2) == 2) ? 4 : 1) + 1;
    return n;
}


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
}

static __inline void update_hash(qlz5_state_decompress * state,
                                 const unsigned char *s)
{
#if QLZ5_COMPRESSION_LEVEL == 1
    ui32 hash;
    hash = hashat(s);
    state->hash[hash].offset = s;
    state->hash_counter[hash] = 1;
#elif QLZ5_COMPRESSION_LEVEL == 2
    ui32 hash;
    unsigned char c;
    hash = hashat(s);
    c = state->hash_counter[hash];
    state->hash[hash].offset[c & (QLZ5_POINTERS - 1)] = s;
    c++;
    state->hash_counter[hash] = c;
#endif
    (void) state;
    (void) s;
}

#if QLZ5_COMPRESSION_LEVEL <= 2
static void update_hash_upto(qlz5_state_decompress * state,
                             unsigned char **lh, const unsigned char *max)
{
    while (*lh < max) {
        (*lh)++;
        update_hash(state, *lh);
    }
}
#endif

static size_t qlz5_compress_core(const unsigned char *source,
                                 unsigned char *destination, size_t size,
                                 qlz5_state_compress * state)
{
    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 + (size >> 1)
                && 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 QLZ5_COMPRESSION_LEVEL == 1
        {
            const unsigned char *o;
            ui32 hash, cached;

            hash = hash_func(fetch);
            cached = fetch ^ state->hash[hash].cache;
            state->hash[hash].cache = fetch;

            o = state->hash[hash].offset + OFFSET_BASE;
            state->hash[hash].offset = CAST(src - OFFSET_BASE);

#ifdef X86X64
            if ((cached & 0xffffff) == 0 && o != OFFSET_BASE
                && (src - o > MINOFFSET
                    || (src == o + 1 && lits >= 3 && src > source + 3
                        && same(src - 3, 6)))) {
                if (cached != 0) {
#else
            if (cached == 0 && o != OFFSET_BASE
                && (src - o > MINOFFSET
                    || (src == o + 1 && lits >= 3 && src > source + 3
                        && same(src - 3, 6)))) {
                if (*(o + 3) != *(src + 3)) {
#endif
                    hash <<= 4;
                    cword_val = (cword_val >> 1) | (1U << 31);
                    fast_write((3 - 2) | hash, dst, 2);
                    src += 3;
                    dst += 2;
                } else {
                    const unsigned char *old_src = src;
                    size_t matchlen;
                    hash <<= 4;

                    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;
                    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++;
                *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 QLZ5_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;


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

            c = state->hash_counter[hash];

            offset2 = state->hash[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 < QLZ5_POINTERS && c > k; k++) {
                o = state->hash[hash].offset[k];
#if QLZ5_COMPRESSION_LEVEL == 3
                if (((fast_read(o, 3) ^ fetch) & 0xffffff) == 0
                    && o < src - MINOFFSET)
#elif QLZ5_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 QLZ5_COMPRESSION_LEVEL == 3
                    if ((m > matchlen) || (m == matchlen && o > offset2))
#elif QLZ5_COMPRESSION_LEVEL == 2
                    if (m > matchlen)
#endif
                    {
                        offset2 = o;
                        matchlen = m;
                        best_k = k;
                    }
                }
            }
            o = offset2;
            state->hash[hash].offset[c & (QLZ5_POINTERS - 1)] = src;
            c++;
            state->hash_counter[hash] = c;

#if QLZ5_COMPRESSION_LEVEL == 3
            if (matchlen > 2 && src - o < 131071) {
                ui32 u;
                size_t offset = src - o;

                for (u = 1; u < matchlen; u++) {
                    hash = hashat(src + u);
                    c = state->hash_counter[hash]++;
                    state->hash[hash].offset[c & (QLZ5_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) | ((ui32) offset << 6) | 2;
                    fast_write(f, dst, 2);
                    dst += 2;
                }

                else if (matchlen <= 33) {
                    ui32 f =
                        ((matchlen - 2) << 2) | ((ui32) offset << 7) | 3;
                    fast_write(f, dst, 3);
                    dst += 3;
                } else {
                    ui32 f =
                        ((matchlen - 3) << 7) | ((ui32) offset << 15) | 3;
                    fast_write(f, dst, 4);
                    dst += 4;
                }
            } else {
                *dst = *src;
                src++;
                dst++;
                cword_val = (cword_val >> 1);
            }
#elif QLZ5_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 QLZ5_COMPRESSION_LEVEL < 3
        if (src <= last_byte - 3) {
#if QLZ5_COMPRESSION_LEVEL == 1
            ui32 hash, fetch;
            fetch = fast_read(src, 3);
            hash = hash_func(fetch);
            state->hash[hash].offset = CAST(src - OFFSET_BASE);
            state->hash[hash].cache = fetch;
#elif QLZ5_COMPRESSION_LEVEL == 2
            ui32 hash;
            unsigned char c;
            hash = hashat(src);
            c = state->hash_counter[hash];
            state->hash[hash].offset[c & (QLZ5_POINTERS - 1)] = src;
            c++;
            state->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 qlz5_size functions can take 9 bytes as argument
    return dst - destination < 9 ? 9 : dst - destination;
}

static size_t qlz5_decompress_core(const unsigned char *source,
                                   unsigned char *destination, size_t size,
                                   qlz5_state_decompress * state,
                                   const unsigned char *history)
{
    const unsigned char *src =
        source + qlz5_size_header((const char *) source);
    unsigned char *dst = destination;
    const unsigned char *last_destination_byte = destination + size - 1;
    ui32 cword_val = 1;
    const unsigned char *last_matchstart =
        last_destination_byte - UNCONDITIONAL_MATCHLEN - UNCOMPRESSED_END;
    unsigned char *last_hashed = destination - 1;
    const unsigned char *last_source_byte =
        source + qlz5_size_compressed((const char *) source) - 1;
    static const ui32 bitlut[16] =
        { 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0 };

    (void) last_source_byte;
    (void) last_hashed;
    (void) state;
    (void) history;

    for (;;) {
        ui32 fetch;

        if (cword_val == 1) {
#ifdef QLZ5_MEMORY_SAFE
            if (src + CWORD_LEN - 1 > last_source_byte)
                return 0;
#endif
            cword_val = fast_read(src, CWORD_LEN);
            src += CWORD_LEN;
        }
#ifdef QLZ5_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 QLZ5_COMPRESSION_LEVEL == 1
            ui32 hash;
            cword_val = cword_val >> 1;
            hash = (fetch >> 4) & 0xfff;
            offset2 =
                (const unsigned char *) (size_t) state->hash[hash].offset;

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

#elif QLZ5_COMPRESSION_LEVEL == 2
            ui32 hash;
            unsigned char c;
            cword_val = cword_val >> 1;
            hash = (fetch >> 5) & 0x7ff;
            c = (unsigned char) (fetch & 0x3);
            offset2 = state->hash[hash].offset[c];

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

#elif QLZ5_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 QLZ5_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 QLZ5_COMPRESSION_LEVEL <= 2
            update_hash_upto(state, &last_hashed, dst - matchlen);
            last_hashed = dst - 1;
#endif
        } else {
            if (dst < last_matchstart) {
                unsigned int n = bitlut[cword_val & 0xf];
#ifdef X86X64
                *(ui32 *) dst = *(ui32 *) src;
#else
                memcpy_up(dst, src, 4);
#endif
                cword_val = cword_val >> n;
                dst += n;
                src += n;
#if QLZ5_COMPRESSION_LEVEL <= 2
                update_hash_upto(state, &last_hashed, dst - 3);
#endif
            } else {
                while (dst <= last_destination_byte) {
                    if (cword_val == 1) {
                        src += CWORD_LEN;
                        cword_val = 1U << 31;
                    }
#ifdef QLZ5_MEMORY_SAFE
                    if (src >= last_source_byte + 1)
                        return 0;
#endif
                    *dst = *src;
                    dst++;
                    src++;
                    cword_val = cword_val >> 1;
                }

#if QLZ5_COMPRESSION_LEVEL <= 2
                update_hash_upto(state, &last_hashed, last_destination_byte - 3);       // todo, use constant
#endif
                return size;
            }

        }
    }
}

size_t qlz5_compress(const void *source, char *destination, size_t size,
                     qlz5_state_compress * state)
{
    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 QLZ5_STREAMING_BUFFER > 0
    if (state->stream_counter + size - 1 >= QLZ5_STREAMING_BUFFER)
#endif
    {
        reset_table_compress(state);
        r = base + qlz5_compress_core((const unsigned char *) source,
                                      (unsigned char *) destination + base,
                                      size, state);
#if QLZ5_STREAMING_BUFFER > 0
        reset_table_compress(state);
#endif
        if (r == base) {
            memcpy(destination + base, source, size);
            r = size + base;
            compressed = 0;
        } else {
            compressed = 1;
        }
        state->stream_counter = 0;
    }
#if QLZ5_STREAMING_BUFFER > 0
    else {
        unsigned char *src = state->stream_buffer + state->stream_counter;

        memcpy(src, source, size);
        r = base + qlz5_compress_core(src,
                                      (unsigned char *) destination + base,
                                      size, state);

        if (r == base) {
            memcpy(destination + base, src, size);
            r = size + base;
            compressed = 0;
            reset_table_compress(state);
        } else {
            compressed = 1;
        }
        state->stream_counter += 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 |= (QLZ5_COMPRESSION_LEVEL << 2);
    *destination |= (1 << 6);
    *destination |=
        ((QLZ5_STREAMING_BUFFER ==
          0 ? 0 : (QLZ5_STREAMING_BUFFER ==
                   100000 ? 1 : (QLZ5_STREAMING_BUFFER ==
                                 1000000 ? 2 : 3))) << 4);

// 76543210
// 01SSLLHC

    return r;
}

size_t qlz5_decompress(const char *source, void *destination,
                       qlz5_state_decompress * state)
{
    size_t dsiz = qlz5_size_decompressed(source);

#if QLZ5_STREAMING_BUFFER > 0
    if (state->stream_counter + qlz5_size_decompressed(source) - 1 >=
        QLZ5_STREAMING_BUFFER)
#endif
    {
        if ((*source & 1) == 1) {
            reset_table_decompress(state);
            dsiz =
                qlz5_decompress_core((const unsigned char *) source,
                                     (unsigned char *) destination, dsiz,
                                     state,
                                     (const unsigned char *) destination);
        } else {
            memcpy(destination, source + qlz5_size_header(source), dsiz);
        }
        state->stream_counter = 0;
        reset_table_decompress(state);
    }
#if QLZ5_STREAMING_BUFFER > 0
    else {
        unsigned char *dst = state->stream_buffer + state->stream_counter;
        if ((*source & 1) == 1) {
            dsiz =
                qlz5_decompress_core((const unsigned char *) source, dst,
                                     dsiz, state, (const unsigned char *)
                                     state->stream_buffer);
        } else {
            memcpy(dst, source + qlz5_size_header(source), dsiz);
            reset_table_decompress(state);
        }
        memcpy(destination, dst, dsiz);
        state->stream_counter += dsiz;
    }
#endif
    return dsiz;
}