    /* gzwrite.c -- zlib functions for writing gzip files
     * Copyright (C) 2004-2017 Mark Adler
     * For conditions of distribution and use, see copyright notice in zlib.h
     */

    #include "gzguts.h"

    /* Local functions */
    local int gz_init OF((gz_statep));
    local int gz_comp OF((gz_statep, int));
    local int gz_zero OF((gz_statep, z_off64_t));
    local z_size_t gz_write OF((gz_statep, voidpc, z_size_t));

    /* Initialize state for writing a gzip file.  Mark initialization by setting
       state->size to non-zero.  Return -1 on a memory allocation failure, or 0 on
       success. */
    local int gz_init(state)
        gz_statep state;
    {
        int ret;
        z_streamp strm = &(state->strm);

        /* allocate input buffer (double size for gzprintf) */
        state->in = (unsigned char *)malloc(state->want << 1);
        if (state->in == NULL) {
            gz_error(state, Z_MEM_ERROR, "out of memory");
            return -1;
        }

        /* only need output buffer and deflate state if compressing */
        if (!state->direct) {
            /* allocate output buffer */
            state->out = (unsigned char *)malloc(state->want);
            if (state->out == NULL) {
                free(state->in);
                gz_error(state, Z_MEM_ERROR, "out of memory");
                return -1;
            }

            /* allocate deflate memory, set up for gzip compression */
            strm->zalloc = Z_NULL;
            strm->zfree = Z_NULL;
            strm->opaque = Z_NULL;
            ret = deflateInit2(strm, state->level, Z_DEFLATED,
                               MAX_WBITS + 16, DEF_MEM_LEVEL, state->strategy);
            if (ret != Z_OK) {
                free(state->out);
                free(state->in);
                gz_error(state, Z_MEM_ERROR, "out of memory");
                return -1;
            }
            strm->next_in = NULL;
        }

        /* mark state as initialized */
        state->size = state->want;

        /* initialize write buffer if compressing */
        if (!state->direct) {
            strm->avail_out = state->size;
            strm->next_out = state->out;
            state->x.next = strm->next_out;
        }
        return 0;
    }

    /* Compress whatever is at avail_in and next_in and write to the output file.
       Return -1 if there is an error writing to the output file or if gz_init()
       fails to allocate memory, otherwise 0.  flush is assumed to be a valid
       deflate() flush value.  If flush is Z_FINISH, then the deflate() state is
       reset to start a new gzip stream.  If gz->direct is true, then simply write
       to the output file without compressing, and ignore flush. */
    local int gz_comp(state, flush)
        gz_statep state;
        int flush;
    {
        int ret, writ;
        unsigned have, put, max = ((unsigned)-1 >> 2) + 1;
        z_streamp strm = &(state->strm);

        /* allocate memory if this is the first time through */
        if (state->size == 0 && gz_init(state) == -1)
            return -1;

        /* write directly if requested */
        if (state->direct) {
            while (strm->avail_in) {
                put = strm->avail_in > max ? max : strm->avail_in;
                writ = write(state->fd, strm->next_in, put);
                if (writ < 0) {
                    gz_error(state, Z_ERRNO, zstrerror());
                    return -1;
                }
                strm->avail_in -= (unsigned)writ;
                strm->next_in += writ;
            }
            return 0;
        }

        /* run deflate() on provided input until it produces no more output */
        ret = Z_OK;
        do {
            /* write out current buffer contents if full, or if flushing, but if
               doing Z_FINISH then don't write until we get to Z_STREAM_END */
            if (strm->avail_out == 0 || (flush != Z_NO_FLUSH &&
                (flush != Z_FINISH || ret == Z_STREAM_END))) {
                while (strm->next_out > state->x.next) {
                    put = strm->next_out - state->x.next > (int)max ? max :
                          (unsigned)(strm->next_out - state->x.next);
                    writ = write(state->fd, state->x.next, put);
                    if (writ < 0) {
                        gz_error(state, Z_ERRNO, zstrerror());
                        return -1;
                    }
                    state->x.next += writ;
                }
                if (strm->avail_out == 0) {
                    strm->avail_out = state->size;
                    strm->next_out = state->out;
                    state->x.next = state->out;
                }
            }

            /* compress */
            have = strm->avail_out;
            ret = deflate(strm, flush);
            if (ret == Z_STREAM_ERROR) {
                gz_error(state, Z_STREAM_ERROR,
                          "internal error: deflate stream corrupt");
                return -1;
            }
            have -= strm->avail_out;
        } while (have);

        /* if that completed a deflate stream, allow another to start */
        if (flush == Z_FINISH)
            deflateReset(strm);

        /* all done, no errors */
        return 0;
    }

    /* Compress len zeros to output.  Return -1 on a write error or memory
       allocation failure by gz_comp(), or 0 on success. */
    local int gz_zero(state, len)
        gz_statep state;
        z_off64_t len;
    {
        int first;
        unsigned n;
        z_streamp strm = &(state->strm);

        /* consume whatever's left in the input buffer */
        if (strm->avail_in && gz_comp(state, Z_NO_FLUSH) == -1)
            return -1;

        /* compress len zeros (len guaranteed > 0) */
        first = 1;
        while (len) {
            n = GT_OFF(state->size) || (z_off64_t)state->size > len ?
                (unsigned)len : state->size;
            if (first) {
                memset(state->in, 0, n);
                first = 0;
            }
            strm->avail_in = n;
            strm->next_in = state->in;
            state->x.pos += n;
            if (gz_comp(state, Z_NO_FLUSH) == -1)
                return -1;
            len -= n;
        }
        return 0;
    }

    /* Write len bytes from buf to file.  Return the number of bytes written.  If
       the returned value is less than len, then there was an error. */
    local z_size_t gz_write(state, buf, len)
        gz_statep state;
        voidpc buf;
        z_size_t len;
    {
        z_size_t put = len;

        /* if len is zero, avoid unnecessary operations */
        if (len == 0)
            return 0;

        /* allocate memory if this is the first time through */
        if (state->size == 0 && gz_init(state) == -1)
            return 0;

        /* check for seek request */
        if (state->seek) {
            state->seek = 0;
            if (gz_zero(state, state->skip) == -1)
                return 0;
        }

        /* for small len, copy to input buffer, otherwise compress directly */
        if (len < state->size) {
            /* copy to input buffer, compress when full */
            do {
                unsigned have, copy;

                if (state->strm.avail_in == 0)
                    state->strm.next_in = state->in;
                have = (unsigned)((state->strm.next_in + state->strm.avail_in) -
                                  state->in);
                copy = state->size - have;
                if (copy > len)
                    copy = len;
                memcpy(state->in + have, buf, copy);
                state->strm.avail_in += copy;
                state->x.pos += copy;
                buf = (const char *)buf + copy;
                len -= copy;
                if (len && gz_comp(state, Z_NO_FLUSH) == -1)
                    return 0;
            } while (len);
        }
        else {
            /* consume whatever's left in the input buffer */
            if (state->strm.avail_in && gz_comp(state, Z_NO_FLUSH) == -1)
                return 0;

            /* directly compress user buffer to file */
            state->strm.next_in = (z_const Bytef *)buf;
            do {
                unsigned n = (unsigned)-1;
                if (n > len)
                    n = len;
                state->strm.avail_in = n;
                state->x.pos += n;
                if (gz_comp(state, Z_NO_FLUSH) == -1)
                    return 0;
                len -= n;
            } while (len);
        }

        /* input was all buffered or compressed */
        return put;
    }

    /* -- see zlib.h -- */
    int ZEXPORT gzwrite(file, buf, len)
        gzFile file;
        voidpc buf;
        unsigned len;
    {
        gz_statep state;

        /* get internal structure */
        if (file == NULL)
            return 0;
        state = (gz_statep)file;

        /* check that we're writing and that there's no error */
        if (state->mode != GZ_WRITE || state->err != Z_OK)
            return 0;

        /* since an int is returned, make sure len fits in one, otherwise return
           with an error (this avoids a flaw in the interface) */
        if ((int)len < 0) {
            gz_error(state, Z_DATA_ERROR, "requested length does not fit in int");
            return 0;
        }

        /* write len bytes from buf (the return value will fit in an int) */
        return (int)gz_write(state, buf, len);
    }

    /* -- see zlib.h -- */
    z_size_t ZEXPORT gzfwrite(buf, size, nitems, file)
        voidpc buf;
        z_size_t size;
        z_size_t nitems;
        gzFile file;
    {
        z_size_t len;
        gz_statep state;

        /* get internal structure */
        if (file == NULL)
            return 0;
        state = (gz_statep)file;

        /* check that we're writing and that there's no error */
        if (state->mode != GZ_WRITE || state->err != Z_OK)
            return 0;

        /* compute bytes to read -- error on overflow */
        len = nitems * size;
        if (size && len / size != nitems) {
            gz_error(state, Z_STREAM_ERROR, "request does not fit in a size_t");
            return 0;
        }

        /* write len bytes to buf, return the number of full items written */
        return len ? gz_write(state, buf, len) / size : 0;
    }

    /* -- see zlib.h -- */
    int ZEXPORT gzputc(file, c)
        gzFile file;
        int c;
    {
        unsigned have;
        unsigned char buf[1];
        gz_statep state;
        z_streamp strm;

        /* get internal structure */
        if (file == NULL)
            return -1;
        state = (gz_statep)file;
        strm = &(state->strm);

        /* check that we're writing and that there's no error */
        if (state->mode != GZ_WRITE || state->err != Z_OK)
            return -1;

        /* check for seek request */
        if (state->seek) {
            state->seek = 0;
            if (gz_zero(state, state->skip) == -1)
                return -1;
        }

        /* try writing to input buffer for speed (state->size == 0 if buffer not
           initialized) */
        if (state->size) {
            if (strm->avail_in == 0)
                strm->next_in = state->in;
            have = (unsigned)((strm->next_in + strm->avail_in) - state->in);
            if (have < state->size) {
                state->in[have] = (unsigned char)c;
                strm->avail_in++;
                state->x.pos++;
                return c & 0xff;
            }
        }

        /* no room in buffer or not initialized, use gz_write() */
        buf[0] = (unsigned char)c;
        if (gz_write(state, buf, 1) != 1)
            return -1;
        return c & 0xff;
    }

    /* -- see zlib.h -- */
    int ZEXPORT gzputs(file, str)
        gzFile file;
        const char *str;
    {
        int ret;
        z_size_t len;
        gz_statep state;

        /* get internal structure */
        if (file == NULL)
            return -1;
        state = (gz_statep)file;

        /* check that we're writing and that there's no error */
        if (state->mode != GZ_WRITE || state->err != Z_OK)
            return -1;

        /* write string */
        len = strlen(str);
        ret = gz_write(state, str, len);
        return ret == 0 && len != 0 ? -1 : ret;
    }

    #if defined(STDC) || defined(Z_HAVE_STDARG_H)
    #include <stdarg.h>

    /* -- see zlib.h -- */
    int ZEXPORTVA gzvprintf(gzFile file, const char *format, va_list va)
    {
        int len;
        unsigned left;
        char *next;
        gz_statep state;
        z_streamp strm;

        /* get internal structure */
        if (file == NULL)
            return Z_STREAM_ERROR;
        state = (gz_statep)file;
        strm = &(state->strm);

        /* check that we're writing and that there's no error */
        if (state->mode != GZ_WRITE || state->err != Z_OK)
            return Z_STREAM_ERROR;

        /* make sure we have some buffer space */
        if (state->size == 0 && gz_init(state) == -1)
            return state->err;

        /* check for seek request */
        if (state->seek) {
            state->seek = 0;
            if (gz_zero(state, state->skip) == -1)
                return state->err;
        }

        /* do the printf() into the input buffer, put length in len -- the input
           buffer is double-sized just for this function, so there is guaranteed to
           be state->size bytes available after the current contents */
        if (strm->avail_in == 0)
            strm->next_in = state->in;
        next = (char *)(state->in + (strm->next_in - state->in) + strm->avail_in);
        next[state->size - 1] = 0;
    #ifdef NO_vsnprintf
    #  ifdef HAS_vsprintf_void
        (void)vsprintf(next, format, va);
        for (len = 0; len < state->size; len++)
            if (next[len] == 0) break;
    #  else
        len = vsprintf(next, format, va);
    #  endif
    #else
    #  ifdef HAS_vsnprintf_void
        (void)vsnprintf(next, state->size, format, va);
        len = strlen(next);
    #  else
        len = vsnprintf(next, state->size, format, va);
    #  endif
    #endif

        /* check that printf() results fit in buffer */
        if (len == 0 || (unsigned)len >= state->size || next[state->size - 1] != 0)
            return 0;

        /* update buffer and position, compress first half if past that */
        strm->avail_in += (unsigned)len;
        state->x.pos += len;
        if (strm->avail_in >= state->size) {
            left = strm->avail_in - state->size;
            strm->avail_in = state->size;
            if (gz_comp(state, Z_NO_FLUSH) == -1)
                return state->err;
            memcpy(state->in, state->in + state->size, left);
            strm->next_in = state->in;
            strm->avail_in = left;
        }
        return len;
    }

    int ZEXPORTVA gzprintf(gzFile file, const char *format, ...)
    {
        va_list va;
        int ret;

        va_start(va, format);
        ret = gzvprintf(file, format, va);
        va_end(va);
        return ret;
    }

    #else /* !STDC && !Z_HAVE_STDARG_H */

    /* -- see zlib.h -- */
    int ZEXPORTVA gzprintf (file, format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10,
                           a11, a12, a13, a14, a15, a16, a17, a18, a19, a20)
        gzFile file;
        const char *format;
        int a1, a2, a3, a4, a5, a6, a7, a8, a9, a10,
            a11, a12, a13, a14, a15, a16, a17, a18, a19, a20;
    {
        unsigned len, left;
        char *next;
        gz_statep state;
        z_streamp strm;

        /* get internal structure */
        if (file == NULL)
            return Z_STREAM_ERROR;
        state = (gz_statep)file;
        strm = &(state->strm);

        /* check that can really pass pointer in ints */
        if (sizeof(int) != sizeof(void *))
            return Z_STREAM_ERROR;

        /* check that we're writing and that there's no error */
        if (state->mode != GZ_WRITE || state->err != Z_OK)
            return Z_STREAM_ERROR;

        /* make sure we have some buffer space */
        if (state->size == 0 && gz_init(state) == -1)
            return state->error;

        /* check for seek request */
        if (state->seek) {
            state->seek = 0;
            if (gz_zero(state, state->skip) == -1)
                return state->error;
        }

        /* do the printf() into the input buffer, put length in len -- the input
           buffer is double-sized just for this function, so there is guaranteed to
           be state->size bytes available after the current contents */
        if (strm->avail_in == 0)
            strm->next_in = state->in;
        next = (char *)(strm->next_in + strm->avail_in);
        next[state->size - 1] = 0;
    #ifdef NO_snprintf
    #  ifdef HAS_sprintf_void
        sprintf(next, format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12,
                a13, a14, a15, a16, a17, a18, a19, a20);
        for (len = 0; len < size; len++)
            if (next[len] == 0)
                break;
    #  else
        len = sprintf(next, format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11,
                      a12, a13, a14, a15, a16, a17, a18, a19, a20);
    #  endif
    #else
    #  ifdef HAS_snprintf_void
        snprintf(next, state->size, format, a1, a2, a3, a4, a5, a6, a7, a8, a9,
                 a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
        len = strlen(next);
    #  else
        len = snprintf(next, state->size, format, a1, a2, a3, a4, a5, a6, a7, a8,
                       a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
    #  endif
    #endif

        /* check that printf() results fit in buffer */
        if (len == 0 || len >= state->size || next[state->size - 1] != 0)
            return 0;

        /* update buffer and position, compress first half if past that */
        strm->avail_in += len;
        state->x.pos += len;
        if (strm->avail_in >= state->size) {
            left = strm->avail_in - state->size;
            strm->avail_in = state->size;
            if (gz_comp(state, Z_NO_FLUSH) == -1)
                return state->err;
            memcpy(state->in, state->in + state->size, left);
            strm->next_in = state->in;
            strm->avail_in = left;
        }
        return (int)len;
    }

    #endif

    /* -- see zlib.h -- */
    int ZEXPORT gzflush(file, flush)
        gzFile file;
        int flush;
    {
        gz_statep state;

        /* get internal structure */
        if (file == NULL)
            return Z_STREAM_ERROR;
        state = (gz_statep)file;

        /* check that we're writing and that there's no error */
        if (state->mode != GZ_WRITE || state->err != Z_OK)
            return Z_STREAM_ERROR;

        /* check flush parameter */
        if (flush < 0 || flush > Z_FINISH)
            return Z_STREAM_ERROR;

        /* check for seek request */
        if (state->seek) {
            state->seek = 0;
            if (gz_zero(state, state->skip) == -1)
                return state->err;
        }

        /* compress remaining data with requested flush */
        (void)gz_comp(state, flush);
        return state->err;
    }

    /* -- see zlib.h -- */
    int ZEXPORT gzsetparams(file, level, strategy)
        gzFile file;
        int level;
        int strategy;
    {
        gz_statep state;
        z_streamp strm;

        /* get internal structure */
        if (file == NULL)
            return Z_STREAM_ERROR;
        state = (gz_statep)file;
        strm = &(state->strm);

        /* check that we're writing and that there's no error */
        if (state->mode != GZ_WRITE || state->err != Z_OK)
            return Z_STREAM_ERROR;

        /* if no change is requested, then do nothing */
        if (level == state->level && strategy == state->strategy)
            return Z_OK;

        /* check for seek request */
        if (state->seek) {
            state->seek = 0;
            if (gz_zero(state, state->skip) == -1)
                return state->err;
        }

        /* change compression parameters for subsequent input */
        if (state->size) {
            /* flush previous input with previous parameters before changing */
            if (strm->avail_in && gz_comp(state, Z_BLOCK) == -1)
                return state->err;
            deflateParams(strm, level, strategy);
        }
        state->level = level;
        state->strategy = strategy;
        return Z_OK;
    }

    /* -- see zlib.h -- */
    int ZEXPORT gzclose_w(file)
        gzFile file;
    {
        int ret = Z_OK;
        gz_statep state;

        /* get internal structure */
        if (file == NULL)
            return Z_STREAM_ERROR;
        state = (gz_statep)file;

        /* check that we're writing */
        if (state->mode != GZ_WRITE)
            return Z_STREAM_ERROR;

        /* check for seek request */
        if (state->seek) {
            state->seek = 0;
            if (gz_zero(state, state->skip) == -1)
                ret = state->err;
        }

        /* flush, free memory, and close file */
        if (gz_comp(state, Z_FINISH) == -1)
            ret = state->err;
        if (state->size) {
            if (!state->direct) {
                (void)deflateEnd(&(state->strm));
                free(state->out);
            }
            free(state->in);
        }
        gz_error(state, Z_OK, NULL);
        free(state->path);
        if (close(state->fd) == -1)
            ret = Z_ERRNO;
        free(state);
        return ret;
    }