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Java example source code file (gzwrite.c)

This example Java source code file (gzwrite.c) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

gz_write, has_snprintf_void, null, stdc, z_errno, z_finish, z_mem_error, z_no_flush, z_null, z_ok, z_stream_error, zexport, zexportva

The gzwrite.c Java example source code

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/* gzwrite.c -- zlib functions for writing gzip files
 * Copyright (C) 2004, 2005, 2010 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));

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

    /* allocate input and output buffers */
    state->in = malloc(state->want);
    state->out = malloc(state->want);
    if (state->in == NULL || state->out == NULL) {
        if (state->out != NULL)
            free(state->out);
        if (state->in != 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,
                       15 + 16, 8, state->strategy);
    if (ret != Z_OK) {
        free(state->in);
        gz_error(state, Z_MEM_ERROR, "out of memory");
        return -1;
    }

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

    /* initialize write buffer */
    strm->avail_out = state->size;
    strm->next_out = state->out;
    state->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, 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. */
local int gz_comp(state, flush)
    gz_statep state;
    int flush;
{
    int ret, got;
    unsigned have;
    z_streamp strm = &(state->strm);

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

    /* 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))) {
            have = (unsigned)(strm->next_out - state->next);
            if (have && ((got = write(state->fd, state->next, have)) < 0 ||
                         (unsigned)got != have)) {
                gz_error(state, Z_ERRNO, zstrerror());
                return -1;
            }
            if (strm->avail_out == 0) {
                strm->avail_out = state->size;
                strm->next_out = state->out;
            }
            state->next = strm->next_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 error, 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->pos += n;
        if (gz_comp(state, Z_NO_FLUSH) == -1)
            return -1;
        len -= n;
    }
    return 0;
}

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

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

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

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

        /* directly compress user buffer to file */
        strm->avail_in = len;
        strm->next_in = (voidp)buf;
        state->pos += len;
        if (gz_comp(state, Z_NO_FLUSH) == -1)
            return 0;
    }

    /* input was all buffered or compressed (put will fit in int) */
    return (int)put;
}

/* -- see zlib.h -- */
int ZEXPORT gzputc(file, c)
    gzFile file;
    int c;
{
    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 (strm->avail_in < state->size) {
        if (strm->avail_in == 0)
            strm->next_in = state->in;
        strm->next_in[strm->avail_in++] = c;
        state->pos++;
        return c;
    }

    /* no room in buffer or not initialized, use gz_write() */
    buf[0] = c;
    if (gzwrite(file, buf, 1) != 1)
        return -1;
    return c;
}

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

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

#ifdef STDC
#include <stdarg.h>

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

    /* 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 0;

    /* make sure we have some buffer space */
    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;
    }

    /* consume whatever's left in the input buffer */
    if (strm->avail_in && gz_comp(state, Z_NO_FLUSH) == -1)
        return 0;

    /* do the printf() into the input buffer, put length in len */
    size = (int)(state->size);
    state->in[size - 1] = 0;
    va_start(va, format);
#ifdef NO_vsnprintf
#  ifdef HAS_vsprintf_void
    (void)vsprintf(state->in, format, va);
    va_end(va);
    for (len = 0; len < size; len++)
        if (state->in[len] == 0) break;
#  else
    len = vsprintf(state->in, format, va);
    va_end(va);
#  endif
#else
#  ifdef HAS_vsnprintf_void
    (void)vsnprintf(state->in, size, format, va);
    va_end(va);
    len = strlen(state->in);
#  else
    len = vsnprintf((char *)(state->in), size, format, va);
    va_end(va);
#  endif
#endif

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

    /* update buffer and position, defer compression until needed */
    strm->avail_in = (unsigned)len;
    strm->next_in = state->in;
    state->pos += len;
    return len;
}

#else /* !STDC */

/* -- 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;
{
    int size, len;
    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 0;

    /* make sure we have some buffer space */
    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;
    }

    /* consume whatever's left in the input buffer */
    if (strm->avail_in && gz_comp(state, Z_NO_FLUSH) == -1)
        return 0;

    /* do the printf() into the input buffer, put length in len */
    size = (int)(state->size);
    state->in[size - 1] = 0;
#ifdef NO_snprintf
#  ifdef HAS_sprintf_void
    sprintf(state->in, 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 (state->in[len] == 0) break;
#  else
    len = sprintf(state->in, 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(state->in, size, format, a1, a2, a3, a4, a5, a6, a7, a8,
             a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
    len = strlen(state->in);
#  else
    len = snprintf(state->in, 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 >= (int)size || state->in[size - 1] != 0)
        return 0;

    /* update buffer and position, defer compression until needed */
    strm->avail_in = (unsigned)len;
    strm->next_in = state->in;
    state->pos += len;
    return len;
}

#endif

/* -- see zlib.h -- */
int ZEXPORT gzflush(file, flush)
    gzFile file;
    int flush;
{
    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 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 -1;
    }

    /* compress remaining data with requested flush */
    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 -1;
    }

    /* 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_PARTIAL_FLUSH) == -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 = 0;
    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;
        ret += gz_zero(state, state->skip);
    }

    /* flush, free memory, and close file */
    ret += gz_comp(state, Z_FINISH);
    (void)deflateEnd(&(state->strm));
    free(state->out);
    free(state->in);
    gz_error(state, Z_OK, NULL);
    free(state->path);
    ret += close(state->fd);
    free(state);
    return ret ? Z_ERRNO : Z_OK;
}

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