zlib: Update from 1.2.5 to 1.2.13

The updated files were extracted from:

https://www.zlib.net/zlib-1.2.13.tar.xz

The archive had an SHA-256 hash value of:

d14c38e313afc35a9a8760dadf26042f51ea0f5d154b0630a31da0540107fb98

Close #4902.

1 files changed, 316 insertions, 170 deletions

diff --git a/cpukit/zlib/gzwrite.c b/cpukit/zlib/gzwrite.c
index e8defc6887..eb8a0e5893 100644
--- a/cpukit/zlib/gzwrite.c
+++ b/cpukit/zlib/gzwrite.c
@@ -1,5 +1,5 @@
 /* gzwrite.c -- zlib functions for writing gzip files
- * Copyright (C) 2004, 2005, 2010 Mark Adler
+ * Copyright (C) 2004-2019 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -9,65 +9,103 @@
 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 failure or 0 on success. */
+   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 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);
+    /* 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;
     }
 
-    /* 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;
+    /* 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 */
-    strm->avail_out = state->size;
-    strm->next_out = state->out;
-    state->next = strm->next_out;
+    /* 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, 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. */
+   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, got;
-    unsigned have;
+    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;
+    }
+
+    /* check for a pending reset */
+    if (state->reset) {
+        /* don't start a new gzip member unless there is data to write */
+        if (strm->avail_in == 0)
+            return 0;
+        deflateReset(strm);
+        state->reset = 0;
+    }
+
     /* run deflate() on provided input until it produces no more output */
     ret = Z_OK;
     do {
@@ -75,17 +113,21 @@ local int gz_comp(state, flush)
            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;
+            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;
             }
-            state->next = strm->next_out;
         }
 
         /* compress */
@@ -101,13 +143,14 @@ local int gz_comp(state, flush)
 
     /* if that completed a deflate stream, allow another to start */
     if (flush == Z_FINISH)
-        deflateReset(strm);
+        state->reset = 1;
 
     /* all done, no errors */
     return 0;
 }
 
-/* Compress len zeros to output.  Return -1 on error, 0 on success. */
+/* 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;
@@ -131,7 +174,7 @@ local int gz_zero(state, len)
         }
         strm->avail_in = n;
         strm->next_in = state->in;
-        state->pos += n;
+        state->x.pos += n;
         if (gz_comp(state, Z_NO_FLUSH) == -1)
             return -1;
         len -= n;
@@ -139,33 +182,14 @@ local int gz_zero(state, len)
     return 0;
 }
 
-/* -- see zlib.h -- */
-int ZEXPORT gzwrite(file, buf, len)
-    gzFile file;
+/* 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;
-    unsigned len;
+    z_size_t 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;
-    }
+    z_size_t put = len;
 
     /* if len is zero, avoid unnecessary operations */
     if (len == 0)
@@ -186,35 +210,103 @@ int ZEXPORT gzwrite(file, buf, len)
     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;
+            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 = (unsigned)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 (strm->avail_in && gz_comp(state, Z_NO_FLUSH) == -1)
+        if (state->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;
+        state->strm.next_in = (z_const Bytef *)buf;
+        do {
+            unsigned n = (unsigned)-1;
+            if (n > len)
+                n = (unsigned)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;
     }
 
-    /* input was all buffered or compressed (put will fit in int) */
-    return (int)put;
+    /* write len bytes to buf, return the number of full items written */
+    return len ? gz_write(state, buf, len) / size : 0;
 }
 
 /* -- see zlib.h -- */
@@ -222,6 +314,7 @@ int ZEXPORT gzputc(file, c)
     gzFile file;
     int c;
 {
+    unsigned have;
     unsigned char buf[1];
     gz_statep state;
     z_streamp strm;
@@ -245,179 +338,225 @@ int ZEXPORT gzputc(file, c)
 
     /* try writing to input buffer for speed (state->size == 0 if buffer not
        initialized) */
-    if (strm->avail_in < state->size) {
+    if (state->size) {
         if (strm->avail_in == 0)
             strm->next_in = state->in;
-        strm->next_in[strm->avail_in++] = c;
-        state->pos++;
-        return c;
+        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] = c;
-    if (gzwrite(file, buf, 1) != 1)
+    buf[0] = (unsigned char)c;
+    if (gz_write(state, buf, 1) != 1)
         return -1;
-    return c;
+    return c & 0xff;
 }
 
 /* -- see zlib.h -- */
-int ZEXPORT gzputs(file, str)
+int ZEXPORT gzputs(file, s)
     gzFile file;
-    const char *str;
+    const char *s;
 {
-    int ret;
-    unsigned len;
+    z_size_t len, put;
+    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 = (unsigned)strlen(str);
-    ret = gzwrite(file, str, len);
-    return ret == 0 && len != 0 ? -1 : ret;
+    len = strlen(s);
+    if ((int)len < 0 || (unsigned)len != len) {
+        gz_error(state, Z_STREAM_ERROR, "string length does not fit in int");
+        return -1;
+    }
+    put = gz_write(state, s, len);
+    return put < len ? -1 : (int)len;
 }
 
-#ifdef STDC
+#if defined(STDC) || defined(Z_HAVE_STDARG_H)
 #include <stdarg.h>
 
 /* -- see zlib.h -- */
-int ZEXPORTVA gzprintf (gzFile file, const char *format, ...)
+int ZEXPORTVA gzvprintf(gzFile file, const char *format, va_list va)
 {
-    int size, len;
+    int len;
+    unsigned left;
+    char *next;
     gz_statep state;
     z_streamp strm;
-    va_list va;
 
     /* get internal structure */
     if (file == NULL)
-        return -1;
+        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 0;
+        return Z_STREAM_ERROR;
 
     /* make sure we have some buffer space */
     if (state->size == 0 && gz_init(state) == -1)
-        return 0;
+        return state->err;
 
     /* check for seek request */
     if (state->seek) {
         state->seek = 0;
         if (gz_zero(state, state->skip) == -1)
-            return 0;
+            return state->err;
     }
 
-    /* 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);
+    /* 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(state->in, format, va);
-    va_end(va);
-    for (len = 0; len < size; len++)
-        if (state->in[len] == 0) break;
+    (void)vsprintf(next, format, va);
+    for (len = 0; len < state->size; len++)
+        if (next[len] == 0) break;
 #  else
-    len = vsprintf(state->in, format, va);
-    va_end(va);
+    len = vsprintf(next, format, va);
 #  endif
 #else
 #  ifdef HAS_vsnprintf_void
-    (void)vsnprintf(state->in, size, format, va);
-    va_end(va);
-    len = strlen(state->in);
+    (void)vsnprintf(next, state->size, format, va);
+    len = strlen(next);
 #  else
-    len = vsnprintf((char *)(state->in), size, format, va);
-    va_end(va);
+    len = vsnprintf(next, state->size, format, va);
 #  endif
 #endif
 
     /* check that printf() results fit in buffer */
-    if (len <= 0 || len >= (int)size || state->in[size - 1] != 0)
+    if (len == 0 || (unsigned)len >= state->size || next[state->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;
+    /* 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;
+        memmove(state->in, state->in + state->size, left);
+        strm->next_in = state->in;
+        strm->avail_in = left;
+    }
     return len;
 }
 
-#else /* !STDC */
+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,
+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;
+    unsigned len, left;
+    char *next;
     gz_statep state;
     z_streamp strm;
 
     /* get internal structure */
     if (file == NULL)
-        return -1;
+        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 0;
+        return Z_STREAM_ERROR;
 
     /* make sure we have some buffer space */
     if (state->size == 0 && gz_init(state) == -1)
-        return 0;
+        return state->error;
 
     /* check for seek request */
     if (state->seek) {
         state->seek = 0;
         if (gz_zero(state, state->skip) == -1)
-            return 0;
+            return state->error;
     }
 
-    /* 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;
+    /* 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(state->in, format, a1, a2, a3, a4, a5, a6, a7, a8,
-            a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
+    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 (state->in[len] == 0) break;
+        if (next[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);
+    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(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);
+    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(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 = 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 >= (int)size || state->in[size - 1] != 0)
+    if (len == 0 || len >= state->size || next[state->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;
+    /* 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;
+        memmove(state->in, state->in + state->size, left);
+        strm->next_in = state->in;
+        strm->avail_in = left;
+    }
+    return (int)len;
 }
 
 #endif
@@ -431,7 +570,7 @@ int ZEXPORT gzflush(file, flush)
 
     /* get internal structure */
     if (file == NULL)
-        return -1;
+        return Z_STREAM_ERROR;
     state = (gz_statep)file;
 
     /* check that we're writing and that there's no error */
@@ -446,11 +585,11 @@ int ZEXPORT gzflush(file, flush)
     if (state->seek) {
         state->seek = 0;
         if (gz_zero(state, state->skip) == -1)
-            return -1;
+            return state->err;
     }
 
     /* compress remaining data with requested flush */
-    gz_comp(state, flush);
+    (void)gz_comp(state, flush);
     return state->err;
 }
 
@@ -481,13 +620,13 @@ int ZEXPORT gzsetparams(file, level, strategy)
     if (state->seek) {
         state->seek = 0;
         if (gz_zero(state, state->skip) == -1)
-            return -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_PARTIAL_FLUSH) == -1)
+        if (strm->avail_in && gz_comp(state, Z_BLOCK) == -1)
             return state->err;
         deflateParams(strm, level, strategy);
     }
@@ -500,7 +639,7 @@ int ZEXPORT gzsetparams(file, level, strategy)
 int ZEXPORT gzclose_w(file)
     gzFile file;
 {
-    int ret = 0;
+    int ret = Z_OK;
     gz_statep state;
 
     /* get internal structure */
@@ -515,17 +654,24 @@ int ZEXPORT gzclose_w(file)
     /* check for seek request */
     if (state->seek) {
         state->seek = 0;
-        ret += gz_zero(state, state->skip);
+        if (gz_zero(state, state->skip) == -1)
+            ret = state->err;
     }
 
     /* flush, free memory, and close file */
-    ret += gz_comp(state, Z_FINISH);
-    (void)deflateEnd(&(state->strm));
-    free(state->out);
-    free(state->in);
+    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);
-    ret += close(state->fd);
+    if (close(state->fd) == -1)
+        ret = Z_ERRNO;
     free(state);
-    return ret ? Z_ERRNO : Z_OK;
+    return ret;
 }