zpipe.patch

--- zpipe.c	2005-12-12 00:38:44.000000000 +0100
+++ myzpipe.c	2014-05-05 21:25:42.000000000 +0200
@@ -1,6 +1,8 @@
 /* zpipe.c: example of proper use of zlib's inflate() and deflate()
    Not copyrighted -- provided to the public domain
-   Version 1.4  11 December 2005  Mark Adler */
+   Version 1.4  11 December 2005  Mark Adler 
+   Version 1.5   5 May 2014       Hubert Tournier
+*/
 
 /* Version history:
    1.0  30 Oct 2004  First version
@@ -10,12 +12,14 @@
    1.3   6 Apr 2005  Remove incorrect assertion in inf()
    1.4  11 Dec 2005  Add hack to avoid MSDOS end-of-line conversions
                      Avoid some compiler warnings for input and output buffers
+   1.5   5 May 2014  Removed the main program, command line and compression parts
+                     to use as a decompression engine only
  */
 
 #include <stdio.h>
 #include <string.h>
 #include <assert.h>
-#include "zlib.h"
+#include <zlib.h>
 
 #if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)
 #  include <fcntl.h>
@@ -27,62 +31,6 @@
 
 #define CHUNK 16384
 
-/* Compress from file source to file dest until EOF on source.
-   def() returns Z_OK on success, Z_MEM_ERROR if memory could not be
-   allocated for processing, Z_STREAM_ERROR if an invalid compression
-   level is supplied, Z_VERSION_ERROR if the version of zlib.h and the
-   version of the library linked do not match, or Z_ERRNO if there is
-   an error reading or writing the files. */
-int def(FILE *source, FILE *dest, int level)
-{
-    int ret, flush;
-    unsigned have;
-    z_stream strm;
-    unsigned char in[CHUNK];
-    unsigned char out[CHUNK];
-
-    /* allocate deflate state */
-    strm.zalloc = Z_NULL;
-    strm.zfree = Z_NULL;
-    strm.opaque = Z_NULL;
-    ret = deflateInit(&strm, level);
-    if (ret != Z_OK)
-        return ret;
-
-    /* compress until end of file */
-    do {
-        strm.avail_in = fread(in, 1, CHUNK, source);
-        if (ferror(source)) {
-            (void)deflateEnd(&strm);
-            return Z_ERRNO;
-        }
-        flush = feof(source) ? Z_FINISH : Z_NO_FLUSH;
-        strm.next_in = in;
-
-        /* run deflate() on input until output buffer not full, finish
-           compression if all of source has been read in */
-        do {
-            strm.avail_out = CHUNK;
-            strm.next_out = out;
-            ret = deflate(&strm, flush);    /* no bad return value */
-            assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
-            have = CHUNK - strm.avail_out;
-            if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
-                (void)deflateEnd(&strm);
-                return Z_ERRNO;
-            }
-        } while (strm.avail_out == 0);
-        assert(strm.avail_in == 0);     /* all input will be used */
-
-        /* done when last data in file processed */
-    } while (flush != Z_FINISH);
-    assert(ret == Z_STREAM_END);        /* stream will be complete */
-
-    /* clean up and return */
-    (void)deflateEnd(&strm);
-    return Z_OK;
-}
-
 /* Decompress from file source to file dest until stream ends or EOF.
    inf() returns Z_OK on success, Z_MEM_ERROR if memory could not be
    allocated for processing, Z_DATA_ERROR if the deflate data is
@@ -173,7 +121,7 @@
 }
 
 /* compress or decompress from stdin to stdout */
-int main(int argc, char **argv)
+int zpipe()
 {
     int ret;
 
@@ -181,25 +129,9 @@
     SET_BINARY_MODE(stdin);
     SET_BINARY_MODE(stdout);
 
-    /* do compression if no arguments */
-    if (argc == 1) {
-        ret = def(stdin, stdout, Z_DEFAULT_COMPRESSION);
-        if (ret != Z_OK)
-            zerr(ret);
-        return ret;
-    }
-
-    /* do decompression if -d specified */
-    else if (argc == 2 && strcmp(argv[1], "-d") == 0) {
-        ret = inf(stdin, stdout);
-        if (ret != Z_OK)
-            zerr(ret);
-        return ret;
-    }
-
-    /* otherwise, report usage */
-    else {
-        fputs("zpipe usage: zpipe [-d] < source > dest\n", stderr);
-        return 1;
-    }
+    /* do decompression */
+    ret = inf(stdin, stdout);
+    if (ret != Z_OK)
+        zerr(ret);
+    return ret;
 }