Minor edits to the documentation in source file contents.

4 files changed, 109 insertions, 93 deletions

diff --git a/zconf.h b/zconf.h
index 0a4828e..d09f186 100644
--- a/zconf.h
+++ b/zconf.h
@@ -251,7 +251,7 @@
  Of course this will generally degrade compression (there's no free lunch).
 
    The memory requirements for inflate are (in bytes) 1 << windowBits
- that is, 32K for windowBits=15 (default value) plus a few kilobytes
+ that is, 32K for windowBits=15 (default value) plus about 7 kilobytes
  for small objects.
 */
 
diff --git a/zconf.h.cmakein b/zconf.h.cmakein
index 752eb88..70942e4 100644
--- a/zconf.h.cmakein
+++ b/zconf.h.cmakein
@@ -253,7 +253,7 @@
  Of course this will generally degrade compression (there's no free lunch).
 
    The memory requirements for inflate are (in bytes) 1 << windowBits
- that is, 32K for windowBits=15 (default value) plus a few kilobytes
+ that is, 32K for windowBits=15 (default value) plus about 7 kilobytes
  for small objects.
 */
 
diff --git a/zconf.h.in b/zconf.h.in
index 0a4828e..d09f186 100644
--- a/zconf.h.in
+++ b/zconf.h.in
@@ -251,7 +251,7 @@
  Of course this will generally degrade compression (there's no free lunch).
 
    The memory requirements for inflate are (in bytes) 1 << windowBits
- that is, 32K for windowBits=15 (default value) plus a few kilobytes
+ that is, 32K for windowBits=15 (default value) plus about 7 kilobytes
  for small objects.
 */
 
diff --git a/zlib.h b/zlib.h
index fc969af..5c99039 100644
--- a/zlib.h
+++ b/zlib.h
@@ -65,7 +65,8 @@ extern "C" {
   with "gz".  The gzip format is different from the zlib format.  gzip is a
   gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
 
-    This library can optionally read and write gzip streams in memory as well.
+    This library can optionally read and write gzip and raw deflate streams in
+  memory as well.
 
     The zlib format was designed to be compact and fast for use in memory
   and on communications channels.  The gzip format was designed for single-
@@ -74,7 +75,7 @@ extern "C" {
 
     The library does not install any signal handler.  The decoder checks
   the consistency of the compressed data, so the library should never crash
-  even in case of corrupted input.
+  even in the case of corrupted input.
 */
 
 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
@@ -87,7 +88,7 @@ typedef struct z_stream_s {
     uInt     avail_in;  /* number of bytes available at next_in */
     uLong    total_in;  /* total number of input bytes read so far */
 
-    Bytef    *next_out; /* next output byte should be put there */
+    Bytef    *next_out; /* next output byte will go here */
     uInt     avail_out; /* remaining free space at next_out */
     uLong    total_out; /* total number of bytes output so far */
 
@@ -98,8 +99,9 @@ typedef struct z_stream_s {
     free_func  zfree;   /* used to free the internal state */
     voidpf     opaque;  /* private data object passed to zalloc and zfree */
 
-    int     data_type;  /* best guess about the data type: binary or text */
-    uLong   adler;      /* adler32 value of the uncompressed data */
+    int     data_type;  /* best guess about the data type: binary or text
+                           for deflate, or the decoding state for inflate */
+    uLong   adler;      /* Adler-32 or CRC-32 value of the uncompressed data */
     uLong   reserved;   /* reserved for future use */
 } z_stream;
 
@@ -142,7 +144,9 @@ typedef gz_header FAR *gz_headerp;
 
      zalloc must return Z_NULL if there is not enough memory for the object.
    If zlib is used in a multi-threaded application, zalloc and zfree must be
-   thread safe.
+   thread safe.  In that case, zlib is thread-safe.  When zalloc and zfree are
+   Z_NULL on entry to the initialization function, they are set to internal
+   routines that use the standard library functions malloc() and free().
 
      On 16-bit systems, the functions zalloc and zfree must be able to allocate
    exactly 65536 bytes, but will not be required to allocate more than this if
@@ -155,7 +159,7 @@ typedef gz_header FAR *gz_headerp;
 
      The fields total_in and total_out can be used for statistics or progress
    reports.  After compression, total_in holds the total size of the
-   uncompressed data and may be saved for use in the decompressor (particularly
+   uncompressed data and may be saved for use by the decompressor (particularly
    if the decompressor wants to decompress everything in a single step).
 */
 
@@ -200,7 +204,7 @@ typedef gz_header FAR *gz_headerp;
 #define Z_TEXT     1
 #define Z_ASCII    Z_TEXT   /* for compatibility with 1.2.2 and earlier */
 #define Z_UNKNOWN  2
-/* Possible values of the data_type field (though see inflate()) */
+/* Possible values of the data_type field for deflate() */
 
 #define Z_DEFLATED   8
 /* The deflate compression method (the only one supported in this version) */
@@ -258,11 +262,11 @@ ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
     enough room in the output buffer), next_in and avail_in are updated and
     processing will resume at this point for the next call of deflate().
 
-  - Provide more output starting at next_out and update next_out and avail_out
+  - Generate more output starting at next_out and update next_out and avail_out
     accordingly.  This action is forced if the parameter flush is non zero.
     Forcing flush frequently degrades the compression ratio, so this parameter
-    should be set only when necessary (in interactive applications).  Some
-    output may be provided even if flush is not set.
+    should be set only when necessary.  Some output may be provided even if
+    flush is zero.
 
     Before the call of deflate(), the application should ensure that at least
   one of the actions is possible, by providing more input and/or consuming more
@@ -271,7 +275,9 @@ ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
   output when it wants, for example when the output buffer is full (avail_out
   == 0), or after each call of deflate().  If deflate returns Z_OK and with
   zero avail_out, it must be called again after making room in the output
-  buffer because there might be more output pending.
+  buffer because there might be more output pending. See deflatePending(),
+  which can be used if desired to determine whether or not there is more ouput
+  in that case.
 
     Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
   decide how much data to accumulate before producing output, in order to
@@ -292,8 +298,8 @@ ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
   input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
   This completes the current deflate block and follows it with an empty fixed
   codes block that is 10 bits long.  This assures that enough bytes are output
-  in order for the decompressor to finish the block before the empty fixed code
-  block.
+  in order for the decompressor to finish the block before the empty fixed
+  codes block.
 
     If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
   for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
@@ -319,34 +325,38 @@ ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
 
     If the parameter flush is set to Z_FINISH, pending input is processed,
   pending output is flushed and deflate returns with Z_STREAM_END if there was
-  enough output space; if deflate returns with Z_OK, this function must be
-  called again with Z_FINISH and more output space (updated avail_out) but no
-  more input data, until it returns with Z_STREAM_END or an error.  After
-  deflate has returned Z_STREAM_END, the only possible operations on the stream
-  are deflateReset or deflateEnd.
-
-    Z_FINISH can be used immediately after deflateInit if all the compression
-  is to be done in a single step.  In this case, avail_out must be at least the
-  value returned by deflateBound (see below).  Then deflate is guaranteed to
-  return Z_STREAM_END.  If not enough output space is provided, deflate will
-  not return Z_STREAM_END, and it must be called again as described above.
-
-    deflate() sets strm->adler to the adler32 checksum of all input read
-  so far (that is, total_in bytes).
+  enough output space.  If deflate returns with Z_OK or Z_BUF_ERROR, this
+  function must be called again with Z_FINISH and more output space (updated
+  avail_out) but no more input data, until it returns with Z_STREAM_END or an
+  error.  After deflate has returned Z_STREAM_END, the only possible operations
+  on the stream are deflateReset or deflateEnd.
+
+    Z_FINISH can be used in the first deflate call after deflateInit if all the
+  compression is to be done in a single step.  In order to complete in one
+  call, avail_out must be at least the value returned by deflateBound (see
+  below).  Then deflate is guaranteed to return Z_STREAM_END.  If not enough
+  output space is provided, deflate will not return Z_STREAM_END, and it must
+  be called again as described above.
+
+    deflate() sets strm->adler to the Adler-32 checksum of all input read
+  so far (that is, total_in bytes).  If a gzip stream is being generated, then
+  strm->adler will be the CRC-32 checksum of the input read so far.  (See
+  deflateInit2 below.)
 
     deflate() may update strm->data_type if it can make a good guess about
-  the input data type (Z_BINARY or Z_TEXT).  In doubt, the data is considered
-  binary.  This field is only for information purposes and does not affect the
-  compression algorithm in any manner.
+  the input data type (Z_BINARY or Z_TEXT).  If in doubt, the data is
+  considered binary.  This field is only for information purposes and does not
+  affect the compression algorithm in any manner.
 
     deflate() returns Z_OK if some progress has been made (more input
   processed or more output produced), Z_STREAM_END if all input has been
   consumed and all output has been produced (only when flush is set to
   Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
-  if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible
-  (for example avail_in or avail_out was zero).  Note that Z_BUF_ERROR is not
-  fatal, and deflate() can be called again with more input and more output
-  space to continue compressing.
+  if next_in or next_out was Z_NULL or the state was inadvertently written over
+  by the application), or Z_BUF_ERROR if no progress is possible (for example
+  avail_in or avail_out was zero).  Note that Z_BUF_ERROR is not fatal, and
+  deflate() can be called again with more input and more output space to
+  continue compressing.
 */
 
 
@@ -369,23 +379,20 @@ ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
 
      Initializes the internal stream state for decompression.  The fields
    next_in, avail_in, zalloc, zfree and opaque must be initialized before by
-   the caller.  If next_in is not Z_NULL and avail_in is large enough (the
-   exact value depends on the compression method), inflateInit determines the
-   compression method from the zlib header and allocates all data structures
-   accordingly; otherwise the allocation will be deferred to the first call of
-   inflate.  If zalloc and zfree are set to Z_NULL, inflateInit updates them to
-   use default allocation functions.
+   the caller.  In the current version of inflate, the provide input is not
+   read or consumed.  Any memory allocation will be deferred to the first call
+   of inflate.  If zalloc and zfree are set to Z_NULL, inflateInit updates them
+   to use default allocation functions.
 
      inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
    memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
    version assumed by the caller, or Z_STREAM_ERROR if the parameters are
    invalid, such as a null pointer to the structure.  msg is set to null if
-   there is no error message.  inflateInit does not perform any decompression
-   apart from possibly reading the zlib header if present: actual decompression
-   will be done by inflate().  (So next_in and avail_in may be modified, but
-   next_out and avail_out are unused and unchanged.) The current implementation
-   of inflateInit() does not process any header information -- that is deferred
-   until inflate() is called.
+   there is no error message.  inflateInit does not perform any decompression.
+   Actual decompression will be done by inflate().  So next_in, and avail_in,
+   next_out, and avail_out are unused and unchanged.  The current
+   implementation of inflateInit() does not process any header information --
+   that is deferred until inflate() is called.
 */
 
 
@@ -401,17 +408,20 @@ ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
 
   - Decompress more input starting at next_in and update next_in and avail_in
     accordingly.  If not all input can be processed (because there is not
-    enough room in the output buffer), next_in is updated and processing will
-    resume at this point for the next call of inflate().
+    enough room in the output buffer), then next_in and avail_on are updated
+    accordingly, and processing will resume at this point for the next call of
+    inflate().
 
-  - Provide more output starting at next_out and update next_out and avail_out
+  - Generate more output starting at next_out and update next_out and avail_out
     accordingly.  inflate() provides as much output as possible, until there is
     no more input data or no more space in the output buffer (see below about
     the flush parameter).
 
     Before the call of inflate(), the application should ensure that at least
   one of the actions is possible, by providing more input and/or consuming more
-  output, and updating the next_* and avail_* values accordingly.  The
+  output, and updating the next_* and avail_* values accordingly.  If the
+  caller of inflate() does not provide both available input and available
+  output space, it is possible that there will be no progress made.  The
   application can consume the uncompressed output when it wants, for example
   when the output buffer is full (avail_out == 0), or after each call of
   inflate().  If inflate returns Z_OK and with zero avail_out, it must be
@@ -428,7 +438,7 @@ ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
   gets to the end of that block, or when it runs out of data.
 
     The Z_BLOCK option assists in appending to or combining deflate streams.
-  Also to assist in this, on return inflate() will set strm->data_type to the
+  To assist in this, on return inflate() always sets strm->data_type to the
   number of unused bits in the last byte taken from strm->next_in, plus 64 if
   inflate() is currently decoding the last block in the deflate stream, plus
   128 if inflate() returned immediately after decoding an end-of-block code or
@@ -454,7 +464,7 @@ ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
   this case all pending input is processed and all pending output is flushed;
   avail_out must be large enough to hold all of the uncompressed data for the
   operation to complete.  (The size of the uncompressed data may have been
-  saved by the compressor for this purpose.) The use of Z_FINISH is not
+  saved by the compressor for this purpose.)  The use of Z_FINISH is not
   required to perform an inflation in one step.  However it may be used to
   inform inflate that a faster approach can be used for the single inflate()
   call.  Z_FINISH also informs inflate to not maintain a sliding window if the
@@ -476,32 +486,33 @@ ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
   chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
   strm->adler to the Adler-32 checksum of all output produced so far (that is,
   total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
-  below.  At the end of the stream, inflate() checks that its computed adler32
+  below.  At the end of the stream, inflate() checks that its computed Adler-32
   checksum is equal to that saved by the compressor and returns Z_STREAM_END
   only if the checksum is correct.
 
     inflate() can decompress and check either zlib-wrapped or gzip-wrapped
   deflate data.  The header type is detected automatically, if requested when
   initializing with inflateInit2().  Any information contained in the gzip
-  header is not retained, so applications that need that information should
-  instead use raw inflate, see inflateInit2() below, or inflateBack() and
-  perform their own processing of the gzip header and trailer.  When processing
+  header is not retained unless inflateGetHeader() is used.  When processing
   gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
-  produced so far.  The CRC-32 is checked against the gzip trailer.
+  produced so far.  The CRC-32 is checked against the gzip trailer, as is the
+  uncompressed length, modulo 2^32.
 
     inflate() returns Z_OK if some progress has been made (more input processed
   or more output produced), Z_STREAM_END if the end of the compressed data has
   been reached and all uncompressed output has been produced, Z_NEED_DICT if a
   preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
   corrupted (input stream not conforming to the zlib format or incorrect check
-  value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
-  next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory,
-  Z_BUF_ERROR if no progress is possible or if there was not enough room in the
-  output buffer when Z_FINISH is used.  Note that Z_BUF_ERROR is not fatal, and
+  value, in which case strm->msg points to a string with a more specific
+  error), Z_STREAM_ERROR if the stream structure was inconsistent (for example
+  next_in or next_out was Z_NULL, or the state was inadvertently written over
+  by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR
+  if no progress was possible or if there was not enough room in the output
+  buffer when Z_FINISH is used.  Note that Z_BUF_ERROR is not fatal, and
   inflate() can be called again with more input and more output space to
   continue decompressing.  If Z_DATA_ERROR is returned, the application may
   then call inflateSync() to look for a good compression block if a partial
-  recovery of the data is desired.
+  recovery of the data is to be attempted.
 */
 
 
@@ -511,9 +522,8 @@ ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
    This function discards any unprocessed input and does not flush any pending
    output.
 
-     inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
-   was inconsistent.  In the error case, msg may be set but then points to a
-   static string (which must not be deallocated).
+     inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state
+   was inconsistent.
 */
 
 
@@ -554,14 +564,15 @@ ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
 
      windowBits can also be -8..-15 for raw deflate.  In this case, -windowBits
    determines the window size.  deflate() will then generate raw deflate data
-   with no zlib header or trailer, and will not compute an adler32 check value.
+   with no zlib header or trailer, and will not compute a check value.
 
      windowBits can also be greater than 15 for optional gzip encoding.  Add
    16 to windowBits to write a simple gzip header and trailer around the
    compressed data instead of a zlib wrapper.  The gzip header will have no
    file name, no extra data, no comment, no modification time (set to zero), no
-   header crc, and the operating system will be set to 255 (unknown).  If a
-   gzip stream is being written, strm->adler is a crc32 instead of an adler32.
+   header crc, and the operating system will be set to the appropriate value,
+   if the operating system was determined at compile time.  If a gzip stream is
+   being written, strm->adler is a CRC-32 instead of an Adler-32.
 
      For raw deflate or gzip encoding, a request for a 256-byte window is
    rejected as invalid, since only the zlib header provides a means of
@@ -626,12 +637,12 @@ ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
    addition, the current implementation of deflate will use at most the window
    size minus 262 bytes of the provided dictionary.
 
-     Upon return of this function, strm->adler is set to the adler32 value
+     Upon return of this function, strm->adler is set to the Adler-32 value
    of the dictionary; the decompressor may later use this value to determine
-   which dictionary has been used by the compressor.  (The adler32 value
+   which dictionary has been used by the compressor.  (The Adler-32 value
    applies to the whole dictionary even if only a subset of the dictionary is
    actually used by the compressor.) If a raw deflate was requested, then the
-   adler32 value is not computed and strm->adler is not set.
+   Adler-32 value is not computed and strm->adler is not set.
 
      deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
    parameter is invalid (e.g.  dictionary being Z_NULL) or the stream state is
@@ -819,7 +830,7 @@ ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
    is for use with other formats that use the deflate compressed data format
    such as zip.  Those formats provide their own check values.  If a custom
    format is developed using the raw deflate format for compressed data, it is
-   recommended that a check value such as an adler32 or a crc32 be applied to
+   recommended that a check value such as an Adler-32 or a CRC-32 be applied to
    the uncompressed data as is done in the zlib, gzip, and zip formats.  For
    most applications, the zlib format should be used as is.  Note that comments
    above on the use in deflateInit2() applies to the magnitude of windowBits.
@@ -828,7 +839,10 @@ ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
    32 to windowBits to enable zlib and gzip decoding with automatic header
    detection, or add 16 to decode only the gzip format (the zlib format will
    return a Z_DATA_ERROR).  If a gzip stream is being decoded, strm->adler is a
-   crc32 instead of an adler32.
+   CRC-32 instead of an Adler-32.  Unlike the gunzip utility and gzread() (see
+   below), inflate() will not automatically decode concatenated gzip streams.
+   inflate() will return Z_STREAM_END at the end of the gzip stream.  The state
+   would need to be reset to continue decoding a subsequent gzip stream.
 
      inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
    memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
@@ -849,7 +863,7 @@ ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
      Initializes the decompression dictionary from the given uncompressed byte
    sequence.  This function must be called immediately after a call of inflate,
    if that call returned Z_NEED_DICT.  The dictionary chosen by the compressor
-   can be determined from the adler32 value returned by that call of inflate.
+   can be determined from the Adler-32 value returned by that call of inflate.
    The compressor and decompressor must use exactly the same dictionary (see
    deflateSetDictionary).  For raw inflate, this function can be called at any
    time to set the dictionary.  If the provided dictionary is smaller than the
@@ -860,7 +874,7 @@ ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
      inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
    parameter is invalid (e.g.  dictionary being Z_NULL) or the stream state is
    inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
-   expected one (incorrect adler32 value).  inflateSetDictionary does not
+   expected one (incorrect Adler-32 value).  inflateSetDictionary does not
    perform any decompression: this will be done by subsequent calls of
    inflate().
 */
@@ -918,7 +932,7 @@ ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
 /*
      This function is equivalent to inflateEnd followed by inflateInit,
-   but does not free and reallocate all the internal decompression state.  The
+   but does not free and reallocate the internal decompression state.  The
    stream will keep attributes that may have been set by inflateInit2.
 
      inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
@@ -930,7 +944,9 @@ ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,
 /*
      This function is the same as inflateReset, but it also permits changing
    the wrap and window size requests.  The windowBits parameter is interpreted
-   the same as it is for inflateInit2.
+   the same as it is for inflateInit2.  If the window size is changed, then the
+   memory allocated for the window is freed, and the window will be reallocated
+   by inflate() if needed.
 
      inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
    stream state was inconsistent (such as zalloc or state being Z_NULL), or if
@@ -982,7 +998,7 @@ ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));
    location in the input stream can be determined from avail_in and data_type
    as noted in the description for the Z_BLOCK flush parameter for inflate.
 
-     inflateMark returns the value noted above or -65536 if the provided
+     inflateMark returns the value noted above, or -65536 if the provided
    source stream state was inconsistent.
 */
 
@@ -1074,9 +1090,9 @@ ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
    This routine would normally be used in a utility that reads zip or gzip
    files and writes out uncompressed files.  The utility would decode the
    header and process the trailer on its own, hence this routine expects only
-   the raw deflate stream to decompress.  This is different from the normal
-   behavior of inflate(), which expects either a zlib or gzip header and
-   trailer around the deflate stream.
+   the raw deflate stream to decompress.  This is different from the default
+   behavior of inflate(), which expects a zlib header and trailer around the
+   deflate stream.
 
      inflateBack() uses two subroutines supplied by the caller that are then
    called by inflateBack() for input and output.  inflateBack() calls those
@@ -1085,12 +1101,12 @@ ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
    parameters and return types are defined above in the in_func and out_func
    typedefs.  inflateBack() will call in(in_desc, &buf) which should return the
    number of bytes of provided input, and a pointer to that input in buf.  If
-   there is no input available, in() must return zero--buf is ignored in that
-   case--and inflateBack() will return a buffer error.  inflateBack() will call
-   out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].  out()
-   should return zero on success, or non-zero on failure.  If out() returns
-   non-zero, inflateBack() will return with an error.  Neither in() nor out()
-   are permitted to change the contents of the window provided to
+   there is no input available, in() must return zero -- buf is ignored in that
+   case -- and inflateBack() will return a buffer error.  inflateBack() will
+   call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].
+   out() should return zero on success, or non-zero on failure.  If out()
+   returns non-zero, inflateBack() will return with an error.  Neither in() nor
+   out() are permitted to change the contents of the window provided to
    inflateBackInit(), which is also the buffer that out() uses to write from.
    The length written by out() will be at most the window size.  Any non-zero
    amount of input may be provided by in().
@@ -1118,7 +1134,7 @@ ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
    using strm->next_in which will be Z_NULL only if in() returned an error.  If
    strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
    non-zero.  (in() will always be called before out(), so strm->next_in is
-   assured to be defined if out() returns non-zero.) Note that inflateBack()
+   assured to be defined if out() returns non-zero.)  Note that inflateBack()
    cannot return Z_OK.
 */
 
@@ -1598,7 +1614,7 @@ ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
    return the updated checksum.  If buf is Z_NULL, this function returns the
    required initial value for the checksum.
 
-     An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
+     An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed
    much faster.
 
    Usage example: