Add #define ZLIB_CONST option to use const in the z_stream interface.

This permits compilers to check for the proper treatment of next_in and
msg in the z_stream structure.  This is an option instead of the default
in order to preserve backward compatibility.  Some applications make use
of the z_stream structure outside of zlib, and perform operations such
as free(strm->next_in), which would not be permitted when next_in is
const.  The #define ZLIB_CONST needs to precede the #include "zlib.h">,
in order to make next_in and msg const pointers in the z_stream type.
This commit is contained in:
Mark Adler 2011-10-18 23:05:37 -07:00
parent 5b48d061c8
commit 5ab9f47745
4 changed files with 20 additions and 2 deletions

View File

@ -214,6 +214,12 @@
# endif
#endif
#if defined(ZLIB_CONST) && !defined(z_const)
# define z_const const
#else
# define z_const
#endif
/* Some Mac compilers merge all .h files incorrectly: */
#if defined(__MWERKS__)||defined(applec)||defined(THINK_C)||defined(__SC__)
# define NO_DUMMY_DECL

View File

@ -216,6 +216,12 @@
# endif
#endif
#if defined(ZLIB_CONST) && !defined(z_const)
# define z_const const
#else
# define z_const
#endif
/* Some Mac compilers merge all .h files incorrectly: */
#if defined(__MWERKS__)||defined(applec)||defined(THINK_C)||defined(__SC__)
# define NO_DUMMY_DECL

View File

@ -214,6 +214,12 @@
# endif
#endif
#if defined(ZLIB_CONST) && !defined(z_const)
# define z_const const
#else
# define z_const
#endif
/* Some Mac compilers merge all .h files incorrectly: */
#if defined(__MWERKS__)||defined(applec)||defined(THINK_C)||defined(__SC__)
# define NO_DUMMY_DECL

4
zlib.h
View File

@ -83,7 +83,7 @@ typedef void (*free_func) OF((voidpf opaque, voidpf address));
struct internal_state;
typedef struct z_stream_s {
Bytef *next_in; /* next input byte */
z_const Bytef *next_in; /* next input byte */
uInt avail_in; /* number of bytes available at next_in */
uLong total_in; /* total number of input bytes read so far */
@ -91,7 +91,7 @@ typedef struct z_stream_s {
uInt avail_out; /* remaining free space at next_out */
uLong total_out; /* total number of bytes output so far */
char *msg; /* last error message, NULL if no error */
z_const char *msg; /* last error message, NULL if no error */
struct internal_state FAR *state; /* not visible by applications */
alloc_func zalloc; /* used to allocate the internal state */