[devel] Make all png_debug macros into *unterminated* statements

or expressions (i.e. a trailing ';' must always be added) and correct
the format statements in various png_debug messages.

1 files changed, 31 insertions, 16 deletions

diff --git a/pngdebug.h b/pngdebug.h
index 81c598f39..bf23853ac 100644
--- a/pngdebug.h
+++ b/pngdebug.h
@@ -5,7 +5,7 @@
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
- * Last changed in libpng version 1.5.0 - March 9, 2010
+ * Last changed in libpng version 1.5.0 - March 10, 2010
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
@@ -16,6 +16,21 @@
  * numbers for PNG_DEBUG mean more debugging information.  This has
  * only been added since version 0.95 so it is not implemented throughout
  * libpng yet, but more support will be added as needed.
+ *
+ * png_debug[1-2]?(level, message ,arg{0-2})
+ *   Expands to a statement (either a simple expression or a compound
+ *   do..while(0) statement) that outputs a message with parameter
+ *   substitution if PNG_DEBUG is defined to 2 or more.  If PNG_DEBUG
+ *   is undefined, 0 or 1 every png_debug expands to a simple expression
+ *   (actually ((void)0)).
+ *
+ *   level: level of detail of message, starting at 0.  A level 'n'
+ *          message is preceded by 'n' tab characters (not implemented
+ *          on Microsoft compilers unless PNG_DEBUG_FILE is also 
+ *          defined, to allow debug DLL compilation with no standard IO).
+ *   message: a printf(3) style text string.  A trailing '\n' is added
+ *            to the message.
+ *   arg: 0 to 2 arguments for printf(3) style substitution in message.
  */
 #ifndef PNGDEBUG_H
 #define PNGDEBUG_H
@@ -50,61 +65,61 @@
 #        ifdef __STDC__
 #          ifndef png_debug
 #            define png_debug(l,m) \
-       { \
+       do { \
        int num_tabs=l; \
        fprintf(PNG_DEBUG_FILE,"%s"m PNG_STRING_NEWLINE,(num_tabs==1 ? "\t" : \
          (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":"")))); \
-       }
+       } while (0)
 #          endif
 #          ifndef png_debug1
 #            define png_debug1(l,m,p1) \
-       { \
+       do { \
        int num_tabs=l; \
        fprintf(PNG_DEBUG_FILE,"%s"m PNG_STRING_NEWLINE,(num_tabs==1 ? "\t" : \
          (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))),p1); \
-       }
+       } while (0)
 #          endif
 #          ifndef png_debug2
 #            define png_debug2(l,m,p1,p2) \
-       { \
+       do { \
        int num_tabs=l; \
        fprintf(PNG_DEBUG_FILE,"%s"m PNG_STRING_NEWLINE,(num_tabs==1 ? "\t" : \
          (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))),p1,p2); \
-       }
+       } while (0)
 #          endif
 #        else /* __STDC __ */
 #          ifndef png_debug
 #            define png_debug(l,m) \
-       { \
+       do { \
        int num_tabs=l; \
        char format[256]; \
        snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
          (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
          m,PNG_STRING_NEWLINE); \
        fprintf(PNG_DEBUG_FILE,format); \
-       }
+       } while (0)
 #          endif
 #          ifndef png_debug1
 #            define png_debug1(l,m,p1) \
-       { \
+       do { \
        int num_tabs=l; \
        char format[256]; \
        snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
          (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
          m,PNG_STRING_NEWLINE); \
        fprintf(PNG_DEBUG_FILE,format,p1); \
-       }
+       } while (0)
 #          endif
 #          ifndef png_debug2
 #            define png_debug2(l,m,p1,p2) \
-       { \
+       do { \
        int num_tabs=l; \
        char format[256]; \
        snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
          (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
          m,PNG_STRING_NEWLINE); \
        fprintf(PNG_DEBUG_FILE,format,p1,p2); \
-       }
+       } while (0)
 #          endif
 #        endif /* __STDC __ */
 #      endif /* (PNG_DEBUG > 1) */
@@ -113,12 +128,12 @@
 #  endif /* (PNG_DEBUG > 0) */
 #endif /* PNG_DEBUG */
 #ifndef png_debug
-#  define png_debug(l, m)
+#  define png_debug(l, m) ((void)0)
 #endif
 #ifndef png_debug1
-#  define png_debug1(l, m, p1)
+#  define png_debug1(l, m, p1) ((void)0)
 #endif
 #ifndef png_debug2
-#  define png_debug2(l, m, p1, p2)
+#  define png_debug2(l, m, p1, p2) ((void)0)
 #endif
 #endif /* PNGDEBUG_H */