Fix bug: don't do png_destroy_write() on a read structure

git-svn-id: http://svn.code.sf.net/p/netpbm/code/trunk@1022 9d0c8265-081b-0410-96cb-a4ca84ce46f8

2 files changed, 13 insertions, 5 deletions

diff --git a/converter/other/pngx.c b/converter/other/pngx.c
index 602fdb33..22124b2a 100644
--- a/converter/other/pngx.c
+++ b/converter/other/pngx.c
@@ -69,6 +69,7 @@ pngx_create(struct pngx ** const pngxPP,
             else
                 *pngxPP = pngxP;
         }
+        pngxP->rw = rw;
     }
 }
 
@@ -77,7 +78,14 @@ pngx_create(struct pngx ** const pngxPP,
 void
 pngx_destroy(struct pngx * const pngxP) {
 
-    png_destroy_write_struct(&pngxP->png_ptr, &pngxP->info_ptr);
+    switch(pngxP->rw) {
+    case PNGX_READ:
+        png_destroy_read_struct(&pngxP->png_ptr, &pngxP->info_ptr, NULL);
+        break;
+    case PNGX_WRITE:
+        png_destroy_write_struct(&pngxP->png_ptr, &pngxP->info_ptr);
+        break;
+    }
 
     free(pngxP);
 }
diff --git a/converter/other/pngx.h b/converter/other/pngx.h
index 81487ca1..6b1aa73c 100644
--- a/converter/other/pngx.h
+++ b/converter/other/pngx.h
@@ -5,14 +5,14 @@
    the PNG library easier and cleaner.
 */
 
+typedef enum {PNGX_READ, PNGX_WRITE} pngx_rw;
+
 struct pngx {
     png_structp png_ptr;
-    png_infop info_ptr;
+    png_infop   info_ptr;
+    pngx_rw     rw;
 };
 
-typedef enum {PNGX_READ, PNGX_WRITE} pngx_rw;
-
-
 void
 pngx_create(struct pngx ** const pngxPP,
             pngx_rw        const rw,