diff --git a/png.c b/png.c
index aa209e50..5f4013df 100644
--- a/png.c
+++ b/png.c
@@ -1,7 +1,7 @@
 
 /* png.c - location for general purpose libpng functions
  *
- * Last changed in libpng 1.2.41 [October 11, 2009]
+ * Last changed in libpng 1.2.41 [October 13, 2009]
  * Copyright (c) 1998-2009 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -19,7 +19,8 @@
 typedef version_1_2_41beta05 Your_png_h_is_not_version_1_2_41beta05;
 
 /* Version information for C files.  This had better match the version
- * string defined in png.h.  */
+ * string defined in png.h.
+ */
 
 #ifdef PNG_USE_GLOBAL_ARRAYS
 /* png_libpng_ver was changed to a function in version 1.0.5c */
@@ -95,9 +96,11 @@ PNG_CONST int FARDATA png_pass_dsp_mask[]
 void PNGAPI
 png_set_sig_bytes(png_structp png_ptr, int num_bytes)
 {
+   png_debug(1, "in png_set_sig_bytes");
+
    if (png_ptr == NULL)
       return;
-   png_debug(1, "in png_set_sig_bytes");
+
    if (num_bytes > 8)
       png_error(png_ptr, "Too many bytes for PNG signature.");
 
@@ -246,8 +249,10 @@ png_create_info_struct(png_structp png_ptr)
    png_infop info_ptr;
 
    png_debug(1, "in png_create_info_struct");
+
    if (png_ptr == NULL)
       return (NULL);
+
 #ifdef PNG_USER_MEM_SUPPORTED
    info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,
       png_ptr->malloc_fn, png_ptr->mem_ptr);
@@ -269,10 +274,12 @@ void PNGAPI
 png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
 {
    png_infop info_ptr = NULL;
+
+   png_debug(1, "in png_destroy_info_struct");
+
    if (png_ptr == NULL)
       return;
 
-   png_debug(1, "in png_destroy_info_struct");
    if (info_ptr_ptr != NULL)
       info_ptr = *info_ptr_ptr;
 
@@ -309,11 +316,11 @@ png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size)
 {
    png_infop info_ptr = *ptr_ptr;
 
+   png_debug(1, "in png_info_init_3");
+
    if (info_ptr == NULL)
       return;
 
-   png_debug(1, "in png_info_init_3");
-
    if (png_sizeof(png_info) > png_info_struct_size)
    {
       png_destroy_struct(info_ptr);
@@ -331,8 +338,10 @@ png_data_freer(png_structp png_ptr, png_infop info_ptr,
    int freer, png_uint_32 mask)
 {
    png_debug(1, "in png_data_freer");
+
    if (png_ptr == NULL || info_ptr == NULL)
       return;
+
    if (freer == PNG_DESTROY_WILL_FREE_DATA)
       info_ptr->free_me |= mask;
    else if (freer == PNG_USER_WILL_FREE_DATA)
@@ -348,10 +357,11 @@ png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
    int num)
 {
    png_debug(1, "in png_free_data");
+
    if (png_ptr == NULL || info_ptr == NULL)
       return;
 
-#if defined(PNG_TEXT_SUPPORTED)
+#ifdef PNG_TEXT_SUPPORTED
    /* Free text item num or (if num == -1) all text items */
 #ifdef PNG_FREE_ME_SUPPORTED
    if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
@@ -379,7 +389,7 @@ png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
    }
 #endif
 
-#if defined(PNG_tRNS_SUPPORTED)
+#ifdef PNG_tRNS_SUPPORTED
    /* Free any tRNS entry */
 #ifdef PNG_FREE_ME_SUPPORTED
    if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
@@ -396,7 +406,7 @@ png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
    }
 #endif
 
-#if defined(PNG_sCAL_SUPPORTED)
+#ifdef PNG_sCAL_SUPPORTED
    /* Free any sCAL entry */
 #ifdef PNG_FREE_ME_SUPPORTED
    if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
@@ -414,7 +424,7 @@ png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
    }
 #endif
 
-#if defined(PNG_pCAL_SUPPORTED)
+#ifdef PNG_pCAL_SUPPORTED
    /* Free any pCAL entry */
 #ifdef PNG_FREE_ME_SUPPORTED
    if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
@@ -441,7 +451,7 @@ png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
    }
 #endif
 
-#if defined(PNG_iCCP_SUPPORTED)
+#ifdef PNG_iCCP_SUPPORTED
    /* Free any iCCP entry */
 #ifdef PNG_FREE_ME_SUPPORTED
    if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
@@ -457,7 +467,7 @@ png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
    }
 #endif
 
-#if defined(PNG_sPLT_SUPPORTED)
+#ifdef PNG_sPLT_SUPPORTED
    /* Free a given sPLT entry, or (if num == -1) all sPLT entries */
 #ifdef PNG_FREE_ME_SUPPORTED
    if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
@@ -492,7 +502,7 @@ png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
    }
 #endif
 
-#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
    if (png_ptr->unknown_chunk.data)
    {
       png_free(png_ptr, png_ptr->unknown_chunk.data);
@@ -530,7 +540,7 @@ png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
    }
 #endif
 
-#if defined(PNG_hIST_SUPPORTED)
+#ifdef PNG_hIST_SUPPORTED
    /* Free any hIST entry */
 #ifdef PNG_FREE_ME_SUPPORTED
    if ((mask & PNG_FREE_HIST)  & info_ptr->free_me)
@@ -563,7 +573,7 @@ png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
       info_ptr->num_palette = 0;
    }
 
-#if defined(PNG_INFO_IMAGE_SUPPORTED)
+#ifdef PNG_INFO_IMAGE_SUPPORTED
    /* Free any image bits attached to the info structure */
 #ifdef PNG_FREE_ME_SUPPORTED
    if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
@@ -605,7 +615,7 @@ png_info_destroy(png_structp png_ptr, png_infop info_ptr)
 
    png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
 
-#if defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
    if (png_ptr->num_chunk_list)
    {
       png_free(png_ptr, png_ptr->chunk_list);
@@ -631,7 +641,7 @@ png_get_io_ptr(png_structp png_ptr)
 }
 
 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
-#if !defined(PNG_NO_STDIO)
+#ifndef PNG_NO_STDIO
 /* Initialize the default input/output functions for the PNG file.  If you
  * use your own read or write routines, you can call either png_set_read_fn()
  * or png_set_write_fn() instead of png_init_io().  If you have defined
@@ -642,13 +652,15 @@ void PNGAPI
 png_init_io(png_structp png_ptr, png_FILE_p fp)
 {
    png_debug(1, "in png_init_io");
+
    if (png_ptr == NULL)
       return;
+
    png_ptr->io_ptr = (png_voidp)fp;
 }
 #endif
 
-#if defined(PNG_TIME_RFC1123_SUPPORTED)
+#ifdef PNG_TIME_RFC1123_SUPPORTED
 /* Convert the supplied time into an RFC 1123 string suitable for use in
  * a "Creation Time" or other text-based time string.
  */
@@ -667,7 +679,7 @@ png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime)
          png_sizeof(char)));
    }
 
-#if defined(_WIN32_WCE)
+#ifdef _WIN32_WCE
    {
       wchar_t time_buf[29];
       wsprintf(time_buf, TEXT("%d %S %d %02d:%02d:%02d +0000"),
@@ -705,7 +717,7 @@ png_charp PNGAPI
 png_get_copyright(png_structp png_ptr)
 {
    png_ptr = png_ptr;  /* Silence compiler warning about unused png_ptr */
-   return ((png_charp) "\n libpng version 1.2.41beta05 - October 11, 2009\n\
+   return ((png_charp) "\n libpng version 1.2.41beta05 - October 13, 2009\n\
    Copyright (c) 1998-2009 Glenn Randers-Pehrson\n\
    Copyright (c) 1996-1997 Andreas Dilger\n\
    Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.\n");
@@ -785,7 +797,7 @@ png_access_version_number(void)
 
 
 #if defined(PNG_READ_SUPPORTED) && defined(PNG_ASSEMBLER_CODE_SUPPORTED)
-#if !defined(PNG_1_0_X)
+#ifndef PNG_1_0_X
 /* This function was added to libpng 1.2.0 */
 int PNGAPI
 png_mmx_support(void)
@@ -810,8 +822,8 @@ png_convert_size(size_t size)
 #endif /* PNG_SIZE_T */
 
 /* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */
-#if defined(PNG_cHRM_SUPPORTED)
-#if !defined(PNG_NO_CHECK_cHRM)
+#ifdef PNG_cHRM_SUPPORTED
+#ifndef PNG_NO_CHECK_cHRM
 
 /*
  *    Multiply two 32-bit numbers, V1 and V2, using 32-bit
@@ -863,6 +875,7 @@ png_check_cHRM_fixed(png_structp png_ptr,
    unsigned long xy_hi,xy_lo,yx_hi,yx_lo;
 
    png_debug(1, "in function png_check_cHRM_fixed");
+
    if (png_ptr == NULL)
       return 0;
 
@@ -921,10 +934,9 @@ png_check_cHRM_fixed(png_structp png_ptr,
 
    return ret;
 }
-#endif /* NO_PNG_CHECK_cHRM */
+#endif /* PNG_NO_CHECK_cHRM */
 #endif /* PNG_cHRM_SUPPORTED */
 
-
 void /* PRIVATE */
 png_check_IHDR(png_structp png_ptr,
    png_uint_32 width, png_uint_32 height, int bit_depth,
@@ -1066,5 +1078,4 @@ png_check_IHDR(png_structp png_ptr,
    if (error == 1)
       png_error(png_ptr, "Invalid IHDR data");
 }
-
 #endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */