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PNG re-work: remove obsolete comment and the associated unused code

This appears to have been copied from libpng's example.c
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1 parent 34e5677 commit 022439ebd35a244bae688ac8d6632b2791d92168 @tonycoz committed Apr 2, 2012
Showing with 0 additions and 33 deletions.
  1. +0 −33 PNG/impng.c
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@@ -1,27 +1,6 @@
#include "impng.h"
#include "png.h"
-/* Check to see if a file is a PNG file using png_sig_cmp(). png_sig_cmp()
- * returns zero if the image is a PNG and nonzero if it isn't a PNG.
- *
- * The function check_if_png() shown here, but not used, returns nonzero (true)
- * if the file can be opened and is a PNG, 0 (false) otherwise.
- *
- * If this call is successful, and you are going to keep the file open,
- * you should call png_set_sig_bytes(png_ptr, PNG_BYTES_TO_CHECK); once
- * you have created the png_ptr, so that libpng knows your application
- * has read that many bytes from the start of the file. Make sure you
- * don't call png_set_sig_bytes() with more than 8 bytes read or give it
- * an incorrect number of bytes read, or you will either have read too
- * many bytes (your fault), or you are telling libpng to read the wrong
- * number of magic bytes (also your fault).
- *
- * Many applications already read the first 2 or 4 bytes from the start
- * of the image to determine the file type, so it would be easiest just
- * to pass the bytes to png_sig_cmp() or even skip that if you know
- * you have a PNG file, and call png_set_sig_bytes().
- */
-
/* this is a way to get number of channels from color space
* Color code to channel number */
@@ -57,18 +36,6 @@ wiol_flush_data(png_structp png_ptr) {
/* XXX : This needs to be added to the io layer */
}
-
-/* Check function demo
-
-int
-check_if_png(char *file_name, FILE **fp) {
- char buf[PNG_BYTES_TO_CHECK];
- if ((*fp = fopen(file_name, "rb")) != NULL) return 0;
- if (fread(buf, 1, PNG_BYTES_TO_CHECK, *fp) != PNG_BYTES_TO_CHECK) return 0;
- return(!png_sig_cmp((png_bytep)buf, (png_size_t)0, PNG_BYTES_TO_CHECK));
-}
-*/
-
static void
error_handler(png_structp png_ptr, png_const_charp msg) {
mm_log((1, "PNG error: '%s'\n", msg));

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