From a0875ea9091f08bb30fb8c693e8a35ba55aace44 Mon Sep 17 00:00:00 2001
From: Bill Currie <bill@taniwha.org>
Date: Thu, 4 Sep 2003 21:24:20 +0000
Subject: [PATCH] eliminate the global variables

---
 libs/image/png.c | 38 +++++++++++++++++---------------------
 1 file changed, 17 insertions(+), 21 deletions(-)

diff --git a/libs/image/png.c b/libs/image/png.c
index 48246108e..d71549c57 100644
--- a/libs/image/png.c
+++ b/libs/image/png.c
@@ -54,21 +54,16 @@ typedef unsigned char	uch;
 typedef unsigned short	ush;
 typedef unsigned long	ulg;
 
-static png_structp png_ptr = NULL;
-static png_infop info_ptr = NULL;
-static QFile *pngfile = NULL;
-
-char tmpBuffer[8192];
-
 /* Qread wrapper for libpng */
 static void 
-user_read_data (png_structp png_ptr, png_bytep data, png_size_t length) {
-	Qread (pngfile, data, length);
+user_read_data (png_structp png_ptr, png_bytep data, png_size_t length)
+{
+	Qread ((QFile *) png_get_io_ptr (png_ptr), data, length);
 }
 
 /* Basicly taken from the libpng example rpng-x */
 static int
-readpng_init (QFile *infile)
+readpng_init (QFile *infile, png_structp *png_ptr, png_infop *info_ptr)
 {
 	uch sig[8];
 
@@ -79,31 +74,30 @@ readpng_init (QFile *infile)
 		return (1);
 	}
 
-	png_ptr = png_create_read_struct (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
-	if (!png_ptr)
+	*png_ptr = png_create_read_struct (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+	if (!*png_ptr)
 		return (2); /* Out of memory! */
 
-	info_ptr = png_create_info_struct (png_ptr);
-	if (!info_ptr) {
-		png_destroy_read_struct (&png_ptr, NULL, NULL);
+	*info_ptr = png_create_info_struct (*png_ptr);
+	if (!*info_ptr) {
+		png_destroy_read_struct (png_ptr, NULL, NULL);
 		return (3); /* Out of memory! */
 	}
 
 	/* setjmp() must be called in every function that calls a PNG-reading
 	 * libpng function */
 
-	if (setjmp(png_jmpbuf(png_ptr))) {
-		png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
+	if (setjmp(png_jmpbuf(*png_ptr))) {
+		png_destroy_read_struct (png_ptr, info_ptr, NULL);
 		return (4);
 	}
 	
-	pngfile = infile;
-	png_set_read_fn (png_ptr, tmpBuffer, user_read_data);
+	png_set_read_fn (*png_ptr, infile, user_read_data);
 	
 	/* Is png_set_sig_bytes needed? */
-	png_set_sig_bytes (png_ptr, 8); /* We allready read the 8 signiture bytes */
+	png_set_sig_bytes (*png_ptr, 8); // We allready read the 8 signiture bytes
 
-	png_read_info (png_ptr, info_ptr); /* read all png info upto the image data */
+	png_read_info (*png_ptr, *info_ptr);//read all png info upto the image data
 
 	return (0);
 }
@@ -113,13 +107,15 @@ tex_t *
 LoadPNG (QFile *infile)
 {
 	double gamma;
+	png_structp png_ptr = NULL;
+	png_infop info_ptr = NULL;
 	png_uint_32  i, rowbytes;
 	png_bytepp  row_pointers = NULL;
 	png_uint_32 width, height;
 	int bit_depth, color_type;
 	tex_t *tex;
 	
-	if (readpng_init(infile) != 0)
+	if (readpng_init(infile, &png_ptr, &info_ptr) != 0)
 		return (NULL);
 		
 	png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, NULL, NULL, NULL);