76 lines
2.6 KiB
C
76 lines
2.6 KiB
C
/*
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* Copyright Notice
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* ----------------
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* Copyright © 1998, 1999 by: Glenn Randers-Pehrson
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* This specification is a modification of the PNG 1.0 specification. It is being
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* provided by the copyright holder under the provisions of the 1996 MIT copyright and license:
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* Copyright © 1996 by: Massachusetts Institute of Technology (MIT)
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* This W3C specification is being provided by the copyright holders under
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* the following license. By obtaining, using and/or copying this specification, you
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* agree that you have read, understood, and will comply with the following terms
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* and conditions:
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* Permission to use, copy, and distribute this specification for any purpose
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* and without fee or royalty is hereby granted, provided that the full text of
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* this NOTICE appears on ALL copies of the specification or portions thereof,
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* including modifications, that you make.
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* THIS SPECIFICATION IS PROVIDED ”AS IS,” AND COPYRIGHT HOLD-ERS
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* MAKE NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR
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* IMPLIED. BY WAY OF EXAMPLE, BUT NOT LIMITATION, COPYRIGHT
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* HOLDERS MAKE NO REPRESENTATIONS OR WARRANTIES OF MERCHANTABILITY
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* OR FITNESS FOR ANY PARTICULAR PURPOSE OR
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* THAT THE USE OF THE SPECIFICATION WILL NOT INFRINGE ANY
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* THIRD PARTY PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER
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* RIGHTS. COPYRIGHT HOLDERS WILL BEAR NO LIABILITY FOR ANY
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* USE OF THIS SPECIFICATION.
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* The name and trademarks of copyright holders may NOT be used in
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* advertising or publicity pertaining to the specification without specific, written
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* prior permission. Title to copyright in this specification and any associated
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* documentation will at all times remain with copyright holders.
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*/
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#pragma once
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// Needed for uint types
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#include <arpa/inet.h>
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// http://www.libpng.org/pub/png/spec/1.2/PNG-Rationale.html#R.PNG-file-signature
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#define PNG_SIGNATURE "\211PNG\r\n\032\n"
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#define PNG_SIGNATURE_SIZE 8
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// The key used to "encrypt/decrypt" the PNG chunks
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#define KEY 42
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typedef struct png_chunk {
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uint32_t length;
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char type[4];
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char *data;
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uint32_t crc;
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} png_chunk;
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// Get FILE from path
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int get_fd(char *path);
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// Store file in heap memory
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char *load_file(char *path);
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// Check if file is a PNG
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int is_png(char *buffer);
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// Get PNG chunk
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png_chunk *get_png_chunk(char *buffer, unsigned int offset);
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// Get all PNG chunks
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png_chunk **get_png_chunks(char *buffer);
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// Get number of chunks
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int get_number_of_chunks(png_chunk **chunks);
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// XOR chunk with key
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void xor_data(png_chunk *chunk);
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// Destroy all chunks
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void destroy_chunks(png_chunk **chunks);
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// Write PNG chunks to file
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void write_png_chunks(char *path, png_chunk **chunks);
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