180 lines
4.2 KiB
C
180 lines
4.2 KiB
C
#ifndef _IPXE_PNG_H
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#define _IPXE_PNG_H
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/** @file
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*
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* Portable Network Graphics (PNG) format
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*
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*/
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FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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#include <stdint.h>
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#include <byteswap.h>
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#include <ipxe/image.h>
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/** A PNG file signature */
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struct png_signature {
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/** Signature bytes */
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uint8_t bytes[8];
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} __attribute__ (( packed ));
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/** PNG file signature */
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#define PNG_SIGNATURE { { 0x89, 'P', 'N', 'G', '\r', '\n', 0x1a, '\n' } }
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/** A PNG chunk header */
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struct png_chunk_header {
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/** Length of the chunk (excluding header and footer) */
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uint32_t len;
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/** Chunk type */
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uint32_t type;
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} __attribute__ (( packed ));
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/** A PNG chunk footer */
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struct png_chunk_footer {
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/** CRC */
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uint32_t crc;
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} __attribute__ (( packed ));
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/** PNG chunk type property bits */
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enum png_chunk_type_bits {
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/** Chunk is ancillary */
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PNG_CHUNK_ANCILLARY = 0x20000000UL,
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/** Chunk is private */
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PNG_CHUNK_PRIVATE = 0x00200000UL,
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/** Reserved */
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PNG_CHUNK_RESERVED = 0x00002000UL,
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/** Chunk is safe to copy */
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PNG_CHUNK_SAFE = 0x00000020UL,
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};
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/**
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* Canonicalise PNG chunk type
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*
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* @v type Raw chunk type
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* @ret type Canonicalised chunk type (excluding property bits)
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*/
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static inline __attribute__ (( always_inline )) uint32_t
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png_canonical_type ( uint32_t type ) {
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return ( type & ~( htonl ( PNG_CHUNK_ANCILLARY | PNG_CHUNK_PRIVATE |
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PNG_CHUNK_RESERVED | PNG_CHUNK_SAFE ) ) );
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}
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/**
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* Define a canonical PNG chunk type
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*
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* @v first First letter (in upper case)
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* @v second Second letter (in upper case)
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* @v third Third letter (in upper case)
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* @v fourth Fourth letter (in upper case)
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* @ret type Canonical chunk type
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*/
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#define PNG_TYPE( first, second, third, fourth ) \
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( ( (first) << 24 ) | ( (second) << 16 ) | ( (third) << 8 ) | (fourth) )
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/** PNG image header chunk type */
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#define PNG_TYPE_IHDR PNG_TYPE ( 'I', 'H', 'D', 'R' )
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/** A PNG image header */
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struct png_image_header {
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/** Width */
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uint32_t width;
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/** Height */
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uint32_t height;
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/** Bit depth */
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uint8_t depth;
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/** Colour type */
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uint8_t colour_type;
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/** Compression method */
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uint8_t compression;
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/** Filter method */
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uint8_t filter;
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/** Interlace method */
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uint8_t interlace;
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} __attribute__ (( packed ));
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/** PNG colour type bits */
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enum png_colour_type {
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/** Palette is used */
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PNG_COLOUR_TYPE_PALETTE = 0x01,
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/** RGB colour is used */
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PNG_COLOUR_TYPE_RGB = 0x02,
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/** Alpha channel is used */
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PNG_COLOUR_TYPE_ALPHA = 0x04,
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};
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/** PNG colour type mask */
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#define PNG_COLOUR_TYPE_MASK 0x07
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/** PNG compression methods */
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enum png_compression_method {
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/** DEFLATE compression with 32kB sliding window */
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PNG_COMPRESSION_DEFLATE = 0x00,
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/** First unknown compression method */
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PNG_COMPRESSION_UNKNOWN = 0x01,
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};
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/** PNG filter methods */
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enum png_filter_method {
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/** Adaptive filtering with five basic types */
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PNG_FILTER_BASIC = 0x00,
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/** First unknown filter method */
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PNG_FILTER_UNKNOWN = 0x01,
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};
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/** PNG interlace methods */
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enum png_interlace_method {
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/** No interlacing */
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PNG_INTERLACE_NONE = 0x00,
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/** Adam7 interlacing */
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PNG_INTERLACE_ADAM7 = 0x01,
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/** First unknown interlace method */
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PNG_INTERLACE_UNKNOWN = 0x02,
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};
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/** PNG palette chunk type */
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#define PNG_TYPE_PLTE PNG_TYPE ( 'P', 'L', 'T', 'E' )
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/** A PNG palette entry */
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struct png_palette_entry {
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/** Red */
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uint8_t red;
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/** Green */
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uint8_t green;
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/** Blue */
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uint8_t blue;
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} __attribute__ (( packed ));
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/** A PNG palette chunk */
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struct png_palette {
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/** Palette entries */
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struct png_palette_entry entries[0];
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} __attribute__ (( packed ));
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/** Maximum number of PNG palette entries */
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#define PNG_PALETTE_COUNT 256
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/** PNG image data chunk type */
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#define PNG_TYPE_IDAT PNG_TYPE ( 'I', 'D', 'A', 'T' )
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/** PNG basic filter types */
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enum png_basic_filter_type {
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/** No filtering */
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PNG_FILTER_BASIC_NONE = 0,
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/** Left byte used as predictor */
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PNG_FILTER_BASIC_SUB = 1,
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/** Above byte used as predictor */
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PNG_FILTER_BASIC_UP = 2,
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/** Above and left bytes used as predictors */
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PNG_FILTER_BASIC_AVERAGE = 3,
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/** Paeth filter */
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PNG_FILTER_BASIC_PAETH = 4,
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};
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/** PNG image end chunk type */
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#define PNG_TYPE_IEND PNG_TYPE ( 'I', 'E', 'N', 'D' )
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extern struct image_type png_image_type __image_type ( PROBE_NORMAL );
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#endif /* _IPXE_PNG_H */
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