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