[png] Add support for PNG images

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/config/config.c

@@ -200,6 +200,9 @@ REQUIRE_OBJECT ( sdi );
 #ifdef IMAGE_PNM
 REQUIRE_OBJECT ( pnm );
 #endif
+#ifdef IMAGE_PNG
+REQUIRE_OBJECT ( png );
+#endif
 
 /*
  * Drag in all requested commands

src/config/general.h

@@ -104,6 +104,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 //#define	IMAGE_EFI		/* EFI image support */
 //#define	IMAGE_SDI		/* SDI image support */
 //#define	IMAGE_PNM		/* PNM image support */
+//#define	IMAGE_PNG		/* PNG image support */
 
 /*
  * Command-line commands to include

src/include/ipxe/errfile.h

@@ -231,6 +231,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #define ERRFILE_efi_image	      ( ERRFILE_IMAGE | 0x00040000 )
 #define ERRFILE_embedded	      ( ERRFILE_IMAGE | 0x00050000 )
 #define ERRFILE_pnm		      ( ERRFILE_IMAGE | 0x00060000 )
+#define ERRFILE_png		      ( ERRFILE_IMAGE | 0x00070000 )
 
 #define ERRFILE_asn1		      ( ERRFILE_OTHER | 0x00000000 )
 #define ERRFILE_chap		      ( ERRFILE_OTHER | 0x00010000 )

src/include/ipxe/png.h

@@ -0,0 +1,179 @@
+#ifndef _IPXE_PNG_H
+#define _IPXE_PNG_H
+
+/** @file
+ *
+ * Portable Network Graphics (PNG) format
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#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 */

src/tests/tests.c

@@ -51,3 +51,4 @@ REQUIRE_OBJECT ( ocsp_test );
 REQUIRE_OBJECT ( cms_test );
 REQUIRE_OBJECT ( pnm_test );
 REQUIRE_OBJECT ( deflate_test );
+REQUIRE_OBJECT ( png_test );