pnm.h

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#ifndef _IPXE_PNM_H
#define _IPXE_PNM_H

/** @file
 *
 * Portable anymap format (PNM)
 *
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <stdint.h>
#include <ipxe/image.h>

/** PNM signature */
struct pnm_signature {
        /** Magic byte ('P') */
        char magic;
        /** PNM type */
        char type;
        /** Whitespace */
        char space;
} __attribute__ (( packed ));

/** PNM magic byte */
#define PNM_MAGIC 'P'

/** PNM context */
struct pnm_context {
        /** PNM type */
        struct pnm_type *type;
        /** Current byte offset */
        size_t offset;
        /** Maximum length of ASCII values */
        size_t ascii_len;
        /** Maximum pixel value */
        unsigned int max;
};

/** Default maximum length of ASCII values */
#define PNM_ASCII_LEN 16

/** PNM type */
struct pnm_type {
        /** PNM type */
        char type;
        /** Number of scalar values per pixel */
        uint8_t depth;
        /** Number of pixels per composite value */
        uint8_t packing;
        /** Flags */
        uint8_t flags;
        /** Extract scalar value
         *
         * @v image             PNM image
         * @v pnm               PNM context
         * @ret value           Value, or negative error
         */
        int ( * scalar ) ( struct image *image, struct pnm_context *pnm );
        /** Convert composite value to 24-bit RGB
         *
         * @v composite         Composite value
         * @v index             Pixel index within this composite value
         * @ret rgb             24-bit RGB value
         */
        uint32_t ( * rgb ) ( uint32_t composite, unsigned int index );
};

/** PNM flags */
enum pnm_flags {
        /** Bitmap format
         *
         * If set, this flag indicates that:
         *
         * - the maximum scalar value is predefined as being equal to
         *   (2^packing-1), and is not present within the file, and
         *
         * - the maximum length of ASCII values is 1.
         */
        PNM_BITMAP = 0x01,
};

extern struct image_type pnm_image_type __image_type ( PROBE_NORMAL );

#endif /* _IPXE_PNM_H */