[Vala] libexif vapi bindings

[Jim Nelson <jim yorba org>]

As part of a project I'm working on, I developed a vapi file for libexif (http://libexif.sourceforge.net/).  This is the first vapi file I've developed, so no promises on completeness or robustness.

If someone with more vapi experience could look it over and offer suggestions for improvement, it would be greatly appreciated.

Caveats:

* Many of the functions and exposed data members are still raw pointers.  Would like to change as many of these as I can to references, however, only if it honors libexif's rules on ref-counting.

* Data.save_data() returns a pointer that *must* be freed with the C library's free() function.  (Not g_free or other variants.)  libexif has an installable memory allocator feature, and I would love to have it use GLib's system.  However, I don't know how to do this purely in vapi.

* A lot of this is untested by me.  Be sure to check the .c output if you encounter bugs.

The vapi can be found at http://trac.yorba.org:8000/browser/photo/trunk/libexif.vapi  i've attached it below as well.
Enjoy,

-- Jim Nelson
Yorba


----------------------------------


[CCode (
    cprefix = "Exif",
    lower_case_cprefix="exif_"
)]
namespace Exif {
    [CCode (
        cname="ExifByteOrder",
        cheader_filename="libexif/exif-byte-order.h",
        cprefix="EXIF_BYTE_ORDER_"
    )]
    public enum ByteOrder {
        INTEL,
        MOTOROLA;

        public weak string get_name();
    }

    [Compact]
    [CCode (
        cname="ExifContent",
        cheader_filename="libexif/exif-content.h",
        ref_function="exif_content_ref",
        ref_function_void=true,
        unref_function="exif_content_unref",
        free_function="exif_content_free"
    )]
    public class Content {
        [CCode (cname="exif_content_new")]
        public Content();
        public void add_entry(Entry entry);
        public void remove_entry(Entry entry);
        public void dump(uint indent = 4);
        public void foreach_entry(ForeachEntryFunc cb, void *user);
        public weak Entry get_entry(Tag tag);
        public void fix();
        public Ifd get_ifd();

        public Entry **entries;
        public int count;
        public Data parent;
    }

    [CCode (
        cheader_filename="libexif/exif-utils.h",
        cprefix="exif_",
        lower_case_cprefix="exif_"
    )]
    namespace Convert {
        public static uint16 get_short(uchar *buffer, ByteOrder byteOrder);
        public static int16 get_sshort(uchar *buffer, ByteOrder byteOrder);
        public static uint32 get_long(uchar *buffer, ByteOrder byteOrder);
        public static int32 get_slong(uchar *buffer, ByteOrder byteOrder);
        public static void set_short(uchar *buffer, ByteOrder byteOrder, uint16 val);
        public static void set_sshort(uchar *buffer, ByteOrder byteOrder, int16 val);
        public static void set_long(uchar *buffer, ByteOrder byteOrder, uint32 val);
        public static void set_slong(uchar *buffer, ByteOrder byteOrder, int32 val);
    }

    [CCode (cheader_filename="libexif/exif-content.h")]
    public static delegate void ForeachEntryFunc(Entry e, void *user);

    [Compact]
    [CCode (
        cname="ExifData",
        cheader_filename="libexif/exif-data.h",
        ref_function="exif_data_ref",
        ref_function_void=true,
        unref_function="exif_data_unref",
        free_function="exif_data_free"
    )]
    public class Data {
        [CCode (cname="exif_data_new")]
        public Data();
        public static Data new_from_file(string path);
        public void dump();
        public void fix();
        public void foreach_content(ForeachContentFunc cb, void *user = null);
        public ByteOrder get_byte_order();
        public void set_option(DataOption option);
        public void unset_option(DataOption option);
        public void save_data(uchar **buffer, uint *size);

        public Content[Ifd.COUNT] ifd;
        public uchar *data;
        public uint size;
    }

    [CCode (cheader_filename="libexif/exif-data.h")]
    public static delegate void ForeachContentFunc(Content c, void *user);

    [CCode (
        cname="ExifDataOption",
        cheader_filename="libexif/exif-data.h",
        cprefix="EXIF_DATA_OPTION_"
    )]
    public enum DataOption {
        IGNORE_UNKNOWN_TAGS,
        FOLLOW_SPECIFICATION,
        DONT_CHANGE_MAKER_NOTE;

        public weak string get_name();
        public weak string get_description();
    }

    [Compact]
    [CCode (
        cname="ExifEntry",
        cheader_filename="libexif/exif-entry.h",
        ref_function="exif_entry_ref",
        ref_function_void=true,
        unref_function="exif_entry_unref"
    )]
    public class Entry {
        [CCode (cname="exif_entry_new")]
        public Entry();
        public void dump(uint indent = 4);
        public void initialize(Tag tag);
        public void fix();
        public weak string get_value(char *val = new char[256], uint maxlen = 256);

        public Tag tag;
        public Format format;
        public ulong components;
        public uchar *data;
        public uint size;
        public Content *parent;
    }

    [CCode (
        cname="ExifFormat",
        cheader_filename="libexif/exif-format.h",
        cprefix="EXIF_FORMAT_"
    )]
    public enum Format {
        BYTE,
        ASCII,
        SHORT,
        LONG,
        RATIONAL,
        SBYTE,
        UNDEFINED,
        SSHORT,
        SLONG,
        SRATIONAL,
        FLOAT,
        DOUBLE;

        public weak string get_name();
        public weak uchar get_size();
    }

    [CCode (
        cname="ExifIfd",
        cheader_filename="libexif/exif-ifd.h",
        cprefix="EXIF_IFD_"
    )]
    public enum Ifd {
        [CCode (cname="EXIF_IFD_0")]
        ZERO,
        [CCode (cname="EXIF_IFD_1")]
        ONE,
        EXIF,
        GPS,
        INTEROPERABILITY,
        COUNT;

        public weak string get_name();
    }

    [Compact]
    [CCode (
        cname="ExifLoader",
        cheader_filename="libexif/exif-loader.h",
        ref_function="exif_loader_ref",
        ref_function_void=true,
        unref_function="exif_loader_unref",
        free_function="exif_loader_free"
    )]
    public class Loader {
        [CCode (cname="exif_loader_new")]
        public Loader();
        public void write_file(string fname);
        public void reset();
        public Data get_data();
    }

    // TODO: Flesh out Log functionality
    [Compact]
    [CCode (
        cname="ExifLog",
        cheader_filename="libexif/exif-loader.h",
        ref_function="exif_log_ref",
        ref_function_void=true,
        unref_function="exif_log_unref",
        free_function="exif_log_free"
    )]
    public class Log {
        [CCode (cname="exif_log_new")]
        public Log();
    }

    [CCode (
        cname="ExifLogCode",
        cheader_filename="libexif/exif-log.h",
        cprefix="EXIF_LOG_CODE_"
    )]
    public enum LogCode {
        NONE,
        DEBUG,
        NO_MEMORY,
        CORRUPT_DATA;

        public weak string get_title();
        public weak string get_message();
    }

    [CCode (
        cname="ExifTag",
        cheader_filename="libexif/exif-tag.h",
        cprefix="EXIF_TAG_"
    )]
    public enum Tag {
        PIXEL_X_DIMENSION,
        PIXEL_Y_DIMENSION,
        BITS_PER_SAMPLE,
        DATE_TIME_ORIGINAL,
        ORIENTATION;

        public weak string get_name_in_ifd(Ifd ifd);
        public weak string get_title_in_ifd(Ifd ifd);
        public weak string get_description_in_ifd(Ifd ifd);
    }
}