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//! https://en.wikipedia.org/wiki/Resource_Interchange_File_Format
//! https://www.moon-soft.com/program/format/windows/ani.htm
//! https://www.gdgsoft.com/anituner/help/aniformat.htm
//! https://www.lomont.org/software/aniexploit/ExploitANI.pdf
//!
//! RIFF( 'ACON'
//! [LIST( 'INFO' <info_data> )]
//! [<DISP_ck>]
//! anih( <ani_header> )
//! [rate( <rate_info> )]
//! ['seq '( <sequence_info> )]
//! LIST( 'fram' icon( <icon_file> ) ... )
//! )
const std = @import("std");
const AF_ICON: u32 = 1;
pub fn isAnimatedIcon(reader: *std.Io.Reader) bool {
const flags = getAniheaderFlags(reader) catch return false;
return flags & AF_ICON == AF_ICON;
}
fn getAniheaderFlags(reader: *std.Io.Reader) !u32 {
const riff_header = try reader.takeArray(4);
if (!std.mem.eql(u8, riff_header, "RIFF")) return error.InvalidFormat;
_ = try reader.takeInt(u32, .little); // size of RIFF chunk
const form_type = try reader.takeArray(4);
if (!std.mem.eql(u8, form_type, "ACON")) return error.InvalidFormat;
while (true) {
const chunk_id = try reader.takeArray(4);
const chunk_len = try reader.takeInt(u32, .little);
if (!std.mem.eql(u8, chunk_id, "anih")) {
// TODO: Move file cursor instead of skipBytes
try reader.discardAll(chunk_len);
continue;
}
const aniheader = try reader.takeStruct(ANIHEADER, .little);
return aniheader.flags;
}
}
/// From Microsoft Multimedia Data Standards Update April 15, 1994
const ANIHEADER = extern struct {
cbSizeof: u32,
cFrames: u32,
cSteps: u32,
cx: u32,
cy: u32,
cBitCount: u32,
cPlanes: u32,
jifRate: u32,
flags: u32,
};
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