diff options
Diffstat (limited to 'src/jpg')
| -rw-r--r-- | src/jpg/marker.zig | 122 | ||||
| -rw-r--r-- | src/jpg/root.zig | 8 | ||||
| -rw-r--r-- | src/jpg/segment.zig | 69 |
3 files changed, 199 insertions, 0 deletions
diff --git a/src/jpg/marker.zig b/src/jpg/marker.zig new file mode 100644 index 0000000..63eefe5 --- /dev/null +++ b/src/jpg/marker.zig @@ -0,0 +1,122 @@ +const std = @import("std"); + +pub const Marker = union(enum) { + pub const Kind = std.meta.Tag(@This()); + + const Tag = struct { + const temporary = 0x1; + const reset = .{ .start = 0xd0, .end = 0xd7 }; + const start_of_frame = .{ + .{ .start = 0xc0, .end = 0xc3 }, + .{ .start = 0xc5, .end = 0xc7 }, + .{ .start = 0xc9, .end = 0xcb }, + }; + const start_of_image = 0xd8; + const end_of_image = 0xd9; + const define_quantization_table = 0xdb; + const define_huffman_table = 0xc4; + const define_restart_interval = 0xdd; + const define_number_of_lines = 0xdc; + const define_hierarchy_progression = 0xde; + const extend_huffman_table = 0xdf; + const application_segment = .{ .start = 0xe0, .end = 0xef }; + const comment = 0xfe; + const start_of_scan = 0xda; + }; + + temporary: void, + reset: u3, + start_of_image: void, + end_of_image: void, + start_of_frame: u4, + define_quantization_table: void, + define_huffman_table: void, + define_restart_interval: void, + define_number_of_lines: void, + define_hierarchy_progression: void, + extend_huffman_table: void, + application_segment: u4, + comment: void, + start_of_scan: void, + + + pub fn from_u8(value: u8) !@This() { + return switch (value) { + Tag.reset.start...Tag.reset.end => .{ + .reset = @intCast(value - Tag.reset.start), + }, + Tag.start_of_frame[0].start...Tag.start_of_frame[0].end => .{ + .start_of_frame = @intCast(value - Tag.start_of_frame[0].start), + }, + Tag.start_of_frame[1].start...Tag.start_of_frame[1].end => .{ + .start_of_frame = @intCast(value - Tag.start_of_frame[1].start + 4), + }, + Tag.start_of_frame[2].start...Tag.start_of_frame[2].end => .{ + .start_of_frame = @intCast(value - Tag.start_of_frame[2].start + 7), + }, + Tag.application_segment.start...Tag.application_segment.end => .{ + .application_segment = @intCast(value - Tag.application_segment.start), + }, + Tag.start_of_image => .{ .start_of_image = void{} }, + Tag.end_of_image => .{ .end_of_image = void{} }, + Tag.define_quantization_table => .{ .define_quantization_table = void{} }, + Tag.define_huffman_table => .{ .define_huffman_table = void{} }, + Tag.define_restart_interval => .{ .define_restart_interval = void{} }, + Tag.define_number_of_lines => .{ .define_number_of_lines = void{} }, + Tag.define_hierarchy_progression => .{ .define_hierarchy_progression = void{} }, + Tag.extend_huffman_table => .{ .extend_huffman_table = void{} }, + Tag.comment => .{ .comment = void{} }, + Tag.start_of_scan => .{ .start_of_scan = void{} }, + Tag.temporary => .{ .temporary = void{} }, + else => error.InvalidByte, + }; + } +}; + +test "marker" { + const Testing = struct { + pub fn empty_tag(value: comptime_int, tag: std.meta.Tag(Marker)) !void { + const marker: Marker = try .from_u8(value); + try std.testing.expectEqual( + tag, + std.meta.activeTag(marker), + ); + } + }; + + for (0..8) |offset| { + const marker: Marker = try .from_u8(0xd0 + @as(u8, @intCast(offset))); + try std.testing.expectEqual(offset, marker.reset); + } + + { + for (0..4) |offset| { + const marker: Marker = try .from_u8(0xc0 + @as(u8, @intCast(offset))); + try std.testing.expectEqual(offset, marker.start_of_frame); + } + + for (0..3) |offset| { + const marker: Marker = try .from_u8(0xc5 + @as(u8, @intCast(offset))); + try std.testing.expectEqual(offset + 4, marker.start_of_frame); + } + + for (0..3) |offset| { + const marker: Marker = try .from_u8(0xc9 + @as(u8, @intCast(offset))); + try std.testing.expectEqual(offset + 7, marker.start_of_frame); + } + } + + for (0..16) |offset| { + const marker: Marker = try .from_u8(0xe0 + @as(u8, @intCast(offset))); + try std.testing.expectEqual(offset, marker.application_segment); + } + + try Testing.empty_tag(Marker.Tag.temporary, .temporary); + try Testing.empty_tag(Marker.Tag.start_of_image, .start_of_image); + try Testing.empty_tag(Marker.Tag.end_of_image, .end_of_image); + try Testing.empty_tag(Marker.Tag.define_quantization_table, .define_quantization_table); + try Testing.empty_tag(Marker.Tag.define_huffman_table, .define_huffman_table); + try Testing.empty_tag(Marker.Tag.define_restart_interval, .define_restart_interval); + try Testing.empty_tag(Marker.Tag.define_number_of_lines, .define_number_of_lines); + try Testing.empty_tag(Marker.Tag.define_hierarchy_progression, .define_hierarchy_progression); +} diff --git a/src/jpg/root.zig b/src/jpg/root.zig new file mode 100644 index 0000000..55b37e8 --- /dev/null +++ b/src/jpg/root.zig @@ -0,0 +1,8 @@ +const std = @import("std"); + +pub const Marker = @import("marker.zig").Marker; +pub const Segment = @import("segment.zig").Segment; + +test { + _ = std.testing.refAllDecls(@This()); +} diff --git a/src/jpg/segment.zig b/src/jpg/segment.zig new file mode 100644 index 0000000..ec1346a --- /dev/null +++ b/src/jpg/segment.zig @@ -0,0 +1,69 @@ +const std = @import("std"); +const jpg = @import("root.zig"); + +pub const Segment = union(jpg.Marker.Kind) { + temporary: void, + reset: void, + start_of_image: void, + end_of_image: void, + start_of_frame: void, + define_quantization_table: void, + define_huffman_table: void, + define_restart_interval: void, + define_number_of_lines: void, + define_hierarchy_progression: void, + extend_huffman_table: void, + application_segment: void, + comment: void, + start_of_scan: void, + + const Self = @This(); + + pub fn read(gpa: std.mem.Allocator, reader: *std.Io.Reader) !Self { + if (try reader.peekByte() != 0xff) { + return error.InvalidMarkerHeader; + } + reader.toss(1); + + const marker = jpg.Marker.from_u8(try reader.peekByte()) + catch return error.InvalidMarkerByte; + reader.toss(1); + + return switch (marker) { + .temporary => .{ .temporary = void{} }, + .reset => .{ .reset = void{} }, + .start_of_image => .{ .start_of_image = void{} }, + .end_of_image => .{ .end_of_image = void{} }, + .start_of_frame => data: { + const buffer = try read_data_with_length(gpa, reader); + defer gpa.free(buffer); + break :data .{ .start_of_frame = void{} }; + }, + .application_segment => data: { + const buffer = try read_data_with_length(gpa, reader); + defer gpa.free(buffer); + break :data .{ .application_segment = void{} }; + }, + else => { + std.debug.panic("unimplemented tag '{s}'\n", .{@tagName(marker)}); + }, + }; + } + + fn read_data_with_length(gpa: std.mem.Allocator, reader: *std.Io.Reader) ![]u8 { + const length = try reader.takeInt(u16, .big); + return try reader.readAlloc(gpa, @intCast(length)); + } +}; + + +test "file" { + const buffer = @embedFile("../testing/rgb.jpg"); + var reader: std.Io.Reader = .fixed(buffer); + + var segment: Segment = try .read(std.testing.allocator, &reader); + try std.testing.expectEqual(.start_of_image, std.meta.activeTag(segment)); + + segment = try .read(std.testing.allocator, &reader); + try std.testing.expectEqual(.application_segment, std.meta.activeTag(segment)); +} |