power_play/src/ase/ase_core.h

////////////////////////////////
//~ Inflator types

#define Ase_HuffBitCount 16

Struct(Ase_Bitbuff)
{
    u8 *data;
    u64 cur_bit;
};

typedef i32 Ase_BlockType; enum
{
    Ase_BlockType_Uncompressed          = 0,
    Ase_BlockType_CompressedFixed       = 1,
    Ase_BlockType_CompressedDynamic     = 2,
    Ase_BlockType_Reserved              = 3
};

Struct(Ase_HuffEntry)
{
    u16 symbol;
    u16 bits_used;
};

Struct(Ase_HuffDict)
{
    u32 max_code_bits;
    u32 entries_count;
    Ase_HuffEntry *entries;
};

////////////////////////////////
//~ Header types

Packed(Struct(Ase_Header)
{
    u32 file_size;
    u16 magic;
    u16 frames;
    u16 width;
    u16 height;
    u16 color_depth;
    u32 flags;
    u16 speed;
    u32 _1;
    u32 _2;
    u8 palette_entry;
    u8 _3[3];
    u16 num_colors;
    u8 pixel_width;
    u8 pixel_height;
    i16 grid_x;
    i16 grid_y;
    u16 grid_width;
    u16 grid_height;
    u8 _4[84];
});

Packed(Struct(Ase_FrameHeader)
{
    u32 bytes;
    u16 magic;
    u16 chunks_old;
    u16 frame_duration_ms;
    u8 _[2];
    u32 chunks_new;
});

////////////////////////////////
//~ Image decoder types

typedef i32 Ase_ChunkKind; enum
{
    Ase_ChunkKind_OldPalette1       = 0x0004,
    Ase_ChunkKind_OldPalette2       = 0x0011,
    Ase_ChunkKind_Layer             = 0x2004,
    Ase_ChunkKind_Cel               = 0x2005,
    Ase_ChunkKind_CelExtra          = 0x2006,
    Ase_ChunkKind_ColorProfile      = 0x2007,
    Ase_ChunkKind_ExternalFiles     = 0x2008,
    Ase_ChunkKind_Mask              = 0x2016,
    Ase_ChunkKind_Path              = 0x2017,
    Ase_ChunkKind_Tags              = 0x2018,
    Ase_ChunkKind_Palette           = 0x2019,
    Ase_ChunkKind_Userdata          = 0x2020,
    Ase_ChunkKind_Slice             = 0x2022,
    Ase_ChunkKind_Tileset           = 0x2023
};

typedef i32 Ase_CelKind; enum
{
    Ase_CelKind_RawImage            = 0,
    Ase_CelKind_Linked              = 1,
    Ase_CelKind_CompressedImage     = 2,
    Ase_CelKind_CompressedTilemap   = 3
};

Struct(Ase_Layer)
{
    u16 flags;
    u16 type;
    u16 child_level;
    u16 blend_mode;
    u8 opacity;
    String name;
    u32 tileset_index;

    u32 index;
    Ase_Layer *next;
};

Struct(Ace_Cel)
{
    u16 layer_index;
    i16 x_pos;
    i16 y_pos;
    u8 opacity;
    Ase_CelKind type;
    i16 z_index;

    /* Linked cel */
    u16 frame_pos;

    /* Compressed image */
    u32 width;
    u32 height;
    u32 *pixels;

    u16 frame_index;
    Ace_Cel *next;
};

////////////////////////////////
//~ Error types

Struct(Ase_Error)
{
    String msg;
    Ase_Error *next;
};

Struct(Ase_ErrorList)
{
    u64 count;
    Ase_Error *first;
    Ase_Error *last;
};

////////////////////////////////
//~ Sheet types

Struct(Ase_Slice)
{
    u32 start;
    i32 x1;
    i32 y1;
    i32 x2;
    i32 y2;
    Ase_Slice *next;
};

Struct(Ase_SliceKey)
{
    String name;
    u32 num_slices;
    Ase_Slice *slice_head;
    Ase_SliceKey *next;
};

Struct(Ase_Span)
{
    String name;
    u32 start;
    u32 end;
    Ase_Span *next;
};

Struct(Ase_Frame)
{
    u32 index;
    u32 x1;
    u32 y1;
    u32 x2;
    u32 y2;
    f64 duration;
    Ase_Frame *next;
};

////////////////////////////////
//~ Decoder result types

Struct(Ase_DecodedImage)
{
    u32 width;
    u32 height;
    u32 *pixels;  /* Array of [width * height] pixels */
    Ase_ErrorList errors;
    b32 success;
};

Struct(Ase_DecodedSheet)
{
    Vec2 image_size;
    Vec2 frame_size;
    u32 num_frames;
    u32 num_spans;
    u32 num_slice_keys;
    Ase_Frame *frame_head;
    Ase_Span *span_head;
    Ase_SliceKey *slice_key_head;
    Ase_ErrorList errors;
    b32 success;
};

////////////////////////////////
//~ Ase bitbuff operations

u32 Ase_PeekBits(Ase_Bitbuff *bb, u32 nbits);
u32 Ase_ConsumeBits(Ase_Bitbuff *bb, u32 nbits);
void Ase_SkipBits(Ase_Bitbuff *bb, u32 nbits);

////////////////////////////////
//~ Inflate operations

u32 Ase_ReverseBits(u32 v, u32 bit_count);
Ase_HuffDict Ase_InitHuffDict(Arena *arena, u32 max_code_bits, u32 *bl_counts, u32 bl_counts_count);
u16 Ase_DecodeHuffDict(Ase_HuffDict *huffman, Ase_Bitbuff *bb);
void Ase_Inflate(u8 *dst, u8 *encoded);

////////////////////////////////
//~ Error handling operations

void Ase_PushError(Arena *arena, Ase_ErrorList *list, String msg_src);

////////////////////////////////
//~ Decoder operations

//- Helpers
u32 Ase_BlendMulU8(u32 a, u32 b);
u32 Ase_Blend(u32 src, u32 dst, u8 opacity);
void Ase_MakeDimensionsSquareish(Ase_Header *header, u32 *frames_x, u32 *frames_y, u64 *image_width, u64 *image_height);

//- Decode image
Ase_DecodedImage Ase_DecodeImage(Arena *arena, String encoded);

//- Decode sheet
Ase_DecodedSheet Ase_DecodeSheet(Arena *arena, String encoded);