moe-bius/opmplay/lxmplay/opmplay.h

#pragma once
#include <stdint.h>
#include "opmfile.h"

// OPMPlay setup defines
#define OPMPLAY_ENABLE_STDIO

#ifdef OPMPLAY_ENABLE_STDIO
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#endif

// LXMPlay import defines
#define opmplay_memcpy  memcpy
#define opmplay_memset  memset
#define opmplay_memcmp  memcmp
#define opmplay_alloc   malloc
#define opmplay_memfree free
#define opmplay_debug_printf(...)  printf(__VA_ARGS__)

#ifdef __cplusplus
extern "C" {
#endif

// general enums
enum {
    OPMPLAY_MAX_CHANNLES            = 16,
    OPMPLAY_MAX_STACK_DEPTH         = 4,
};

// return error codes
enum {
    OPMPLAY_ERR_OK                  = 0,
    OPMPLAY_ERR_END_OF_STREAM       = 1,
    OPMPLAY_ERR_BAD_FILE_STRUCTURE  = -1,
    OPMPLAY_ERR_MEMALLOC            = -2,
    OPMPLAY_ERR_NULLPTR             = -3,
    OPMPLAY_ERR_NO_SOUNDRAM         = -4,
    OPMPLAY_ERR_DEVICE              = -5,
    OPMPLAY_ERR_BAD_PARAMETER       = -6,
    OPMPLAY_ERR_IO                  = -7,


    OPMPLAY_ERR_UNKNOWN             = -20,
};

enum {
    OPMPLAY_IO_USER                 = 0,
    OPMPLAY_IO_FILE                 = 1,
    OPMPLAY_IO_MEMORY               = 2,
};

// file I/O structs
struct opmplay_io_t {
    uint32_t    type;          // i/o type
    union {
        void* buf;
#ifdef OPMPLAY_ENABLE_STDIO
        FILE* io;
#endif
    };
    uint32_t    size;

    // internal
    uint32_t    offset;
    uint32_t(*read)(opmplay_io_t* io, void* dst, uint32_t size);    // returns bytes read
    uint32_t(*seek)(opmplay_io_t* io, uint32_t offset);             // returns 0 if success
};

struct opmplay_channel_stack_t {
    const uint8_t* ptr;
    uint16_t       frames_to_play;
};

struct opmplay_channel_context_t {
    // stack 
    opmplay_channel_stack_t stack[OPMPLAY_MAX_STACK_DEPTH];
    uint16_t                stack_pos;

    // stream data
    struct {
        uint16_t            samples_to_play;
        uint16_t            delay;
        uint16_t            reload;

        const uint8_t*      data;
        const uint8_t*      ptr;
        const uint8_t*      loop; // if active
    } stream;

    // private stuff
    uint8_t                 block;  // cached block register
};

struct opmplay_context_t {
    // LXM file header
    opm_header_t                header;

    // channel context
    opmplay_channel_context_t   channels[OPMPLAY_MAX_CHANNLES];

    // position data 
    struct {
        uint16_t            frame;
        uint16_t            frame_looped;
        uint32_t            samples;
    } pos;

    // private stuff
    uint8_t                 ssg_r7[2];              // cached SSG mask register
    uint8_t                 extch3_block[2][3];     // cached extch3 block
};


// init context
int opmplay_init(opmplay_context_t* ctx);

// free context
int opmplay_free(opmplay_context_t* ctx);

// load file header
int opmplay_load_header(opmplay_context_t* ctx, opmplay_io_t* io);

// load file contents
int opmplay_load_module(opmplay_context_t* ctx, opmplay_io_t* io);

// reset to start
int opmplay_rewind(opmplay_context_t* ctx);

// play one tick, render changes to opl3 device
int opmplay_tick(opmplay_context_t* ctx);

#ifdef __cplusplus
}
#endif