// POSIX compatibility support for posix fd.

#pragma once
// posix_fd.h - file descriptor table (internal to posix.dll).
#include <stdint.h>
#include <stdbool.h>

typedef enum {
    FD_FREE,
    FD_FILE,
    FD_CONSOLE_R,   // fd 0 - reads from keyboard via SysReadKeyboardChar
    FD_CONSOLE_W,   // fd 1, 2 - writes via SysWriteConsole
    FD_DEVNULL,     // /dev/null
    FD_DEVZERO,     // /dev/zero
    FD_SOCKET,      // kernel socket handle
} FD_TYPE;

typedef struct {
    FD_TYPE  Type;
    uint32_t KHandle;   // kernel handle; 0 for console/devnull/devzero
    bool     Used;
} FD_ENTRY;

#define FD_MAX        64
#define FD_TABLE_PIDS 32   // circular, indexed by pid % FD_TABLE_PIDS

// Called from _start before main(); sets up fds 0/1/2 for this process.
__declspec(dllexport) void PosixFdInit(void);

// Allocate the lowest free fd >= 3. Returns -1 and sets errno=EMFILE on failure.
__declspec(dllexport) int FdAlloc(uint32_t pid, FD_TYPE type, uint32_t khandle);

// Look up an fd. Returns NULL and sets errno=EBADF if invalid.
__declspec(dllexport) FD_ENTRY* FdGet(uint32_t pid, int fd);

// Release an fd slot (does NOT close the kernel handle).
__declspec(dllexport) void FdFree(uint32_t pid, int fd);

int PosixStatusToErrno(uint32_t s);