feat(term): getting/setting terminal config flags

5 files changed, 1086 insertions, 5 deletions

diff --git a/src/bitflags.c b/src/bitflags.c
new file mode 100644
index 0000000..89a88b7
--- /dev/null
+++ b/src/bitflags.c
@@ -0,0 +1,235 @@
+/// Bitflags module.
+// The bitflag object makes it easy to manipulate flags in a bitmask.
+//
+// It has metamethods that do the hard work, adding flags sets them, substracting
+// unsets them. Comparing flags checks if all flags in the second set are also set
+// in the first set. The `has` method checks if all flags in the second set are
+// also set in the first set, but behaves slightly different.
+//
+// Indexing allows checking values or setting them by bit index (eg. 0-7 for flags
+// in the first byte).
+//
+// _NOTE_: unavailable flags (eg. Windows flags on a Posix system) should not be
+// omitted, but be assigned a value of 0. This is because the `has` method will
+// return `false` if the flags are checked and the value is 0.
+//
+// See `system.bitflag` (the constructor) for extensive examples on usage.
+// @classmod bitflags
+#include "bitflags.h"
+
+#define BITFLAGS_MT_NAME "LuaSystem.BitFlags"
+
+typedef struct {
+    LSBF_BITFLAG flags;
+} LS_BitFlags;
+
+/// Bit flags.
+// Bitflag objects can be used to easily manipulate and compare bit flags.
+// These are primarily for use with the terminal functions, but can be used
+// in other places as well.
+// @section bitflags
+
+
+// pushes a new LS_BitFlags object with the given value onto the stack
+void lsbf_pushbitflags(lua_State *L, LSBF_BITFLAG value) {
+    LS_BitFlags *obj = (LS_BitFlags *)lua_newuserdata(L, sizeof(LS_BitFlags));
+    if (!obj) luaL_error(L, "Memory allocation failed");
+    luaL_getmetatable(L, BITFLAGS_MT_NAME);
+    lua_setmetatable(L, -2);
+    obj->flags = value;
+}
+
+// gets the LS_BitFlags value at the given index. Returns a Lua error if it is not
+// a LS_BitFlags object.
+LSBF_BITFLAG lsbf_checkbitflags(lua_State *L, int index) {
+    LS_BitFlags *obj = (LS_BitFlags *)luaL_checkudata(L, index, BITFLAGS_MT_NAME);
+    return obj->flags;
+}
+
+/***
+Creates a new bitflag object from the given value.
+@function system.bitflag
+@tparam[opt=0] number value the value to create the bitflag object from.
+@treturn bitflag bitflag object with the given values set.
+@usage
+local sys = require 'system'
+local flags = sys.bitflag(2)    -- b0010
+
+-- get state of individual bits
+print(flags[0])                 -- false
+print(flags[1])                 -- true
+
+-- set individual bits
+flags[0] = true                 -- b0011
+print(flags:value())            -- 3
+print(flags)                    -- "bitflags: 3"
+
+-- adding flags (bitwise OR)
+local flags1 = sys.bitflag(1)   -- b0001
+local flags2 = sys.bitflag(2)   -- b0010
+local flags3 = flags1 + flags2  -- b0011
+
+-- substracting flags (bitwise AND NOT)
+print(flags3:value())           -- 3
+flag3 = flag3 - flag3           -- b0000
+print(flags3:value())           -- 0
+
+-- comparing flags
+local flags4 = sys.bitflag(7)   -- b0111
+local flags5 = sys.bitflag(255) -- b11111111
+print(flags5 >= flags4)         -- true, all bits in flags4 are set in flags5
+
+-- comparing with 0 flags: comparison and `has` behave differently
+local flags6 = sys.bitflag(0)   -- b0000
+local flags7 = sys.bitflag(1)   -- b0001
+print(flags6 < flags7)          -- true, flags6 is a subset of flags7
+print(flags7:has(flags6))       -- false, flags6 is not set in flags7
+*/
+static int lsbf_new(lua_State *L) {
+    LSBF_BITFLAG flags = 0;
+    if (lua_gettop(L) > 0) {
+        flags = luaL_checkinteger(L, 1);
+    }
+    lsbf_pushbitflags(L, flags);
+    return 1;
+}
+
+/***
+Retrieves the numeric value of the bitflag object.
+@function bitflag:value
+@treturn number the numeric value of the bitflags.
+@usage
+local sys = require 'system'
+local flags = sys.bitflag()     -- b0000
+flags[0] = true                 -- b0001
+flags[2] = true                 -- b0101
+print(flags:value())            -- 5
+*/
+static int lsbf_value(lua_State *L) {
+    lua_pushinteger(L, lsbf_checkbitflags(L, 1));
+    return 1;
+}
+
+static int lsbf_tostring(lua_State *L) {
+    lua_pushfstring(L, "bitflags: %d", lsbf_checkbitflags(L, 1));
+    return 1;
+}
+
+static int lsbf_add(lua_State *L) {
+    lsbf_pushbitflags(L, lsbf_checkbitflags(L, 1) | lsbf_checkbitflags(L, 2));
+    return 1;
+}
+
+static int lsbf_sub(lua_State *L) {
+    lsbf_pushbitflags(L, lsbf_checkbitflags(L, 1) & ~lsbf_checkbitflags(L, 2));
+    return 1;
+}
+
+static int lsbf_eq(lua_State *L) {
+    lua_pushboolean(L, lsbf_checkbitflags(L, 1) == lsbf_checkbitflags(L, 2));
+    return 1;
+}
+
+static int lsbf_le(lua_State *L) {
+    LSBF_BITFLAG a = lsbf_checkbitflags(L, 1);
+    LSBF_BITFLAG b = lsbf_checkbitflags(L, 2);
+    // Check if all bits in b are also set in a
+    lua_pushboolean(L, (a & b) == a);
+    return 1;
+}
+
+/***
+Checks if the given flags are set.
+This is different from the `>=` and `<=` operators because if the flag to check
+has a value `0`, it will always return `false`. So if there are flags that are
+unsupported on a platform, they can be set to 0 and the `has` function will
+return `false` if the flags are checked.
+@function bitflag:has
+@tparam bitflag subset the flags to check for.
+@treturn boolean true if all the flags are set, false otherwise.
+@usage
+local sys = require 'system'
+local flags = sys.bitflag(12)   -- b1100
+local myflags = sys.bitflag(15) -- b1111
+print(flags:has(myflags))       -- false, not all bits in myflags are set in flags
+print(myflags:has(flags))       -- true, all bits in flags are set in myflags
+*/
+static int lsbf_has(lua_State *L) {
+    LSBF_BITFLAG a = lsbf_checkbitflags(L, 1);
+    LSBF_BITFLAG b = lsbf_checkbitflags(L, 2);
+    // Check if all bits in b are also set in a, and b is not 0
+    lua_pushboolean(L, (a | b) == a && b != 0);
+    return 1;
+}
+
+static int lsbf_lt(lua_State *L) {
+    LSBF_BITFLAG a = lsbf_checkbitflags(L, 1);
+    LSBF_BITFLAG b = lsbf_checkbitflags(L, 2);
+    // Check if a is strictly less than b, meaning a != b and a is a subset of b
+    lua_pushboolean(L, (a != b) && ((a & b) == a));
+    return 1;
+}
+
+static int lsbf_index(lua_State *L) {
+    if (!lua_isnumber(L, 2)) {
+        // the parameter isn't a number, just lookup the key in the metatable
+        lua_getmetatable(L, 1);
+        lua_pushvalue(L, 2);
+        lua_gettable(L, -2);
+        return 1;
+    }
+
+    int index = luaL_checkinteger(L, 2);
+    if (index < 0 || index >= sizeof(LSBF_BITFLAG) * 8) {
+        return luaL_error(L, "index out of range");
+    }
+    lua_pushboolean(L, (lsbf_checkbitflags(L, 1) & (1 << index)) != 0);
+    return 1;
+}
+
+static int lsbf_newindex(lua_State *L) {
+    LS_BitFlags *obj = (LS_BitFlags *)luaL_checkudata(L, 1, BITFLAGS_MT_NAME);
+
+    if (!lua_isnumber(L, 2)) {
+        return luaL_error(L, "index must be a number");
+    }
+    int index = luaL_checkinteger(L, 2);
+    if (index < 0 || index >= sizeof(LSBF_BITFLAG) * 8) {
+        return luaL_error(L, "index out of range");
+    }
+
+    luaL_checkany(L, 3);
+    if (lua_toboolean(L, 3)) {
+        obj->flags |= (1 << index);
+    } else {
+        obj->flags &= ~(1 << index);
+    }
+    return 0;
+}
+
+static const struct luaL_Reg lsbf_funcs[] = {
+    {"bitflag", lsbf_new},
+    {NULL, NULL}
+};
+
+static const struct luaL_Reg lsbf_methods[] = {
+    {"value", lsbf_value},
+    {"has", lsbf_has},
+    {"__tostring", lsbf_tostring},
+    {"__add", lsbf_add},
+    {"__sub", lsbf_sub},
+    {"__eq", lsbf_eq},
+    {"__le", lsbf_le},
+    {"__lt", lsbf_lt},
+    {"__index", lsbf_index},
+    {"__newindex", lsbf_newindex},
+    {NULL, NULL}
+};
+
+void bitflags_open(lua_State *L) {
+    luaL_newmetatable(L, BITFLAGS_MT_NAME);
+    luaL_setfuncs(L, lsbf_methods, 0);
+    lua_pop(L, 1);
+
+    luaL_setfuncs(L, lsbf_funcs, 0);
+}
diff --git a/src/bitflags.h b/src/bitflags.h
new file mode 100644
index 0000000..0e47246
--- /dev/null
+++ b/src/bitflags.h
@@ -0,0 +1,21 @@
+#ifndef LSBITFLAGS_H
+#define LSBITFLAGS_H
+
+#include <lua.h>
+#include "compat.h"
+#include <lauxlib.h>
+#include <stdlib.h>
+
+// type used to store the bitflags
+#define LSBF_BITFLAG lua_Integer
+
+// Validates that the given index is a bitflag object and returns its value.
+// If the index is not a bitflag object, a Lua error is raised.
+// The value will be left on the stack.
+LSBF_BITFLAG lsbf_checkbitflags(lua_State *L, int index);
+
+// Pushes a new bitflag object with the given value onto the stack.
+// Might raise a Lua error if memory allocation fails.
+void lsbf_pushbitflags(lua_State *L, LSBF_BITFLAG value);
+
+#endif
diff --git a/src/compat.h b/src/compat.h
index 35f9ef2..7a1fcee 100644
--- a/src/compat.h
+++ b/src/compat.h
@@ -13,6 +13,17 @@ void luaL_setfuncs(lua_State *L, const luaL_Reg *l, int nup);
 #include <sys/types.h>
 #endif
 
+// Windows compatibility; define DWORD and TRUE/FALSE on non-Windows
+#ifndef _WIN32
+#ifndef DWORD
+#define DWORD unsigned long
+#endif
+#ifndef TRUE
+#define TRUE 1
+#define FALSE 0
+#endif
+#endif
+
 #ifdef _MSC_VER
 // MSVC Windows doesn't have ssize_t, so we define it here
 #if SIZE_MAX == UINT_MAX
diff --git a/src/core.c b/src/core.c
index 729023f..d233ecc 100644
--- a/src/core.c
+++ b/src/core.c
@@ -16,6 +16,7 @@ void time_open(lua_State *L);
 void environment_open(lua_State *L);
 void random_open(lua_State *L);
 void term_open(lua_State *L);
+void bitflags_open(lua_State *L);
 
 /*-------------------------------------------------------------------------
  * Initializes all library modules.
@@ -32,6 +33,7 @@ LUAEXPORT int luaopen_system_core(lua_State *L) {
     lua_pushboolean(L, 0);
 #endif
     lua_rawset(L, -3);
+    bitflags_open(L); // must be first, used by others
     time_open(L);
     random_open(L);
     term_open(L);
diff --git a/src/term.c b/src/term.c
index 2adb1e9..062394d 100644
--- a/src/term.c
+++ b/src/term.c
@@ -1,37 +1,849 @@
 /// @submodule system
+
+// Unix: see https://blog.nelhage.com/2009/12/a-brief-introduction-to-termios-termios3-and-stty/
+// Windows: see https://learn.microsoft.com/en-us/windows/console/console-reference
+
 #include <lua.h>
 #include <lauxlib.h>
 #include <lualib.h>
 #include "compat.h"
+#include "bitflags.h"
 
 #ifndef _MSC_VER
 # include <unistd.h>
 #endif
 
+#ifdef _WIN32
+# include <windows.h>
+#else
+# include <termios.h>
+# include <string.h>
+# include <errno.h>
+# include <fcntl.h>
+# include <sys/ioctl.h>
+# include <unistd.h>
+#endif
+
+#ifdef _WIN32
+// after an error is returned, GetLastError() result can be passed to this function to get a string
+// representation of the error on the stack.
+// result will be nil+error on the stack, always 2 results.
+static void termFormatError(lua_State *L, DWORD errorCode, const char* prefix) {
+//static void FormatErrorAndReturn(lua_State *L, DWORD errorCode, const char* prefix) {
+    LPSTR messageBuffer = NULL;
+    FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
+                   NULL, errorCode, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPSTR)&messageBuffer, 0, NULL);
+
+    lua_pushnil(L);
+    if (messageBuffer) {
+        if (prefix) {
+            lua_pushfstring(L, "%s: %s", prefix, messageBuffer);
+        } else {
+            lua_pushstring(L, messageBuffer);
+        }
+        LocalFree(messageBuffer);
+    } else {
+        lua_pushfstring(L, "%sError code %d", prefix ? prefix : "", errorCode);
+    }
+}
+#else
+static int pusherror(lua_State *L, const char *info)
+{
+	lua_pushnil(L);
+	if (info==NULL)
+		lua_pushstring(L, strerror(errno));
+	else
+		lua_pushfstring(L, "%s: %s", info, strerror(errno));
+	lua_pushinteger(L, errno);
+	return 3;
+}
+#endif
 
 /***
 Checks if a file-handle is a TTY.
 
 @function isatty
-@tparam file file the file-handle to check
+@tparam file file the file-handle to check, one of `io.stdin`, `io.stdout`, `io.stderr`.
 @treturn boolean true if the file is a tty
+@usage
+local system = require('system')
+if system.isatty(io.stdin) then
+    -- enable ANSI coloring etc on Windows, does nothing in Posix.
+    local flags = system.getconsoleflags(io.stdout)
+    system.setconsoleflags(io.stdout, flags + sys.COF_VIRTUAL_TERMINAL_PROCESSING)
+end
 */
-static int lua_isatty(lua_State* L) {
+static int lst_isatty(lua_State* L) {
     FILE **fh = (FILE **) luaL_checkudata(L, 1, LUA_FILEHANDLE);
     lua_pushboolean(L, isatty(fileno(*fh)));
     return 1;
 }
 
 
+/*-------------------------------------------------------------------------
+ * Windows Get/SetConsoleMode functions
+ *-------------------------------------------------------------------------*/
 
-static luaL_Reg func[] = {
-    { "isatty", lua_isatty },
-    { NULL, NULL }
+typedef struct ls_RegConst {
+  const char *name;
+  DWORD value;
+} ls_RegConst;
+
+// Define a macro to check if a constant is defined and set it to 0 if not.
+// This is needed because some flags are not defined on all platforms. So we
+// still export the constants, but they will be all 0, and hence not do anything.
+#ifdef _WIN32
+#define CHECK_WIN_FLAG_OR_ZERO(flag) flag
+#define CHECK_NIX_FLAG_OR_ZERO(flag) 0
+#else
+#define CHECK_WIN_FLAG_OR_ZERO(flag) 0
+#define CHECK_NIX_FLAG_OR_ZERO(flag) flag
+#endif
+
+// Export Windows constants to Lua
+static const struct ls_RegConst win_console_in_flags[] = {
+    // Console Input Flags
+    {"CIF_ECHO_INPUT", CHECK_WIN_FLAG_OR_ZERO(ENABLE_ECHO_INPUT)},
+    {"CIF_INSERT_MODE", CHECK_WIN_FLAG_OR_ZERO(ENABLE_INSERT_MODE)},
+    {"CIF_LINE_INPUT", CHECK_WIN_FLAG_OR_ZERO(ENABLE_LINE_INPUT)},
+    {"CIF_MOUSE_INPUT", CHECK_WIN_FLAG_OR_ZERO(ENABLE_MOUSE_INPUT)},
+    {"CIF_PROCESSED_INPUT", CHECK_WIN_FLAG_OR_ZERO(ENABLE_PROCESSED_INPUT)},
+    {"CIF_QUICK_EDIT_MODE", CHECK_WIN_FLAG_OR_ZERO(ENABLE_QUICK_EDIT_MODE)},
+    {"CIF_WINDOW_INPUT", CHECK_WIN_FLAG_OR_ZERO(ENABLE_WINDOW_INPUT)},
+    {"CIF_VIRTUAL_TERMINAL_INPUT", CHECK_WIN_FLAG_OR_ZERO(ENABLE_VIRTUAL_TERMINAL_INPUT)},
+    {"CIF_EXTENDED_FLAGS", CHECK_WIN_FLAG_OR_ZERO(ENABLE_EXTENDED_FLAGS)},
+    {"CIF_AUTO_POSITION", CHECK_WIN_FLAG_OR_ZERO(ENABLE_AUTO_POSITION)},
+    {NULL, 0}
+};
+
+static const struct ls_RegConst win_console_out_flags[] = {
+    // Console Output Flags
+    {"COF_PROCESSED_OUTPUT", CHECK_WIN_FLAG_OR_ZERO(ENABLE_PROCESSED_OUTPUT)},
+    {"COF_WRAP_AT_EOL_OUTPUT", CHECK_WIN_FLAG_OR_ZERO(ENABLE_WRAP_AT_EOL_OUTPUT)},
+    {"COF_VIRTUAL_TERMINAL_PROCESSING", CHECK_WIN_FLAG_OR_ZERO(ENABLE_VIRTUAL_TERMINAL_PROCESSING)},
+    {"COF_DISABLE_NEWLINE_AUTO_RETURN", CHECK_WIN_FLAG_OR_ZERO(DISABLE_NEWLINE_AUTO_RETURN)},
+    {"COF_ENABLE_LVB_GRID_WORLDWIDE", CHECK_WIN_FLAG_OR_ZERO(ENABLE_LVB_GRID_WORLDWIDE)},
+    {NULL, 0}
+};
+
+
+// Export Unix constants to Lua
+static const struct ls_RegConst nix_tcsetattr_actions[] = {
+    // The optional actions for tcsetattr
+    {"TCSANOW", CHECK_NIX_FLAG_OR_ZERO(TCSANOW)},
+    {"TCSADRAIN", CHECK_NIX_FLAG_OR_ZERO(TCSADRAIN)},
+    {"TCSAFLUSH", CHECK_NIX_FLAG_OR_ZERO(TCSAFLUSH)},
+    {NULL, 0}
+};
+
+static const struct ls_RegConst nix_console_i_flags[] = {
+    // Input flags (c_iflag)
+    {"I_IGNBRK", CHECK_NIX_FLAG_OR_ZERO(IGNBRK)},
+    {"I_BRKINT", CHECK_NIX_FLAG_OR_ZERO(BRKINT)},
+    {"I_IGNPAR", CHECK_NIX_FLAG_OR_ZERO(IGNPAR)},
+    {"I_PARMRK", CHECK_NIX_FLAG_OR_ZERO(PARMRK)},
+    {"I_INPCK", CHECK_NIX_FLAG_OR_ZERO(INPCK)},
+    {"I_ISTRIP", CHECK_NIX_FLAG_OR_ZERO(ISTRIP)},
+    {"I_INLCR", CHECK_NIX_FLAG_OR_ZERO(INLCR)},
+    {"I_IGNCR", CHECK_NIX_FLAG_OR_ZERO(IGNCR)},
+    {"I_ICRNL", CHECK_NIX_FLAG_OR_ZERO(ICRNL)},
+#ifndef __APPLE__
+    {"I_IUCLC", CHECK_NIX_FLAG_OR_ZERO(IUCLC)}, // Might not be available on all systems
+#else
+    {"I_IUCLC", 0},
+#endif
+    {"I_IXON", CHECK_NIX_FLAG_OR_ZERO(IXON)},
+    {"I_IXANY", CHECK_NIX_FLAG_OR_ZERO(IXANY)},
+    {"I_IXOFF", CHECK_NIX_FLAG_OR_ZERO(IXOFF)},
+    {"I_IMAXBEL", CHECK_NIX_FLAG_OR_ZERO(IMAXBEL)},
+    {NULL, 0}
 };
 
+static const struct ls_RegConst nix_console_o_flags[] = {
+    // Output flags (c_oflag)
+    {"O_OPOST", CHECK_NIX_FLAG_OR_ZERO(OPOST)},
+#ifndef __APPLE__
+    {"O_OLCUC", CHECK_NIX_FLAG_OR_ZERO(OLCUC)}, // Might not be available on all systems
+#else
+    {"O_OLCUC", 0},
+#endif
+    {"O_ONLCR", CHECK_NIX_FLAG_OR_ZERO(ONLCR)},
+    {"O_OCRNL", CHECK_NIX_FLAG_OR_ZERO(OCRNL)},
+    {"O_ONOCR", CHECK_NIX_FLAG_OR_ZERO(ONOCR)},
+    {"O_ONLRET", CHECK_NIX_FLAG_OR_ZERO(ONLRET)},
+    {"O_OFILL", CHECK_NIX_FLAG_OR_ZERO(OFILL)},
+    {"O_OFDEL", CHECK_NIX_FLAG_OR_ZERO(OFDEL)},
+    {"O_NLDLY", CHECK_NIX_FLAG_OR_ZERO(NLDLY)},
+    {"O_CRDLY", CHECK_NIX_FLAG_OR_ZERO(CRDLY)},
+    {"O_TABDLY", CHECK_NIX_FLAG_OR_ZERO(TABDLY)},
+    {"O_BSDLY", CHECK_NIX_FLAG_OR_ZERO(BSDLY)},
+    {"O_VTDLY", CHECK_NIX_FLAG_OR_ZERO(VTDLY)},
+    {"O_FFDLY", CHECK_NIX_FLAG_OR_ZERO(FFDLY)},
+    {NULL, 0}
+};
+
+static const struct ls_RegConst nix_console_l_flags[] = {
+    // Local flags (c_lflag)
+    {"L_ISIG", CHECK_NIX_FLAG_OR_ZERO(ISIG)},
+    {"L_ICANON", CHECK_NIX_FLAG_OR_ZERO(ICANON)},
+#ifndef __APPLE__
+    {"L_XCASE", CHECK_NIX_FLAG_OR_ZERO(XCASE)}, // Might not be available on all systems
+#else
+    {"L_XCASE", 0},
+#endif
+    {"L_ECHO", CHECK_NIX_FLAG_OR_ZERO(ECHO)},
+    {"L_ECHOE", CHECK_NIX_FLAG_OR_ZERO(ECHOE)},
+    {"L_ECHOK", CHECK_NIX_FLAG_OR_ZERO(ECHOK)},
+    {"L_ECHONL", CHECK_NIX_FLAG_OR_ZERO(ECHONL)},
+    {"L_NOFLSH", CHECK_NIX_FLAG_OR_ZERO(NOFLSH)},
+    {"L_TOSTOP", CHECK_NIX_FLAG_OR_ZERO(TOSTOP)},
+    {"L_ECHOCTL", CHECK_NIX_FLAG_OR_ZERO(ECHOCTL)}, // Might not be available on all systems
+    {"L_ECHOPRT", CHECK_NIX_FLAG_OR_ZERO(ECHOPRT)}, // Might not be available on all systems
+    {"L_ECHOKE", CHECK_NIX_FLAG_OR_ZERO(ECHOKE)}, // Might not be available on all systems
+    {"L_FLUSHO", CHECK_NIX_FLAG_OR_ZERO(FLUSHO)},
+    {"L_PENDIN", CHECK_NIX_FLAG_OR_ZERO(PENDIN)},
+    {"L_IEXTEN", CHECK_NIX_FLAG_OR_ZERO(IEXTEN)},
+    {NULL, 0}
+};
+
+static DWORD win_valid_in_flags = 0;
+static DWORD win_valid_out_flags = 0;
+static DWORD nix_valid_i_flags = 0;
+static DWORD nix_valid_o_flags = 0;
+static DWORD nix_valid_l_flags = 0;
+static void initialize_valid_flags()
+{
+    win_valid_in_flags = 0;
+    for (int i = 0; win_console_in_flags[i].name != NULL; i++)
+    {
+        win_valid_in_flags |= win_console_in_flags[i].value;
+    }
+    win_valid_out_flags = 0;
+    for (int i = 0; win_console_out_flags[i].name != NULL; i++)
+    {
+        win_valid_out_flags |= win_console_out_flags[i].value;
+    }
+    nix_valid_i_flags = 0;
+    for (int i = 0; nix_console_i_flags[i].name != NULL; i++)
+    {
+        nix_valid_i_flags |= nix_console_i_flags[i].value;
+    }
+    nix_valid_o_flags = 0;
+    for (int i = 0; nix_console_o_flags[i].name != NULL; i++)
+    {
+        nix_valid_o_flags |= nix_console_o_flags[i].value;
+    }
+    nix_valid_l_flags = 0;
+    for (int i = 0; nix_console_l_flags[i].name != NULL; i++)
+    {
+        nix_valid_l_flags |= nix_console_l_flags[i].value;
+    }
+}
+
+#ifdef _WIN32
+// first item on the stack should be io.stdin, io.stderr, or io.stdout, second item
+// should be the flags to validate.
+// If it returns NULL, then it leaves nil+err on the stack
+static HANDLE get_console_handle(lua_State *L, int flags_optional)
+{
+    if (lua_gettop(L) < 1) {
+        luaL_argerror(L, 1, "expected file handle");
+    }
+
+    HANDLE handle;
+    DWORD valid;
+    FILE *file = *(FILE **)luaL_checkudata(L, 1, LUA_FILEHANDLE);
+    if (file == stdin && file != NULL) {
+        handle = GetStdHandle(STD_INPUT_HANDLE);
+        valid = win_valid_in_flags;
+
+    } else if (file == stdout && file != NULL) {
+        handle =  GetStdHandle(STD_OUTPUT_HANDLE);
+        valid = win_valid_out_flags;
+
+    } else if (file == stderr && file != NULL) {
+        handle =  GetStdHandle(STD_ERROR_HANDLE);
+        valid = win_valid_out_flags;
+
+    } else {
+        luaL_argerror(L, 1, "invalid file handle"); // does not return
+    }
+
+    if (handle == INVALID_HANDLE_VALUE) {
+        termFormatError(L, GetLastError(), "failed to retrieve std handle");
+        lua_error(L); // does not return
+    }
+
+    if (handle == NULL) {
+        lua_pushnil(L);
+        lua_pushliteral(L, "failed to get console handle");
+        return NULL;
+    }
+
+    if (flags_optional && lua_gettop(L) < 2) {
+        return handle;
+    }
+
+    if (lua_gettop(L) < 2) {
+        luaL_argerror(L, 2, "expected flags");
+    }
+
+    LSBF_BITFLAG flags = lsbf_checkbitflags(L, 2);
+    if ((flags & ~valid) != 0) {
+        luaL_argerror(L, 2, "invalid flags");
+    }
+
+    return handle;
+}
+#else
+// first item on the stack should be io.stdin, io.stderr, or io.stdout. Throws a
+// Lua error if the file is not one of these.
+static int get_console_handle(lua_State *L)
+{
+    FILE **file = (FILE **)luaL_checkudata(L, 1, LUA_FILEHANDLE);
+    if (file == NULL || *file == NULL) {
+        return luaL_argerror(L, 1, "expected file handle"); // call doesn't return
+    }
+
+    // Check if the file is stdin, stdout, or stderr
+    if (*file == stdin || *file == stdout || *file == stderr) {
+        // Push the file descriptor onto the Lua stack
+        return fileno(*file);
+    }
+
+    return luaL_argerror(L, 1, "invalid file handle"); // does not return
+}
+#endif
+
+
+
+/***
+Sets the console flags (Windows).
+The `CIF_` and `COF_` constants are available on the module table. Where `CIF` are the
+input flags (for use with `io.stdin`) and `COF` are the output flags (for use with
+`io.stdout`/`io.stderr`).
+
+To see flag status and constant names check `listconsoleflags`.
+
+Note: not all combinations of flags are allowed, as some are mutually exclusive or mutually required.
+See [setconsolemode documentation](https://learn.microsoft.com/en-us/windows/console/setconsolemode)
+@function setconsoleflags
+@tparam file file the file-handle to set the flags on
+@tparam bitflags bitflags the flags to set/unset
+@treturn[1] boolean `true` on success
+@treturn[2] nil
+@treturn[2] string error message
+@usage
+local system = require('system')
+system.listconsoleflags(io.stdout) -- List all the available flags and their current status
+
+local flags = system.getconsoleflags(io.stdout)
+assert(system.setconsoleflags(io.stdout,
+        flags + system.COF_VIRTUAL_TERMINAL_PROCESSING)
+
+system.listconsoleflags(io.stdout) -- List again to check the differences
+*/
+static int lst_setconsoleflags(lua_State *L)
+{
+#ifdef _WIN32
+    HANDLE console_handle = get_console_handle(L, 0);
+    if (console_handle == NULL) {
+        return 2; // error message is already on the stack
+    }
+    LSBF_BITFLAG new_console_mode = lsbf_checkbitflags(L, 2);
+
+    DWORD prev_console_mode;
+    if (GetConsoleMode(console_handle, &prev_console_mode) == 0)
+    {
+        termFormatError(L, GetLastError(), "failed to get console mode");
+        return 2;
+    }
+
+    int success = SetConsoleMode(console_handle, new_console_mode) != 0;
+    if (!success)
+    {
+        termFormatError(L, GetLastError(), "failed to set console mode");
+        return 2;
+    }
+
+#endif
+    lua_pushboolean(L, 1);
+    return 1;
+}
+
+
+
+/***
+Gets console flags (Windows).
+@function getconsoleflags
+@tparam file file the file-handle to get the flags from.
+@treturn[1] bitflags the current console flags.
+@treturn[2] nil
+@treturn[2] string error message
+@usage
+local system = require('system')
+
+local flags = system.getconsoleflags(io.stdout)
+print("Current stdout flags:", tostring(flags))
+
+if flags:has(system.COF_VIRTUAL_TERMINAL_PROCESSING + system.COF_PROCESSED_OUTPUT) then
+    print("Both flags are set")
+else
+    print("At least one flag is not set")
+end
+*/
+static int lst_getconsoleflags(lua_State *L)
+{
+    DWORD console_mode = 0;
+
+#ifdef _WIN32
+    HANDLE console_handle = get_console_handle(L, 1);
+    if (console_handle == NULL) {
+        return 2; // error message is already on the stack
+    }
+
+    if (GetConsoleMode(console_handle, &console_mode) == 0)
+    {
+        lua_pushnil(L);
+        lua_pushliteral(L, "failed to get console mode");
+        return 2;
+    }
+
+#endif
+    lsbf_pushbitflags(L, console_mode);
+    return 1;
+}
+
+
+
+/*-------------------------------------------------------------------------
+ * Unix tcgetattr/tcsetattr functions
+ *-------------------------------------------------------------------------*/
+// Code modified from the LuaPosix library by Gary V. Vaughan
+// see https://github.com/luaposix/luaposix
+
+/***
+Get termios state.
+The terminal attributes is a table with the following fields:
+
+- `iflag` input flags
+- `oflag` output flags
+- `cflag` control flags
+- `lflag` local flags
+- `ispeed` input speed
+- `ospeed` output speed
+- `cc` control characters
+
+@function tcgetattr
+@tparam file fd file handle to operate on, one of `io.stdin`, `io.stdout`, `io.stderr`
+@treturn[1] termios terminal attributes, if successful. On Windows the bitflags are all 0, and the `cc` table is empty.
+@treturn[2] nil
+@treturn[2] string error message
+@treturn[2] int errnum
+@return error message if failed
+@usage
+local system = require('system')
+
+local status = assert(tcgetattr(io.stdin))
+if status.iflag:has(system.I_IGNBRK) then
+    print("Ignoring break condition")
+end
+*/
+static int lst_tcgetattr(lua_State *L)
+{
+#ifndef _WIN32
+    int r, i;
+    struct termios t;
+    int fd = get_console_handle(L);
+
+    r = tcgetattr(fd, &t);
+    if (r == -1) return pusherror(L, NULL);
+
+    lua_newtable(L);
+    lsbf_pushbitflags(L, t.c_iflag);
+    lua_setfield(L, -2, "iflag");
+
+    lsbf_pushbitflags(L, t.c_oflag);
+    lua_setfield(L, -2, "oflag");
+
+    lsbf_pushbitflags(L, t.c_lflag);
+    lua_setfield(L, -2, "lflag");
+
+    lsbf_pushbitflags(L, t.c_cflag);
+    lua_setfield(L, -2, "cflag");
+
+    lua_pushinteger(L, cfgetispeed(&t));
+    lua_setfield(L, -2, "ispeed");
+
+    lua_pushinteger(L, cfgetospeed(&t));
+    lua_setfield(L, -2, "ospeed");
+
+    lua_newtable(L);
+    for (i=0; i<NCCS; i++)
+    {
+        lua_pushinteger(L, i);
+        lua_pushinteger(L, t.c_cc[i]);
+        lua_settable(L, -3);
+    }
+    lua_setfield(L, -2, "cc");
+
+#else
+    lua_newtable(L);
+    lsbf_pushbitflags(L, 0);
+    lua_setfield(L, -2, "iflag");
+    lsbf_pushbitflags(L, 0);
+    lua_setfield(L, -2, "oflag");
+    lsbf_pushbitflags(L, 0);
+    lua_setfield(L, -2, "lflag");
+    lsbf_pushbitflags(L, 0);
+    lua_setfield(L, -2, "cflag");
+    lua_pushinteger(L, 0);
+    lua_setfield(L, -2, "ispeed");
+    lua_pushinteger(L, 0);
+    lua_setfield(L, -2, "ospeed");
+    lua_newtable(L);
+    lua_setfield(L, -2, "cc");
+
+#endif
+    return 1;
+}
+
+
+
+/***
+Set termios state.
+This function will set the flags as given.
+
+The `I_`, `O_`, and `L_` constants are available on the module table. They are the respective
+flags for the `iflags`, `oflags`, and `lflags` bitmasks.
+
+To see flag status and constant names check `listtermflags`. For their meaning check
+[the manpage](https://www.man7.org/linux/man-pages/man3/termios.3.html).
+
+_Note_: not all combinations of flags are allowed, as some are mutually exclusive or mutually required.
+See [setconsolemode documentation](https://learn.microsoft.com/en-us/windows/console/setconsolemode)
+
+_Note_: only `iflag`, `oflag`, and `lflag` are supported at the moment. The other fields are ignored.
+@function tcsetattr
+@tparam file fd file handle to operate on, one of `io.stdin`, `io.stdout`, `io.stderr`
+@int actions one of `TCSANOW`, `TCSADRAIN`, `TCSAFLUSH`
+@tparam table termios a table with bitflag fields:
+@tparam[opt] bitflags termios.iflag if given will set the input flags
+@tparam[opt] bitflags termios.oflag if given will set the output flags
+@tparam[opt] bitflags termios.lflag if given will set the local flags
+@treturn[1] bool `true`, if successful. Always returns `true` on Windows.
+@return[2] nil
+@treturn[2] string error message
+@treturn[2] int errnum
+@usage
+local system = require('system')
+
+local status = assert(tcgetattr(io.stdin))
+if not status.lflag:has(system.L_ECHO) then
+    -- if echo is off, turn echoing newlines on
+    tcsetattr(io.stdin, system.TCSANOW, { lflag = status.lflag + system.L_ECHONL }))
+end
+*/
+static int lst_tcsetattr(lua_State *L)
+{
+#ifndef _WIN32
+    struct termios t;
+    int r, i;
+    int fd = get_console_handle(L);     // first is the console handle
+    int act = luaL_checkinteger(L, 2);  // second is the action to take
+    luaL_checktype(L, 3, LUA_TTABLE);   // third is the termios table with fields
+
+    r = tcgetattr(fd, &t);
+    if (r == -1) return pusherror(L, NULL);
+
+    lua_getfield(L, 3, "iflag");
+    if (!lua_isnil(L, -1)) {
+        t.c_iflag = lsbf_checkbitflags(L, -1);
+    }
+    lua_pop(L, 1);
+
+    lua_getfield(L, 3, "oflag");
+    if (!lua_isnil(L, -1)) {
+        t.c_oflag = lsbf_checkbitflags(L, -1);
+    }
+    lua_pop(L, 1);
+
+    lua_getfield(L, 3, "lflag");
+    if (!lua_isnil(L, -1)) {
+        t.c_lflag = lsbf_checkbitflags(L, -1);
+    }
+    lua_pop(L, 1);
+
+    // Skipping the others for now
+
+    // lua_getfield(L, 3, "cflag"); t.c_cflag = optint(L, -1, 0); lua_pop(L, 1);
+    // lua_getfield(L, 3, "ispeed"); cfsetispeed( &t, optint(L, -1, B0) ); lua_pop(L, 1);
+    // lua_getfield(L, 3, "ospeed"); cfsetospeed( &t, optint(L, -1, B0) ); lua_pop(L, 1);
+
+    // lua_getfield(L, 3, "cc");
+    // for (i=0; i<NCCS; i++)
+    // {
+    //     lua_pushinteger(L, i);
+    //     lua_gettable(L, -2);
+    //     t.c_cc[i] = optint(L, -1, 0);
+    //     lua_pop(L, 1);
+    // }
+
+    r = tcsetattr(fd, act, &t);
+    if (r == -1) return pusherror(L, NULL);
+#endif
+
+    lua_pushboolean(L, 1);
+    return 1;
+}
+
+
+
+/***
+Enables or disables non-blocking mode for a file (Posix).
+@function setnonblock
+@tparam file fd file handle to operate on, one of `io.stdin`, `io.stdout`, `io.stderr`
+@tparam boolean make_non_block a truthy value will enable non-blocking mode, a falsy value will disable it.
+@treturn[1] bool `true`, if successful
+@treturn[2] nil
+@treturn[2] string error message
+@treturn[2] int errnum
+@see getnonblock
+@usage
+local sys = require('system')
+
+-- set io.stdin to non-blocking mode
+local old_setting = sys.getnonblock(io.stdin)
+sys.setnonblock(io.stdin, true)
+
+-- do stuff
+
+-- restore old setting
+sys.setnonblock(io.stdin, old_setting)
+*/
+static int lst_setnonblock(lua_State *L)
+{
+#ifndef _WIN32
+
+    int fd = get_console_handle(L);
+
+    int flags = fcntl(fd, F_GETFL, 0);
+    if (flags == -1) {
+        return pusherror(L, "Error getting handle flags: ");
+    }
+    if (lua_toboolean(L, 2)) {
+        // truthy: set non-blocking
+        flags |= O_NONBLOCK;
+    } else {
+        // falsy: set disable non-blocking
+        flags &= ~O_NONBLOCK;
+    }
+    if (fcntl(fd, F_SETFL, flags) == -1) {
+        return pusherror(L, "Error changing O_NONBLOCK: ");
+    }
+
+#endif
+
+    lua_pushboolean(L, 1);
+    return 1;
+}
+
+
+
+/***
+Gets non-blocking mode status for a file (Posix).
+@function getnonblock
+@tparam file fd file handle to operate on, one of `io.stdin`, `io.stdout`, `io.stderr`
+@treturn[1] bool `true` if set to non-blocking, `false` if not. Always returns `false` on Windows.
+@treturn[2] nil
+@treturn[2] string error message
+@treturn[2] int errnum
+*/
+static int lst_getnonblock(lua_State *L)
+{
+#ifndef _WIN32
+
+    int fd = get_console_handle(L);
+
+    // Set O_NONBLOCK
+    int flags = fcntl(fd, F_GETFL, 0);
+    if (flags == -1) {
+        return pusherror(L, "Error getting handle flags: ");
+    }
+    if (flags & O_NONBLOCK) {
+        lua_pushboolean(L, 1);
+    } else {
+        lua_pushboolean(L, 0);
+    }
+
+#else
+    lua_pushboolean(L, 0);
+
+#endif
+    return 1;
+}
+
+
+
+/*-------------------------------------------------------------------------
+ * Reading keyboard input
+ *-------------------------------------------------------------------------*/
+
+/***
+Reads a key from the console non-blocking.
+On Posix, `io.stdin` must be set to non-blocking mode using `setnonblock`
+before calling this function. Otherwise it will block.
+
+@function readkey
+@treturn[1] integer the key code of the key that was pressed
+@treturn[2] nil if no key was pressed
+*/
+static int lst_readkey(lua_State *L) {
+#ifdef _WIN32
+    if (_kbhit()) {
+        lua_pushinteger(L, _getch());
+        return 1;
+    }
+    return 0;
+
+#else
+    char ch;
+    if (read(STDIN_FILENO, &ch, 1) > 0) {
+        lua_pushinteger(L, ch);
+        return 1;
+    }
+    return 0;
+
+#endif
+}
+
+/***
+Checks if a key has been pressed without reading it.
+On Posix, `io.stdin` must be set to non-blocking mode using `setnonblock`
+before calling this function. Otherwise it will block.
+
+@function keypressed
+@treturn boolean true if a key has been pressed, nil if not.
+*/
+static int lst_keypressed(lua_State *L) {
+#ifdef _WIN32
+    if (kbhit()) {
+        lua_pushboolean(L, 1);
+        return 1;
+    }
+    return 0;
+
+#else
+    char ch;
+    if (read(STDIN_FILENO, &ch, 1) > 0) {
+        // key was read, push back to stdin
+        ungetc(ch, stdin);
+        lua_pushboolean(L, 1);
+        return 1;
+    }
+    return 0;
+
+#endif
+}
+
+/*-------------------------------------------------------------------------
+ * Retrieve terminal size
+ *-------------------------------------------------------------------------*/
+
+
+/***
+Get the size of the terminal in columns and rows.
+@function termsize
+@treturn[1] int the number of columns
+@treturn[1] int the number of rows
+@treturn[2] nil
+@treturn[2] string error message
+*/
+static int lst_termsize(lua_State *L) {
+    int columns, rows;
+
+#ifdef _WIN32
+    CONSOLE_SCREEN_BUFFER_INFO csbi;
+    if (!GetConsoleScreenBufferInfo(GetStdHandle(STD_OUTPUT_HANDLE), &csbi)) {
+        termFormatError(L, GetLastError(), "Failed to get terminal size.");
+        return 2;
+    }
+    columns = csbi.srWindow.Right - csbi.srWindow.Left + 1;
+    rows = csbi.srWindow.Bottom - csbi.srWindow.Top + 1;
+
+#else
+    struct winsize ws;
+    if (ioctl(1, TIOCGWINSZ, &ws) == -1) {
+        return pusherror(L, "Failed to get terminal size.");
+    }
+    columns = ws.ws_col;
+    rows = ws.ws_row;
+
+#endif
+    lua_pushinteger(L, columns);
+    lua_pushinteger(L, rows);
+    return 2;
+}
+
+
+
 /*-------------------------------------------------------------------------
  * Initializes module
  *-------------------------------------------------------------------------*/
+
+static luaL_Reg func[] = {
+    { "isatty", lst_isatty },
+    { "getconsoleflags", lst_getconsoleflags },
+    { "setconsoleflags", lst_setconsoleflags },
+    { "tcgetattr", lst_tcgetattr },
+    { "tcsetattr", lst_tcsetattr },
+    { "getnonblock", lst_setnonblock },
+    { "setnonblock", lst_setnonblock },
+    { "readkey", lst_readkey },
+    { "keypressed", lst_keypressed },
+    { "termsize", lst_termsize },
+    { NULL, NULL }
+};
+
+
+
 void term_open(lua_State *L) {
+    // set up constants and export the constants in module table
+    initialize_valid_flags();
+    // Windows flags
+    for (int i = 0; win_console_in_flags[i].name != NULL; i++)
+    {
+        lsbf_pushbitflags(L, win_console_in_flags[i].value);
+        lua_setfield(L, -2, win_console_in_flags[i].name);
+    }
+    for (int i = 0; win_console_out_flags[i].name != NULL; i++)
+    {
+        lsbf_pushbitflags(L, win_console_out_flags[i].value);
+        lua_setfield(L, -2, win_console_out_flags[i].name);
+    }
+    // Unix flags
+    for (int i = 0; nix_console_i_flags[i].name != NULL; i++)
+    {
+        lsbf_pushbitflags(L, nix_console_i_flags[i].value);
+        lua_setfield(L, -2, nix_console_i_flags[i].name);
+    }
+    for (int i = 0; nix_console_o_flags[i].name != NULL; i++)
+    {
+        lsbf_pushbitflags(L, nix_console_o_flags[i].value);
+        lua_setfield(L, -2, nix_console_o_flags[i].name);
+    }
+    for (int i = 0; nix_console_l_flags[i].name != NULL; i++)
+    {
+        lsbf_pushbitflags(L, nix_console_l_flags[i].value);
+        lua_setfield(L, -2, nix_console_l_flags[i].name);
+    }
+    // Unix tcsetattr actions
+    for (int i = 0; nix_tcsetattr_actions[i].name != NULL; i++)
+    {
+        lua_pushinteger(L, nix_tcsetattr_actions[i].value);
+        lua_setfield(L, -2, nix_tcsetattr_actions[i].name);
+    }
+
+    // export functions
     luaL_setfuncs(L, func, 0);
 }