Added Lua 5.3's UTF-8 module to LÖVE. Resolves issue #951.

The module must be required before use, i.e. utf8 = require("utf8").  API documentation can be found here: http://www.lua.org/manual/5.3/manual.html#6.5

Removing the last unicode character in a string (for proper backspace support in text boxes, for example) can be done using utf8.offset, e.g. text = text:sub(1, utf8.offset(text, -1) - 1).

CMakeLists.txt

@@ -1001,6 +1001,18 @@ set(LOVE_SRC_3P_LUASOCKET
 add_library(love_3p_luasocket ${LOVE_SRC_3P_LUASOCKET})
 target_link_libraries(love_3p_luasocket ${MEGA_LUA})
 
+#
+# Lua 5.3's UTF-8 library
+#
+set(LOVE_SRC_3P_LUAUTF8
+	src/libraries/luautf8/lprefix.h
+	src/libraries/luautf8/lutf8lib.c
+	src/libraries/luautf8/lutf8lib.h
+)
+
+add_library(love_3p_luautf8 ${LOVE_SRC_3P_LUAUTF8})
+target_link_libraries(love_3p_luautf8 ${MEGA_LUA})
+
 #
 # noise1234
 #
@@ -1054,6 +1066,7 @@ set(LOVE_3P
 	love_3p_ddsparse
 	love_3p_enet
 	love_3p_luasocket
+	love_3p_luautf8
 	love_3p_noise1234
 	love_3p_wuff
 )

platform/macosx/love-framework.xcodeproj/project.pbxproj

@@ -272,6 +272,9 @@
 		FA9B4A0816E1578300074F42 /* SDL2.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = FA9B4A0716E1578300074F42 /* SDL2.framework */; };
 		FA9FC0B0173D6E3E005027FF /* wrap_Window.cpp in Sources */ = {isa = PBXBuildFile; fileRef = FA9FC0AE173D6E3E005027FF /* wrap_Window.cpp */; };
 		FA9FC0B1173D6E3E005027FF /* wrap_Window.h in Headers */ = {isa = PBXBuildFile; fileRef = FA9FC0AF173D6E3E005027FF /* wrap_Window.h */; };
+		FAA0A45E1A704016009487CB /* lprefix.h in Headers */ = {isa = PBXBuildFile; fileRef = FAA0A45C1A704016009487CB /* lprefix.h */; };
+		FAA0A45F1A704016009487CB /* lutf8lib.c in Sources */ = {isa = PBXBuildFile; fileRef = FAA0A45D1A704016009487CB /* lutf8lib.c */; };
+		FAA0A4611A70431A009487CB /* lutf8lib.h in Headers */ = {isa = PBXBuildFile; fileRef = FAA0A4601A70431A009487CB /* lutf8lib.h */; };
 		FAA627CE18E7E1560080752D /* CoreServices.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = FAA627CD18E7E1560080752D /* CoreServices.framework */; };
 		FAAC6B02170A373B008A61C5 /* CompressedData.cpp in Sources */ = {isa = PBXBuildFile; fileRef = FAAC6B00170A373A008A61C5 /* CompressedData.cpp */; };
 		FAAC6B03170A373B008A61C5 /* CompressedData.h in Headers */ = {isa = PBXBuildFile; fileRef = FAAC6B01170A373A008A61C5 /* CompressedData.h */; };
@@ -832,6 +835,9 @@
 		FA9B4A0716E1578300074F42 /* SDL2.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = SDL2.framework; path = /Library/Frameworks/SDL2.framework; sourceTree = "<absolute>"; };
 		FA9FC0AE173D6E3E005027FF /* wrap_Window.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = wrap_Window.cpp; sourceTree = "<group>"; };
 		FA9FC0AF173D6E3E005027FF /* wrap_Window.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = wrap_Window.h; sourceTree = "<group>"; };
+		FAA0A45C1A704016009487CB /* lprefix.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = lprefix.h; sourceTree = "<group>"; };
+		FAA0A45D1A704016009487CB /* lutf8lib.c */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.c; path = lutf8lib.c; sourceTree = "<group>"; };
+		FAA0A4601A70431A009487CB /* lutf8lib.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = lutf8lib.h; sourceTree = "<group>"; };
 		FAA627CD18E7E1560080752D /* CoreServices.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = CoreServices.framework; path = System/Library/Frameworks/CoreServices.framework; sourceTree = SDKROOT; };
 		FAAC6B00170A373A008A61C5 /* CompressedData.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = CompressedData.cpp; sourceTree = "<group>"; };
 		FAAC6B01170A373A008A61C5 /* CompressedData.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = CompressedData.h; sourceTree = "<group>"; };
@@ -1392,6 +1398,7 @@
 				FAE010D7170DDE99006F29D0 /* ddsparse */,
 				FA5FDC5E1788D548002F0ED2 /* enet */,
 				3AED1DE005A53DDB07902760 /* luasocket */,
+				FAA0A45B1A704016009487CB /* luautf8 */,
 				FA0354691731F3A700284828 /* noise1234 */,
 				36C14C81334735EC54E33637 /* utf8 */,
 				FAF6704318184FF800DBDEEA /* Wuff */,
@@ -1920,6 +1927,16 @@
 			path = math;
 			sourceTree = "<group>";
 		};
+		FAA0A45B1A704016009487CB /* luautf8 */ = {
+			isa = PBXGroup;
+			children = (
+				FAA0A45C1A704016009487CB /* lprefix.h */,
+				FAA0A45D1A704016009487CB /* lutf8lib.c */,
+				FAA0A4601A70431A009487CB /* lutf8lib.h */,
+			);
+			path = luautf8;
+			sourceTree = "<group>";
+		};
 		FAE010D7170DDE99006F29D0 /* ddsparse */ = {
 			isa = PBXGroup;
 			children = (
@@ -1976,6 +1993,7 @@
 				FAF272B616E3D46400CC193A /* Thread.h in Headers */,
 				FAF272B816E3D46400CC193A /* threads.h in Headers */,
 				FA5454C316F1310000D30303 /* MathModule.h in Headers */,
+				FAA0A45E1A704016009487CB /* lprefix.h in Headers */,
 				FAAC6B03170A373B008A61C5 /* CompressedData.h in Headers */,
 				FAE010DB170DDE99006F29D0 /* ddsinfo.h in Headers */,
 				FAE010DD170DDE99006F29D0 /* ddsparse.h in Headers */,
@@ -2011,6 +2029,7 @@
 				FA5FDC831788D548002F0ED2 /* types.h in Headers */,
 				FA0A4BF5182E1AD600E1E4D2 /* MotorJoint.h in Headers */,
 				FA5FDC841788D548002F0ED2 /* unix.h in Headers */,
+				FAA0A4611A70431A009487CB /* lutf8lib.h in Headers */,
 				FA0A4BF1182E0C2800E1E4D2 /* b2MotorJoint.h in Headers */,
 				FA5FDC851788D548002F0ED2 /* utility.h in Headers */,
 				FAF6704D18184FF800DBDEEA /* wuff.h in Headers */,
@@ -2320,6 +2339,7 @@
 				FA9FC0B0173D6E3E005027FF /* wrap_Window.cpp in Sources */,
 				FAB0078F1740C12D00A9664D /* Joystick.cpp in Sources */,
 				FAB007931740C28900A9664D /* Joystick.cpp in Sources */,
+				FAA0A45F1A704016009487CB /* lutf8lib.c in Sources */,
 				FAB007971740C87D00A9664D /* wrap_Joystick.cpp in Sources */,
 				FAC5710017402D1100D147E4 /* BezierCurve.cpp in Sources */,
 				FAC5710217402D1100D147E4 /* wrap_BezierCurve.cpp in Sources */,

src/common/config.h

@@ -109,6 +109,7 @@
 #	define LOVE_ENABLE_KEYBOARD_SDL
 #	define LOVE_ENABLE_LOVE
 #	define LOVE_ENABLE_LUASOCKET
+#	define LOVE_ENABLE_LUAUTF8
 #	define LOVE_ENABLE_MATH
 #	define LOVE_ENABLE_MOUSE
 #	define LOVE_ENABLE_MOUSE_SDL

src/libraries/luautf8/lprefix.h

@@ -0,0 +1,45 @@
+/*
+** $Id: lprefix.h,v 1.2 2014/12/29 16:54:13 roberto Exp $
+** Definitions for Lua code that must come before any other header file
+** See Copyright Notice in lutf8lib.c
+*/
+
+#ifndef lprefix_h
+#define lprefix_h
+
+
+/*
+** Allows POSIX/XSI stuff
+*/
+#if !defined(LUA_USE_C89)	/* { */
+
+#if !defined(_XOPEN_SOURCE)
+#define _XOPEN_SOURCE           600
+#elif _XOPEN_SOURCE == 0
+#undef _XOPEN_SOURCE  /* use -D_XOPEN_SOURCE=0 to undefine it */
+#endif
+
+/*
+** Allows manipulation of large files in gcc and some other compilers
+*/
+#if !defined(LUA_32BITS) && !defined(_FILE_OFFSET_BITS)
+#define _LARGEFILE_SOURCE       1
+#define _FILE_OFFSET_BITS       64
+#endif
+
+#endif				/* } */
+
+
+/*
+** Windows stuff
+*/
+#if defined(_WIN32) 	/* { */
+
+#if !defined(_CRT_SECURE_NO_WARNINGS)
+#define _CRT_SECURE_NO_WARNINGS  /* avoid warnings about ISO C functions */
+#endif
+
+#endif			/* } */
+
+#endif
+

src/libraries/luautf8/lutf8lib.c

@@ -0,0 +1,290 @@
+/*
+** $Id: lutf8lib.c,v 1.13 2014/11/02 19:19:04 roberto Exp $
+** Standard library for UTF-8 manipulation
+** Modified by the LOVE Development Team to work with Lua 5.1's API
+*/
+
+/******************************************************************************
+ * Copyright (C) 1994-2015 Lua.org, PUC-Rio, 2015 LOVE Development Team.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ ******************************************************************************/
+
+#define lutf8lib_c
+
+#include "lprefix.h"
+
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "lutf8lib.h"
+
+#include "lauxlib.h"
+#include "lualib.h"
+
+#define MAXUNICODE	0x10FFFF
+
+#define iscont(p)	((*(p) & 0xC0) == 0x80)
+
+
+/* from strlib */
+/* translate a relative string position: negative means back from end */
+static lua_Integer u_posrelat (lua_Integer pos, size_t len) {
+  if (pos >= 0) return pos;
+  else if (0u - (size_t)pos > len) return 0;
+  else return (lua_Integer)len + pos + 1;
+}
+
+
+/*
+** Decode one UTF-8 sequence, returning NULL if byte sequence is invalid.
+*/
+static const char *utf8_decode (const char *o, int *val) {
+  static unsigned int limits[] = {0xFF, 0x7F, 0x7FF, 0xFFFF};
+  const unsigned char *s = (const unsigned char *)o;
+  unsigned int c = s[0];
+  unsigned int res = 0;  /* final result */
+  if (c < 0x80)  /* ascii? */
+    res = c;
+  else {
+    int count = 0;  /* to count number of continuation bytes */
+    while (c & 0x40) {  /* still have continuation bytes? */
+      int cc = s[++count];  /* read next byte */
+      if ((cc & 0xC0) != 0x80)  /* not a continuation byte? */
+        return NULL;  /* invalid byte sequence */
+      res = (res << 6) | (cc & 0x3F);  /* add lower 6 bits from cont. byte */
+      c <<= 1;  /* to test next bit */
+    }
+    res |= ((c & 0x7F) << (count * 5));  /* add first byte */
+    if (count > 3 || res > MAXUNICODE || res <= limits[count])
+      return NULL;  /* invalid byte sequence */
+    s += count;  /* skip continuation bytes read */
+  }
+  if (val) *val = res;
+  return (const char *)s + 1;  /* +1 to include first byte */
+}
+
+
+/*
+** utf8len(s [, i [, j]]) --> number of characters that start in the
+** range [i,j], or nil + current position if 's' is not well formed in
+** that interval
+*/
+static int utflen (lua_State *L) {
+  int n = 0;
+  size_t len;
+  const char *s = luaL_checklstring(L, 1, &len);
+  lua_Integer posi = u_posrelat(luaL_optinteger(L, 2, 1), len);
+  lua_Integer posj = u_posrelat(luaL_optinteger(L, 3, -1), len);
+  luaL_argcheck(L, 1 <= posi && --posi <= (lua_Integer)len, 2,
+                   "initial position out of string");
+  luaL_argcheck(L, --posj < (lua_Integer)len, 3,
+                   "final position out of string");
+  while (posi <= posj) {
+    const char *s1 = utf8_decode(s + posi, NULL);
+    if (s1 == NULL) {  /* conversion error? */
+      lua_pushnil(L);  /* return nil ... */
+      lua_pushinteger(L, posi + 1);  /* ... and current position */
+      return 2;
+    }
+    posi = s1 - s;
+    n++;
+  }
+  lua_pushinteger(L, n);
+  return 1;
+}
+
+
+/*
+** codepoint(s, [i, [j]])  -> returns codepoints for all characters
+** that start in the range [i,j]
+*/
+static int codepoint (lua_State *L) {
+  size_t len;
+  const char *s = luaL_checklstring(L, 1, &len);
+  lua_Integer posi = u_posrelat(luaL_optinteger(L, 2, 1), len);
+  lua_Integer pose = u_posrelat(luaL_optinteger(L, 3, posi), len);
+  int n;
+  const char *se;
+  luaL_argcheck(L, posi >= 1, 2, "out of range");
+  luaL_argcheck(L, pose <= (lua_Integer)len, 3, "out of range");
+  if (posi > pose) return 0;  /* empty interval; return no values */
+  n = (int)(pose -  posi + 1);
+  if (posi + n <= pose)  /* (lua_Integer -> int) overflow? */
+    return luaL_error(L, "string slice too long");
+  luaL_checkstack(L, n, "string slice too long");
+  n = 0;
+  se = s + pose;
+  for (s += posi - 1; s < se;) {
+    int code;
+    s = utf8_decode(s, &code);
+    if (s == NULL)
+      return luaL_error(L, "invalid UTF-8 code");
+    lua_pushinteger(L, code);
+    n++;
+  }
+  return n;
+}
+
+
+static void pushutfchar (lua_State *L, int arg) {
+  lua_Integer code = luaL_checkinteger(L, arg);
+  luaL_argcheck(L, 0 <= code && code <= MAXUNICODE, arg, "value out of range");
+  lua_pushfstring(L, "%U", (long)code);
+}
+
+
+/*
+** utfchar(n1, n2, ...)  -> char(n1)..char(n2)...
+*/
+static int utfchar (lua_State *L) {
+  int n = lua_gettop(L);  /* number of arguments */
+  if (n == 1)  /* optimize common case of single char */
+    pushutfchar(L, 1);
+  else {
+    int i;
+    luaL_Buffer b;
+    luaL_buffinit(L, &b);
+    for (i = 1; i <= n; i++) {
+      pushutfchar(L, i);
+      luaL_addvalue(&b);
+    }
+    luaL_pushresult(&b);
+  }
+  return 1;
+}
+
+
+/*
+** offset(s, n, [i])  -> index where n-th character counting from
+**   position 'i' starts; 0 means character at 'i'.
+*/
+static int byteoffset (lua_State *L) {
+  size_t len;
+  const char *s = luaL_checklstring(L, 1, &len);
+  lua_Integer n  = luaL_checkinteger(L, 2);
+  lua_Integer posi = (n >= 0) ? 1 : len + 1;
+  posi = u_posrelat(luaL_optinteger(L, 3, posi), len);
+  luaL_argcheck(L, 1 <= posi && --posi <= (lua_Integer)len, 3,
+                   "position out of range");
+  if (n == 0) {
+    /* find beginning of current byte sequence */
+    while (posi > 0 && iscont(s + posi)) posi--;
+  }
+  else {
+    if (iscont(s + posi))
+      luaL_error(L, "initial position is a continuation byte");
+    if (n < 0) {
+       while (n < 0 && posi > 0) {  /* move back */
+         do {  /* find beginning of previous character */
+           posi--;
+         } while (posi > 0 && iscont(s + posi));
+         n++;
+       }
+     }
+     else {
+       n--;  /* do not move for 1st character */
+       while (n > 0 && posi < (lua_Integer)len) {
+         do {  /* find beginning of next character */
+           posi++;
+         } while (iscont(s + posi));  /* (cannot pass final '\0') */
+         n--;
+       }
+     }
+  }
+  if (n == 0)  /* did it find given character? */
+    lua_pushinteger(L, posi + 1);
+  else  /* no such character */
+    lua_pushnil(L);
+  return 1;  
+}
+
+
+static int iter_aux (lua_State *L) {
+  size_t len;
+  const char *s = luaL_checklstring(L, 1, &len);
+  lua_Integer n = lua_tointeger(L, 2) - 1;
+  if (n < 0)  /* first iteration? */
+    n = 0;  /* start from here */
+  else if (n < (lua_Integer)len) {
+    n++;  /* skip current byte */
+    while (iscont(s + n)) n++;  /* and its continuations */
+  }
+  if (n >= (lua_Integer)len)
+    return 0;  /* no more codepoints */
+  else {
+    int code;
+    const char *next = utf8_decode(s + n, &code);
+    if (next == NULL || iscont(next))
+      return luaL_error(L, "invalid UTF-8 code");
+    lua_pushinteger(L, n + 1);
+    lua_pushinteger(L, code);
+    return 2;
+  }
+}
+
+
+static int iter_codes (lua_State *L) {
+  luaL_checkstring(L, 1);
+  lua_pushcfunction(L, iter_aux);
+  lua_pushvalue(L, 1);
+  lua_pushinteger(L, 0);
+  return 3;
+}
+
+
+/* pattern to match a single UTF-8 character */
+#if LUA_VERSION_NUM >= 502
+#define UTF8PATT	"[\0-\x7F\xC2-\xF4][\x80-\xBF]*"
+#else
+/* lua 5.1 doesn't support literal null bytes in patterns */
+#define UTF8PATT	"[%z\x01-\x7F\xC2-\xF4][\x80-\xBF]*"
+#endif
+
+
+static struct luaL_Reg funcs[] = {
+  {"offset", byteoffset},
+  {"codepoint", codepoint},
+  {"char", utfchar},
+  {"len", utflen},
+  {"codes", iter_codes},
+  /* placeholders */
+  {"charpattern", NULL},
+  {NULL, NULL}
+};
+
+
+/* modified version of luaopen_utf8, designed to work with lua 5.1-5.3 */
+int luaopen_luautf8 (lua_State *L) {
+  luaL_Reg *l;
+  lua_createtable(L, 0, (int) (sizeof(funcs) / sizeof(luaL_Reg)) - 1);
+  for (l = funcs; l->name != NULL; l++) {
+    if (l->func != NULL) {
+      lua_pushcfunction(L, l->func);
+      lua_setfield(L, -2, l->name);
+    }
+  }
+  lua_pushliteral(L, UTF8PATT);
+  lua_setfield(L, -2, "charpattern");
+  return 1;
+}
+

src/libraries/luautf8/lutf8lib.h

@@ -0,0 +1,17 @@
+
+#ifndef LUAUTF8_LUTF8LIB_H
+#define LUAUTF8_LUTF8LIB_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "lua.h"
+
+LUALIB_API int luaopen_luautf8(lua_State *L);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LOVE_LUAUTF8_LUTF8LIB_H */

src/modules/love/love.cpp

@@ -43,6 +43,9 @@
 #ifdef LOVE_ENABLE_ENET
 #	include "libraries/enet/lua-enet.h"
 #endif
+#ifdef LOVE_ENABLE_LUAUTF8
+#	include "libraries/luautf8/lutf8lib.h"
+#endif
 
 // Scripts
 #include "scripts/boot.lua.h"
@@ -228,9 +231,7 @@ int luaopen_love(lua_State * L)
 
 	// Preload module loaders.
 	for (int i = 0; modules[i].name != 0; i++)
-	{
 		love::luax_preload(L, modules[i].func, modules[i].name);
-	}
 
 #ifdef LOVE_ENABLE_LUASOCKET
 	love::luasocket::__open(L);
@@ -238,6 +239,9 @@ int luaopen_love(lua_State * L)
 #ifdef LOVE_ENABLE_ENET
 	love::luax_preload(L, luaopen_enet, "enet");
 #endif
+#ifdef LOVE_ENABLE_LUAUTF8
+	love::luax_preload(L, luaopen_luautf8, "utf8");
+#endif
 
 	return 1;
 }