This library provides minimal support for the UTF-16 encoding. Operations that query the meaning of a character, such as character classification, are outside its scope. Since strings in Lua can have embedded zeros, the library uses the default Lua string type to hold the UTF-16 data. The encoding of a particular string is the user's responsibility. Unless specifically mentioned, all functions expect a byte (and not UTF-16 code unit) position as an argument. They assume that the given position is either the start of a code point (a self-represented UTF-16 character or a high UTF-16 surrogate) or one plus the length (in bytes) of the subject string. Negative positions (in bytes) count from the end of the string.
Gets zero or more integers, converts each one to its corresponding UTF-16 code units and returns a string with the concatenation of all these code units.
Returns values so that the construction for p, c in utf8.codes(s) do body end will iterate over all code points in string s, with p being the position (in bytes) and c the code point of each character. It raises an error if it meets any invalid UTF-16 sequence.
Returns the code points (as integers) from all UTF-16 characters in s that start between byte position i and j (both included). The default for i is 1 and for j is i. It raises an error if it meets any invalid UF-16 sequence.
Returns the number of UTF-8 characters in string s that start between positions i and j (both inclusive). The default for i is 1 and for j is -1. If it finds any invalid byte sequence, returns a false value plus the position of the first invalid byte.
Returns the position (in bytes) where the encoding of the i-th code point of s (counting from pos) starts. A negative i gets characters before pos. The default for pos is 1 when i is non-negative and #s + 1 otherwise, so that utf16.offset(s, -i) gets the offset of the i-th character from the end of the string. If the specified character is neither in the UTF-16 string nor right after its end, the function returns nil. As a special case, when i is 0 the function returns the start of the encoding of the character that contains the i-th byte of s. This function assumes that s is a valid UTF-16 string.
Open a Visual Studio Command Prompt (choosing the same platform as the one used when compiling Lua) in the source directory and execute nmake. The variables LUA_INCLUDE, LUA_LIBNAME and LUA_LIBPATH can be set either in Makefile or at the command line, for example with nmake LUA_INCLUDE=C:\Lua54\include LUA_LIBNAME=lua54.lib LUA_LIBPATH=C:\Lua54\lib. Lua must have been compiled as DLL (to allow using modules). The resulting utf16.dll must be manually moved to the target directory.
At the command prompt, in the source directory, execute make -f GNUmakefile mingw. The variables LUA_CFLAGS and LUA_LIBS can be set either in GNUmakefile or at the command line, for example with make -f GNUmakefile LUA_CFLAGS=-I/opt/local/include LUA_LIBS=-L/opt/local/lib -llua54. The resulting utf16.dll must be manually moved to the target directory.
At the command prompt, in the source directory, execute make -f GNUmakefile macos. The variable LUA_CFLAGS can be set either in GNUmakefile or at the command line, for example with make -f GNUmakefile LUA_CFLAGS=-I/opt/local/include. LUA_LIBS is ignored (this configuration uses -undefined dynamic_lookup linker option). The resulting utf16.so must be manually moved to the target directory.
At the command prompt, in the source directory, execute make -f GNUmakefile. The variables LUA_CFLAGS and LUA_LIBS can be set either in GNUmakefile or at the command line, for example with make -f GNUmakefile LUA_CFLAGS=-I/opt/local/include LUA_LIBS=-L/opt/local/lib -llua54. The resulting utf16.so must be manually moved to the target directory.