Add core:text/regex

core/text/regex/regex.odin

@@ -0,0 +1,434 @@
+package regex
+
+import "core:text/regex/common"
+import "core:text/regex/compiler"
+import "core:text/regex/optimizer"
+import "core:text/regex/parser"
+import "core:text/regex/virtual_machine"
+
+Flag           :: common.Flag
+Flags          :: common.Flags
+Parser_Error   :: parser.Error
+Compiler_Error :: compiler.Error
+
+Creation_Error :: enum {
+	None,
+	Bad_Delimiter,
+	Expected_Delimiter,
+	Unknown_Flag,
+}
+
+Error :: union #shared_nil {
+	Parser_Error,
+	Compiler_Error,
+	Creation_Error,
+}
+
+Capture :: struct {
+	pos: [][2]int,
+	groups: []string,
+}
+
+Regular_Expression :: struct {
+	original_pattern: string,
+	flags: Flags,
+	class_data: []virtual_machine.Rune_Class_Data,
+	program: []virtual_machine.Opcode `fmt:"-"`,
+}
+
+
+@(rodata)
+Flag_To_Letter := #sparse[Flag]u8 {
+	.Global            = 'g',
+	.Multiline         = 'm',
+	.Case_Insensitive  = 'i',
+	.Ignore_Whitespace = 'x',
+	.Unicode           = 'u',
+	.No_Capture        = 'n',
+	.No_Optimization   = '-',
+}
+
+/*
+Create a regular expression from a string pattern and a set of flags.
+
+*Allocates Using Provided Allocators*
+
+Inputs:
+- pattern: The pattern to compile.
+- flags: A `bit_set` of RegEx flags.
+- permanent_allocator: The allocator to use for the final regular expression. (default: context.allocator)
+- temporary_allocator: The allocator to use for the intermediate compilation stages. (default: context.temp_allocator)
+
+Returns:
+- result: The regular expression.
+- err: An error, if one occurred.
+*/
+@require_results
+create :: proc(
+	pattern: string,
+	flags: Flags = {},
+	permanent_allocator := context.allocator,
+	temporary_allocator := context.temp_allocator,
+) -> (result: Regular_Expression, err: Error) {
+
+	// For the sake of speed and simplicity, we first run all the intermediate
+	// processes such as parsing and compilation through the temporary
+	// allocator.
+	program: [dynamic]virtual_machine.Opcode = ---
+	class_data: [dynamic]parser.Rune_Class_Data = ---
+	{
+		context.allocator = temporary_allocator
+
+		ast := parser.parse(pattern, flags) or_return
+
+		if .No_Optimization not_in flags {
+			ast, _ = optimizer.optimize(ast, flags)
+		}
+
+		program, class_data = compiler.compile(ast, flags) or_return
+	}
+
+	// When that's successful, re-allocate all at once with the permanent
+	// allocator so everything can be tightly packed.
+	context.allocator = permanent_allocator
+
+	result.original_pattern = pattern
+	result.flags = flags
+
+	if len(class_data) > 0 {
+		result.class_data = make([]virtual_machine.Rune_Class_Data, len(class_data))
+	}
+	for data, i in class_data {
+		if len(data.runes) > 0 {
+			result.class_data[i].runes = make([]rune, len(data.runes))
+			copy(result.class_data[i].runes, data.runes[:])
+		}
+		if len(data.ranges) > 0 {
+			result.class_data[i].ranges = make([]virtual_machine.Rune_Class_Range, len(data.ranges))
+			copy(result.class_data[i].ranges, data.ranges[:])
+		}
+	}
+
+	result.program = make([]virtual_machine.Opcode, len(program))
+	copy(result.program, program[:])
+
+	return
+}
+
+/*
+Create a regular expression from a delimited string pattern, such as one
+provided by users of a program or those found in a configuration file.
+
+They are in the form of:
+
+	[DELIMITER] [regular expression] [DELIMITER] [flags]
+
+For example, the following strings are valid:
+
+	/hellope/i
+	#hellope#i
+	•hellope•i
+	つhellopeつi
+
+The delimiter is determined by the very first rune in the string.
+The only restriction is that the delimiter cannot be `\`, as that rune is used
+to escape the delimiter if found in the middle of the string.
+
+All runes after the closing delimiter will be parsed as flags:
+
+- 'g': Global
+- 'm': Multiline
+- 'i': Case_Insensitive
+- 'x': Ignore_Whitespace
+- 'u': Unicode
+- 'n': No_Capture
+- '-': No_Optimization
+
+
+*Allocates Using Provided Allocators*
+
+Inputs:
+- pattern: The delimited pattern with optional flags to compile.
+- str: The string to match against.
+- permanent_allocator: The allocator to use for the final regular expression. (default: context.allocator)
+- temporary_allocator: The allocator to use for the intermediate compilation stages. (default: context.temp_allocator)
+
+Returns:
+- result: The regular expression.
+- err: An error, if one occurred.
+*/
+@require_results
+create_by_user :: proc(
+	pattern: string,
+	permanent_allocator := context.allocator,
+	temporary_allocator := context.temp_allocator,
+) -> (result: Regular_Expression, err: Error) {
+
+	if len(pattern) == 0 {
+		err = .Expected_Delimiter
+		return
+	}
+
+	delimiter: rune
+	start := -1
+	end := -1
+
+	flags: Flags
+
+	escaping: bool
+	parse_loop: for r, i in pattern {
+		if delimiter == 0 {
+			if r == '\\' {
+				err = .Bad_Delimiter
+				return
+			}
+			delimiter = r
+			continue parse_loop
+		}
+
+		if start == -1 {
+			start = i
+		}
+
+		if escaping {
+			escaping = false
+			continue parse_loop
+		}
+
+		switch r {
+		case '\\':
+			escaping = true
+		case delimiter:
+			end = i
+			break parse_loop
+		}
+	}
+
+	if end == -1 {
+		err = .Expected_Delimiter
+		return
+	}
+
+	// `start` is also the size of the delimiter, which is why it's being added
+	// to `end` here.
+	for r in pattern[start + end:] {
+		switch r {
+		case 'g': flags += { .Global }
+		case 'm': flags += { .Multiline }
+		case 'i': flags += { .Case_Insensitive }
+		case 'x': flags += { .Ignore_Whitespace }
+		case 'u': flags += { .Unicode }
+		case 'n': flags += { .No_Capture }
+		case '-': flags += { .No_Optimization }
+		case:
+			err = .Unknown_Flag
+			return
+		}
+	}
+
+	return create(pattern[start:end], flags, permanent_allocator, temporary_allocator)
+}
+
+/*
+Match a regular expression against a string and allocate the results into the
+returned `capture` structure.
+
+The resulting capture strings will be slices to the string `str`, not wholly
+copied strings, so they won't need to be individually deleted.
+
+*Allocates Using Provided Allocators*
+
+Inputs:
+- regex: The regular expression.
+- str: The string to match against.
+- permanent_allocator: The allocator to use for the capture results. (default: context.allocator)
+- temporary_allocator: The allocator to use for the virtual machine. (default: context.temp_allocator)
+
+Returns:
+- capture: The capture groups found in the string.
+- success: True if the regex matched the string.
+*/
+@require_results
+match_and_allocate_capture :: proc(
+	regex: Regular_Expression,
+	str: string,
+	permanent_allocator := context.allocator,
+	temporary_allocator := context.temp_allocator,
+) -> (capture: Capture, success: bool) {
+
+	saved: ^[2 * common.MAX_CAPTURE_GROUPS]int
+
+	{
+		context.allocator = temporary_allocator
+
+		vm := virtual_machine.create(regex.program, str)
+		vm.class_data = regex.class_data
+
+		if .Unicode in regex.flags {
+			saved, success = virtual_machine.run(&vm, true)
+		} else {
+			saved, success = virtual_machine.run(&vm, false)
+		}
+	}
+
+	if saved != nil {
+		context.allocator = permanent_allocator
+
+		num_groups := 0
+		for i := 0; i < len(saved); i += 2 {
+			a, b := saved[i], saved[i + 1]
+			if a == -1 || b == -1 {
+				continue
+			}
+			num_groups += 1
+		}
+
+		if num_groups > 0 {
+			capture.groups = make([]string, num_groups)
+			capture.pos = make([][2]int, num_groups)
+			n := 0
+
+			#no_bounds_check for i := 0; i < len(saved); i += 2 {
+				a, b := saved[i], saved[i + 1]
+				if a == -1 || b == -1 {
+					continue
+				}
+
+				capture.groups[n] = str[a:b]
+				capture.pos[n] = {a, b}
+				n += 1
+			}
+		}
+	}
+
+	return
+}
+
+/*
+Match a regular expression against a string and save the capture results into
+the provided `capture` structure.
+
+The resulting capture strings will be slices to the string `str`, not wholly
+copied strings, so they won't need to be individually deleted.
+
+*Allocates Using Provided Allocator*
+
+Inputs:
+- regex: The regular expression.
+- str: The string to match against.
+- capture: A pointer to a Capture structure with `groups` and `pos` already allocated.
+- temporary_allocator: The allocator to use for the virtual machine. (default: context.temp_allocator)
+
+Returns:
+- num_groups: The number of capture groups set into `capture`.
+- success: True if the regex matched the string.
+*/
+@require_results
+match_with_preallocated_capture :: proc(
+	regex: Regular_Expression,
+	str: string,
+	capture: ^Capture,
+	temporary_allocator := context.temp_allocator,
+) -> (num_groups: int, success: bool) {
+
+	assert(capture != nil, "Pre-allocated RegEx capture must not be nil.")
+	assert(len(capture.groups) >= common.MAX_CAPTURE_GROUPS,
+		"Pre-allocated RegEx capture `groups` must be at least 10 elements long.")
+	assert(len(capture.pos) >= common.MAX_CAPTURE_GROUPS,
+		"Pre-allocated RegEx capture `pos` must be at least 10 elements long.")
+
+	saved: ^[2 * common.MAX_CAPTURE_GROUPS]int
+
+	{
+		context.allocator = temporary_allocator
+
+		vm := virtual_machine.create(regex.program, str)
+		vm.class_data = regex.class_data
+
+		if .Unicode in regex.flags {
+			saved, success = virtual_machine.run(&vm, true)
+		} else {
+			saved, success = virtual_machine.run(&vm, false)
+		}
+	}
+
+	if saved != nil {
+		n := 0
+
+		#no_bounds_check for i := 0; i < len(saved); i += 2 {
+			a, b := saved[i], saved[i + 1]
+			if a == -1 || b == -1 {
+				continue
+			}
+
+			capture.groups[n] = str[a:b]
+			capture.pos[n] = {a, b}
+			n += 1
+		}
+	}
+
+	return
+}
+
+match :: proc {
+	match_and_allocate_capture,
+	match_with_preallocated_capture,
+}
+
+/*
+Allocate a `Capture` in advance for use with `match`. This can save some time
+if you plan on performing several matches at once and only need the results
+between matches.
+
+Inputs:
+- allocator: (default: context.allocator)
+
+Returns:
+- result: The `Capture` with the maximum number of groups allocated.
+*/
+@require_results
+preallocate_capture :: proc(allocator := context.allocator) -> (result: Capture) {
+	context.allocator = allocator
+	result.pos = make([][2]int, common.MAX_CAPTURE_GROUPS)
+	result.groups = make([]string, common.MAX_CAPTURE_GROUPS)
+	return
+}
+
+/*
+Free all data allocated by the `create*` procedures.
+
+*Frees Using Provided Allocator*
+
+Inputs:
+- regex: A regular expression.
+- allocator: (default: context.allocator)
+*/
+destroy_regex :: proc(regex: Regular_Expression, allocator := context.allocator) {
+	context.allocator = allocator
+	delete(regex.program)
+	for data in regex.class_data {
+		delete(data.runes)
+		delete(data.ranges)
+	}
+	delete(regex.class_data)
+}
+
+/*
+Free all data allocated by the `match_and_allocate_capture` procedure.
+
+*Frees Using Provided Allocator*
+
+Inputs:
+- capture: A Capture.
+- allocator: (default: context.allocator)
+*/
+destroy_capture :: proc(capture: Capture, allocator := context.allocator) {
+	context.allocator = allocator
+	delete(capture.groups)
+	delete(capture.pos)
+}
+
+destroy :: proc {
+	destroy_regex,
+	destroy_capture,
+}