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package flag
import "core:runtime"
import "core:strings"
import "core:reflect"
import "core:fmt"
import "core:mem"
import "core:strconv"
Flag_Error :: enum {
None,
No_Base_Struct,
Arg_Error,
Arg_Unsupported_Field_Type,
Arg_Not_Defined,
Arg_Non_Optional,
Value_Parse_Error,
Tag_Error,
}
Flag :: struct {
optional: bool,
type: ^runtime.Type_Info,
data: rawptr,
tag_ptr: rawptr,
parsed: bool,
}
Flag_Context :: struct {
seen_flags: map[string]Flag,
}
parse_args :: proc(ctx: ^Flag_Context, args: []string) -> Flag_Error {
using runtime;
args := args;
for {
if len(args) == 0 {
return .None;
}
arg := args[0];
if len(arg) < 2 || arg[0] != '-' {
return .Arg_Error;
}
minus_count := 1;
if arg[1] == '-' {
minus_count += 1;
if len(arg) == 2 {
return .Arg_Error;
}
}
name := arg[minus_count:];
if len(name) == 0 {
return .Arg_Error;
}
args = args[1:];
assign_index := strings.index(name, "=");
value := "";
if assign_index > 0 {
value = name[assign_index + 1:];
name = name[0:assign_index];
}
flag := &ctx.seen_flags[name];
if flag == nil {
return .Arg_Not_Defined;
}
if reflect.is_boolean(flag.type) {
tmp: b64 = true;
mem.copy(flag.data, &tmp, flag.type.size);
flag.parsed = true;
continue;
} else if value == "" { // must be in the next argument
if len(args) == 0 {
return .Arg_Error;
}
value = args[0];
args = args[1:];
}
#partial switch _ in flag.type.variant {
case Type_Info_Integer:
if v, ok := strconv.parse_int(value); ok {
mem.copy(flag.data, &v, flag.type.size);
} else {
return .Value_Parse_Error;
}
case Type_Info_String:
raw_string := cast(^mem.Raw_String)flag.data;
raw_string.data = strings.ptr_from_string(value);
raw_string.len = len(value);
case Type_Info_Float:
switch flag.type.size {
case 32:
if v, ok := strconv.parse_f32(value); ok {
mem.copy(flag.data, &v, flag.type.size);
} else {
return .Value_Parse_Error;
}
case 64:
if v, ok := strconv.parse_f64(value); ok {
mem.copy(flag.data, &v, flag.type.size);
} else {
return .Value_Parse_Error;
}
}
}
flag.parsed = true;
}
return .None;
}
reflect_args_structure :: proc(ctx: ^Flag_Context, v: any) -> Flag_Error {
using runtime;
if !reflect.is_struct(type_info_of(v.id)) {
return .No_Base_Struct;
}
names := reflect.struct_field_names(v.id);
types := reflect.struct_field_types(v.id);
offsets := reflect.struct_field_offsets(v.id);
tags := reflect.struct_field_tags(v.id);
for name, i in names {
flag: Flag;
type := types[i];
if named_type, ok := type.variant.(Type_Info_Named); ok {
if union_type, ok := named_type.base.variant.(Type_Info_Union); ok && len(union_type.variants) == 1 {
flag.optional = true;
flag.tag_ptr = rawptr(uintptr(union_type.tag_offset) + uintptr(v.data) + uintptr(offsets[i]));
type = union_type.variants[0];
} else {
return .Arg_Unsupported_Field_Type;
}
}
#partial switch _ in type.variant {
case Type_Info_Integer, Type_Info_String, Type_Info_Boolean, Type_Info_Float:
flag.type = type;
flag.data = rawptr(uintptr(v.data) + uintptr(offsets[i]));
case:
return .Arg_Unsupported_Field_Type;
}
flag_name: string;
if value, ok := reflect.struct_tag_lookup(tags[i], "flag"); ok {
flag_name = cast(string)value;
} else {
return .Tag_Error;
}
ctx.seen_flags[flag_name] = flag;
}
return .None;
}
parse :: proc(v: any, args: []string) -> Flag_Error {
if v == nil {
return .None;
}
ctx: Flag_Context;
if res := reflect_args_structure(&ctx, v); res != .None {
return res;
}
if res := parse_args(&ctx, args); res != .None {
return res;
}
//validate that the required flags were actually set
for k, v in ctx.seen_flags {
if v.optional && v.parsed {
tag_value: i32 = 1;
mem.copy(v.tag_ptr, &tag_value, 4); //4 constant is probably not portable, but it works for me currently
} else if !v.parsed && !v.optional {
return .Arg_Non_Optional;
}
}
return .None;
}
usage :: proc(v: any) -> string {
return "failed";
}
|
