eq2go/internal/packets/parser/helpers.go

package parser

import (
	"reflect"
	"strconv"
)

// getDynamicLength gets length from another field with stack support
func (p *Parser) getDynamicLength(fieldName string) int {
	if cachedValue, exists := p.fieldCache[fieldName]; exists {
		return p.valueToInt(cachedValue)
	}

	if p.currentStruct.IsValid() {
		if field := p.currentStruct.FieldByName(fieldName); field.IsValid() {
			return p.valueToInt(field.Interface())
		}
	}

	for i := len(p.structStack) - 1; i >= 0; i-- {
		if field := p.structStack[i].FieldByName(fieldName); field.IsValid() {
			return p.valueToInt(field.Interface())
		}
	}

	return 0
}

// convertValue converts string to appropriate type for comparison
func (p *Parser) convertValue(valueStr string, reference any) (any, error) {
	switch reference.(type) {
	case uint8, int8:
		if val, err := strconv.ParseInt(valueStr, 0, 8); err == nil {
			return uint8(val), nil
		}
	case uint16, int16:
		if val, err := strconv.ParseInt(valueStr, 0, 16); err == nil {
			return uint16(val), nil
		}
	case uint32, int32:
		if val, err := strconv.ParseInt(valueStr, 0, 32); err == nil {
			return uint32(val), nil
		}
	case uint64, int64:
		if val, err := strconv.ParseInt(valueStr, 0, 64); err == nil {
			return uint64(val), nil
		}
	case float32:
		if val, err := strconv.ParseFloat(valueStr, 32); err == nil {
			return float32(val), nil
		}
	case float64:
		if val, err := strconv.ParseFloat(valueStr, 64); err == nil {
			return val, nil
		}
	case string:
		return valueStr, nil
	}

	if val, err := strconv.ParseInt(valueStr, 0, 32); err == nil {
		return int(val), nil
	}

	return valueStr, nil
}

// compareValues performs comparison between two values
func (p *Parser) compareValues(a, b any, op string) bool {
	aVal := p.valueToInt64(a)
	bVal := p.valueToInt64(b)

	switch op {
	case "==":
		return aVal == bVal
	case "!=":
		return aVal != bVal
	case ">":
		return aVal > bVal
	case ">=":
		return aVal >= bVal
	case "<":
		return aVal < bVal
	case "<=":
		return aVal <= bVal
	case "&":
		return (aVal & bVal) != 0
	case "|":
		return (aVal | bVal) != 0
	}

	return false
}

// valueToInt converts various types to int
func (p *Parser) valueToInt(v any) int {
	switch val := v.(type) {
	case uint8:
		return int(val)
	case int8:
		return int(val)
	case uint16:
		return int(val)
	case int16:
		return int(val)
	case uint32:
		return int(val)
	case int32:
		return int(val)
	case uint64:
		return int(val)
	case int64:
		return int(val)
	case int:
		return val
	}
	return 0
}

// valueToInt64 converts various types to int64 for comparison
func (p *Parser) valueToInt64(v any) int64 {
	switch val := v.(type) {
	case uint8:
		return int64(val)
	case int8:
		return int64(val)
	case uint16:
		return int64(val)
	case int16:
		return int64(val)
	case uint32:
		return int64(val)
	case int32:
		return int64(val)
	case uint64:
		return int64(val)
	case int64:
		return val
	case int:
		return int64(val)
	case float32:
		return int64(val)
	case float64:
		return int64(val)
	}
	return 0
}

// isTruthy checks if a value is truthy
func (p *Parser) isTruthy(v any) bool {
	switch val := v.(type) {
	case bool:
		return val
	case uint8, int8, uint16, int16, uint32, int32, uint64, int64, int:
		return p.valueToInt64(val) != 0
	case string:
		return val != ""
	}
	return false
}

// handleOversizedField handles fields that exceed their oversized value
func (p *Parser) handleOversizedField(field reflect.Value, oversizedByte byte, length int) error {
	if field.Kind() == reflect.Slice {
		slice := reflect.MakeSlice(field.Type(), 1, 1)
		if slice.Len() > 0 {
			elem := slice.Index(0)
			if elem.CanSet() {
				switch elem.Kind() {
				case reflect.Uint8:
					elem.SetUint(uint64(oversizedByte))
				case reflect.Int8:
					elem.SetInt(int64(int8(oversizedByte)))
				default:
					elem.SetUint(uint64(oversizedByte))
				}
			}
		}
		field.Set(slice)
	} else {
		switch field.Kind() {
		case reflect.Uint8:
			field.SetUint(uint64(oversizedByte))
		case reflect.Int8:
			field.SetInt(int64(int8(oversizedByte)))
		default:
			field.SetUint(uint64(oversizedByte))
		}
	}

	return nil
}