opentofu/flatmap/expand.go
Mitchell Hashimoto ad2f448911 flatmap: expand
2014-07-01 13:25:54 -07:00

74 lines
1.5 KiB
Go

package flatmap
import (
"fmt"
"strconv"
"strings"
)
// Expand takes a map and a key (prefix) and expands that value into
// a more complex structure. This is the reverse of the Flatten operation.
func Expand(m map[string]string, key string) interface{} {
// If the key is exactly a key in the map, just return it
if v, ok := m[key]; ok {
if num, err := strconv.ParseInt(v, 0, 0); err == nil {
return int(num)
} else if v == "true" {
return true
} else if v == "false" {
return false
}
return v
}
// Check if the key is an array, and if so, expand the array
if _, ok := m[key+".#"]; ok {
return expandArray(m, key)
}
// Check if this is a prefix in the map
prefix := key + "."
for k, _ := range m {
if strings.HasPrefix(k, prefix) {
return expandMap(m, prefix)
}
}
return nil
}
func expandArray(m map[string]string, prefix string) []interface{} {
num, err := strconv.ParseInt(m[prefix+".#"], 0, 0)
if err != nil {
panic(err)
}
result := make([]interface{}, num)
for i := 0; i < int(num); i++ {
result[i] = Expand(m, fmt.Sprintf("%s.%d", prefix, i))
}
return result
}
func expandMap(m map[string]string, prefix string) map[string]interface{} {
result := make(map[string]interface{})
for k, _ := range m {
if !strings.HasPrefix(k, prefix) {
continue
}
key := k[len(prefix):]
idx := strings.Index(key, ".")
if idx == -1 {
idx = len(k)
}
// It contains a period, so it is a more complex structure
result[key] = Expand(m, k[:idx])
}
return result
}