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grammar_sqlite.go
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grammar_sqlite.go
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package qb
import (
"unsafe"
)
type sqliteGrammar struct{}
var _ Grammar = (*sqliteGrammar)(nil)
func init() {
RegisterGrammar("sqlite3", SQLiteGrammar)
}
// SQLiteGrammar returns a specific grammar for sqlite
func SQLiteGrammar() Grammar {
return &sqliteGrammar{}
}
// Wrap wraps a string in quotes
func (g *sqliteGrammar) Wrap(s string) string {
var dot int
for i := 0; i < len(s); i++ {
if s[i] == '.' {
dot++
}
}
if dot == 0 {
return "`" + s + "`"
}
var (
n = dot*2 + 2 + len(s)
b = make([]byte, n)
w = 0
x = 0
)
for i := 0; i < len(s); i++ {
if s[i] == '.' {
w += copy(b[w:], "`"+s[x:i]+"`.")
x = i + 1
}
}
copy(b[w:], "`"+s[x:]+"`")
return *(*string)(unsafe.Pointer(&b))
}
// Placeholder returns n count placeholders
func (g *sqliteGrammar) Placeholder(n int) string {
if n < 0 {
panic("qb: negative Placeholder count")
}
if n == 0 {
return ""
}
if n == 1 {
return "?"
}
var (
p = ", ?"
b = make([]byte, len(p)*n)
w = copy(b, p)
)
for w < len(b) {
copy(b[w:], b[:w])
w *= 2
}
if len(b) >= len(p) {
b = b[2:]
}
return *(*string)(unsafe.Pointer(&b))
}