package org.lilystudio.smarty4j.statement.function;
import static org.objectweb.asm.Opcodes.*;
import java.util.Map;
import org.lilystudio.smarty4j.ParseException;
import org.lilystudio.smarty4j.Template;
import org.lilystudio.smarty4j.TemplateWriter;
import org.lilystudio.smarty4j.expression.IExpression;
import org.lilystudio.smarty4j.expression.VariableExpression;
import org.lilystudio.smarty4j.statement.Function;
import org.lilystudio.smarty4j.statement.ParameterCharacter;
import org.objectweb.asm.MethodVisitor;
/**
* bytes函数，语法与一般的函数不同，变量名直接跟在bytes后，
* 用于在混合输出时输出二进制流。如果要使用这个函数，
* 在merge时必须传入的为OutputStream，而不是Writer，否则将产生运行异常。
*
* <pre>
* {bytes $DATA}
* </pre>
*
* @see org.lilystudio.smarty4j.Template#merge(org.lilystudio.smarty4j.Context,
* java.io.OutputStream)
*
* @version 1.0.0, 2010/10/01
* @author 欧阳先伟
* @since Smarty 1.0
*/
public class $bytes extends Function {
/** 需要输出的表达式 */
private IExpression exp;
@Override
public void syntax(Template template, Object[] words, int wordSize)
throws ParseException {
Object var = words[3];
if ((wordSize > 4) || !(var instanceof VariableExpression)) {
throw new ParseException("参数错误");
}
exp = (IExpression) var;
}
public ParameterCharacter[] getDefinitions() {
return null;
}
public void parse(MethodVisitor mw, int local,
Map<String, Integer> variableNames) {
// OutputStream out = ((OutputStreamWriter)
// writer).getOutputStream();
// out.write((byte[]) exps[0]);
// out.flush();
mw.visitVarInsn(ALOAD, WRITER);
mw.visitTypeInsn(CHECKCAST, TemplateWriter.NAME);
mw.visitMethodInsn(INVOKEVIRTUAL, TemplateWriter.NAME, "getOutputStream",
"()Ljava/io/OutputStream;");
mw.visitInsn(DUP);
exp.parse(mw, local, variableNames);
mw.visitTypeInsn(CHECKCAST, "[B");
mw.visitMethodInsn(INVOKEVIRTUAL, "java/io/OutputStream", "write", "([B)V");
mw.visitMethodInsn(INVOKEVIRTUAL, "java/io/OutputStream", "flush", "()V");
}
}