| negative,
* <code>len</code> is negative, or <code>len</code> is greater than
* <code>b.length - off</code>
* @exception IOException if an I/O error occurs.
*/
public int read(byte b[], int off, int len) throws IOException {
return readBytes(b, off, len);
}
看出readBytes是关键的所在，windows的native code中只有
JNIEXPORT void JNICALL
Java_java_io_FileInputStream_close0(JNIEnv *env, jobject this) {
handleClose(env, this, fis_fd);
}
是平台相关的。
其他的在share中
FileInputStream.c代码
jfieldID fis_fd; /* id for jobject ''fd'' in java.io.FileInputStream */
/**************************************************************
* static methods to store field ID''s in initializers
*/
java源码FileInputStream(3)
时间:2010-12-14
得到fd的值，这个很重要
JNIEXPORT void JNICALL
Java_java_io_FileInputStream_initIDs(JNIEnv *env, jclass fdClass) {
fis_fd = (*env)->GetFieldID(env, fdClass, "fd", "Ljava/io/FileDescriptor;");
}
/**************************************************************
* Input stream
*/
JNIEXPORT void JNICALL
Java_java_io_FileInputStream_open(JNIEnv *env, jobject this, jstring path) {
fileOpen(env, this, path, fis_fd, O_RDONLY);
}
JNIEXPORT jint JNICALL
Java_java_io_FileInputStream_read(JNIEnv *env, jobject this) {
return readSingle(env, this, fis_fd);
}
JNIEXPORT jint JNICALL
Java_java_io_FileInputStream_readBytes(JNIEnv *env, jobject this,
jbyteArray bytes, jint off, jint len) {
return readBytes(env, this, bytes, off, len, fis_fd);
}
JNIEXPORT jlong JNICALL
Java_java_io_FileInputStream_skip(JNIEnv *env, jobject this, jlong toSkip) {
jlong cur = jlong_zero;
jlong end = jlong_zero;
FD fd = GET_FD(this, fis_fd);
if ((cur = IO_Lseek(fd, (jlong)0, (jint)SEEK_CUR)) == -1) {
JNU_ThrowIOExceptionWithLastError(env, "Seek error");
} else if ((end = IO_Lseek(fd, toSkip, (jint)SEEK_CUR)) == -1) {
JNU_ThrowIOExceptionWithLastError(env, "Seek error");
}
return (end - cur);
}
JNIEXPORT jint JNICALL
Java_java_io_FileInputStream_available(JNIEnv *env, jobject this) {
jlong ret;
FD fd = GET_FD(this, fis_fd);
if (IO_Available(fd, &ret)) {
if (ret > INT_MAX) {
ret = (jlong) INT_MAX;
}
return jlong_to_jint(ret);
}
JNU_ThrowIOExceptionWithLastError(env, NULL);
return 0;
}
java源码FileInputStream(4)
时间:2010-12-14
主要是readBytes的实现，打开io_util.c文件
/* IO helper functions */
int
readSingle(JNIEnv *env, jobject this, jfieldID fid) {
int nread;
char ret;
FD fd = GET_FD(this, fid);
nread = IO_Read(fd, &ret, 1);
if (nread == 0) { /* EOF */
return -1;
} else if (nread == JVM_IO_ERR) { /* error */
JNU_ThrowIOExceptionWithLastError(env, "Read error");
} else if (nread == JVM_IO_INTR) {
JNU_ThrowByName(env, "java/io/InterruptedIOException", 0);
}
return ret & 0xFF;
}
/* The maximum size of a stack-allocated buffer.
*/
#define BUF_SIZE 8192
int
readBytes(JNIEnv *env, jobject this, jbyteArray bytes,
jint off, jint len, jfieldID fid
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