java/src/crc16.c

   1 #include "a.h"
   2 #include "a/crc.h"
   3 #include "liba_crc16.h"
   4
   5 #undef L
   6 #define L Java_liba_crc16
   7 static struct
   8 {
   9     jmethodID _new;
  10     jfieldID ctx;
  11 } L = {NULL, NULL};
  12
  13 JNIEXPORT void JNICALL Java_liba_crc16_clinit(JNIEnv *_env, jclass _cls)
  14 {
  15     jclass _nbb = (*_env)->FindClass(_env, "Ljava/nio/ByteBuffer;");
  16     L._new = (*_env)->GetStaticMethodID(_env, _nbb, "allocateDirect", "(I)Ljava/nio/ByteBuffer;");
  17     L.ctx = (*_env)->GetFieldID(_env, _cls, "ctx", "Ljava/nio/ByteBuffer;");
  18 }
  19
  20 struct crc16
  21 {
  22     a_u16 table[0x100];
  23     a_u16 (*eval)(a_u16 const table[0x100], void const *pdata, a_size nbyte, a_u16 value);
  24 };
  25
  26 JNIEXPORT void JNICALL Java_liba_crc16_init(JNIEnv *_env, jobject _obj, jshort poly, jboolean reversed)
  27 {
  28     jobject _ctx = (*_env)->CallObjectMethod(_env, _obj, L._new, (jint)sizeof(struct crc16));
  29     struct crc16 *ctx = (struct crc16 *)(*_env)->GetDirectBufferAddress(_env, _ctx);
  30     (*_env)->SetObjectField(_env, _obj, L.ctx, _ctx);
  31     if (reversed)
  32     {
  33         a_crc16l_init(ctx->table, (a_u16)poly);
  34         ctx->eval = a_crc16l;
  35     }
  36     else
  37     {
  38         a_crc16m_init(ctx->table, (a_u16)poly);
  39         ctx->eval = a_crc16m;
  40     }
  41 }
  42
  43 JNIEXPORT jshortArray JNICALL Java_liba_crc16_table(JNIEnv *_env, jobject _obj)
  44 {
  45     jobject _ctx = (*_env)->GetObjectField(_env, _obj, L.ctx);
  46     struct crc16 *ctx = (struct crc16 *)(*_env)->GetDirectBufferAddress(_env, _ctx);
  47     jshortArray table = (*_env)->NewShortArray(_env, A_LEN(ctx->table));
  48     (*_env)->SetShortArrayRegion(_env, table, 0, A_LEN(ctx->table), (jshort *)ctx->table);
  49     return table;
  50 }
  51
  52 JNIEXPORT jobject JNICALL Java_liba_crc16_gen(JNIEnv *_env, jobject _obj, jshort poly, jboolean reversed)
  53 {
  54     jobject _ctx = (*_env)->GetObjectField(_env, _obj, L.ctx);
  55     struct crc16 *ctx = (struct crc16 *)(*_env)->GetDirectBufferAddress(_env, _ctx);
  56     if (reversed)
  57     {
  58         a_crc16l_init(ctx->table, (a_u16)poly);
  59         ctx->eval = a_crc16l;
  60     }
  61     else
  62     {
  63         a_crc16m_init(ctx->table, (a_u16)poly);
  64         ctx->eval = a_crc16m;
  65     }
  66     return _obj;
  67 }
  68
  69 JNIEXPORT jshort JNICALL Java_liba_crc16_eval(JNIEnv *_env, jobject _obj, jbyteArray block, jshort value)
  70 {
  71     jobject _ctx = (*_env)->GetObjectField(_env, _obj, L.ctx);
  72     struct crc16 *ctx = (struct crc16 *)(*_env)->GetDirectBufferAddress(_env, _ctx);
  73     jsize n = (*_env)->GetArrayLength(_env, block);
  74     jbyte *p = (*_env)->GetByteArrayElements(_env, block, NULL);
  75     value = (jshort)ctx->eval(ctx->table, p, (a_size)n, (a_u16)value);
  76     (*_env)->ReleaseByteArrayElements(_env, block, p, JNI_ABORT);
  77     return value;
  78 }
  79
  80 JNIEXPORT jbyteArray JNICALL Java_liba_crc16_pack(JNIEnv *_env, jobject _obj, jbyteArray block, jshort value)
  81 {
  82     jobject _ctx = (*_env)->GetObjectField(_env, _obj, L.ctx);
  83     struct crc16 *ctx = (struct crc16 *)(*_env)->GetDirectBufferAddress(_env, _ctx);
  84     jsize block_n = (*_env)->GetArrayLength(_env, block);
  85     jbyteArray res = (*_env)->NewByteArray(_env, block_n + 2);
  86     jbyte *block_p = (*_env)->GetByteArrayElements(_env, block, NULL);
  87     value = (jshort)ctx->eval(ctx->table, block_p, (a_size)block_n, (a_u16)value);
  88     ctx->eval == a_crc16m ? a_u16_setb(&value, (a_u16)value) : a_u16_setl(&value, (a_u16)value);
  89     (*_env)->SetByteArrayRegion(_env, res, 0, block_n, block_p);
  90     (*_env)->ReleaseByteArrayElements(_env, block, block_p, JNI_ABORT);
  91     (*_env)->SetByteArrayRegion(_env, res, block_n, 2, (jbyte *)&value);
  92     return res;
  93 }