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/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* Implementation of an expandable byte buffer. Designed for serializing
* primitive values, e.g. JDWP replies.
*/
#include "jdwp/ExpandBuf.h"
#include "Bits.h"
#include "Common.h"
#include <stdlib.h>
#include <string.h>
/*
* Data structure used to track buffer use.
*/
struct ExpandBuf {
u1* storage;
int curLen;
int maxLen;
};
#define kInitialStorage 64
/*
* Allocate a JdwpBuf and some initial storage.
*/
ExpandBuf* expandBufAlloc()
{
ExpandBuf* newBuf;
newBuf = (ExpandBuf*) malloc(sizeof(*newBuf));
newBuf->storage = (u1*) malloc(kInitialStorage);
newBuf->curLen = 0;
newBuf->maxLen = kInitialStorage;
return newBuf;
}
/*
* Free a JdwpBuf and associated storage.
*/
void expandBufFree(ExpandBuf* pBuf)
{
if (pBuf == NULL)
return;
free(pBuf->storage);
free(pBuf);
}
/*
* Get a pointer to the start of the buffer.
*/
u1* expandBufGetBuffer(ExpandBuf* pBuf)
{
return pBuf->storage;
}
/*
* Get the amount of data currently in the buffer.
*/
size_t expandBufGetLength(ExpandBuf* pBuf)
{
return pBuf->curLen;
}
/*
* Ensure that the buffer has enough space to hold incoming data. If it
* doesn't, resize the buffer.
*/
static void ensureSpace(ExpandBuf* pBuf, int newCount)
{
u1* newPtr;
if (pBuf->curLen + newCount <= pBuf->maxLen)
return;
while (pBuf->curLen + newCount > pBuf->maxLen)
pBuf->maxLen *= 2;
newPtr = (u1*) realloc(pBuf->storage, pBuf->maxLen);
if (newPtr == NULL) {
LOGE("realloc(%d) failed", pBuf->maxLen);
abort();
}
pBuf->storage = newPtr;
}
/*
* Allocate some space in the buffer.
*/
u1* expandBufAddSpace(ExpandBuf* pBuf, int gapSize)
{
u1* gapStart;
ensureSpace(pBuf, gapSize);
gapStart = pBuf->storage + pBuf->curLen;
/* do we want to garbage-fill the gap for debugging? */
pBuf->curLen += gapSize;
return gapStart;
}
/*
* Append a byte.
*/
void expandBufAdd1(ExpandBuf* pBuf, u1 val)
{
ensureSpace(pBuf, sizeof(val));
*(pBuf->storage + pBuf->curLen) = val;
pBuf->curLen++;
}
/*
* Append two big-endian bytes.
*/
void expandBufAdd2BE(ExpandBuf* pBuf, u2 val)
{
ensureSpace(pBuf, sizeof(val));
set2BE(pBuf->storage + pBuf->curLen, val);
pBuf->curLen += sizeof(val);
}
/*
* Append four big-endian bytes.
*/
void expandBufAdd4BE(ExpandBuf* pBuf, u4 val)
{
ensureSpace(pBuf, sizeof(val));
set4BE(pBuf->storage + pBuf->curLen, val);
pBuf->curLen += sizeof(val);
}
/*
* Append eight big-endian bytes.
*/
void expandBufAdd8BE(ExpandBuf* pBuf, u8 val)
{
ensureSpace(pBuf, sizeof(val));
set8BE(pBuf->storage + pBuf->curLen, val);
pBuf->curLen += sizeof(val);
}
/*
* Add a UTF8 string as a 4-byte length followed by a non-NULL-terminated
* string.
*
* Because these strings are coming out of the VM, it's safe to assume that
* they can be null-terminated (either they don't have null bytes or they
* have stored null bytes in a multi-byte encoding).
*/
void expandBufAddUtf8String(ExpandBuf* pBuf, const u1* str)
{
int strLen = strlen((const char*)str);
ensureSpace(pBuf, sizeof(u4) + strLen);
setUtf8String(pBuf->storage + pBuf->curLen, str);
pBuf->curLen += sizeof(u4) + strLen;
}
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