MBinBuffer made a bit smarter to allow the decent people to return it from functions

2 files changed, 106 insertions, 25 deletions

diff --git a/src/mir_core/src/binbuffer.cpp b/src/mir_core/src/binbuffer.cpp
index e5aef775bd..d558dcc7b7 100644
--- a/src/mir_core/src/binbuffer.cpp
+++ b/src/mir_core/src/binbuffer.cpp
@@ -17,15 +17,81 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
 
 #include "stdafx.h"
 
-MBinBuffer::MBinBuffer() :
-	m_buf(nullptr),
-	m_len(0)
+struct BufImpl
 {
+	uint32_t size, lockCount;
+
+	BufImpl* alloc(size_t newSize)
+	{
+		bool bEmpty = (this == nullptr);
+		auto *res = (BufImpl *)mir_realloc(this, newSize + sizeof(BufImpl));
+		if (bEmpty) {
+			res->lockCount = 1;
+			res->size = 0;
+		}
+		return res;
+	}
+
+	BufImpl* realloc(size_t newSize)
+	{
+		bool bEmpty;
+		newSize += sizeof(BufImpl);
+		if (this != nullptr) {
+			newSize += size;
+			bEmpty = false;
+		}
+		else bEmpty = true;
+
+		auto *res = (BufImpl *)mir_realloc(this, newSize);
+		if (bEmpty) {
+			res->lockCount = 1;
+			res->size = 0;
+		}
+		return res;
+	}
+
+	void free()
+	{
+		if (this == nullptr)
+			return;
+
+		if (lockCount == 1)
+			mir_free(this);
+		else
+			lockCount--;
+	}
+};
+
+__forceinline BufImpl* ptr2buf(char *p)
+{
+	return (p == nullptr) ? nullptr : (BufImpl*)p-1;
+}
+
+/////////////////////////////////////////////////////////////////////////////////////////
+
+MBinBuffer::MBinBuffer()
+{}
+
+MBinBuffer::MBinBuffer(const MBinBuffer &orig)
+{
+	ptr2buf(m_buf)->free();
+
+	BufImpl *p = ptr2buf(m_buf = orig.m_buf);
+	if (p)
+		p->lockCount++;
+}
+
+MBinBuffer::MBinBuffer(size_t preAlloc)
+{
+	BufImpl *p = (BufImpl *)mir_alloc(sizeof(BufImpl) + preAlloc);
+	p->lockCount = 1;
+	p->size = (unsigned)preAlloc;
+	m_buf = (char*)(p + 1);
 }
 
 MBinBuffer::~MBinBuffer()
 {
-	mir_free(m_buf);
+	ptr2buf(m_buf)->free();
 }
 
 void MBinBuffer::append(const void *pBuf, size_t bufLen)
@@ -33,12 +99,13 @@ void MBinBuffer::append(const void *pBuf, size_t bufLen)
 	if (pBuf == nullptr || bufLen == 0)
 		return;
 
-	m_buf = (char*)mir_realloc(m_buf, bufLen + m_len);
-	if (m_buf) {
-		memcpy(m_buf + m_len, pBuf, bufLen);
-		m_len += bufLen;
+	BufImpl *p = ptr2buf(m_buf)->realloc(bufLen);
+	if (p) {
+		m_buf = (char*)(p + 1);
+		memcpy(m_buf + p->size, pBuf, bufLen);
+		p->size += (unsigned)bufLen;
 	}
-	else m_len = 0;
+	else m_buf = nullptr;
 }
 
 void MBinBuffer::appendBefore(const void *pBuf, size_t bufLen)
@@ -46,13 +113,14 @@ void MBinBuffer::appendBefore(const void *pBuf, size_t bufLen)
 	if (pBuf == nullptr || bufLen == 0)
 		return;
 
-	m_buf = (char*)mir_realloc(m_buf, bufLen + m_len);
-	if (m_buf) {
-		memmove(m_buf + bufLen, m_buf, m_len);
+	BufImpl *p = ptr2buf(m_buf)->realloc(bufLen);
+	if (p) {
+		m_buf = (char *)(p + 1);
+		memmove(m_buf + bufLen, m_buf, p->size);
 		memcpy(m_buf, pBuf, bufLen);
-		m_len += bufLen;
+		p->size += (unsigned)bufLen;
 	}
-	else m_len = 0;
+	else m_buf = nullptr;
 }
 
 void MBinBuffer::assign(const void *pBuf, size_t bufLen)
@@ -60,25 +128,36 @@ void MBinBuffer::assign(const void *pBuf, size_t bufLen)
 	if (pBuf == nullptr || bufLen == 0)
 		return;
 
-	m_buf = (char *)mir_realloc(m_buf, bufLen);
-	if (m_buf) {
+	BufImpl *p = ptr2buf(m_buf)->alloc(bufLen);
+	if (p) {
+		p->size = (unsigned)bufLen;
+		m_buf = (char *)(p + 1);
 		memcpy(m_buf, pBuf, bufLen);
-		m_len = bufLen;
 	}
-	else m_len = 0;
+	else m_buf = nullptr;
+}
+
+size_t MBinBuffer::length() const
+{
+	BufImpl *p = ptr2buf(m_buf);
+	return (p) ? p->size : 0;
 }
 
 void MBinBuffer::remove(size_t sz)
 {
-	if (sz > m_len)
-		m_len = sz;
+	BufImpl *p = ptr2buf(m_buf);
+	if (!p)
+		return;
+
+	if (sz > p->size)
+		sz = p->size;
 
-	if (m_len == sz) {
-		m_len = 0;
-		mir_free(m_buf); m_buf = nullptr;
+	if (p->size == sz) {
+		p->free();
+		m_buf = nullptr;
 	}
 	else {
-		memmove(m_buf, m_buf + sz, m_len - sz);
-		m_len -= sz;
+		memmove(m_buf, m_buf + sz, p->size - sz);
+		p->size -= (unsigned)sz;
 	}
 }
diff --git a/src/mir_core/src/mir_core.def b/src/mir_core/src/mir_core.def
index 9409e6d133..619b069b3a 100644
--- a/src/mir_core/src/mir_core.def
+++ b/src/mir_core/src/mir_core.def
@@ -1541,3 +1541,5 @@ Miranda_WaitOnHandle @1760
 Miranda_WaitOnHandleEx @1761

 _Utils_CorrectFontSize@4 @1762 NONAME

 ?OnResize@CDlgBase@@MAEXXZ @1763 NONAME

+??0MBinBuffer@@QAE@ABV0@@Z @1764 NONAME

+??0MBinBuffer@@QAE@I@Z @1765 NONAME