diff options
Diffstat (limited to 'source/ByteBuffer.cpp')
| -rw-r--r-- | source/ByteBuffer.cpp | 324 |
1 files changed, 324 insertions, 0 deletions
diff --git a/source/ByteBuffer.cpp b/source/ByteBuffer.cpp new file mode 100644 index 000000000..d25eb8e0b --- /dev/null +++ b/source/ByteBuffer.cpp @@ -0,0 +1,324 @@ +
+// ByteBuffer.cpp
+
+// Implements the cByteBuffer class representing a ringbuffer of bytes
+
+#include "Globals.h"
+
+#include "ByteBuffer.h"
+#include "Endianness.h"
+
+
+
+
+
+#define NEEDBYTES(Num) if (!CanReadBytes(Num)) return false;
+
+
+
+
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// cByteBuffer:
+
+cByteBuffer::cByteBuffer(int a_BufferSize) :
+ m_Buffer(new char[a_BufferSize + 1]),
+ m_BufferSize(a_BufferSize + 1),
+ m_DataStart(0),
+ m_WritePos(0),
+ m_ReadPos(0)
+{
+ // Allocating one byte more than the buffer size requested, so that we can distinguish between
+ // completely-full and completely-empty states
+}
+
+
+
+
+
+cByteBuffer::~cByteBuffer()
+{
+ delete m_Buffer;
+}
+
+
+
+
+
+bool cByteBuffer::Write(const char * a_Bytes, int a_Count)
+{
+ if (GetFreeSpace() < a_Count)
+ {
+ return false;
+ }
+ int TillEnd = m_BufferSize - m_WritePos;
+ if (TillEnd < a_Count)
+ {
+ // Need to wrap around the ringbuffer end
+ memcpy(m_Buffer + m_WritePos, a_Bytes, TillEnd);
+ m_WritePos = 0;
+ a_Bytes += TillEnd;
+ a_Count -= TillEnd;
+ }
+
+ // We're guaranteed that we'll fit in a single write op
+ memcpy(m_Buffer + m_WritePos, a_Bytes, a_Count);
+ m_WritePos += a_Count;
+ return true;
+}
+
+
+
+
+
+int cByteBuffer::GetFreeSpace(void) const
+{
+ if (m_WritePos >= m_DataStart)
+ {
+ // Wrap around the buffer end:
+ return m_BufferSize - m_WritePos + m_DataStart - 1;
+ }
+ // Single free space partition:
+ return m_DataStart - m_WritePos - 1;
+}
+
+
+
+
+
+/// Returns the number of bytes that are currently in the ringbuffer. Note GetReadableBytes()
+int cByteBuffer::GetUsedSpace(void) const
+{
+ return m_BufferSize - GetFreeSpace();
+}
+
+
+
+
+
+/// Returns the number of bytes that are currently available for reading (may be less than UsedSpace due to some data having been read already)
+int cByteBuffer::GetReadableSpace(void) const
+{
+ if (m_ReadPos > m_WritePos)
+ {
+ // Wrap around the buffer end:
+ return m_BufferSize - m_ReadPos + m_WritePos;
+ }
+ // Single readable space partition:
+ return m_WritePos - m_ReadPos ;
+}
+
+
+
+
+
+bool cByteBuffer::CanReadBytes(int a_Count) const
+{
+ return (a_Count <= GetReadableSpace());
+}
+
+
+
+
+
+bool cByteBuffer::ReadChar(char & a_Value)
+{
+ NEEDBYTES(1);
+ a_Value = m_Buffer[m_ReadPos++];
+ return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadByte(unsigned char & a_Value)
+{
+ NEEDBYTES(1);
+ a_Value = (unsigned char)(m_Buffer[m_ReadPos++]);
+ return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadBEShort(short & a_Value)
+{
+ NEEDBYTES(2);
+ ReadBuf(&a_Value, 2);
+ a_Value = ntohs(a_Value);
+ return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadBEInt(int & a_Value)
+{
+ NEEDBYTES(4);
+ ReadBuf(&a_Value, 4);
+ a_Value = ntohl(a_Value);
+ return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadBEInt64(Int64 & a_Value)
+{
+ NEEDBYTES(8);
+ ReadBuf(&a_Value, 8);
+ a_Value = NetworkToHostLong8(&a_Value);
+ return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadBEFloat(float & a_Value)
+{
+ NEEDBYTES(4);
+ ReadBuf(&a_Value, 4);
+ a_Value = NetworkToHostFloat4(&a_Value);
+ return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadBEDouble(double & a_Value)
+{
+ NEEDBYTES(8);
+ ReadBuf(&a_Value, 8);
+ a_Value = NetworkToHostDouble8(&a_Value);
+ return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadBool(bool & a_Value)
+{
+ NEEDBYTES(1);
+ a_Value = (m_Buffer[m_ReadPos++] != 0);
+ return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadBEUTF16String16(AString & a_Value)
+{
+ short Length;
+ if (!ReadBEShort(Length))
+ {
+ return false;
+ }
+ return ReadUTF16String(a_Value, Length);
+}
+
+
+
+
+
+bool cByteBuffer::ReadBuf(void * a_Buffer, int a_Count)
+{
+ NEEDBYTES(a_Count);
+ char * Dst = (char *)a_Buffer; // So that we can do byte math
+ int BytesToEndOfBuffer = m_BufferSize - m_ReadPos;
+ if (BytesToEndOfBuffer < a_Count)
+ {
+ // Reading across the ringbuffer end, read the first part and adjust parameters:
+ memcpy(Dst, m_Buffer + m_ReadPos, BytesToEndOfBuffer);
+ Dst += BytesToEndOfBuffer;
+ a_Count -= BytesToEndOfBuffer;
+ m_ReadPos = 0;
+ }
+
+ // Read the rest of the bytes in a single read (guaranteed to fit):
+ memcpy(Dst, m_Buffer + m_ReadPos, a_Count);
+ m_ReadPos += a_Count;
+ return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadString(AString & a_String, int a_Count)
+{
+ NEEDBYTES(a_Count);
+ a_String.clear();
+ a_String.reserve(a_Count);
+ int BytesToEndOfBuffer = m_BufferSize - m_ReadPos;
+ if (BytesToEndOfBuffer < a_Count)
+ {
+ // Reading across the ringbuffer end, read the first part and adjust parameters:
+ a_String.assign(m_Buffer + m_ReadPos, BytesToEndOfBuffer);
+ a_Count -= BytesToEndOfBuffer;
+ m_ReadPos = 0;
+ }
+
+ // Read the rest of the bytes in a single read (guaranteed to fit):
+ a_String.append(m_Buffer + m_ReadPos, a_Count);
+ m_ReadPos += a_Count;
+ return true;
+}
+
+
+
+
+
+bool cByteBuffer::ReadUTF16String(AString & a_String, int a_NumChars)
+{
+ // Reads 2 * a_NumChars bytes and interprets it as a UTF16 string, converting it into UTF8 string a_String
+ AString RawData;
+ if (!ReadString(RawData, a_NumChars * 2))
+ {
+ return false;
+ }
+ RawBEToUTF8((short *)(RawData.data()), a_NumChars, a_String);
+ return true;
+}
+
+
+
+
+
+void cByteBuffer::CommitRead(void)
+{
+ m_DataStart = m_ReadPos;
+}
+
+
+
+
+
+void cByteBuffer::ResetRead(void)
+{
+ m_ReadPos = m_DataStart;
+}
+
+
+
+
+
+void cByteBuffer::AdvanceReadPos(int a_Count)
+{
+ m_ReadPos += a_Count;
+ if (m_ReadPos > m_BufferSize)
+ {
+ m_ReadPos -= m_BufferSize;
+ }
+}
+
+
+
+
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