Implement a buffer for the TCP stream to go into

midiproc/buffer.c

@@ -0,0 +1,137 @@
+//
+// Copyright(C) 2017 Alex Mayfield
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation; either version 2
+// of the License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// DESCRIPTION:
+//     A simple buffer and reader implementation.
+//
+
+#include "buffer.h"
+
+//
+// Create a new buffer.
+//
+buffer_t *NewBuffer()
+{
+    buffer_t *buf = malloc(sizeof(buffer_t));
+
+    buf->buffer_end = buf->buffer + BUFFER_SIZE;
+    Buffer_Clear(buf);
+
+    return buf;
+}
+
+//
+// Free a buffer.
+//
+void DeleteBuffer(buffer_t* buf)
+{
+    free(buf);
+}
+
+//
+// Return the data in the buffer.
+//
+int Buffer_Data(buffer_t *buf, byte **data)
+{
+    *data = buf->data;
+    return buf->data_len;
+}
+
+//
+// Push data onto the end of the buffer.
+//
+boolean Buffer_Push(buffer_t *buf, const void *data, int len)
+{
+    if (len <= 0)
+    {
+        return true;
+    }
+
+    ptrdiff_t space_begin = buf->data - buf->buffer;
+    ptrdiff_t space_end = buf->buffer_end - buf->data_end;
+
+    if (len > space_end)
+    {
+        if (len > space_begin + space_end)
+        {
+            // Don't overflow the buffer.
+            return false;
+        }
+
+        // Move our data to the front of the buffer.
+        memmove(buf->buffer, buf->data, buf->data_len);
+        buf->data = buf->buffer;
+        buf->data_end = buf->buffer + buf->data_len;
+    }
+
+    // Append to the buffer.
+    memcpy(buf->data_end, data, len);
+    buf->data_len += len;
+    buf->data_end = buf->data + buf->data_len;
+
+    return true;
+}
+
+
+//
+// Shift len bytes off of the front of the buffer.
+//
+void Buffer_Shift(buffer_t *buf, int len)
+{
+    if (len <= 0)
+    {
+        return;
+    }
+
+    ptrdiff_t max_shift = buf->data_end - buf->data;
+    if (len >= max_shift)
+    {
+        Buffer_Clear(buf);
+    }
+    else
+    {
+        buf->data += len;
+        buf->data_len -= len;
+    }
+}
+
+//
+// Clear the buffer.
+//
+void Buffer_Clear(buffer_t *buf)
+{
+    buf->data = buf->buffer;
+    buf->data_end = buf->buffer;
+    buf->data_len = 0;
+}
+
+//
+// Create a new buffer reader
+//
+buffer_reader_t *NewReader(buffer_t* buffer)
+{
+    buffer_reader_t *reader = malloc(sizeof(buffer_reader_t));
+
+    reader->buffer = buffer;
+    reader->pos = 0;
+
+    return reader;
+}
+
+//
+// Delete a buffer reader
+//
+void DeleteReader(buffer_reader_t *reader)
+{
+    free(reader);
+}

midiproc/buffer.h

@@ -0,0 +1,46 @@
+//
+// Copyright(C) 2017 Alex Mayfield
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation; either version 2
+// of the License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// DESCRIPTION:
+//     A simple buffer and reader implementation.
+//
+
+#ifndef __BUFFER__
+#define __BUFFER__
+
+#include "../src/doomtype.h"
+
+#define BUFFER_SIZE 1024
+
+typedef struct {
+    byte  buffer[BUFFER_SIZE]; // Buffer.
+    byte* buffer_end;          // End of Buffer.
+    byte* data;                // Start of actual data.
+    byte* data_end;            // End of actual data.
+    int   data_len;            // Length of actual data.
+} buffer_t;
+
+typedef struct {
+    buffer_t *buffer;
+    int       pos;
+} buffer_reader_t;
+
+buffer_t *NewBuffer();
+void DeleteBuffer(buffer_t* buf);
+int Buffer_Data(buffer_t *buf, byte **data);
+boolean Buffer_Push(buffer_t *buf, const void *data, int len);
+void Buffer_Shift(buffer_t *buf, int len);
+void Buffer_Clear(buffer_t *buf);
+
+#endif
+