1 files changed, 115 insertions, 0 deletions
diff --git a/libretro/memstream.c b/libretro/memstream.c
new file mode 100644
index 0000000..4e1ac21
--- /dev/null
+++ b/libretro/memstream.c
@@ -0,0 +1,115 @@
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include "memstream.h"
+
+static uint8_t* g_buffer = NULL;
+static size_t g_size = 0;
+
+static size_t last_file_size = 0;
+
+struct memstream
+{
+   uint8_t *m_buf;
+   size_t m_size;
+   size_t m_ptr;
+};
+
+void memstream_set_buffer(uint8_t *buffer, size_t size)
+{
+   g_buffer = buffer;
+   g_size = size;
+}
+
+size_t memstream_get_last_size()
+{
+   return last_file_size;
+}
+
+static void memstream_init(memstream_t *stream, uint8_t *buffer, size_t max_size)
+{
+   stream->m_buf = buffer;
+   stream->m_size = max_size;
+   stream->m_ptr = 0;
+}
+
+memstream_t *memstream_open()
+{
+	memstream_t *stream;
+   if (!g_buffer || !g_size)
+      return NULL;
+
+   stream = (memstream_t*)calloc(1, sizeof(*stream));
+   memstream_init(stream, g_buffer, g_size);
+
+   g_buffer = NULL;
+   g_size = 0;
+   return stream;
+}
+
+void memstream_close(memstream_t *stream)
+{
+   last_file_size = stream->m_ptr;
+   free(stream);
+}
+
+size_t memstream_read(memstream_t *stream, void *data, size_t bytes)
+{
+   size_t avail = stream->m_size - stream->m_ptr;
+   if (bytes > avail)
+      bytes = avail;
+
+   memcpy(data, stream->m_buf + stream->m_ptr, bytes);
+   stream->m_ptr += bytes;
+   return bytes;
+}
+
+size_t memstream_write(memstream_t *stream, const void *data, size_t bytes)
+{
+   size_t avail = stream->m_size - stream->m_ptr;
+   if (bytes > avail)
+      bytes = avail;
+
+   memcpy(stream->m_buf + stream->m_ptr, data, bytes);
+   stream->m_ptr += bytes;
+   return bytes;
+}
+
+int memstream_seek(memstream_t *stream, int offset, int whence)
+{
+   size_t ptr;
+   if (whence == SEEK_SET)
+      ptr = offset;
+   else if (whence == SEEK_CUR)
+      ptr = stream->m_ptr + offset;
+   else if (whence == SEEK_END)
+      ptr = stream->m_size + offset;
+   else
+      return -1;
+
+   if (ptr <= stream->m_size)
+   {
+      stream->m_ptr = ptr;
+      return 0;
+   }
+   else
+      return -1;
+}
+
+size_t memstream_pos(memstream_t *stream)
+{
+   return stream->m_ptr;
+}
+
+char *memstream_gets(memstream_t *stream, char *buffer, size_t len)
+{
+   return NULL;
+}
+
+int memstream_getc(memstream_t *stream)
+{
+   if (stream->m_ptr >= stream->m_size)
+      return EOF;
+   else
+      return stream->m_buf[stream->m_ptr++];
+}