initial code repo

[stor4nfv.git] / src / ceph / src / common / PrebufferedStreambuf.cc

diff --git a/src/ceph/src/common/PrebufferedStreambuf.cc b/src/ceph/src/common/PrebufferedStreambuf.cc
new file mode 100644 (file)
index 0000000..fe27ef5
--- /dev/null
+++ b/src/ceph/src/common/PrebufferedStreambuf.cc
@@ -0,0 +1,102 @@
+
+#include "common/PrebufferedStreambuf.h"
+#include <string.h>
+PrebufferedStreambuf::PrebufferedStreambuf(char *buf, size_t len)
+  : m_buf(buf), m_buf_len(len)
+{
+  // init output buffer
+  this->setp(m_buf, m_buf + m_buf_len);
+
+  // so we underflow on first read
+  this->setg(0, 0, 0);
+}
+
+PrebufferedStreambuf::int_type PrebufferedStreambuf::overflow(int_type c)
+{
+  int old_len = m_overflow.size();
+  if (old_len == 0) {
+    m_overflow.resize(80);
+  } else {
+    m_overflow.resize(old_len * 2);
+  }
+  m_overflow[old_len] = c;
+  this->setp(&m_overflow[old_len + 1], &*m_overflow.begin() + m_overflow.size());
+  return std::char_traits<char>::not_eof(c);
+}
+
+PrebufferedStreambuf::int_type PrebufferedStreambuf::underflow()
+{
+  if (this->gptr() == 0) {
+    // first read; start with the static buffer
+    if (m_overflow.size())
+      // there is overflow, so start with entire prealloc buffer
+      this->setg(m_buf, m_buf, m_buf + m_buf_len);
+    else if (this->pptr() == m_buf)
+      // m_buf is empty
+      return traits_ty::eof();  // no data
+    else
+      // set up portion of m_buf we've filled
+      this->setg(m_buf, m_buf, this->pptr());
+    return *this->gptr();
+  }
+  if (this->gptr() == m_buf + m_buf_len && m_overflow.size()) {
+    // at end of m_buf; continue with the overflow string
+    this->setg(&m_overflow[0], &m_overflow[0], this->pptr());
+    return *this->gptr();
+  }
+
+  // otherwise we must be at the end (of m_buf and/or m_overflow)
+  return traits_ty::eof();
+}
+
+std::string PrebufferedStreambuf::get_str() const
+{
+  if (m_overflow.size()) {
+    std::string s(m_buf, m_buf + m_buf_len);
+    s.append(&m_overflow[0], this->pptr() - &m_overflow[0]);
+    return s;
+  } else if (this->pptr() == m_buf) {
+    return std::string();
+  } else {
+    return std::string(m_buf, this->pptr() - m_buf);
+  }  
+}
+// returns current size of content
+size_t PrebufferedStreambuf::size() const
+{
+  if (m_overflow.size() == 0) {
+    return this->pptr() - m_buf;
+  } else {
+    return m_buf_len + this->pptr() - &m_overflow[0];
+  }
+}
+
+// extracts up to avail chars of content
+int PrebufferedStreambuf::snprintf(char* dst, size_t avail) const
+{
+  size_t o_size = m_overflow.size();
+  size_t len_a;
+  size_t len_b;
+  if (o_size>0) {
+    len_a = m_buf_len;
+    len_b = this->pptr() - &m_overflow[0];
+  } else {
+    len_a = this->pptr() - m_buf;
+    len_b = 0;
+  }
+  if (avail > len_a + len_b) {
+    memcpy(dst, m_buf, len_a);
+    memcpy(dst + m_buf_len, m_overflow.c_str(), len_b);
+    dst[len_a + len_b] = 0;
+  } else {
+    if (avail > len_a) {
+      memcpy(dst, m_buf, len_a);
+      memcpy(dst + m_buf_len, m_overflow.c_str(), avail - len_a - 1);
+      dst[avail - 1] = 0;
+    } else {
+      memcpy(dst, m_buf, avail - 1);
+      dst[avail - 1] = 0;
+    }
+  }
+  return len_a + len_b;
+}