Diff: circbuff.cpp

Revision:

0:2df78a4443cd

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/circbuff.cpp	Sun Apr 10 15:47:33 2016 +1000
@@ -0,0 +1,106 @@
+#include "circbuff.h"
+
+CircBuff::CircBuff(uint16_t buffSize)
+{
+    // set up the buffer with parsed size
+    m_buffSize = buffSize;
+    m_buf = new unsigned char [m_buffSize];
+    for (int i = 0; i < m_buffSize; i++) {
+        m_buf[i] = 0;
+    }
+
+    // init indexes
+    m_start = 0;
+    m_end   = 0;
+}
+
+CircBuff::~CircBuff()
+{
+    delete m_buf;
+}
+
+void CircBuff::putc(unsigned char c)
+{
+    // get the remaining space left in the buffer by checking end and start idx
+    uint16_t remSize = remainingSize();
+
+    // check we have enough room for the new array passed in
+    if (remSize == 0) {
+        return;
+    }
+
+    // else copy the byte in
+    m_buf[m_end++] = c;
+    if (m_end == m_buffSize) {
+        m_end = 0;  // wrap around
+    }
+
+}
+
+void CircBuff::add(unsigned char *s)
+{
+    // check if can write? How to check if we have connected.
+    uint16_t sSize = 0, i = 0, j = 0;
+
+    // get the length of the passed array (it should be null terminated, but include max buffer size for caution)
+    for (sSize = 0; (sSize < m_buffSize) && (s[sSize] != 0); sSize++);
+
+    // get the remaining space left in the buffer by checking end and start idx
+    uint16_t remSize = remainingSize();
+
+    // check we have enough room for the new array passed in
+    if (sSize > remSize) {
+        return;
+    }
+
+    // copy the array in
+    for (i = 0; i < sSize; i++) {
+        m_buf[m_end++] = s[i];
+        if (m_end == m_buffSize) {
+            m_end = 0;  // wrap around
+        }
+    }
+}
+
+uint16_t CircBuff::remainingSize()
+{
+    // get the remaining space left in the buffer by checking end and start idx
+    uint16_t retval = 0;
+    if (m_start == m_end) {
+        retval = m_buffSize;
+    }
+    else if (m_start < m_end) {
+        // the distance between the start and end point
+        // subtract that from the total length of the buffer
+        retval = m_buffSize - (m_end - m_start);
+    }
+    else {
+        // the amount of space left is whatever is between the end point and the start point
+        retval = m_start - m_end;
+    }
+    return retval;
+}
+
+uint16_t CircBuff::read(unsigned char *s, uint16_t len)
+{
+    if (m_start == m_end) {
+        return 0; // there is nothing stored in the circular buffer
+    }
+
+    // start copying the desired amount over
+    for (int i = 0; i < len; i++) {
+        s[i] = m_buf[m_start++];
+        
+        if (m_start == m_buffSize) {
+            m_start = 0;    // wrap start pointer
+        }
+
+        if (m_start == m_end) {
+            s[++i] = 0;
+            return (i); // we have reached the end of the buffer
+        }
+    }
+    return len;
+}
+
+