DataFlash: started on file interface

libraries/DataFlash/DataFlash.h

@@ -30,7 +30,7 @@ public:
     virtual void WriteBlock(const void *pBuffer, uint16_t size) = 0;
 
     /*
-      read a packet, stripping off the header bytes
+      read a packet. The header byte have already been read.
     */
     virtual void ReadPacket(void *pkt, uint16_t size) = 0;
 
@@ -66,5 +66,6 @@ public:
 #define HEAD_BYTE2  0x95    // Decimal 149
 
 #include "DataFlash_Block.h"
+#include "DataFlash_File.h"
 
 #endif

libraries/DataFlash/DataFlash_Block.h

@@ -31,7 +31,7 @@ public:
     void WriteBlock(const void *pBuffer, uint16_t size);
 
     /*
-      read a packet, stripping off the header bytes
+      read a packet. The header byte have already been read.
     */
     void ReadPacket(void *pkt, uint16_t size);
 

libraries/DataFlash/DataFlash_File.h

@@ -0,0 +1,64 @@
+/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
+
+/* 
+   DataFlash logging - file oriented variant
+
+   This uses posix file IO to create log files called logNN.dat in the
+   given directory
+ */
+
+#ifndef DataFlash_File_h
+#define DataFlash_File_h
+
+class DataFlash_File : DataFlash_Class
+{
+public:
+    // constructor
+    DataFlash_File(const char *log_directory);
+
+    // initialisation
+    void Init(void);
+    bool CardInserted(void);
+
+    // erase handling
+    bool NeedErase(void);
+    void EraseAll();
+
+    /* Write a block of data at current offset */
+    void WriteBlock(const void *pBuffer, uint16_t size);
+
+    /*
+      read a packet. The header byte have already been read.
+    */
+    void ReadPacket(void *pkt, uint16_t size);
+
+    // high level interface
+    uint16_t find_last_log(void);
+    void get_log_boundaries(uint8_t log_num, uint16_t & start_page, uint16_t & end_page);
+    uint8_t get_num_logs(void);
+    void start_new_log(void);
+    uint16_t log_read_process(uint8_t log_num,
+                              uint16_t start_page, uint16_t end_page, 
+                              void (*callback)(uint8_t msgid));
+    void DumpPageInfo(AP_HAL::BetterStream *port);
+    void ShowDeviceInfo(AP_HAL::BetterStream *port);
+
+private:
+    int _write_fd;
+    int _read_fd;
+    bool _initialised;
+    const char *_log_directory;
+
+    // write buffer
+    uint8_t *_writebuf;
+    const uint16_t _writebuf_size;
+    volatile uint16_t _writebuf_head;
+    volatile uint16_t _writebuf_tail;
+
+    /* construct a file name given a log number. Caller must free. */
+    char *_log_file_name(uint8_t log_num);
+};
+
+
+#endif // DataFlash_File_h
+