Added search functionality using binary search

include/sta/drivers/w25qxx.hpp

@@ -4,6 +4,8 @@
 #include <sta/bus/spi/device.hpp>
 #include <sta/drivers/w25qxx_defs.hpp>
 
+#include <functional>
+
 
 namespace sta
 {
@@ -53,8 +55,21 @@ namespace sta
          */
         W25Qxx(SPIDevice * device, DelayUsFunc delay, AddressMode addrMode = AddressMode::_24BIT);
 
+        /**
+         * @brief Initialize the flash chip.
+         * 
+         * @return uint8_t Returns 1 if successful, 0 otherwise.
+         */
         uint8_t init();
 
+        /**
+         * @brief Find the last page satisfying the given criterion. Uses a binary search to find this page.
+         * 
+         * @param criterion A function evaluating the criterion on a page.
+         * @return uint32_t The last address such that the criterion is satisfied.
+         */
+        uint32_t findLastPage(std::function<bool(uint8_t*)> criterion);
+
         /**
          * @brief Set the Address Mode object
          * 
@@ -173,8 +188,6 @@ namespace sta
          * @return uint8_t 
          */
         uint8_t pageProgram(uint32_t address, uint8_t * buffer, size_t length);
-
-
     public:
         /*
          * Erase operations

src/w25qxx.cpp

@@ -44,6 +44,31 @@ namespace sta
         return 1;
     }
 
+    uint32_t W25Qxx::findLastPage(std::function<bool(uint8_t*)> criterion)
+    {
+        uint32_t left   = 0;
+        uint32_t right  = 0xFFFFFFFF & (addrMode_ == AddressMode::_32BIT ? 0xFFFFFFFF : 0x00FFFFFF);
+        uint32_t middle;
+        uint8_t * page = new uint8_t[256];
+
+        while (left < right)
+        {
+            middle = (left + right) / 2 + 1;
+            readData(middle, page, 256);
+
+            if (criterion(page))
+            {
+                left = middle;
+            }
+            else
+            {
+                right = middle-1;
+            }
+        }
+
+        return middle;
+    }
+
     uint8_t W25Qxx::setAddressMode(AddressMode addrMode)
     {
         busWrite(W25QXX_4_BYTE_ADDR_ENABLE);