Initial bit maps support

xtoskrnl/rtl/bitmap.c

@@ -0,0 +1,186 @@
+/**
+ * PROJECT:         ExectOS
+ * COPYRIGHT:       See COPYING.md in the top level directory
+ * FILE:            xtoskrnl/rtl/bitmap.c
+ * DESCRIPTION:     Bit maps support related routines
+ * DEVELOPERS:      Rafal Kupiec <belliash@codingworkshop.eu.org>
+ */
+
+#include <xtos.h>
+
+
+/**
+ * Clears all bits in the bit map.
+ *
+ * @param BitMap
+ *        Supplies a pointer to the bit map.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since NT 3.5
+ */
+XTAPI
+VOID
+RtlClearAllBits(IN PRTL_BITMAP BitMap)
+{
+    /* Clear all bits */
+    RtlSetMemory(BitMap->Buffer, 0, ((BitMap->Size + BITS_PER_LONG - 1) / BITS_PER_LONG) * sizeof(ULONG_PTR));
+}
+
+/**
+ * Clears a single bit in the bit map.
+ *
+ * @param BitMap
+ *        Supplies a pointer to the bit map.
+ *
+ * @param Bit
+ *        Specifies the number of the bit to be cleared.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since NT 5.1
+ */
+XTAPI
+VOID
+RtlClearBit(IN PRTL_BITMAP BitMap,
+            IN ULONG_PTR Bit)
+{
+    /* Check if bit is in range */
+    if(Bit >= BitMap->Size)
+    {
+        /* Supplied bit exceeds bit map size */
+        return;
+    }
+
+    /* Clear specified bit */
+    BitMap->Buffer[Bit / BITS_PER_LONG] &= ~(1 << (Bit & (BITS_PER_LONG - 1)));
+}
+
+/**
+ * Dumps the contents of the bit map.
+ *
+ * @param BitMap
+ *        Supplies a pointer to the bit map.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+VOID
+RtlDumpBitMap(IN PRTL_BITMAP BitMap)
+{
+    ULONG_PTR Index;
+
+    /* Dump bit map buffer information */
+    DebugPrint(L"BitMap Buffer: 0x%zX (%lu bytes)\n", BitMap->Buffer, BitMap->Size);
+
+    /* Dump bit map buffer content */
+    for(Index = 0; Index < (BitMap->Size + BITS_PER_LONG - 1) / BITS_PER_LONG; Index++)
+    {
+        DebugPrint(L"  %8zu: %08lx\n", Index, BitMap->Buffer[Index]);
+    }
+}
+
+/**
+ * Initializes a bit map.
+ *
+ * @param BitMap
+ *        Supplies a pointer to the bit map to initialize.
+ *
+ * @param Buffer
+ *        Supplies a pointer to the buffer that will be used as a bit map.
+ *
+ * @param Size
+ *        Supplies a size of the bit map.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since NT 3.5
+ */
+XTAPI
+VOID
+RtlInitializeBitMap(IN PRTL_BITMAP BitMap,
+                    IN PULONG_PTR Buffer,
+                    IN ULONG Size)
+{
+    /* Initialize bit map */
+    BitMap->Buffer = Buffer;
+    BitMap->Size = Size;
+}
+
+/**
+ * Sets all bits in the bit map.
+ *
+ * @param BitMap
+ *        Supplies a pointer to the bit map.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since NT 3.5
+ */
+XTAPI
+VOID
+RtlSetAllBits(IN PRTL_BITMAP BitMap)
+{
+    /* Set all bits */
+    RtlSetMemory(BitMap->Buffer, 0xFF, ((BitMap->Size + BITS_PER_LONG - 1) / BITS_PER_LONG) * sizeof(ULONG_PTR));
+}
+
+/**
+ * Sets a single bit in the bit map.
+ *
+ * @param BitMap
+ *        Supplies a pointer to the bit map.
+ *
+ * @param Bit
+ *        Specifies the number of the bit to be set.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since NT 5.1
+ */
+XTAPI
+VOID
+RtlSetBit(IN PRTL_BITMAP BitMap,
+          IN ULONG_PTR Bit)
+{
+    /* Check if bit is in range */
+    if(Bit >= BitMap->Size)
+    {
+        /* Supplied bit exceeds bit map size */
+        return;
+    }
+
+    /* Set specified bit */
+    BitMap->Buffer[Bit / BITS_PER_LONG] |= 1 << (Bit & (BITS_PER_LONG - 1));
+}
+
+/**
+ * Tests a state of a single bit in the bit map.
+ *
+ * @param BitMap
+ *        Supplies a pointer to the bit map.
+ *
+ * @param Bit
+ *        Specifies the number of the bit to be tested.
+ *
+ * @return This routine returns TRUE when bit is set, or FALSE otherwise.
+ *
+ * @since NT 5.1
+ */
+XTAPI
+BOOLEAN
+RtlTestBit(IN PRTL_BITMAP BitMap,
+           IN ULONG_PTR Bit)
+{
+    /* Check if bit is in range */
+    if(Bit >= BitMap->Size)
+    {
+        /* Supplied bit exceeds bit map size, return FALSE */
+        return FALSE;
+    }
+
+    /* Test specified bit and return result */
+    return ((BitMap->Buffer[Bit / BITS_PER_LONG] >> (Bit & (BITS_PER_LONG - 1))) & 1) ? TRUE : FALSE;
+}