Changes to support compilation with UEFI GPT fdisk library.

4 files changed, 43 insertions, 13 deletions

diff --git a/NEWS b/NEWS
index 468943d..96810c7 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,10 @@
 0.8.11 (?/?/2014):
 ------------------
 
+- Small code changes to support compilation as EFI application with the
+  UEFI GPT fdisk library
+  (http://sourceforge.net/projects/uefigptfdisk/?source=directory)
+
 - Added new partition type codes for Ceph
   (https://github.com/ceph/ceph/blob/9bcc42a3e6b08521694b5c0228b2c6ed7b3d312e/src/ceph-disk#L76-L81):
   4FBD7E29-9D25-41B8-AFD0-062C0CEFF05D/0xf800 (Ceph OSD),
diff --git a/gpt.cc b/gpt.cc
index fdffb25..18247c5 100644
--- a/gpt.cc
+++ b/gpt.cc
@@ -38,6 +38,23 @@ using namespace std;
 #define log2(x) (log((double) x) / log(2.0))
 #endif // Microsoft Visual C++
 
+#ifdef EFI
+// in UEFI mode MMX registers are not yet available so using the
+// x86_64 ABI to move "double" values around is not an option.
+#ifdef log2
+#undef log2
+#endif
+#define log2(x) log2_32( x )
+static inline uint32_t log2_32(uint32_t v) {
+   int r = -1;
+   while (v >= 1) {
+      r++;
+      v >>= 1;
+   }
+   return r;
+}
+#endif
+
 /****************************************
  *                                      *
  * GPTData class and related structures *
diff --git a/support.cc b/support.cc
index dbcfa00..ef53444 100644
--- a/support.cc
+++ b/support.cc
@@ -217,30 +217,39 @@ uint64_t IeeeToInt(string inValue, uint64_t sSize, uint64_t low, uint64_t high,
 // Takes a size and converts this to a size in IEEE-1541-2002 units (KiB, MiB,
 // GiB, TiB, PiB, or EiB), returned in C++ string form. The size is either in
 // units of the sector size or, if that parameter is omitted, in bytes.
-// (sectorSize defaults to 1).
+// (sectorSize defaults to 1). Note that this function uses peculiar
+// manual computation of decimal value rather than simply setting
+// theValue.precision() because this isn't possible using the available
+// EFI library.
 string BytesToIeee(uint64_t size, uint32_t sectorSize) {
-   float sizeInIeee;
-   unsigned int index = 0;
+   uint64_t sizeInIeee;
+   uint64_t previousIeee;
+   float decimalIeee;
+   uint index = 0;
    string units, prefixes = " KMGTPEZ";
    ostringstream theValue;
 
-   sizeInIeee = size * (float) sectorSize;
-   while ((sizeInIeee > 1024.0) && (index < (prefixes.length() - 1))) {
+   sizeInIeee = previousIeee = size * (uint64_t) sectorSize;
+   while ((sizeInIeee > 1024) && (index < (prefixes.length() - 1))) {
       index++;
-      sizeInIeee /= 1024.0;
+      previousIeee = sizeInIeee;
+      sizeInIeee /= 1024;
    } // while
-   theValue.setf(ios::fixed);
    if (prefixes[index] == ' ') {
-      units = " bytes";
-      theValue.precision(0);
+      theValue << sizeInIeee << " bytes";
    } else {
       units = "  iB";
       units[1] = prefixes[index];
-      theValue.precision(1);
+      decimalIeee = ((float) previousIeee -
+                     ((float) sizeInIeee * 1024.0) + 51.2) / 102.4;
+      if (decimalIeee >= 10.0) {
+         decimalIeee = 0.0;
+         sizeInIeee++;
+      }
+      theValue << sizeInIeee << "." << (uint32_t) decimalIeee << units;
    } // if/else
-   theValue << sizeInIeee << units;
    return theValue.str();
-} // BlocksToIeee()
+} // BytesToIeee()
 
 // Converts two consecutive characters in the input string into a
 // number, interpreting the string as a hexadecimal number, starting
diff --git a/support.h b/support.h
index 14102fd..3e6fe08 100644
--- a/support.h
+++ b/support.h
@@ -8,7 +8,7 @@
 #ifndef __GPTSUPPORT
 #define __GPTSUPPORT
 
-#define GPTFDISK_VERSION "0.8.10.1"
+#define GPTFDISK_VERSION "0.8.10.2"
 
 #if defined (__FreeBSD__) || defined (__FreeBSD_kernel__) || defined (__APPLE__)
 // Darwin (Mac OS) & FreeBSD: disk IOCTLs are different, and there is no lseek64