[llvm] r218463 - [Support] Add type-safe alternative to llvm::format()
Nick Kledzik
kledzik at apple.com
Thu Sep 25 13:30:59 PDT 2014
Author: kledzik
Date: Thu Sep 25 15:30:58 2014
New Revision: 218463
URL: http://llvm.org/viewvc/llvm-project?rev=218463&view=rev
Log:
[Support] Add type-safe alternative to llvm::format()
llvm::format() is somewhat unsafe. The compiler does not check that integer
parameter size matches the %x or %d size and it does not complain when a
StringRef is passed for a %s. And correctly using a StringRef with format() is
ugly because you have to convert it to a std::string then call c_str().
The cases where llvm::format() is useful is controlling how numbers and
strings are printed, especially when you want fixed width output. This
patch adds some new formatting functions to raw_streams to format numbers
and StringRefs in a type safe manner. Some examples:
OS << format_hex(255, 6) => "0x00ff"
OS << format_hex(255, 4) => "0xff"
OS << format_decimal(0, 5) => " 0"
OS << format_decimal(255, 5) => " 255"
OS << right_justify(Str, 5) => " foo"
OS << left_justify(Str, 5) => "foo "
Modified:
llvm/trunk/include/llvm/Support/Format.h
llvm/trunk/include/llvm/Support/raw_ostream.h
llvm/trunk/lib/Support/raw_ostream.cpp
llvm/trunk/unittests/Support/raw_ostream_test.cpp
Modified: llvm/trunk/include/llvm/Support/Format.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/Format.h?rev=218463&r1=218462&r2=218463&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/Format.h (original)
+++ llvm/trunk/include/llvm/Support/Format.h Thu Sep 25 15:30:58 2014
@@ -23,6 +23,8 @@
#ifndef LLVM_SUPPORT_FORMAT_H
#define LLVM_SUPPORT_FORMAT_H
+#include "llvm/ADT/StringRef.h"
+
#include <cassert>
#include <cstdio>
#ifdef _MSC_VER
@@ -225,6 +227,66 @@ format(const char *Fmt, const T1 &Val1,
Val5, Val6);
}
+/// This is a helper class used for left_justify() and right_justify().
+class FormattedString {
+ StringRef Str;
+ unsigned Width;
+ bool RightJustify;
+ friend class raw_ostream;
+public:
+ FormattedString(StringRef S, unsigned W, bool R)
+ : Str(S), Width(W), RightJustify(R) { }
+};
+
+/// left_justify - append spaces after string so total output is
+/// \p Width characters. If \p Str is larger that \p Width, full string
+/// is written with no padding.
+inline FormattedString left_justify(StringRef Str, unsigned Width) {
+ return FormattedString(Str, Width, false);
+}
+
+/// right_justify - add spaces before string so total output is
+/// \p Width characters. If \p Str is larger that \p Width, full string
+/// is written with no padding.
+inline FormattedString right_justify(StringRef Str, unsigned Width) {
+ return FormattedString(Str, Width, true);
+}
+
+/// This is a helper class used for format_hex() and format_decimal().
+class FormattedNumber {
+ uint64_t HexValue;
+ int64_t DecValue;
+ unsigned Width;
+ bool Hex;
+ bool Upper;
+ friend class raw_ostream;
+public:
+ FormattedNumber(uint64_t HV, int64_t DV, unsigned W, bool H, bool U)
+ : HexValue(HV), DecValue(DV), Width(W), Hex(H), Upper(U) { }
+};
+
+/// format_hex - Output \p N as a fixed width hexadecimal. If number will not
+/// fit in width, full number is still printed. Examples:
+/// OS << format_hex(255, 4) => 0xff
+/// OS << format_hex(255, 4, true) => 0xFF
+/// OS << format_hex(255, 6) => 0x00ff
+/// OS << format_hex(255, 2) => 0xff
+inline FormattedNumber format_hex(uint64_t N, unsigned Width, bool Upper=false) {
+ assert(Width <= 18 && "hex width must be <= 18");
+ return FormattedNumber(N, 0, Width, true, Upper);
+}
+
+/// format_decimal - Output \p N as a right justified, fixed-width decimal. If
+/// number will not fit in width, full number is still printed. Examples:
+/// OS << format_decimal(0, 5) => " 0"
+/// OS << format_decimal(255, 5) => " 255"
+/// OS << format_decimal(-1, 3) => " -1"
+/// OS << format_decimal(12345, 3) => "12345"
+inline FormattedNumber format_decimal(int64_t N, unsigned Width) {
+ return FormattedNumber(0, N, Width, false, false);
+}
+
+
} // end namespace llvm
#endif
Modified: llvm/trunk/include/llvm/Support/raw_ostream.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/raw_ostream.h?rev=218463&r1=218462&r2=218463&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/raw_ostream.h (original)
+++ llvm/trunk/include/llvm/Support/raw_ostream.h Thu Sep 25 15:30:58 2014
@@ -21,6 +21,8 @@
namespace llvm {
class format_object_base;
+ class FormattedString;
+ class FormattedNumber;
template <typename T>
class SmallVectorImpl;
@@ -211,6 +213,12 @@ public:
// Formatted output, see the format() function in Support/Format.h.
raw_ostream &operator<<(const format_object_base &Fmt);
+ // Formatted output, see the leftJustify() function in Support/Format.h.
+ raw_ostream &operator<<(const FormattedString &);
+
+ // Formatted output, see the formatHex() function in Support/Format.h.
+ raw_ostream &operator<<(const FormattedNumber &);
+
/// indent - Insert 'NumSpaces' spaces.
raw_ostream &indent(unsigned NumSpaces);
Modified: llvm/trunk/lib/Support/raw_ostream.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/raw_ostream.cpp?rev=218463&r1=218462&r2=218463&view=diff
==============================================================================
--- llvm/trunk/lib/Support/raw_ostream.cpp (original)
+++ llvm/trunk/lib/Support/raw_ostream.cpp Thu Sep 25 15:30:58 2014
@@ -20,6 +20,7 @@
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Format.h"
+#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Process.h"
#include "llvm/Support/Program.h"
#include <cctype>
@@ -394,6 +395,62 @@ raw_ostream &raw_ostream::operator<<(con
}
}
+raw_ostream &raw_ostream::operator<<(const FormattedString &FS) {
+ unsigned Len = FS.Str.size();
+ int PadAmount = FS.Width - Len;
+ if (FS.RightJustify && (PadAmount > 0))
+ this->indent(PadAmount);
+ this->operator<<(FS.Str);
+ if (!FS.RightJustify && (PadAmount > 0))
+ this->indent(PadAmount);
+ return *this;
+}
+
+raw_ostream &raw_ostream::operator<<(const FormattedNumber &FN) {
+ if (FN.Hex) {
+ unsigned Nibbles = (64 - countLeadingZeros(FN.HexValue)+3)/4;
+ unsigned Width = (FN.Width > Nibbles+2) ? FN.Width : Nibbles+2;
+
+ char NumberBuffer[20] = "0x0000000000000000";
+ char *EndPtr = NumberBuffer+Width;
+ char *CurPtr = EndPtr;
+ const char A = FN.Upper ? 'A' : 'a';
+ unsigned long long N = FN.HexValue;
+ while (N) {
+ uintptr_t x = N % 16;
+ *--CurPtr = (x < 10 ? '0' + x : A + x - 10);
+ N /= 16;
+ }
+
+ return write(NumberBuffer, Width);
+ } else {
+ // Zero is a special case.
+ if (FN.DecValue == 0) {
+ this->indent(FN.Width-1);
+ return *this << '0';
+ }
+ char NumberBuffer[32];
+ char *EndPtr = NumberBuffer+sizeof(NumberBuffer);
+ char *CurPtr = EndPtr;
+ bool Neg = (FN.DecValue < 0);
+ uint64_t N = Neg ? -FN.DecValue : FN.DecValue;
+ while (N) {
+ *--CurPtr = '0' + char(N % 10);
+ N /= 10;
+ }
+ int Len = EndPtr - CurPtr;
+ int Pad = FN.Width - Len;
+ if (Neg)
+ --Pad;
+ if (Pad > 0)
+ this->indent(Pad);
+ if (Neg)
+ *this << '-';
+ return write(CurPtr, Len);
+ }
+}
+
+
/// indent - Insert 'NumSpaces' spaces.
raw_ostream &raw_ostream::indent(unsigned NumSpaces) {
static const char Spaces[] = " "
Modified: llvm/trunk/unittests/Support/raw_ostream_test.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Support/raw_ostream_test.cpp?rev=218463&r1=218462&r2=218463&view=diff
==============================================================================
--- llvm/trunk/unittests/Support/raw_ostream_test.cpp (original)
+++ llvm/trunk/unittests/Support/raw_ostream_test.cpp Thu Sep 25 15:30:58 2014
@@ -143,4 +143,41 @@ TEST(raw_ostreamTest, WriteEscaped) {
EXPECT_EQ("\\001\\010\\200", Str);
}
+TEST(raw_ostreamTest, Justify) {
+ EXPECT_EQ("xyz ", printToString(left_justify("xyz", 6), 6));
+ EXPECT_EQ("abc", printToString(left_justify("abc", 3), 3));
+ EXPECT_EQ("big", printToString(left_justify("big", 1), 3));
+ EXPECT_EQ(" xyz", printToString(right_justify("xyz", 6), 6));
+ EXPECT_EQ("abc", printToString(right_justify("abc", 3), 3));
+ EXPECT_EQ("big", printToString(right_justify("big", 1), 3));
+}
+
+TEST(raw_ostreamTest, FormatHex) {
+ EXPECT_EQ("0x1234", printToString(format_hex(0x1234, 6), 6));
+ EXPECT_EQ("0x001234", printToString(format_hex(0x1234, 8), 8));
+ EXPECT_EQ("0x00001234", printToString(format_hex(0x1234, 10), 10));
+ EXPECT_EQ("0x1234", printToString(format_hex(0x1234, 4), 6));
+ EXPECT_EQ("0xff", printToString(format_hex(255, 4), 4));
+ EXPECT_EQ("0xFF", printToString(format_hex(255, 4, true), 4));
+ EXPECT_EQ("0x1", printToString(format_hex(1, 3), 3));
+ EXPECT_EQ("0x12", printToString(format_hex(0x12, 3), 4));
+ EXPECT_EQ("0x123", printToString(format_hex(0x123, 3), 5));
+ EXPECT_EQ("0xffffffffffffffff",
+ printToString(format_hex(UINT64_MAX, 18), 18));
+ EXPECT_EQ("0x8000000000000000",
+ printToString(format_hex((INT64_MIN), 18), 18));
+}
+
+TEST(raw_ostreamTest, FormatDecimal) {
+ EXPECT_EQ(" 0", printToString(format_decimal(0, 4), 4));
+ EXPECT_EQ(" -1", printToString(format_decimal(-1, 4), 4));
+ EXPECT_EQ(" -1", printToString(format_decimal(-1, 6), 6));
+ EXPECT_EQ("1234567890", printToString(format_decimal(1234567890, 10), 10));
+ EXPECT_EQ(" 9223372036854775807",
+ printToString(format_decimal(INT64_MAX, 21), 21));
+ EXPECT_EQ(" -9223372036854775808",
+ printToString(format_decimal(INT64_MIN, 21), 21));
+}
+
+
}
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