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Implement left alignment.

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This commit is contained in:
Victor Zverovich 2012-12-22 14:05:56 -08:00
parent c5f4ecb25a
commit be6e54de36
3 changed files with 63 additions and 42 deletions
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73
format.cc
View File

@ -53,12 +53,7 @@ using fmt::FormatSpec;
namespace {
// Flags.
enum { PLUS_FLAG = 1, ZERO_FLAG = 2, HEX_PREFIX_FLAG = 4 };
// Alignment.
enum Alignment {
ALIGN_DEFAULT, ALIGN_LEFT, ALIGN_RIGHT, ALIGN_CENTER, ALIGN_NUMERIC
};
enum { PLUS_FLAG = 1, HEX_PREFIX_FLAG = 2 };
void ReportUnknownType(char code, const char *type) {
if (std::isprint(static_cast<unsigned char>(code))) {
@ -111,6 +106,34 @@ void Formatter::ReportError(const char *s, const std::string &message) const {
throw fmt::FormatError("unmatched '{' in format");
}
char *Formatter::PrepareFilledBuffer(
unsigned size, FormatSpec spec, char sign) {
if (spec.width <= size) {
char *p = GrowBuffer(size);
*p = sign;
return p + size - 1;
}
char *p = GrowBuffer(spec.width);
char *end = p + spec.width;
if (spec.align == ALIGN_LEFT) {
*p = sign;
p += size;
std::fill(p, end, spec.fill);
} else if (spec.align == ALIGN_NUMERIC) {
if (sign) {
*p++ = sign;
--size;
}
std::fill(p, end - size, spec.fill);
p = end;
} else {
*(end - size) = sign;
std::fill(p, end - size, spec.fill);
p = end;
}
return p - 1;
}
template <typename T>
void Formatter::FormatInt(T value, FormatSpec spec) {
unsigned size = 0;
@ -125,16 +148,13 @@ void Formatter::FormatInt(T value, FormatSpec spec) {
sign = '+';
++size;
}
size_t start = buffer_.size();
char *p = 0;
switch (spec.type) {
case 0: case 'd': {
UnsignedType n = abs_value;
do {
++size;
} while ((n /= 10) != 0);
unsigned width = std::max(spec.width, size);
p = GrowBuffer(width) + width - 1;
char *p = PrepareFilledBuffer(size, spec, sign);
n = abs_value;
do {
*p-- = '0' + (n % 10);
@ -148,8 +168,7 @@ void Formatter::FormatInt(T value, FormatSpec spec) {
do {
++size;
} while ((n >>= 4) != 0);
unsigned width = std::max(spec.width, size);
p = GrowBuffer(width) + width - 1;
char *p = PrepareFilledBuffer(size, spec, sign);
n = abs_value;
const char *digits = spec.type == 'x' ?
"0123456789abcdef" : "0123456789ABCDEF";
@ -167,8 +186,7 @@ void Formatter::FormatInt(T value, FormatSpec spec) {
do {
++size;
} while ((n >>= 3) != 0);
unsigned width = std::max(spec.width, size);
p = GrowBuffer(width) + width - 1;
char *p = PrepareFilledBuffer(size, spec, sign);
n = abs_value;
do {
*p-- = '0' + (n & 7);
@ -179,13 +197,6 @@ void Formatter::FormatInt(T value, FormatSpec spec) {
ReportUnknownType(spec.type, "integer");
break;
}
if (sign) {
if ((spec.flags & ZERO_FLAG) != 0)
buffer_[start++] = sign;
else
*p-- = sign;
}
std::fill(&buffer_[start], p + 1, spec.fill);
}
template <typename T>
@ -210,14 +221,16 @@ void Formatter::FormatDouble(T value, const FormatSpec &spec, int precision) {
}
// Build format string.
enum { MAX_FORMAT_SIZE = 9}; // longest format: %+0*.*Lg
enum { MAX_FORMAT_SIZE = 10}; // longest format: %+0*.*Lg
char format[MAX_FORMAT_SIZE];
char *format_ptr = format;
unsigned width = spec.width;
*format_ptr++ = '%';
if ((spec.flags & PLUS_FLAG) != 0)
*format_ptr++ = '+';
if ((spec.flags & ZERO_FLAG) != 0)
if (spec.align == ALIGN_LEFT)
*format_ptr++ = '-';
else if (spec.align == ALIGN_NUMERIC)
*format_ptr++ = '0';
if (width != 0)
*format_ptr++ = '*';
@ -307,23 +320,23 @@ void Formatter::DoFormat() {
// Parse fill and alignment.
if (char c = *s) {
const char *p = s + 1;
Alignment align = ALIGN_DEFAULT;
spec.align = ALIGN_DEFAULT;
do {
switch (*p) {
case '<':
align = ALIGN_LEFT;
spec.align = ALIGN_LEFT;
break;
case '>':
align = ALIGN_RIGHT;
spec.align = ALIGN_RIGHT;
break;
case '=':
align = ALIGN_NUMERIC;
spec.align = ALIGN_NUMERIC;
break;
case '^':
align = ALIGN_CENTER;
spec.align = ALIGN_CENTER;
break;
}
if (align != ALIGN_DEFAULT) {
if (spec.align != ALIGN_DEFAULT) {
if (p != s && c != '{' && c != '}') {
s += 2;
spec.fill = c;
@ -350,7 +363,7 @@ void Formatter::DoFormat() {
if (*s == '0') {
if (arg.type > LAST_NUMERIC_TYPE)
ReportError(s, "format specifier '0' requires numeric argument");
spec.flags |= ZERO_FLAG;
spec.align = ALIGN_NUMERIC;
spec.fill = '0';
}
// Zero may be parsed again as a part of the width, but it is simpler

9
format.h
View File

@ -123,13 +123,18 @@ class FormatError : public std::runtime_error {
: std::runtime_error(message) {}
};
enum Alignment {
ALIGN_DEFAULT, ALIGN_LEFT, ALIGN_RIGHT, ALIGN_CENTER, ALIGN_NUMERIC
};
struct FormatSpec {
Alignment align;
unsigned flags;
unsigned width;
char type;
char fill;
FormatSpec() : flags(0), width(0), type(0), fill(' ') {}
FormatSpec() : align(ALIGN_DEFAULT), flags(0), width(0), type(0), fill(' ') {}
};
// Formatter provides string formatting functionality similar to Python's
@ -266,6 +271,8 @@ class Formatter {
void ReportError(const char *s, const std::string &message) const;
char *PrepareFilledBuffer(unsigned size, FormatSpec spec, char sign);
// Formats an integer.
template <typename T>
void FormatInt(T value, FormatSpec spec);

23
format_test.cc
View File

@ -259,19 +259,20 @@ TEST(FormatterTest, EmptySpecs) {
EXPECT_EQ("42", str(Format("{0:}") << 42));
}
TEST(FormatterTest, Align) {
// TODO
EXPECT_EQ(" 42", str(Format("{0:>4}") << 42));
EXPECT_EQ(" -42", str(Format("{0:>5}") << -42));
EXPECT_EQ(" 42", str(Format("{0:>5}") << 42u));
EXPECT_EQ(" -42", str(Format("{0:>5}") << -42l));
EXPECT_EQ(" 42", str(Format("{0:>5}") << 42ul));
EXPECT_EQ(" -42", str(Format("{0:>5}") << -42.0));
EXPECT_EQ(" -42", str(Format("{0:>5}") << -42.0l));
TEST(FormatterTest, LeftAlign) {
EXPECT_EQ("42 ", str(Format("{0:<4}") << 42));
EXPECT_EQ("42 ", str(Format("{0:<4o}") << 042));
EXPECT_EQ("42 ", str(Format("{0:<4x}") << 0x42));
EXPECT_EQ("-42 ", str(Format("{0:<5}") << -42));
EXPECT_EQ("42 ", str(Format("{0:<5}") << 42u));
EXPECT_EQ("-42 ", str(Format("{0:<5}") << -42l));
EXPECT_EQ("42 ", str(Format("{0:<5}") << 42ul));
EXPECT_EQ("-42 ", str(Format("{0:<5}") << -42.0));
EXPECT_EQ("-42 ", str(Format("{0:<5}") << -42.0l));
EXPECT_EQ("c ", str(Format("{0:<5}") << 'c'));
EXPECT_EQ("abc ", str(Format("{0:<5}") << "abc"));
EXPECT_EQ(" 0xface",
str(Format("{0:>8}") << reinterpret_cast<void*>(0xface)));
EXPECT_EQ("0xface ",
str(Format("{0:<8}") << reinterpret_cast<void*>(0xface)));
EXPECT_EQ("def ", str(Format("{0:<5}") << TestString("def")));
}