mirror of
https://github.com/fmtlib/fmt.git
synced 2024-10-02 13:02:03 +00:00
364 lines
9.4 KiB
C++
364 lines
9.4 KiB
C++
/*
|
|
Small, safe and fast string formatting library for C++
|
|
Author: Victor Zverovich
|
|
*/
|
|
|
|
#include "format.h"
|
|
|
|
#include <stdint.h>
|
|
|
|
#include <cassert>
|
|
#include <climits>
|
|
#include <cstring>
|
|
#include <algorithm>
|
|
|
|
using std::size_t;
|
|
|
|
namespace {
|
|
|
|
// Flags.
|
|
enum { PLUS_FLAG = 1, ZERO_FLAG = 2, HEX_PREFIX_FLAG = 4 };
|
|
|
|
// Throws Exception(message) if format contains '}', otherwise throws
|
|
// FormatError reporting unmatched '{'. The idea is that unmatched '{'
|
|
// should override other errors.
|
|
void ReportError(const char *s, const std::string &message) {
|
|
for (int num_open_braces = 1; *s; ++s) {
|
|
if (*s == '{') {
|
|
++num_open_braces;
|
|
} else if (*s == '}') {
|
|
if (--num_open_braces == 0)
|
|
throw fmt::FormatError(message);
|
|
}
|
|
}
|
|
throw fmt::FormatError("unmatched '{' in format");
|
|
}
|
|
|
|
void ReportUnknownType(char code, const char *type) {
|
|
if (std::isprint(code)) {
|
|
throw fmt::FormatError(
|
|
str(fmt::Format("unknown format code '{0}' for {1}") << code << type));
|
|
}
|
|
throw fmt::FormatError(
|
|
str(fmt::Format("unknown format code '\\x{0:02x}' for {1}")
|
|
<< static_cast<unsigned>(code) << type));
|
|
}
|
|
|
|
// Parses an unsigned integer advancing s to the end of the parsed input.
|
|
// This function assumes that the first character of s is a digit.
|
|
unsigned ParseUInt(const char *&s) {
|
|
assert('0' <= *s && *s <= '9');
|
|
unsigned value = 0;
|
|
do {
|
|
unsigned new_value = value * 10 + (*s++ - '0');
|
|
if (new_value < value) // Check if value wrapped around.
|
|
ReportError(s, "number is too big in format");
|
|
value = new_value;
|
|
} while ('0' <= *s && *s <= '9');
|
|
return value;
|
|
}
|
|
|
|
// Information about an integer type.
|
|
template <typename T>
|
|
struct IntTraits {
|
|
typedef T UnsignedType;
|
|
static bool IsNegative(T) { return false; }
|
|
};
|
|
|
|
template <>
|
|
struct IntTraits<int> {
|
|
typedef unsigned UnsignedType;
|
|
static bool IsNegative(int value) { return value < 0; }
|
|
};
|
|
|
|
template <>
|
|
struct IntTraits<long> {
|
|
typedef unsigned long UnsignedType;
|
|
static bool IsNegative(long value) { return value < 0; }
|
|
};
|
|
|
|
template <typename T>
|
|
struct IsLongDouble { enum {VALUE = 0}; };
|
|
|
|
template <>
|
|
struct IsLongDouble<long double> { enum {VALUE = 1}; };
|
|
}
|
|
|
|
template <typename T>
|
|
void fmt::Formatter::FormatInt(T value, unsigned flags, int width, char type) {
|
|
int size = 0;
|
|
char sign = 0;
|
|
typedef typename IntTraits<T>::UnsignedType UnsignedType;
|
|
UnsignedType abs_value = value;
|
|
if (IntTraits<T>::IsNegative(value)) {
|
|
sign = '-';
|
|
++size;
|
|
abs_value = -value;
|
|
} else if ((flags & PLUS_FLAG) != 0) {
|
|
sign = '+';
|
|
++size;
|
|
}
|
|
char fill = (flags & ZERO_FLAG) != 0 ? '0' : ' ';
|
|
size_t start = buffer_.size();
|
|
char *p = 0;
|
|
switch (type) {
|
|
case 0: case 'd': {
|
|
UnsignedType n = abs_value;
|
|
do {
|
|
++size;
|
|
} while ((n /= 10) != 0);
|
|
width = std::max(width, size);
|
|
p = GrowBuffer(width) + width - 1;
|
|
n = abs_value;
|
|
do {
|
|
*p-- = '0' + (n % 10);
|
|
} while ((n /= 10) != 0);
|
|
break;
|
|
}
|
|
case 'x': case 'X': {
|
|
UnsignedType n = abs_value;
|
|
bool print_prefix = (flags & HEX_PREFIX_FLAG) != 0;
|
|
if (print_prefix) size += 2;
|
|
do {
|
|
++size;
|
|
} while ((n >>= 4) != 0);
|
|
width = std::max(width, size);
|
|
p = GrowBuffer(width) + width - 1;
|
|
n = abs_value;
|
|
const char *digits = type == 'x' ? "0123456789abcdef" : "0123456789ABCDEF";
|
|
do {
|
|
*p-- = digits[n & 0xf];
|
|
} while ((n >>= 4) != 0);
|
|
if (print_prefix) {
|
|
*p-- = type;
|
|
*p-- = '0';
|
|
}
|
|
break;
|
|
}
|
|
case 'o': {
|
|
UnsignedType n = abs_value;
|
|
do {
|
|
++size;
|
|
} while ((n >>= 3) != 0);
|
|
width = std::max(width, size);
|
|
p = GrowBuffer(width) + width - 1;
|
|
n = abs_value;
|
|
do {
|
|
*p-- = '0' + (n & 7);
|
|
} while ((n >>= 3) != 0);
|
|
break;
|
|
}
|
|
default:
|
|
ReportUnknownType(type, "integer");
|
|
break;
|
|
}
|
|
if (sign) {
|
|
if ((flags & ZERO_FLAG) != 0)
|
|
buffer_[start++] = sign;
|
|
else
|
|
*p-- = sign;
|
|
}
|
|
std::fill(&buffer_[start], p + 1, fill);
|
|
}
|
|
|
|
template <typename T>
|
|
void fmt::Formatter::FormatDouble(
|
|
T value, unsigned flags, int width, int precision, char type) {
|
|
// Check type.
|
|
switch (type) {
|
|
case 0:
|
|
type = 'g';
|
|
break;
|
|
case 'e': case 'E': case 'f': case 'F': case 'g': case 'G':
|
|
break;
|
|
default:
|
|
ReportUnknownType(type, "double");
|
|
break;
|
|
}
|
|
|
|
// Build format string.
|
|
enum { MAX_FORMAT_SIZE = 9}; // longest format: %+0*.*Lg
|
|
char format[MAX_FORMAT_SIZE];
|
|
char *format_ptr = format;
|
|
*format_ptr++ = '%';
|
|
if ((flags & PLUS_FLAG) != 0)
|
|
*format_ptr++ = '+';
|
|
if ((flags & ZERO_FLAG) != 0)
|
|
*format_ptr++ = '0';
|
|
if (width > 0)
|
|
*format_ptr++ = '*';
|
|
if (precision >= 0) {
|
|
*format_ptr++ = '.';
|
|
*format_ptr++ = '*';
|
|
}
|
|
if (IsLongDouble<T>::VALUE)
|
|
*format_ptr++ = 'L';
|
|
*format_ptr++ = type;
|
|
*format_ptr = '\0';
|
|
|
|
// Format using snprintf.
|
|
size_t offset = buffer_.size();
|
|
for (;;) {
|
|
size_t size = buffer_.capacity() - offset;
|
|
int n = 0;
|
|
if (width <= 0) {
|
|
n = precision < 0 ?
|
|
snprintf(&buffer_[offset], size, format, value) :
|
|
snprintf(&buffer_[offset], size, format, precision, value);
|
|
} else {
|
|
n = precision < 0 ?
|
|
snprintf(&buffer_[offset], size, format, width, value) :
|
|
snprintf(&buffer_[offset], size, format, width, precision, value);
|
|
}
|
|
if (n >= 0 && offset + n < buffer_.capacity()) {
|
|
GrowBuffer(n);
|
|
return;
|
|
}
|
|
buffer_.reserve(n >= 0 ? offset + n + 1 : 2 * buffer_.capacity());
|
|
}
|
|
}
|
|
|
|
void fmt::Formatter::DoFormat() {
|
|
const char *start = format_;
|
|
format_ = 0;
|
|
const char *s = start;
|
|
while (*s) {
|
|
char c = *s++;
|
|
if (c != '{' && c != '}') continue;
|
|
if (*s == c) {
|
|
buffer_.append(start, s);
|
|
start = ++s;
|
|
continue;
|
|
}
|
|
if (c == '}')
|
|
throw FormatError("unmatched '}' in format");
|
|
buffer_.append(start, s - 1);
|
|
|
|
// Parse argument index.
|
|
if (*s < '0' || *s > '9')
|
|
ReportError(s, "missing argument index in format string");
|
|
unsigned arg_index = ParseUInt(s);
|
|
if (arg_index >= args_.size())
|
|
ReportError(s, "argument index is out of range in format");
|
|
const Arg &arg = *args_[arg_index];
|
|
|
|
unsigned flags = 0;
|
|
int width = 0;
|
|
int precision = -1;
|
|
char type = 0;
|
|
if (*s == ':') {
|
|
++s;
|
|
if (*s == '+') {
|
|
++s;
|
|
if (arg.type > LAST_NUMERIC_TYPE)
|
|
ReportError(s, "format specifier '+' requires numeric argument");
|
|
if (arg.type == UINT || arg.type == ULONG) {
|
|
ReportError(s,
|
|
"format specifier '+' requires signed argument");
|
|
}
|
|
flags |= PLUS_FLAG;
|
|
}
|
|
if (*s == '0') {
|
|
++s;
|
|
if (arg.type > LAST_NUMERIC_TYPE)
|
|
ReportError(s, "format specifier '0' requires numeric argument");
|
|
flags |= ZERO_FLAG;
|
|
}
|
|
|
|
// Parse width.
|
|
if ('0' <= *s && *s <= '9') {
|
|
unsigned value = ParseUInt(s);
|
|
if (value > INT_MAX)
|
|
ReportError(s, "number is too big in format");
|
|
width = value;
|
|
}
|
|
|
|
// Parse precision.
|
|
if (*s == '.') {
|
|
++s;
|
|
precision = 0;
|
|
if ('0' <= *s && *s <= '9') {
|
|
unsigned value = ParseUInt(s);
|
|
if (value > INT_MAX)
|
|
ReportError(s, "number is too big in format");
|
|
precision = value;
|
|
} else {
|
|
ReportError(s, "missing precision in format");
|
|
}
|
|
if (arg.type != DOUBLE && arg.type != LONG_DOUBLE) {
|
|
ReportError(s,
|
|
"precision specifier requires floating-point argument");
|
|
}
|
|
}
|
|
|
|
// Parse type.
|
|
if (*s != '}' && *s)
|
|
type = *s++;
|
|
}
|
|
|
|
if (*s++ != '}')
|
|
throw FormatError("unmatched '{' in format");
|
|
start = s;
|
|
|
|
// Format argument.
|
|
switch (arg.type) {
|
|
case INT:
|
|
FormatInt(arg.int_value, flags, width, type);
|
|
break;
|
|
case UINT:
|
|
FormatInt(arg.uint_value, flags, width, type);
|
|
break;
|
|
case LONG:
|
|
FormatInt(arg.long_value, flags, width, type);
|
|
break;
|
|
case ULONG:
|
|
FormatInt(arg.ulong_value, flags, width, type);
|
|
break;
|
|
case DOUBLE:
|
|
FormatDouble(arg.double_value, flags, width, precision, type);
|
|
break;
|
|
case LONG_DOUBLE:
|
|
FormatDouble(arg.long_double_value, flags, width, precision, type);
|
|
break;
|
|
case CHAR: {
|
|
if (type && type != 'c')
|
|
ReportUnknownType(type, "char");
|
|
char *out = GrowBuffer(std::max(width, 1));
|
|
*out++ = arg.int_value;
|
|
if (width > 1)
|
|
std::fill_n(out, width - 1, ' ');
|
|
break;
|
|
}
|
|
case STRING: {
|
|
if (type && type != 's')
|
|
ReportUnknownType(type, "string");
|
|
const char *str = arg.string.value;
|
|
size_t size = arg.string.size;
|
|
if (size == 0 && *str)
|
|
size = std::strlen(str);
|
|
char *out = GrowBuffer(std::max<size_t>(width, size));
|
|
out = std::copy(str, str + size, out);
|
|
if (static_cast<unsigned>(width) > size)
|
|
std::fill_n(out, width - size, ' ');
|
|
break;
|
|
}
|
|
case POINTER:
|
|
if (type && type != 'p')
|
|
ReportUnknownType(type, "pointer");
|
|
FormatInt(reinterpret_cast<uintptr_t>(
|
|
arg.pointer_value), HEX_PREFIX_FLAG, width, 'x');
|
|
break;
|
|
case CUSTOM:
|
|
if (type)
|
|
ReportUnknownType(type, "object");
|
|
(this->*arg.custom.format)(arg.custom.value, width);
|
|
break;
|
|
default:
|
|
assert(false);
|
|
break;
|
|
}
|
|
}
|
|
buffer_.append(start, s + 1);
|
|
buffer_.resize(buffer_.size() - 1); // Don't count the terminating zero.
|
|
}
|