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//===-- runtime/format.h ----------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// FORMAT string processing
#ifndef FORTRAN_RUNTIME_FORMAT_H_
#define FORTRAN_RUNTIME_FORMAT_H_
#include "environment.h"
#include "io-error.h"
#include "terminator.h"
#include "flang/common/Fortran.h"
#include "flang/decimal/decimal.h"
#include <cinttypes>
#include <optional>
namespace Fortran::runtime::io {
enum EditingFlags {
blankZero = 1, // BLANK=ZERO or BZ edit
decimalComma = 2, // DECIMAL=COMMA or DC edit
signPlus = 4, // SIGN=PLUS or SP edit
};
struct MutableModes {
std::uint8_t editingFlags{0}; // BN, DP, SS
enum decimal::FortranRounding round{
executionEnvironment
.defaultOutputRoundingMode}; // RP/ROUND='PROCESSOR_DEFAULT'
bool pad{false}; // PAD= mode on READ
char delim{'\0'}; // DELIM=
short scale{0}; // kP
};
// A single edit descriptor extracted from a FORMAT
struct DataEdit {
char descriptor; // capitalized: one of A, I, B, O, Z, F, E(N/S/X), D, G
// Special internal data edit descriptors to distinguish list-directed I/O
static constexpr char ListDirected{'g'}; // non-COMPLEX list-directed
static constexpr char ListDirectedRealPart{'r'}; // emit "(r," or "(r;"
static constexpr char ListDirectedImaginaryPart{'z'}; // emit "z)"
constexpr bool IsListDirected() const {
return descriptor == ListDirected || descriptor == ListDirectedRealPart ||
descriptor == ListDirectedImaginaryPart;
}
char variation{'\0'}; // N, S, or X for EN, ES, EX
std::optional<int> width; // the 'w' field; optional for A
std::optional<int> digits; // the 'm' or 'd' field
std::optional<int> expoDigits; // 'Ee' field
MutableModes modes;
int repeat{1};
};
// FormatControl<A> requires that A have these member functions;
// these default implementations just crash if called.
struct DefaultFormatControlCallbacks : public IoErrorHandler {
using IoErrorHandler::IoErrorHandler;
DataEdit GetNextDataEdit(int = 1);
bool Emit(const char *, std::size_t);
bool Emit(const char16_t *, std::size_t);
bool Emit(const char32_t *, std::size_t);
bool AdvanceRecord(int = 1);
bool HandleAbsolutePosition(std::int64_t);
bool HandleRelativePosition(std::int64_t);
};
// Generates a sequence of DataEdits from a FORMAT statement or
// default-CHARACTER string. Driven by I/O item list processing.
// Errors are fatal. See clause 13.4 in Fortran 2018 for background.
template<typename CONTEXT> class FormatControl {
public:
using Context = CONTEXT;
using CharType = typename Context::CharType;
FormatControl() {}
FormatControl(const Terminator &, const CharType *format,
std::size_t formatLength, int maxHeight = maxMaxHeight);
// Determines the max parenthesis nesting level by scanning and validating
// the FORMAT string.
static int GetMaxParenthesisNesting(
const Terminator &, const CharType *format, std::size_t formatLength);
// For attempting to allocate in a user-supplied stack area
static std::size_t GetNeededSize(int maxHeight) {
return sizeof(FormatControl) -
sizeof(Iteration) * (maxMaxHeight - maxHeight);
}
// Extracts the next data edit descriptor, handling control edit descriptors
// along the way.
DataEdit GetNextDataEdit(Context &, int maxRepeat = 1);
// Emit any remaining character literals after the last data item.
void FinishOutput(Context &);
private:
static constexpr std::uint8_t maxMaxHeight{100};
struct Iteration {
static constexpr int unlimited{-1};
int start{0}; // offset in format_ of '(' or a repeated edit descriptor
int remaining{0}; // while >0, decrement and iterate
};
void SkipBlanks() {
while (offset_ < formatLength_ && format_[offset_] == ' ') {
++offset_;
}
}
CharType PeekNext() {
SkipBlanks();
return offset_ < formatLength_ ? format_[offset_] : '\0';
}
CharType GetNextChar(const Terminator &terminator) {
SkipBlanks();
if (offset_ >= formatLength_) {
terminator.Crash("FORMAT missing at least one ')'");
}
return format_[offset_++];
}
int GetIntField(const Terminator &, CharType firstCh = '\0');
// Advances through the FORMAT until the next data edit
// descriptor has been found; handles control edit descriptors
// along the way. Returns the repeat count that appeared
// before the descriptor (defaulting to 1) and leaves offset_
// pointing to the data edit.
int CueUpNextDataEdit(Context &, bool stop = false);
static constexpr CharType Capitalize(CharType ch) {
return ch >= 'a' && ch <= 'z' ? ch + 'A' - 'a' : ch;
}
// Data members are arranged and typed so as to reduce size.
// This structure may be allocated in stack space loaned by the
// user program for internal I/O.
const std::uint8_t maxHeight_{maxMaxHeight};
std::uint8_t height_{0};
const CharType *format_{nullptr};
int formatLength_{0};
int offset_{0}; // next item is at format_[offset_]
// must be last, may be incomplete
Iteration stack_[maxMaxHeight];
};
}
#endif // FORTRAN_RUNTIME_FORMAT_H_
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