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llvm-project/flang/runtime/edit-input.cpp

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//===-- runtime/edit-input.cpp --------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "edit-input.h"
#include "namelist.h"
#include "flang/Common/real.h"
#include "flang/Common/uint128.h"
#include <algorithm>
namespace Fortran::runtime::io {
static bool EditBOZInput(IoStatementState &io, const DataEdit &edit, void *n,
int base, int totalBitSize) {
std::optional<int> remaining;
std::optional<char32_t> next{io.PrepareInput(edit, remaining)};
common::UnsignedInt128 value{0};
for (; next; next = io.NextInField(remaining, edit)) {
char32_t ch{*next};
if (ch == ' ' || ch == '\t') {
continue;
}
int digit{0};
if (ch >= '0' && ch <= '1') {
digit = ch - '0';
} else if (base >= 8 && ch >= '2' && ch <= '7') {
digit = ch - '0';
} else if (base >= 10 && ch >= '8' && ch <= '9') {
digit = ch - '0';
} else if (base == 16 && ch >= 'A' && ch <= 'Z') {
digit = ch + 10 - 'A';
} else if (base == 16 && ch >= 'a' && ch <= 'z') {
digit = ch + 10 - 'a';
} else {
io.GetIoErrorHandler().SignalError(
"Bad character '%lc' in B/O/Z input field", ch);
return false;
}
value *= base;
value += digit;
}
// TODO: check for overflow
std::memcpy(n, &value, totalBitSize >> 3);
return true;
}
static inline char32_t GetDecimalPoint(const DataEdit &edit) {
return edit.modes.editingFlags & decimalComma ? char32_t{','} : char32_t{'.'};
}
// Prepares input from a field, and consumes the sign, if any.
// Returns true if there's a '-' sign.
static bool ScanNumericPrefix(IoStatementState &io, const DataEdit &edit,
std::optional<char32_t> &next, std::optional<int> &remaining) {
next = io.PrepareInput(edit, remaining);
bool negative{false};
if (next) {
negative = *next == '-';
if (negative || *next == '+') {
io.GotChar();
io.SkipSpaces(remaining);
next = io.NextInField(remaining, edit);
}
}
return negative;
}
bool EditIntegerInput(
IoStatementState &io, const DataEdit &edit, void *n, int kind) {
RUNTIME_CHECK(io.GetIoErrorHandler(), kind >= 1 && !(kind & (kind - 1)));
switch (edit.descriptor) {
case DataEdit::ListDirected:
if (IsNamelistName(io)) {
return false;
}
break;
case 'G':
case 'I':
break;
case 'B':
return EditBOZInput(io, edit, n, 2, kind << 3);
case 'O':
return EditBOZInput(io, edit, n, 8, kind << 3);
case 'Z':
return EditBOZInput(io, edit, n, 16, kind << 3);
case 'A': // legacy extension
return EditDefaultCharacterInput(
io, edit, reinterpret_cast<char *>(n), kind);
default:
io.GetIoErrorHandler().SignalError(IostatErrorInFormat,
"Data edit descriptor '%c' may not be used with an INTEGER data item",
edit.descriptor);
return false;
}
std::optional<int> remaining;
std::optional<char32_t> next;
bool negate{ScanNumericPrefix(io, edit, next, remaining)};
common::UnsignedInt128 value{0};
bool any{negate};
for (; next; next = io.NextInField(remaining, edit)) {
char32_t ch{*next};
if (ch == ' ' || ch == '\t') {
if (edit.modes.editingFlags & blankZero) {
ch = '0'; // BZ mode - treat blank as if it were zero
} else {
continue;
}
}
int digit{0};
if (ch >= '0' && ch <= '9') {
digit = ch - '0';
} else {
io.GetIoErrorHandler().SignalError(
"Bad character '%lc' in INTEGER input field", ch);
return false;
}
value *= 10;
value += digit;
any = true;
}
if (negate) {
value = -value;
}
if (any || !io.GetConnectionState().IsAtEOF()) {
std::memcpy(n, &value, kind); // a blank field means zero
}
return any;
}
// Parses a REAL input number from the input source as a normalized
// fraction into a supplied buffer -- there's an optional '-', a
// decimal point, and at least one digit. The adjusted exponent value
// is returned in a reference argument. The returned value is the number
// of characters that (should) have been written to the buffer -- this can
// be larger than the buffer size and can indicate overflow. Replaces
// blanks with zeroes if appropriate.
static int ScanRealInput(char *buffer, int bufferSize, IoStatementState &io,
const DataEdit &edit, int &exponent) {
std::optional<int> remaining;
std::optional<char32_t> next;
int got{0};
std::optional<int> decimalPoint;
auto Put{[&](char ch) -> void {
if (got < bufferSize) {
buffer[got] = ch;
}
++got;
}};
if (ScanNumericPrefix(io, edit, next, remaining)) {
Put('-');
}
if (next.value_or(' ') == ' ') { // empty/blank field means zero
remaining.reset();
if (!io.GetConnectionState().IsAtEOF()) {
Put('0');
}
return got;
}
char32_t decimal{GetDecimalPoint(edit)};
char32_t first{*next >= 'a' && *next <= 'z' ? *next + 'A' - 'a' : *next};
if (first == 'N' || first == 'I') {
// NaN or infinity - convert to upper case
// Subtle: a blank field of digits could be followed by 'E' or 'D',
for (; next &&
((*next >= 'a' && *next <= 'z') || (*next >= 'A' && *next <= 'Z'));
next = io.NextInField(remaining, edit)) {
if (*next >= 'a' && *next <= 'z') {
Put(*next - 'a' + 'A');
} else {
Put(*next);
}
}
if (next && *next == '(') { // NaN(...)
while (next && *next != ')') {
next = io.NextInField(remaining, edit);
}
}
exponent = 0;
} else if (first == decimal || (first >= '0' && first <= '9') ||
first == 'E' || first == 'D' || first == 'Q') {
Put('.'); // input field is normalized to a fraction
auto start{got};
bool bzMode{(edit.modes.editingFlags & blankZero) != 0};
for (; next; next = io.NextInField(remaining, edit)) {
char32_t ch{*next};
if (ch == ' ' || ch == '\t') {
if (bzMode) {
ch = '0'; // BZ mode - treat blank as if it were zero
} else {
continue;
}
}
if (ch == '0' && got == start && !decimalPoint) {
// omit leading zeroes before the decimal
} else if (ch >= '0' && ch <= '9') {
Put(ch);
} else if (ch == decimal && !decimalPoint) {
// the decimal point is *not* copied to the buffer
decimalPoint = got - start; // # of digits before the decimal point
} else {
break;
}
}
if (got == start) {
Put('0'); // emit at least one digit
}
if (next &&
(*next == 'e' || *next == 'E' || *next == 'd' || *next == 'D' ||
*next == 'q' || *next == 'Q')) {
// Optional exponent letter. Blanks are allowed between the
// optional exponent letter and the exponent value.
io.SkipSpaces(remaining);
next = io.NextInField(remaining, edit);
}
// The default exponent is -kP, but the scale factor doesn't affect
// an explicit exponent.
exponent = -edit.modes.scale;
if (next &&
(*next == '-' || *next == '+' || (*next >= '0' && *next <= '9') ||
(bzMode && (*next == ' ' || *next == '\t')))) {
bool negExpo{*next == '-'};
if (negExpo || *next == '+') {
next = io.NextInField(remaining, edit);
}
for (exponent = 0; next; next = io.NextInField(remaining, edit)) {
if (*next >= '0' && *next <= '9') {
exponent = 10 * exponent + *next - '0';
} else if (bzMode && (*next == ' ' || *next == '\t')) {
exponent = 10 * exponent;
} else {
break;
}
}
if (negExpo) {
exponent = -exponent;
}
}
if (decimalPoint) {
exponent += *decimalPoint;
} else {
// When no decimal point (or comma) appears in the value, the 'd'
// part of the edit descriptor must be interpreted as the number of
// digits in the value to be interpreted as being to the *right* of
// the assumed decimal point (13.7.2.3.2)
exponent += got - start - edit.digits.value_or(0);
}
} else {
// TODO: hex FP input
exponent = 0;
return 0;
}
// Consume the trailing ')' of a list-directed or NAMELIST complex
// input value.
if (edit.descriptor == DataEdit::ListDirectedImaginaryPart) {
if (next && (*next == ' ' || *next == '\t')) {
next = io.NextInField(remaining, edit);
}
if (!next) { // NextInField fails on separators like ')'
next = io.GetCurrentChar();
if (next && *next == ')') {
io.HandleRelativePosition(1);
}
}
} else if (remaining) {
while (next && (*next == ' ' || *next == '\t')) {
next = io.NextInField(remaining, edit);
}
if (next) {
return 0; // error: unused nonblank character in fixed-width field
}
}
return got;
}
// If no special modes are in effect and the form of the input value
// that's present in the input stream is acceptable to the decimal->binary
// converter without modification, this fast path for real input
// saves time by avoiding memory copies and reformatting of the exponent.
template <int PRECISION>
static bool TryFastPathRealInput(
IoStatementState &io, const DataEdit &edit, void *n) {
if (edit.modes.editingFlags & (blankZero | decimalComma)) {
return false;
}
if (edit.modes.scale != 0) {
return false;
}
const char *str{nullptr};
std::size_t got{io.GetNextInputBytes(str)};
if (got == 0 || str == nullptr ||
!io.GetConnectionState().recordLength.has_value()) {
return false; // could not access reliably-terminated input stream
}
const char *p{str};
std::int64_t maxConsume{
std::min<std::int64_t>(got, edit.width.value_or(got))};
const char *limit{str + maxConsume};
decimal::ConversionToBinaryResult<PRECISION> converted{
decimal::ConvertToBinary<PRECISION>(p, edit.modes.round, limit)};
if (converted.flags & decimal::Invalid) {
return false;
}
if (edit.digits.value_or(0) != 0 &&
std::memchr(str, '.', p - str) == nullptr) {
// No explicit decimal point, and edit descriptor is Fw.d (or other)
// with d != 0, which implies scaling.
return false;
}
for (; p < limit && (*p == ' ' || *p == '\t'); ++p) {
}
if (edit.descriptor == DataEdit::ListDirectedImaginaryPart) {
// Need to consume a trailing ')' and any white space after
if (p >= limit || *p != ')') {
return false;
}
for (++p; p < limit && (*p == ' ' || *p == '\t'); ++p) {
}
}
if (edit.width && p < str + *edit.width) {
return false; // unconverted characters remain in fixed width field
}
// Success on the fast path!
// TODO: raise converted.flags as exceptions?
*reinterpret_cast<decimal::BinaryFloatingPointNumber<PRECISION> *>(n) =
converted.binary;
io.HandleRelativePosition(p - str);
return true;
}
template <int KIND>
bool EditCommonRealInput(IoStatementState &io, const DataEdit &edit, void *n) {
constexpr int binaryPrecision{common::PrecisionOfRealKind(KIND)};
if (TryFastPathRealInput<binaryPrecision>(io, edit, n)) {
return true;
}
// Fast path wasn't available or didn't work; go the more general route
static constexpr int maxDigits{
common::MaxDecimalConversionDigits(binaryPrecision)};
static constexpr int bufferSize{maxDigits + 18};
char buffer[bufferSize];
int exponent{0};
int got{ScanRealInput(buffer, maxDigits + 2, io, edit, exponent)};
if (got >= maxDigits + 2) {
io.GetIoErrorHandler().Crash("EditCommonRealInput: buffer was too small");
return false;
}
if (got == 0) {
io.GetIoErrorHandler().SignalError("Bad REAL input value");
return false;
}
bool hadExtra{got > maxDigits};
if (exponent != 0) {
buffer[got++] = 'e';
if (exponent < 0) {
buffer[got++] = '-';
exponent = -exponent;
}
if (exponent > 9999) {
exponent = 9999; // will convert to +/-Inf
}
if (exponent > 999) {
int dig{exponent / 1000};
buffer[got++] = '0' + dig;
int rest{exponent - 1000 * dig};
dig = rest / 100;
buffer[got++] = '0' + dig;
rest -= 100 * dig;
dig = rest / 10;
buffer[got++] = '0' + dig;
buffer[got++] = '0' + (rest - 10 * dig);
} else if (exponent > 99) {
int dig{exponent / 100};
buffer[got++] = '0' + dig;
int rest{exponent - 100 * dig};
dig = rest / 10;
buffer[got++] = '0' + dig;
buffer[got++] = '0' + (rest - 10 * dig);
} else if (exponent > 9) {
int dig{exponent / 10};
buffer[got++] = '0' + dig;
buffer[got++] = '0' + (exponent - 10 * dig);
} else {
buffer[got++] = '0' + exponent;
}
}
buffer[got] = '\0';
const char *p{buffer};
decimal::ConversionToBinaryResult<binaryPrecision> converted{
decimal::ConvertToBinary<binaryPrecision>(p, edit.modes.round)};
if (hadExtra) {
converted.flags = static_cast<enum decimal::ConversionResultFlags>(
converted.flags | decimal::Inexact);
}
// TODO: raise converted.flags as exceptions?
*reinterpret_cast<decimal::BinaryFloatingPointNumber<binaryPrecision> *>(n) =
converted.binary;
return true;
}
template <int KIND>
bool EditRealInput(IoStatementState &io, const DataEdit &edit, void *n) {
constexpr int binaryPrecision{common::PrecisionOfRealKind(KIND)};
switch (edit.descriptor) {
case DataEdit::ListDirected:
if (IsNamelistName(io)) {
return false;
}
return EditCommonRealInput<KIND>(io, edit, n);
case DataEdit::ListDirectedRealPart:
case DataEdit::ListDirectedImaginaryPart:
case 'F':
case 'E': // incl. EN, ES, & EX
case 'D':
case 'G':
return EditCommonRealInput<KIND>(io, edit, n);
case 'B':
return EditBOZInput(
io, edit, n, 2, common::BitsForBinaryPrecision(binaryPrecision));
case 'O':
return EditBOZInput(
io, edit, n, 8, common::BitsForBinaryPrecision(binaryPrecision));
case 'Z':
return EditBOZInput(
io, edit, n, 16, common::BitsForBinaryPrecision(binaryPrecision));
case 'A': // legacy extension
return EditDefaultCharacterInput(
io, edit, reinterpret_cast<char *>(n), KIND);
default:
io.GetIoErrorHandler().SignalError(IostatErrorInFormat,
"Data edit descriptor '%c' may not be used for REAL input",
edit.descriptor);
return false;
}
}
// 13.7.3 in Fortran 2018
bool EditLogicalInput(IoStatementState &io, const DataEdit &edit, bool &x) {
switch (edit.descriptor) {
case DataEdit::ListDirected:
if (IsNamelistName(io)) {
return false;
}
break;
case 'L':
case 'G':
break;
default:
io.GetIoErrorHandler().SignalError(IostatErrorInFormat,
"Data edit descriptor '%c' may not be used for LOGICAL input",
edit.descriptor);
return false;
}
std::optional<int> remaining;
std::optional<char32_t> next{io.PrepareInput(edit, remaining)};
if (next && *next == '.') { // skip optional period
next = io.NextInField(remaining, edit);
}
if (!next) {
io.GetIoErrorHandler().SignalError("Empty LOGICAL input field");
return false;
}
switch (*next) {
case 'T':
case 't':
x = true;
break;
case 'F':
case 'f':
x = false;
break;
default:
io.GetIoErrorHandler().SignalError(
"Bad character '%lc' in LOGICAL input field", *next);
return false;
}
if (remaining) { // ignore the rest of the field
io.HandleRelativePosition(*remaining);
} else if (edit.descriptor == DataEdit::ListDirected) {
while (io.NextInField(remaining, edit)) { // discard rest of field
}
}
return true;
}
// See 13.10.3.1 paragraphs 7-9 in Fortran 2018
static bool EditDelimitedCharacterInput(
IoStatementState &io, char *x, std::size_t length, char32_t delimiter) {
bool result{true};
while (true) {
auto ch{io.GetCurrentChar()};
if (!ch) {
if (io.AdvanceRecord()) {
continue;
} else {
result = false; // EOF in character value
break;
}
}
io.HandleRelativePosition(1);
if (*ch == delimiter) {
auto next{io.GetCurrentChar()};
if (next && *next == delimiter) {
// Repeated delimiter: use as character value
io.HandleRelativePosition(1);
} else {
break; // closing delimiter
}
}
if (length > 0) {
*x++ = *ch;
--length;
}
}
std::fill_n(x, length, ' ');
return result;
}
static bool EditListDirectedDefaultCharacterInput(
IoStatementState &io, char *x, std::size_t length, const DataEdit &edit) {
auto ch{io.GetCurrentChar()};
if (ch && (*ch == '\'' || *ch == '"')) {
io.HandleRelativePosition(1);
return EditDelimitedCharacterInput(io, x, length, *ch);
}
if (IsNamelistName(io) || io.GetConnectionState().IsAtEOF()) {
return false;
}
// Undelimited list-directed character input: stop at a value separator
// or the end of the current record.
std::optional<int> remaining{length};
while (std::optional<char32_t> next{io.NextInField(remaining, edit)}) {
switch (*next) {
case ' ':
case '\t':
case ',':
case ';':
case '/':
remaining = 0; // value separator: stop
break;
default:
*x++ = *next;
--length;
}
}
std::fill_n(x, length, ' ');
return true;
}
bool EditDefaultCharacterInput(
IoStatementState &io, const DataEdit &edit, char *x, std::size_t length) {
switch (edit.descriptor) {
case DataEdit::ListDirected:
return EditListDirectedDefaultCharacterInput(io, x, length, edit);
case 'A':
case 'G':
break;
default:
io.GetIoErrorHandler().SignalError(IostatErrorInFormat,
"Data edit descriptor '%c' may not be used with a CHARACTER data item",
edit.descriptor);
return false;
}
if (io.GetConnectionState().IsAtEOF()) {
return false;
}
std::optional<int> remaining{length};
if (edit.width && *edit.width > 0) {
remaining = *edit.width;
}
// When the field is wider than the variable, we drop the leading
// characters. When the variable is wider than the field, there's
// trailing padding.
std::int64_t skip{*remaining - static_cast<std::int64_t>(length)};
while (std::optional<char32_t> next{io.NextInField(remaining, edit)}) {
if (skip > 0) {
--skip;
io.GotChar(-1);
} else {
*x++ = *next;
--length;
}
}
std::fill_n(x, length, ' ');
return true;
}
template bool EditRealInput<2>(IoStatementState &, const DataEdit &, void *);
template bool EditRealInput<3>(IoStatementState &, const DataEdit &, void *);
template bool EditRealInput<4>(IoStatementState &, const DataEdit &, void *);
template bool EditRealInput<8>(IoStatementState &, const DataEdit &, void *);
template bool EditRealInput<10>(IoStatementState &, const DataEdit &, void *);
// TODO: double/double
template bool EditRealInput<16>(IoStatementState &, const DataEdit &, void *);
} // namespace Fortran::runtime::io
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