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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 "utf.h"
#include "flang/Common/real.h"
#include "flang/Common/uint128.h"
#include <algorithm>
#include <cfenv>
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) {
bool bzMode{(edit.modes.editingFlags & blankZero) != 0};
next = io.PrepareInput(edit, remaining, !bzMode);
bool negative{false};
if (next) {
negative = *next == '-';
if (negative || *next == '+') {
if (!bzMode) {
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 EditCharacterInput(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('-');
}
bool bzMode{(edit.modes.editingFlags & blankZero) != 0};
if (!next || (!bzMode && *next == ' ')) { // 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') ||
(bzMode && (first == ' ' || first == '\t')) || first == 'E' ||
first == 'D' || first == 'Q') {
Put('.'); // input field is normalized to a fraction
auto start{got};
bool anyDigit{false};
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) {
anyDigit = true;
// omit leading zeroes before the decimal
} else if (ch >= '0' && ch <= '9') {
anyDigit = true;
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) {
if (anyDigit) {
Put('0'); // emit at least one digit
} else {
return 0; // no digits, invalid input
}
}
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 ')'
std::size_t byteCount{0};
next = io.GetCurrentChar(byteCount);
if (next && *next == ')') {
io.HandleRelativePosition(byteCount);
}
}
} 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;
}
static void RaiseFPExceptions(decimal::ConversionResultFlags flags) {
#undef RAISE
#ifdef feraisexcept // a macro in some environments; omit std::
#define RAISE feraiseexcept
#else
#define RAISE std::feraiseexcept
#endif
if (flags & decimal::ConversionResultFlags::Overflow) {
RAISE(FE_OVERFLOW);
}
if (flags & decimal::ConversionResultFlags::Inexact) {
RAISE(FE_INEXACT);
}
if (flags & decimal::ConversionResultFlags::Invalid) {
RAISE(FE_INVALID);
}
#undef RAISE
}
// 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!
*reinterpret_cast<decimal::BinaryFloatingPointNumber<PRECISION> *>(n) =
converted.binary;
io.HandleRelativePosition(p - str);
// Set FP exception flags
if (converted.flags != decimal::ConversionResultFlags::Exact) {
RaiseFPExceptions(converted.flags);
}
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(IostatBadRealInput);
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);
}
*reinterpret_cast<decimal::BinaryFloatingPointNumber<binaryPrecision> *>(n) =
converted.binary;
// Set FP exception flags
if (converted.flags != decimal::ConversionResultFlags::Exact) {
RaiseFPExceptions(converted.flags);
}
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 EditCharacterInput(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
template <typename CHAR>
static bool EditDelimitedCharacterInput(
IoStatementState &io, CHAR *x, std::size_t length, char32_t delimiter) {
bool result{true};
while (true) {
std::size_t byteCount{0};
auto ch{io.GetCurrentChar(byteCount)};
if (!ch) {
if (io.AdvanceRecord()) {
continue;
} else {
result = false; // EOF in character value
break;
}
}
io.HandleRelativePosition(byteCount);
if (*ch == delimiter) {
auto next{io.GetCurrentChar(byteCount)};
if (next && *next == delimiter) {
// Repeated delimiter: use as character value
io.HandleRelativePosition(byteCount);
} else {
break; // closing delimiter
}
}
if (length > 0) {
*x++ = *ch;
--length;
}
}
std::fill_n(x, length, ' ');
return result;
}
template <typename CHAR>
static bool EditListDirectedCharacterInput(
IoStatementState &io, CHAR *x, std::size_t length, const DataEdit &edit) {
std::size_t byteCount{0};
auto ch{io.GetCurrentChar(byteCount)};
if (ch && (*ch == '\'' || *ch == '"')) {
io.HandleRelativePosition(byteCount);
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. Subtlety: the "remaining" count
// here is a dummy that's used to avoid the interpretation of separators
// in NextInField.
std::optional<int> remaining{maxUTF8Bytes};
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;
remaining = maxUTF8Bytes;
}
}
std::fill_n(x, length, ' ');
return true;
}
template <typename CHAR>
bool EditCharacterInput(
IoStatementState &io, const DataEdit &edit, CHAR *x, std::size_t length) {
switch (edit.descriptor) {
case DataEdit::ListDirected:
return EditListDirectedCharacterInput(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;
}
const ConnectionState &connection{io.GetConnectionState()};
if (connection.IsAtEOF()) {
return false;
}
std::size_t 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.
const char *input{nullptr};
std::size_t ready{0};
bool hitEnd{false};
// Skip leading bytes.
// These bytes don't count towards INQUIRE(IOLENGTH=).
std::size_t skip{remaining > length ? remaining - length : 0};
// Transfer payload bytes; these do count.
while (remaining > 0) {
if (ready == 0) {
ready = io.GetNextInputBytes(input);
if (ready == 0) {
hitEnd = true;
break;
}
}
std::size_t chunk;
bool skipping{skip > 0};
if (connection.isUTF8) {
chunk = MeasureUTF8Bytes(*input);
if (skipping) {
--skip;
} else if (auto ucs{DecodeUTF8(input)}) {
*x++ = *ucs;
--length;
} else if (chunk == 0) {
// error recovery: skip bad encoding
chunk = 1;
}
--remaining;
} else {
if (skipping) {
chunk = std::min<std::size_t>(skip, ready);
skip -= chunk;
} else {
chunk = std::min<std::size_t>(remaining, ready);
std::memcpy(x, input, chunk);
x += chunk;
length -= chunk;
}
remaining -= chunk;
}
input += chunk;
if (!skipping) {
io.GotChar(chunk);
}
io.HandleRelativePosition(chunk);
ready -= chunk;
}
// Pad the remainder of the input variable, if any.
std::fill_n(x, length, ' ');
if (hitEnd) {
io.CheckForEndOfRecord(); // signal any needed error
}
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 *);
template bool EditCharacterInput(
IoStatementState &, const DataEdit &, char *, std::size_t);
template bool EditCharacterInput(
IoStatementState &, const DataEdit &, char16_t *, std::size_t);
template bool EditCharacterInput(
IoStatementState &, const DataEdit &, char32_t *, std::size_t);
} // namespace Fortran::runtime::io
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