1 //===-- runtime/internal-unit.cpp -----------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "internal-unit.h"
10 #include "io-error.h"
11 #include "flang/Runtime/descriptor.h"
12 #include <algorithm>
13 #include <type_traits>
14 
15 namespace Fortran::runtime::io {
16 
17 template <Direction DIR>
18 InternalDescriptorUnit<DIR>::InternalDescriptorUnit(
19     Scalar scalar, std::size_t length) {
20   isFixedRecordLength = true;
21   recordLength = length;
22   endfileRecordNumber = 2;
23   void *pointer{reinterpret_cast<void *>(const_cast<char *>(scalar))};
24   descriptor().Establish(TypeCode{CFI_type_char}, length, pointer, 0, nullptr,
25       CFI_attribute_pointer);
26 }
27 
28 template <Direction DIR>
29 InternalDescriptorUnit<DIR>::InternalDescriptorUnit(
30     const Descriptor &that, const Terminator &terminator) {
31   RUNTIME_CHECK(terminator, that.type().IsCharacter());
32   Descriptor &d{descriptor()};
33   RUNTIME_CHECK(
34       terminator, that.SizeInBytes() <= d.SizeInBytes(maxRank, true, 0));
35   new (&d) Descriptor{that};
36   d.Check();
37   isFixedRecordLength = true;
38   recordLength = d.ElementBytes();
39   endfileRecordNumber = d.Elements() + 1;
40 }
41 
42 template <Direction DIR> void InternalDescriptorUnit<DIR>::EndIoStatement() {
43   if constexpr (DIR == Direction::Output) { // blank fill
44     while (char *record{CurrentRecord()}) {
45       if (furthestPositionInRecord <
46           recordLength.value_or(furthestPositionInRecord)) {
47         std::fill_n(record + furthestPositionInRecord,
48             *recordLength - furthestPositionInRecord, ' ');
49       }
50       furthestPositionInRecord = 0;
51       ++currentRecordNumber;
52     }
53   }
54 }
55 
56 template <Direction DIR>
57 bool InternalDescriptorUnit<DIR>::Emit(
58     const char *data, std::size_t bytes, IoErrorHandler &handler) {
59   if constexpr (DIR == Direction::Input) {
60     handler.Crash("InternalDescriptorUnit<Direction::Input>::Emit() called");
61     return false && data[bytes] != 0; // bogus compare silences GCC warning
62   } else {
63     if (bytes <= 0) {
64       return true;
65     }
66     char *record{CurrentRecord()};
67     if (!record) {
68       handler.SignalError(IostatInternalWriteOverrun);
69       return false;
70     }
71     auto furthestAfter{std::max(furthestPositionInRecord,
72         positionInRecord + static_cast<std::int64_t>(bytes))};
73     bool ok{true};
74     if (furthestAfter > static_cast<std::int64_t>(recordLength.value_or(0))) {
75       handler.SignalError(IostatRecordWriteOverrun);
76       furthestAfter = recordLength.value_or(0);
77       bytes = std::max(std::int64_t{0}, furthestAfter - positionInRecord);
78       ok = false;
79     } else if (positionInRecord > furthestPositionInRecord) {
80       std::fill_n(record + furthestPositionInRecord,
81           positionInRecord - furthestPositionInRecord, ' ');
82     }
83     std::memcpy(record + positionInRecord, data, bytes);
84     positionInRecord += bytes;
85     furthestPositionInRecord = furthestAfter;
86     return ok;
87   }
88 }
89 
90 template <Direction DIR>
91 std::optional<char32_t> InternalDescriptorUnit<DIR>::GetCurrentChar(
92     IoErrorHandler &handler) {
93   if constexpr (DIR == Direction::Output) {
94     handler.Crash(
95         "InternalDescriptorUnit<Direction::Output>::GetCurrentChar() called");
96     return std::nullopt;
97   }
98   const char *record{CurrentRecord()};
99   if (!record) {
100     handler.SignalEnd();
101     return std::nullopt;
102   }
103   if (positionInRecord >= recordLength.value_or(positionInRecord)) {
104     return std::nullopt;
105   }
106   if (isUTF8) {
107     // TODO: UTF-8 decoding
108   }
109   return record[positionInRecord];
110 }
111 
112 template <Direction DIR>
113 bool InternalDescriptorUnit<DIR>::AdvanceRecord(IoErrorHandler &handler) {
114   if (currentRecordNumber >= endfileRecordNumber.value_or(0)) {
115     handler.SignalEnd();
116     return false;
117   }
118   if constexpr (DIR == Direction::Output) { // blank fill
119     if (furthestPositionInRecord <
120         recordLength.value_or(furthestPositionInRecord)) {
121       char *record{CurrentRecord()};
122       RUNTIME_CHECK(handler, record != nullptr);
123       std::fill_n(record + furthestPositionInRecord,
124           *recordLength - furthestPositionInRecord, ' ');
125     }
126   }
127   ++currentRecordNumber;
128   BeginRecord();
129   return true;
130 }
131 
132 template <Direction DIR>
133 void InternalDescriptorUnit<DIR>::BackspaceRecord(IoErrorHandler &handler) {
134   RUNTIME_CHECK(handler, currentRecordNumber > 1);
135   --currentRecordNumber;
136   BeginRecord();
137 }
138 
139 template class InternalDescriptorUnit<Direction::Output>;
140 template class InternalDescriptorUnit<Direction::Input>;
141 } // namespace Fortran::runtime::io
142