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   recordLength = length;
21   endfileRecordNumber = 2;
22   void *pointer{reinterpret_cast<void *>(const_cast<char *>(scalar))};
23   descriptor().Establish(TypeCode{CFI_type_char}, length, pointer, 0, nullptr,
24       CFI_attribute_pointer);
25 }
26 
27 template <Direction DIR>
28 InternalDescriptorUnit<DIR>::InternalDescriptorUnit(
29     const Descriptor &that, const Terminator &terminator) {
30   RUNTIME_CHECK(terminator, that.type().IsCharacter());
31   Descriptor &d{descriptor()};
32   RUNTIME_CHECK(
33       terminator, that.SizeInBytes() <= d.SizeInBytes(maxRank, true, 0));
34   new (&d) Descriptor{that};
35   d.Check();
36   recordLength = d.ElementBytes();
37   endfileRecordNumber = d.Elements() + 1;
38 }
39 
40 template <Direction DIR> void InternalDescriptorUnit<DIR>::EndIoStatement() {
41   if constexpr (DIR == Direction::Output) {
42     // Clear the remainder of the current record if anything was written
43     // to it, or if it is the only record.
44     auto end{endfileRecordNumber.value_or(0)};
45     if (currentRecordNumber < end &&
46         (end == 2 || furthestPositionInRecord > 0)) {
47       BlankFillOutputRecord();
48     }
49   }
50 }
51 
52 template <Direction DIR>
53 bool InternalDescriptorUnit<DIR>::Emit(
54     const char *data, std::size_t bytes, IoErrorHandler &handler) {
55   if constexpr (DIR == Direction::Input) {
56     handler.Crash("InternalDescriptorUnit<Direction::Input>::Emit() called");
57     return false && data[bytes] != 0; // bogus compare silences GCC warning
58   } else {
59     if (bytes <= 0) {
60       return true;
61     }
62     char *record{CurrentRecord()};
63     if (!record) {
64       handler.SignalError(IostatInternalWriteOverrun);
65       return false;
66     }
67     auto furthestAfter{std::max(furthestPositionInRecord,
68         positionInRecord + static_cast<std::int64_t>(bytes))};
69     bool ok{true};
70     if (furthestAfter > static_cast<std::int64_t>(recordLength.value_or(0))) {
71       handler.SignalError(IostatRecordWriteOverrun);
72       furthestAfter = recordLength.value_or(0);
73       bytes = std::max(std::int64_t{0}, furthestAfter - positionInRecord);
74       ok = false;
75     } else if (positionInRecord > furthestPositionInRecord) {
76       std::fill_n(record + furthestPositionInRecord,
77           positionInRecord - furthestPositionInRecord, ' ');
78     }
79     std::memcpy(record + positionInRecord, data, bytes);
80     positionInRecord += bytes;
81     furthestPositionInRecord = furthestAfter;
82     return ok;
83   }
84 }
85 
86 template <Direction DIR>
87 std::size_t InternalDescriptorUnit<DIR>::GetNextInputBytes(
88     const char *&p, IoErrorHandler &handler) {
89   if constexpr (DIR == Direction::Output) {
90     handler.Crash("InternalDescriptorUnit<Direction::Output>::"
91                   "GetNextInputBytes() called");
92     return 0;
93   } else {
94     const char *record{CurrentRecord()};
95     if (!record) {
96       handler.SignalEnd();
97       return 0;
98     } else if (positionInRecord >= recordLength.value_or(positionInRecord)) {
99       return 0;
100     } else {
101       p = &record[positionInRecord];
102       return *recordLength - positionInRecord;
103     }
104   }
105 }
106 
107 template <Direction DIR>
108 bool InternalDescriptorUnit<DIR>::AdvanceRecord(IoErrorHandler &handler) {
109   if (currentRecordNumber >= endfileRecordNumber.value_or(0)) {
110     handler.SignalEnd();
111     return false;
112   }
113   if constexpr (DIR == Direction::Output) {
114     BlankFillOutputRecord();
115   }
116   ++currentRecordNumber;
117   BeginRecord();
118   return true;
119 }
120 
121 template <Direction DIR>
122 void InternalDescriptorUnit<DIR>::BlankFillOutputRecord() {
123   if constexpr (DIR == Direction::Output) {
124     if (furthestPositionInRecord <
125         recordLength.value_or(furthestPositionInRecord)) {
126       char *record{CurrentRecord()};
127       std::fill_n(record + furthestPositionInRecord,
128           *recordLength - furthestPositionInRecord, ' ');
129     }
130   }
131 }
132 
133 template <Direction DIR>
134 void InternalDescriptorUnit<DIR>::BackspaceRecord(IoErrorHandler &handler) {
135   RUNTIME_CHECK(handler, currentRecordNumber > 1);
136   --currentRecordNumber;
137   BeginRecord();
138 }
139 
140 template class InternalDescriptorUnit<Direction::Output>;
141 template class InternalDescriptorUnit<Direction::Input>;
142 } // namespace Fortran::runtime::io
143