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[libc] Templatize the scanf Reader interface #131037

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Merged
merged 4 commits into from
Mar 18, 2025
Merged

[libc] Templatize the scanf Reader interface #131037

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2610f9a
[libc] Templatize the scanf Reader interface
petrhosek Feb 18, 2025
bcb6d61
Merge ReadBuffer and Reader
petrhosek Mar 13, 2025
7fb8a00
Fix formatting
petrhosek Mar 13, 2025
848c876
Split StringReader into its own header
petrhosek Mar 17, 2025
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12 changes: 2 additions & 10 deletions libc/src/stdio/scanf_core/CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -61,10 +61,8 @@ if(NOT(TARGET libc.src.__support.File.file) AND LLVM_LIBC_FULL_BUILD AND
return()
endif()

add_object_library(
add_header_library(
scanf_main
SRCS
scanf_main.cpp
HDRS
scanf_main.h
DEPENDS
Expand All @@ -87,14 +85,8 @@ add_header_library(
${use_system_file}
)

add_object_library(
add_header_library(
converter
SRCS
converter.cpp
string_converter.cpp
int_converter.cpp
float_converter.cpp
ptr_converter.cpp
HDRS
converter.h
converter_utils.h
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73 changes: 0 additions & 73 deletions libc/src/stdio/scanf_core/converter.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -26,78 +26,5 @@
namespace LIBC_NAMESPACE_DECL {
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this file can be deleted.

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Done.

namespace scanf_core {

int convert(Reader *reader, const FormatSection &to_conv) {
int ret_val = 0;
switch (to_conv.conv_name) {
case '%':
return raw_match(reader, "%");
case 's':
ret_val = raw_match(reader, " ");
if (ret_val != READ_OK)
return ret_val;
return convert_string(reader, to_conv);
case 'c':
case '[':
return convert_string(reader, to_conv);
case 'd':
case 'i':
case 'u':
case 'o':
case 'x':
case 'X':
ret_val = raw_match(reader, " ");
if (ret_val != READ_OK)
return ret_val;
return convert_int(reader, to_conv);
#ifndef LIBC_COPT_SCANF_DISABLE_FLOAT
case 'f':
case 'F':
case 'e':
case 'E':
case 'a':
case 'A':
case 'g':
case 'G':
ret_val = raw_match(reader, " ");
if (ret_val != READ_OK)
return ret_val;
return convert_float(reader, to_conv);
#endif // LIBC_COPT_SCANF_DISABLE_FLOAT
case 'n':
return convert_current_pos(reader, to_conv);
case 'p':
ret_val = raw_match(reader, " ");
if (ret_val != READ_OK)
return ret_val;
return convert_pointer(reader, to_conv);
default:
return raw_match(reader, to_conv.raw_string);
}
return -1;
}

// raw_string is assumed to have a positive size.
int raw_match(Reader *reader, cpp::string_view raw_string) {
char cur_char = reader->getc();
int ret_val = READ_OK;
for (size_t i = 0; i < raw_string.size(); ++i) {
// Any space character matches any number of space characters.
if (internal::isspace(raw_string[i])) {
while (internal::isspace(cur_char)) {
cur_char = reader->getc();
}
} else {
if (raw_string[i] == cur_char) {
cur_char = reader->getc();
} else {
ret_val = MATCHING_FAILURE;
break;
}
}
}
reader->ungetc(cur_char);
return ret_val;
}

} // namespace scanf_core
} // namespace LIBC_NAMESPACE_DECL
83 changes: 81 additions & 2 deletions libc/src/stdio/scanf_core/converter.h
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Expand Up @@ -10,10 +10,19 @@
#define LLVM_LIBC_SRC_STDIO_SCANF_CORE_CONVERTER_H

#include "src/__support/CPP/string_view.h"
#include "src/__support/ctype_utils.h"
#include "src/__support/macros/config.h"
#include "src/stdio/scanf_core/core_structs.h"
#include "src/stdio/scanf_core/reader.h"

#ifndef LIBC_COPT_SCANF_DISABLE_FLOAT
#include "src/stdio/scanf_core/float_converter.h"
#endif // LIBC_COPT_SCANF_DISABLE_FLOAT
#include "src/stdio/scanf_core/current_pos_converter.h"
#include "src/stdio/scanf_core/int_converter.h"
#include "src/stdio/scanf_core/ptr_converter.h"
#include "src/stdio/scanf_core/string_converter.h"

#include <stddef.h>

namespace LIBC_NAMESPACE_DECL {
Expand All @@ -22,11 +31,81 @@ namespace scanf_core {
// convert will call a conversion function to convert the FormatSection into
// its string representation, and then that will write the result to the
// reader.
int convert(Reader *reader, const FormatSection &to_conv);
template <typename T>
int convert(Reader<T> *reader, const FormatSection &to_conv) {
int ret_val = 0;
switch (to_conv.conv_name) {
case '%':
return raw_match(reader, "%");
case 's':
ret_val = raw_match(reader, " ");
if (ret_val != READ_OK)
return ret_val;
return convert_string(reader, to_conv);
case 'c':
case '[':
return convert_string(reader, to_conv);
case 'd':
case 'i':
case 'u':
case 'o':
case 'x':
case 'X':
ret_val = raw_match(reader, " ");
if (ret_val != READ_OK)
return ret_val;
return convert_int(reader, to_conv);
#ifndef LIBC_COPT_SCANF_DISABLE_FLOAT
case 'f':
case 'F':
case 'e':
case 'E':
case 'a':
case 'A':
case 'g':
case 'G':
ret_val = raw_match(reader, " ");
if (ret_val != READ_OK)
return ret_val;
return convert_float(reader, to_conv);
#endif // LIBC_COPT_SCANF_DISABLE_FLOAT
case 'n':
return convert_current_pos(reader, to_conv);
case 'p':
ret_val = raw_match(reader, " ");
if (ret_val != READ_OK)
return ret_val;
return convert_pointer(reader, to_conv);
default:
return raw_match(reader, to_conv.raw_string);
}
return -1;
}

// raw_match takes a raw string and matches it to the characters obtained from
// the reader.
int raw_match(Reader *reader, cpp::string_view raw_string);
template <typename T>
int raw_match(Reader<T> *reader, cpp::string_view raw_string) {
char cur_char = reader->getc();
int ret_val = READ_OK;
for (size_t i = 0; i < raw_string.size(); ++i) {
// Any space character matches any number of space characters.
if (internal::isspace(raw_string[i])) {
while (internal::isspace(cur_char)) {
cur_char = reader->getc();
}
} else {
if (raw_string[i] == cur_char) {
cur_char = reader->getc();
} else {
ret_val = MATCHING_FAILURE;
break;
}
}
}
reader->ungetc(cur_char);
return ret_val;
}

} // namespace scanf_core
} // namespace LIBC_NAMESPACE_DECL
Expand Down
3 changes: 2 additions & 1 deletion libc/src/stdio/scanf_core/current_pos_converter.h
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Expand Up @@ -19,7 +19,8 @@
namespace LIBC_NAMESPACE_DECL {
namespace scanf_core {

LIBC_INLINE int convert_current_pos(Reader *reader,
template <typename T>
LIBC_INLINE int convert_current_pos(Reader<T> *reader,
const FormatSection &to_conv) {
write_int_with_length(reader->chars_read(), to_conv);
return READ_OK;
Expand Down
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