[libc-commits] [libc] [libc]: Implement strfrom* functions and utils (PR #85438)
Vinayak Dev via libc-commits
libc-commits at lists.llvm.org
Fri Mar 15 10:40:32 PDT 2024
https://github.com/vinayakdsci created https://github.com/llvm/llvm-project/pull/85438
Fixes #84244.
Still a Work-In-Progress
>From d4046e89f15478b942cd5b78c863b7eff5aaed7c Mon Sep 17 00:00:00 2001
From: Vinayak Dev <vinayakdev.sci at gmail.com>
Date: Fri, 15 Mar 2024 23:00:57 +0530
Subject: [PATCH] [libc]: Implement strfrom* functions and utils
---
libc/config/linux/x86_64/entrypoints.txt | 1 +
libc/spec/stdc.td | 2 +
libc/src/stdlib/CMakeLists.txt | 21 ++++
libc/src/stdlib/str_from_util.h | 132 +++++++++++++++++++++++
libc/src/stdlib/strfromf.cpp | 44 ++++++++
libc/src/stdlib/strfromf.h | 21 ++++
libc/test/src/stdlib/CMakeLists.txt | 11 +-
libc/test/src/stdlib/strfromf_test.cpp | 94 ++++++++++++++++
8 files changed, 325 insertions(+), 1 deletion(-)
create mode 100644 libc/src/stdlib/str_from_util.h
create mode 100644 libc/src/stdlib/strfromf.cpp
create mode 100644 libc/src/stdlib/strfromf.h
create mode 100644 libc/test/src/stdlib/strfromf_test.cpp
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index a8b416aa9a0cda..80eece5cbaf862 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -180,6 +180,7 @@ set(TARGET_LIBC_ENTRYPOINTS
libc.src.stdlib.qsort_r
libc.src.stdlib.rand
libc.src.stdlib.srand
+ libc.src.stdlib.strfromf
libc.src.stdlib.strtod
libc.src.stdlib.strtof
libc.src.stdlib.strtol
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index 2bc9bc8b9b1a6f..489a5e88233ff0 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -946,6 +946,8 @@ def StdC : StandardSpec<"stdc"> {
FunctionSpec<"rand", RetValSpec<IntType>, [ArgSpec<VoidType>]>,
FunctionSpec<"srand", RetValSpec<VoidType>, [ArgSpec<UnsignedIntType>]>,
+ FunctionSpec<"strfromf", RetValSpec<IntType>, [ArgSpec<CharRestrictedPtr>, ArgSpec<SizeTType>, ArgSpec<ConstCharRestrictedPtr>, ArgSpec<FloatType>]>,
+
FunctionSpec<"strtof", RetValSpec<FloatType>, [ArgSpec<ConstCharRestrictedPtr>, ArgSpec<CharRestrictedPtrPtr>]>,
FunctionSpec<"strtod", RetValSpec<DoubleType>, [ArgSpec<ConstCharRestrictedPtr>, ArgSpec<CharRestrictedPtrPtr>]>,
FunctionSpec<"strtold", RetValSpec<LongDoubleType>, [ArgSpec<ConstCharRestrictedPtr>, ArgSpec<CharRestrictedPtrPtr>]>,
diff --git a/libc/src/stdlib/CMakeLists.txt b/libc/src/stdlib/CMakeLists.txt
index bd0bcffe0045d1..1d9da1afbad851 100644
--- a/libc/src/stdlib/CMakeLists.txt
+++ b/libc/src/stdlib/CMakeLists.txt
@@ -52,6 +52,27 @@ add_entrypoint_object(
libc.config.linux.app_h
)
+add_entrypoint_object(
+ strfromf
+ SRCS
+ strfromf.cpp
+ HDRS
+ strfromf.h
+ DEPENDS
+ .str_from_util
+)
+
+add_header_library(
+ str_from_util
+ HDRS
+ str_from_util.h
+ DEPENDS
+ libc.src.stdio.printf_core.converter_atlas
+ libc.src.stdio.printf_core.core_structs
+ libc.src.stdio.printf_core.writer
+ libc.src.__support.str_to_integer
+)
+
add_entrypoint_object(
strtof
SRCS
diff --git a/libc/src/stdlib/str_from_util.h b/libc/src/stdlib/str_from_util.h
new file mode 100644
index 00000000000000..33597d1ea77a6f
--- /dev/null
+++ b/libc/src/stdlib/str_from_util.h
@@ -0,0 +1,132 @@
+//===-- Implementation header for strfromx() utilitites -------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// According to the C23 standard, any input character sequences except a
+// precision specifier and the usual floating point formats, namely
+// %{a,A,e,E,f,F,g,G}, are not allowed and any code that does otherwise results
+// in undefined behaviour; which in this case is that the buffer string is
+// simply populated with the format string. The case of the value of buffer size
+// being 0 or the input being NULL should be handled in the calling function
+// (strfromf, strfromd, strfroml) itself.
+
+#ifndef LLVM_LIBC_SRC_STDLIB_STRFROM_UTIL_H
+#define LLVM_LIBC_SRC_STDLIB_STRFROM_UTIL_H
+
+#include "src/__support/str_to_integer.h"
+#include "src/stdio/printf_core/converter_atlas.h"
+#include "src/stdio/printf_core/core_structs.h"
+#include "src/stdio/printf_core/writer.h"
+
+#include <stddef.h>
+
+namespace LIBC_NAMESPACE::internal {
+
+template <typename T> struct type_of { using type = T; };
+
+template <> struct type_of<float> {
+ using type = fputil::FPBits<float>::StorageType;
+};
+template <> struct type_of<double> {
+ using type = fputil::FPBits<double>::StorageType;
+};
+template <> struct type_of<long double> {
+ using type = fputil::FPBits<long double>::StorageType;
+};
+
+template <typename T> using type_of_v = typename type_of<T>::type;
+
+template <typename T>
+printf_core::FormatSection parse_format_string(const char *__restrict format,
+ T fp) {
+ printf_core::FormatSection section;
+ size_t cur_pos = 0;
+
+ if (format[cur_pos] == '%') {
+ section.has_conv = true;
+ ++cur_pos;
+
+ // handle precision
+ section.precision = -1;
+ if (format[cur_pos] == '.') {
+ ++cur_pos;
+ section.precision = 0;
+
+ // The standard does not allow the '*' (asterisk) operator for strfromx()
+ // functions
+ if (internal::isdigit(format[cur_pos])) {
+ auto result = internal::strtointeger<int>(format + cur_pos, 10);
+ section.precision += result.value;
+ cur_pos += result.parsed_len;
+ }
+ }
+
+ section.conv_name = format[cur_pos];
+ switch (format[cur_pos]) {
+ case '%':
+ section.has_conv = true;
+ break;
+ case 'a':
+ case 'A':
+ case 'e':
+ case 'E':
+ case 'f':
+ case 'F':
+ case 'g':
+ case 'G':
+ section.conv_val_raw = cpp::bit_cast<type_of_v<T>>(fp);
+ break;
+ default:
+ // error out, invalid format specifier
+ section.has_conv = false;
+ while (format[cur_pos] != '\0')
+ ++cur_pos;
+ break;
+ }
+
+ if (format[cur_pos] != '\0')
+ ++cur_pos;
+ } else {
+ section.has_conv = false;
+ // We are looking for exactly one section, so no more '%'
+ while (format[cur_pos] != '\0')
+ ++cur_pos;
+ }
+
+ section.raw_string = {format, cur_pos};
+ return section;
+}
+
+int convert(const printf_core::FormatSection §ion,
+ printf_core::Writer *writer) {
+ if (!section.has_conv)
+ return writer->write(section.raw_string);
+
+ switch (section.conv_name) {
+ case '%':
+ return writer->write("%");
+ case 'f':
+ case 'F':
+ return convert_float_decimal(writer, section);
+ case 'e':
+ case 'E':
+ return convert_float_dec_exp(writer, section);
+ case 'a':
+ case 'A':
+ return convert_float_hex_exp(writer, section);
+ case 'g':
+ case 'G':
+ return convert_float_dec_auto(writer, section);
+ default:
+ return writer->write(section.raw_string);
+ }
+ return -1;
+}
+
+} // namespace LIBC_NAMESPACE::internal
+
+#endif // LLVM_LIBC_SRC_STDLIB_STRFROM_UTIL_H
diff --git a/libc/src/stdlib/strfromf.cpp b/libc/src/stdlib/strfromf.cpp
new file mode 100644
index 00000000000000..fc626e115c57a8
--- /dev/null
+++ b/libc/src/stdlib/strfromf.cpp
@@ -0,0 +1,44 @@
+//===-- Implementation of strfromf ------------------------------*- C++ -*-===//
+//
+// 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 "src/stdlib/strfromf.h"
+#include "src/stdlib/str_from_util.h"
+
+#include <stdarg.h>
+#include <stddef.h>
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(int, strfromf,
+ (char *__restrict s, size_t n, const char *__restrict format,
+ float fp)) {
+
+ if (!s)
+ return 0;
+
+ printf_core::FormatSection section =
+ internal::parse_format_string(format, (double)fp);
+ printf_core::WriteBuffer wb(s, (n > 0 ? n - 1 : 0));
+ printf_core::Writer writer(&wb);
+
+ int result = 0;
+ if (section.has_conv)
+ result = internal::convert(section, &writer);
+ else
+ result = writer.write(section.raw_string);
+
+ if (result < 0)
+ return result;
+
+ if (n > 0)
+ wb.buff[wb.buff_cur] = '\0';
+
+ return writer.get_chars_written();
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/stdlib/strfromf.h b/libc/src/stdlib/strfromf.h
new file mode 100644
index 00000000000000..caaeb072da2730
--- /dev/null
+++ b/libc/src/stdlib/strfromf.h
@@ -0,0 +1,21 @@
+//===-- Implementation header for strfromf ------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_STDLIB_STRFROMF_H
+#define LLVM_LIBC_SRC_STDLIB_STRFROMF_H
+
+#include <stddef.h>
+
+namespace LIBC_NAMESPACE {
+
+int strfromf(char *__restrict s, size_t n, const char *__restrict format,
+ float fp);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_STDLIB_STRTOF_H
diff --git a/libc/test/src/stdlib/CMakeLists.txt b/libc/test/src/stdlib/CMakeLists.txt
index 5488a61c4ef187..cb42bc56f51c5f 100644
--- a/libc/test/src/stdlib/CMakeLists.txt
+++ b/libc/test/src/stdlib/CMakeLists.txt
@@ -168,6 +168,16 @@ add_libc_test(
.strtol_test_support
)
+add_libc_test(
+ strfromf_test
+ SUITE
+ libc-stdlib-tests
+ SRCS
+ strfromf_test.cpp
+ DEPENDS
+ libc.src.stdlib.strfromf
+)
+
add_libc_test(
abs_test
SUITE
@@ -259,7 +269,6 @@ add_libc_test(
libc.src.stdlib.qsort
)
-
add_libc_test(
qsort_r_test
SUITE
diff --git a/libc/test/src/stdlib/strfromf_test.cpp b/libc/test/src/stdlib/strfromf_test.cpp
new file mode 100644
index 00000000000000..b8311635613fe8
--- /dev/null
+++ b/libc/test/src/stdlib/strfromf_test.cpp
@@ -0,0 +1,94 @@
+//===-- Unittests for strfromf --------------------------------------------===//
+//
+// 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 "src/stdlib/strfromf.h"
+#include "test/UnitTest/Test.h"
+
+TEST(LlvmLibcStrfromfTest, DecimalFloatFormat) {
+ char buff[100];
+ int written;
+
+ written = LIBC_NAMESPACE::strfromf(buff, 16, "%f", 1.0);
+ EXPECT_EQ(written, 8);
+ ASSERT_STREQ(buff, "1.000000");
+
+ written = LIBC_NAMESPACE::strfromf(buff, 20, "%f", 1234567890);
+ EXPECT_EQ(written, 17);
+ ASSERT_STREQ(buff, "1234567936.000000");
+
+ written = LIBC_NAMESPACE::strfromf(buff, 5, "%f", "1234567890.0");
+ EXPECT_EQ(written, 17);
+ ASSERT_STREQ(buff, "1234");
+
+ written = LIBC_NAMESPACE::strfromf(buff, 67, "%.3f", 1.0);
+ EXPECT_EQ(written, 5);
+ ASSERT_STREQ(buff, "1.000");
+
+ written = LIBC_NAMESPACE::strfromf(buff, 20, "%1f", 1234567890.0);
+ EXPECT_EQ(written, 3);
+ ASSERT_STREQ(buff, "%1f");
+
+ written = LIBC_NAMESPACE::strfromf(nullptr, 0, "%f", 1.0);
+ EXPECT_EQ(written, 0);
+}
+
+TEST(LlvmLibcStrfromfTest, HexExpFloatFormat) {
+ char buff[100];
+ int written;
+
+ written = LIBC_NAMESPACE::strfromf(buff, 0, "%a", 1234567890.0);
+ EXPECT_EQ(written, 0);
+
+ written = LIBC_NAMESPACE::strfromf(buff, 20, "%a", 1234567890.0);
+ EXPECT_EQ(written, 14);
+ ASSERT_STREQ(buff, "0x1.26580cp+30");
+
+ written = LIBC_NAMESPACE::strfromf(buff, 20, "%A", 1234567890.0);
+ EXPECT_EQ(written, 14);
+ ASSERT_STREQ(buff, "0X1.26580CP+30");
+}
+
+TEST(LlvmLibcStrfromfTest, DecimalExpFloatFormat) {
+ char buff[100];
+ int written;
+ written = LIBC_NAMESPACE::strfromf(buff, 20, "%.9e", 1234567890.0);
+ EXPECT_EQ(written, 15);
+ ASSERT_STREQ(buff, "1.234567936e+09");
+
+ written = LIBC_NAMESPACE::strfromf(buff, 20, "%.9E", 1234567890.0);
+ EXPECT_EQ(written, 15);
+ ASSERT_STREQ(buff, "1.234567936E+09");
+}
+
+TEST(LlvmLibcStrfromfTest, AutoDecimalFloatFormat) {
+ char buff[100];
+ int written;
+
+ written = LIBC_NAMESPACE::strfromf(buff, 20, "%.9g", 1234567890.0);
+ EXPECT_EQ(written, 15);
+ ASSERT_STREQ(buff, "1.23456794e+09");
+
+ written = LIBC_NAMESPACE::strfromf(buff, 20, "%.9G", 1234567890.0);
+ EXPECT_EQ(written, 15);
+ ASSERT_STREQ(buff, "1.23456794E+09");
+}
+
+TEST(LlvmLibcStrfromfTest, ImproperFormatString) {
+
+ char buff[100];
+ int retval;
+ retval = LIBC_NAMESPACE::strfromf(
+ buff, 37, "A simple string with no conversions.", 1.0);
+ EXPECT_EQ(retval, 36);
+ ASSERT_STREQ(buff, "A simple string with no conversions.");
+
+ retval = LIBC_NAMESPACE::strfromf(
+ buff, 37, "%A simple string with one conversion, should overwrite.", 1.0);
+ EXPECT_EQ(retval, 6);
+ ASSERT_STREQ(buff, "0X1P+0");
+}
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