ICU-22365 C API for ULocaleBuilder

See #2520

ICU-22365 Fix comments

icu4c/source/common/BUILD.bazel

@@ -609,6 +609,7 @@ cc_library(
         "uloc.cpp",
         "uloc_tag.cpp",
         "uloc_keytype.cpp",
+        "ulocbuilder.cpp",
         "uresbund.cpp",
         "uresdata.cpp",
         "wintz.cpp",

icu4c/source/common/common.vcxproj

@@ -167,6 +167,7 @@
     <ClCompile Include="uidna.cpp" />
     <ClCompile Include="uts46.cpp" />
     <ClCompile Include="localebuilder.cpp" />
+    <ClCompile Include="ulocbuilder.cpp" />
     <ClCompile Include="localematcher.cpp" />
     <ClCompile Include="localeprioritylist.cpp" />
     <ClCompile Include="locavailable.cpp" />

icu4c/source/common/common.vcxproj.filters

@@ -322,6 +322,9 @@
     <ClCompile Include="localebuilder.cpp">
       <Filter>locales &amp; resources</Filter>
     </ClCompile>
+    <ClCompile Include="ulocbuilder.cpp">
+      <Filter>locales &amp; resources</Filter>
+    </ClCompile>
     <ClCompile Include="localematcher.cpp">
       <Filter>locales &amp; resources</Filter>
     </ClCompile>
@@ -1132,6 +1135,9 @@
     <CustomBuild Include="unicode\localebuilder.h">
       <Filter>locales &amp; resources</Filter>
     </CustomBuild>
+    <CustomBuild Include="unicode\ulocbuilder.h">
+      <Filter>locales &amp; resources</Filter>
+    </CustomBuild>
     <CustomBuild Include="unicode\localematcher.h">
       <Filter>locales &amp; resources</Filter>
     </CustomBuild>

icu4c/source/common/common_uwp.vcxproj

@@ -301,6 +301,7 @@
     <ClCompile Include="uidna.cpp" />
     <ClCompile Include="uts46.cpp" />
     <ClCompile Include="localebuilder.cpp" />
+    <ClCompile Include="ulocbuilder.cpp" />
     <ClCompile Include="localematcher.cpp" />
     <ClCompile Include="localeprioritylist.cpp" />
     <ClCompile Include="locavailable.cpp" />

icu4c/source/common/sources.txt

@@ -139,6 +139,7 @@ ulist.cpp
 uloc.cpp
 uloc_keytype.cpp
 uloc_tag.cpp
+ulocbuilder.cpp
 umapfile.cpp
 umath.cpp
 umutablecptrie.cpp

icu4c/source/common/ulocbuilder.cpp

@@ -0,0 +1,145 @@
+// © 2023 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+
+#include <utility>
+
+#include "unicode/bytestream.h"
+#include "unicode/localebuilder.h"
+#include "unicode/locid.h"
+#include "unicode/stringpiece.h"
+#include "unicode/umachine.h"
+#include "unicode/ulocbuilder.h"
+#include "cstring.h"
+
+using icu::CheckedArrayByteSink;
+using icu::StringPiece;
+
+#define EXTERNAL(i) ((ULocaleBuilder*)(i))
+#define INTERNAL(e) ((icu::LocaleBuilder*)(e))
+
+ULocaleBuilder* ulocbld_open() {
+    return EXTERNAL(new icu::LocaleBuilder());
+}
+
+void ulocbld_close(ULocaleBuilder* builder) {
+    if (builder == nullptr) return;
+    delete INTERNAL(builder);
+}
+
+void ulocbld_setLocale(ULocaleBuilder* builder, const char* locale, int32_t length) {
+    if (builder == nullptr) return;
+    icu::Locale l;
+    if (length < 0 || locale[length] == '\0') {
+        l = icu::Locale(locale);
+    } else {
+        if (length >= ULOC_FULLNAME_CAPACITY) {
+            l.setToBogus();
+        } else {
+            // locale is not null termined but Locale API require one.
+            // Create a null termined version in buf.
+            char buf[ULOC_FULLNAME_CAPACITY];
+            uprv_memcpy(buf, locale, length);
+            buf[length] = '\0';
+            l = icu::Locale(buf);
+        }
+    }
+    INTERNAL(builder)->setLocale(l);
+}
+
+#define STRING_PIECE(s, l) ((l)<0 ? StringPiece(s) : StringPiece((s), (l)))
+
+#define IMPL_ULOCBLD_SETTER(N) \
+void ulocbld_##N(ULocaleBuilder* bld, const char* s, int32_t l) { \
+    if (bld == nullptr) return; \
+    INTERNAL(bld)->N(STRING_PIECE(s,l)); \
+}
+
+IMPL_ULOCBLD_SETTER(setLanguageTag)
+IMPL_ULOCBLD_SETTER(setLanguage)
+IMPL_ULOCBLD_SETTER(setScript)
+IMPL_ULOCBLD_SETTER(setRegion)
+IMPL_ULOCBLD_SETTER(setVariant)
+IMPL_ULOCBLD_SETTER(addUnicodeLocaleAttribute)
+IMPL_ULOCBLD_SETTER(removeUnicodeLocaleAttribute)
+
+void ulocbld_setExtension(ULocaleBuilder* builder, char key, const char* value, int32_t length) {
+    if (builder == nullptr) return;
+    INTERNAL(builder)->setExtension(key, STRING_PIECE(value, length));
+}
+
+void ulocbld_setUnicodeLocaleKeyword(
+    ULocaleBuilder* builder, const char* key, int32_t keyLength,
+    const char* type, int32_t typeLength) {
+    if (builder == nullptr) return;
+    INTERNAL(builder)->setUnicodeLocaleKeyword(
+        STRING_PIECE(key, keyLength), STRING_PIECE(type, typeLength));
+}
+
+void ulocbld_clear(ULocaleBuilder* builder) {
+    if (builder == nullptr) return;
+    INTERNAL(builder)->clear();
+}
+
+void ulocbld_clearExtensions(ULocaleBuilder* builder) {
+    if (builder == nullptr) return;
+    INTERNAL(builder)->clearExtensions();
+}
+
+int32_t ulocbld_buildLocaleID(ULocaleBuilder* builder,
+                              char* buffer, int32_t bufferCapacity, UErrorCode* err) {
+    if (builder == nullptr) {
+        *err = U_ILLEGAL_ARGUMENT_ERROR;
+        return 0;
+    }
+    icu::Locale l = INTERNAL(builder)->build(*err);
+    if (U_FAILURE(*err)) return 0;
+    int32_t length = (int32_t)(uprv_strlen(l.getName()));
+    if (length <= bufferCapacity) {
+        uprv_strncpy(buffer, l.getName(), length);
+        if (length < bufferCapacity) {
+            buffer[length] = '\0';
+        } else {
+            *err = U_STRING_NOT_TERMINATED_WARNING;
+        }
+        return length;
+    }
+    *err = U_BUFFER_OVERFLOW_ERROR;
+    uprv_memcpy(buffer, l.getName(), bufferCapacity);
+    return length;
+}
+
+int32_t ulocbld_buildLanguageTag(ULocaleBuilder* builder,
+                  char* buffer, int32_t bufferCapacity, UErrorCode* err) {
+    if (builder == nullptr) {
+        *err = U_ILLEGAL_ARGUMENT_ERROR;
+        return 0;
+    }
+    icu::Locale l = INTERNAL(builder)->build(*err);
+    if (U_FAILURE(*err)) return 0;
+    CheckedArrayByteSink sink(buffer, bufferCapacity);
+    l.toLanguageTag(sink, *err);
+    if (U_FAILURE(*err)) {
+        return 0;
+    }
+    if (sink.Overflowed()) {
+        *err = U_BUFFER_OVERFLOW_ERROR;
+        return sink.NumberOfBytesAppended();
+    }
+    int32_t written = sink.NumberOfBytesWritten();
+
+    if (written <  bufferCapacity) {
+        // null terminate
+        buffer[written] = '\0';
+    } else {
+        *err = U_STRING_NOT_TERMINATED_WARNING;
+    }
+    return written;
+}
+
+UBool ulocbld_copyErrorTo(const ULocaleBuilder* builder, UErrorCode *outErrorCode) {
+    if (builder == nullptr) {
+        *outErrorCode = U_ILLEGAL_ARGUMENT_ERROR;
+        return true;
+    }
+    return INTERNAL(builder)->copyErrorTo(*outErrorCode);
+}