Natively support %x and %X in Format

1 files changed, 110 insertions, 0 deletions

diff --git a/library/cpp/yt/string/format.cpp b/library/cpp/yt/string/format.cpp
new file mode 100644
index 0000000000..6c824e8ba3
--- /dev/null
+++ b/library/cpp/yt/string/format.cpp
@@ -0,0 +1,110 @@
+#include "format.h"
+#include "string.h"
+
+namespace NYT::NDetail {
+
+////////////////////////////////////////////////////////////////////////////////
+
+template <class TValue>
+void FormatValueViaSprintf(
+    TStringBuilderBase* builder,
+    TValue value,
+    TStringBuf format,
+    TStringBuf genericSpec)
+{
+    constexpr int MaxFormatSize = 64;
+    constexpr int SmallResultSize = 64;
+
+    auto copyFormat = [] (char* destination, const char* source, int length) {
+        int position = 0;
+        for (int index = 0; index < length; ++index) {
+            if (IsQuotationSpecSymbol(source[index])) {
+                continue;
+            }
+            destination[position] = source[index];
+            ++position;
+        }
+        return destination + position;
+    };
+
+    char formatBuf[MaxFormatSize];
+    YT_VERIFY(format.length() >= 1 && format.length() <= MaxFormatSize - 2); // one for %, one for \0
+    formatBuf[0] = '%';
+    if (format[format.length() - 1] == GenericSpecSymbol) {
+        char* formatEnd = copyFormat(formatBuf + 1, format.begin(), format.length() - 1);
+        ::memcpy(formatEnd, genericSpec.begin(), genericSpec.length());
+        formatEnd[genericSpec.length()] = '\0';
+    } else {
+        char* formatEnd = copyFormat(formatBuf + 1, format.begin(), format.length());
+        *formatEnd = '\0';
+    }
+
+    char* result = builder->Preallocate(SmallResultSize);
+    size_t resultSize = ::snprintf(result, SmallResultSize, formatBuf, value);
+    if (resultSize >= SmallResultSize) {
+        result = builder->Preallocate(resultSize + 1);
+        YT_VERIFY(::snprintf(result, resultSize + 1, formatBuf, value) == static_cast<int>(resultSize));
+    }
+    builder->Advance(resultSize);
+}
+
+#define XX(type) \
+    template \
+    void FormatValueViaSprintf( \
+        TStringBuilderBase* builder, \
+        type value, \
+        TStringBuf format, \
+        TStringBuf genericSpec);
+
+XX(i32)
+XX(ui32)
+XX(i64)
+XX(ui64)
+XX(float)
+XX(double)
+XX(const void*)
+
+#undef XX
+
+template <class TValue>
+void FormatIntValue(
+    TStringBuilderBase* builder,
+    TValue value,
+    TStringBuf format,
+    TStringBuf genericSpec)
+{
+    if (format == TStringBuf("v")) {
+        constexpr int MaxResultSize = 64;
+        char buffer[MaxResultSize];
+        char* end = buffer + MaxResultSize;
+        char* start = WriteDecIntToBufferBackwards(end, value);
+        builder->AppendString(TStringBuf(start, end));
+    } else if (format == TStringBuf("x") || format == TStringBuf("X")) {
+        constexpr int MaxResultSize = 64;
+        char buffer[MaxResultSize];
+        char* end = buffer + MaxResultSize;
+        char* start = WriteHexIntToBufferBackwards(end, value, format[0] == 'X');
+        builder->AppendString(TStringBuf(start, end));
+    } else {
+        FormatValueViaSprintf(builder, value, format, genericSpec);
+    }
+}
+
+#define XX(type) \
+    template \
+    void FormatIntValue( \
+        TStringBuilderBase* builder, \
+        type value, \
+        TStringBuf format, \
+        TStringBuf genericSpec);
+
+XX(i32)
+XX(ui32)
+XX(i64)
+XX(ui64)
+
+#undef XX
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT::NDetail