1 //===-- Implementation of vsnprintf -----------------------------*- C++ -*-===// 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 "src/stdio/vsnprintf.h" 10 11 #include "src/__support/arg_list.h" 12 #include "src/stdio/printf_core/printf_main.h" 13 #include "src/stdio/printf_core/writer.h" 14 15 #include <stdarg.h> 16 #include <stddef.h> 17 18 namespace LIBC_NAMESPACE { 19 20 LLVM_LIBC_FUNCTION(int, vsnprintf, 21 (char *__restrict buffer, size_t buffsz, 22 const char *__restrict format, va_list vlist)) { 23 internal::ArgList args(vlist); // This holder class allows for easier copying 24 // and pointer semantics, as well as handling 25 // destruction automatically. 26 printf_core::WriteBuffer wb(buffer, (buffsz > 0 ? buffsz - 1 : 0)); 27 printf_core::Writer writer(&wb); 28 29 int ret_val = printf_core::printf_main(&writer, format, args); 30 if (buffsz > 0) // if the buffsz is 0 the buffer may be a null pointer. 31 wb.buff[wb.buff_cur] = '\0'; 32 return ret_val; 33 } 34 35 } // namespace LIBC_NAMESPACE 36