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/__support/macros/config.h" 13 #include "src/stdio/printf_core/printf_main.h" 14 #include "src/stdio/printf_core/writer.h" 15 16 #include <stdarg.h> 17 #include <stddef.h> 18 19 namespace LIBC_NAMESPACE_DECL { 20 21 LLVM_LIBC_FUNCTION(int, vsnprintf, 22 (char *__restrict buffer, size_t buffsz, 23 const char *__restrict format, va_list vlist)) { 24 internal::ArgList args(vlist); // This holder class allows for easier copying 25 // and pointer semantics, as well as handling 26 // destruction automatically. 27 printf_core::WriteBuffer wb(buffer, (buffsz > 0 ? buffsz - 1 : 0)); 28 printf_core::Writer writer(&wb); 29 30 int ret_val = printf_core::printf_main(&writer, format, args); 31 if (buffsz > 0) // if the buffsz is 0 the buffer may be a null pointer. 32 wb.buff[wb.buff_cur] = '\0'; 33 return ret_val; 34 } 35 36 } // namespace LIBC_NAMESPACE_DECL 37