1 //===-- Implementation of snprintf ------------------------------*- 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/snprintf.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, snprintf, 21 (char *__restrict buffer, size_t buffsz, 22 const char *__restrict format, ...)) { 23 va_list vlist; 24 va_start(vlist, format); 25 internal::ArgList args(vlist); // This holder class allows for easier copying 26 // and pointer semantics, as well as handling 27 // destruction automatically. 28 va_end(vlist); 29 printf_core::WriteBuffer wb(buffer, (buffsz > 0 ? buffsz - 1 : 0)); 30 printf_core::Writer writer(&wb); 31 32 int ret_val = printf_core::printf_main(&writer, format, args); 33 if (buffsz > 0) // if the buffsz is 0 the buffer may be a null pointer. 34 wb.buff[wb.buff_cur] = '\0'; 35 return ret_val; 36 } 37 38 } // namespace LIBC_NAMESPACE 39