libc/src/stdio/printf_core/printf_config.h

   1 //===-- Printf Configuration Handler ----------------------------*- 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 #ifndef LLVM_LIBC_SRC_STDIO_PRINTF_CORE_PRINTF_CONFIG_H
  10 #define LLVM_LIBC_SRC_STDIO_PRINTF_CORE_PRINTF_CONFIG_H
  11
  12 // The index array buffer is always initialized when printf is called. In cases
  13 // where index mode is necessary but memory is limited, or when index mode
  14 // performance is important and memory is available, this compile option
  15 // provides a knob to adjust memory usage to an appropriate level. 128 is picked
  16 // as the default size since that's big enough to handle even extreme cases and
  17 // the runtime penalty for not having enough space is severe.
  18 // When an index mode argument is requested, if its index is before the most
  19 // recently read index, then the arg list must be restarted from the beginning,
  20 // and all of the arguments before the new index must be requested with the
  21 // correct types. The index array caches the types of the values in the arg
  22 // list. For every number between the last index cached in the array and the
  23 // requested index, the format string must be parsed again to find the
  24 // type of that index. As an example, if the format string has 20 indexes, and
  25 // the index array is 10, then when the 20th index is requested the first 10
  26 // types can be found immediately, and then the format string must be parsed 10
  27 // times to find the types of the next 10 arguments.
  28 #ifndef LIBC_COPT_PRINTF_INDEX_ARR_LEN
  29 #define LIBC_COPT_PRINTF_INDEX_ARR_LEN 128
  30 #endif
  31
  32 // TODO(michaelrj): Provide a proper interface for these options.
  33 // LIBC_COPT_FLOAT_TO_STR_USE_MEGA_LONG_DOUBLE_TABLE
  34 // LIBC_COPT_FLOAT_TO_STR_USE_DYADIC_FLOAT
  35 // LIBC_COPT_FLOAT_TO_STR_USE_DYADIC_FLOAT_LD
  36 // LIBC_COPT_FLOAT_TO_STR_USE_INT_CALC
  37 // LIBC_COPT_FLOAT_TO_STR_NO_TABLE
  38 // LIBC_COPT_PRINTF_HEX_LONG_DOUBLE
  39
  40 // TODO(michaelrj): Move the other printf configuration options into this file.
  41
  42 // LIBC_COPT_PRINTF_NO_NULLPTR_CHECKS
  43
  44 #endif // LLVM_LIBC_SRC_STDIO_PRINTF_CORE_PRINTF_CONFIG_H