xref: /aosp_15_r20/external/llvm-libc/src/stdio/printf_core/printf_config.h (revision 71db0c75aadcf003ffe3238005f61d7618a3fead)
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 // If fixed point is available and the user hasn't explicitly opted out, then
33 // enable fixed point.
34 #if defined(LIBC_COMPILER_HAS_FIXED_POINT) &&                                  \
35     !defined(LIBC_COPT_PRINTF_DISABLE_FIXED_POINT)
36 #define LIBC_INTERNAL_PRINTF_HAS_FIXED_POINT
37 #endif
38 
39 // TODO(michaelrj): Provide a proper interface for these options.
40 // LIBC_COPT_FLOAT_TO_STR_USE_MEGA_LONG_DOUBLE_TABLE
41 // LIBC_COPT_FLOAT_TO_STR_USE_DYADIC_FLOAT
42 // LIBC_COPT_FLOAT_TO_STR_USE_DYADIC_FLOAT_LD
43 // LIBC_COPT_FLOAT_TO_STR_USE_INT_CALC
44 // LIBC_COPT_FLOAT_TO_STR_NO_TABLE
45 // LIBC_COPT_PRINTF_HEX_LONG_DOUBLE
46 
47 // TODO(michaelrj): Move the other printf configuration options into this file.
48 
49 // LIBC_COPT_PRINTF_NO_NULLPTR_CHECKS
50 
51 #endif // LLVM_LIBC_SRC_STDIO_PRINTF_CORE_PRINTF_CONFIG_H
52