100 lines
2.3 KiB
C++
100 lines
2.3 KiB
C++
/* SPDX-License-Identifier: GPL-2.0-or-later */
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#include "IO_string_utils.hh"
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/* Note: we could use C++17 <charconv> from_chars to parse
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* floats, but even if some compilers claim full support,
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* their standard libraries are not quite there yet.
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* LLVM/libc++ only has a float parser since LLVM 14,
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* and gcc/libstdc++ since 11.1. So until at least these are
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* the minimum spec, use an external library. */
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#include "fast_float.h"
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#include <charconv>
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namespace blender::io {
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StringRef read_next_line(StringRef &buffer)
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{
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const char *start = buffer.begin();
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const char *end = buffer.end();
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size_t len = 0;
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char prev = 0;
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const char *ptr = start;
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while (ptr < end) {
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char c = *ptr++;
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if (c == '\n' && prev != '\\') {
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break;
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}
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prev = c;
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++len;
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}
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buffer = StringRef(ptr, end);
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return StringRef(start, len);
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}
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static bool is_whitespace(char c)
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{
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return c <= ' ' || c == '\\';
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}
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StringRef drop_whitespace(StringRef str)
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{
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while (!str.is_empty() && is_whitespace(str[0])) {
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str = str.drop_prefix(1);
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}
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return str;
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}
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StringRef drop_non_whitespace(StringRef str)
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{
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while (!str.is_empty() && !is_whitespace(str[0])) {
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str = str.drop_prefix(1);
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}
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return str;
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}
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static StringRef drop_plus(StringRef str)
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{
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if (!str.is_empty() && str[0] == '+') {
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str = str.drop_prefix(1);
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}
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return str;
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}
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StringRef parse_float(StringRef str, float fallback, float &dst, bool skip_space)
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{
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if (skip_space) {
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str = drop_whitespace(str);
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}
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str = drop_plus(str);
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fast_float::from_chars_result res = fast_float::from_chars(str.begin(), str.end(), dst);
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if (res.ec == std::errc::invalid_argument || res.ec == std::errc::result_out_of_range) {
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dst = fallback;
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}
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return StringRef(res.ptr, str.end());
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}
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StringRef parse_floats(StringRef str, float fallback, float *dst, int count)
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{
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for (int i = 0; i < count; ++i) {
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str = parse_float(str, fallback, dst[i]);
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}
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return str;
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}
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StringRef parse_int(StringRef str, int fallback, int &dst, bool skip_space)
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{
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if (skip_space) {
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str = drop_whitespace(str);
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}
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str = drop_plus(str);
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std::from_chars_result res = std::from_chars(str.begin(), str.end(), dst);
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if (res.ec == std::errc::invalid_argument || res.ec == std::errc::result_out_of_range) {
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dst = fallback;
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}
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return StringRef(res.ptr, str.end());
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}
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} // namespace blender::io
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