diff options
author | Aras Pranckevicius <aras@nesnausk.org> | 2022-05-06 14:53:56 +0300 |
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committer | Aras Pranckevicius <aras@nesnausk.org> | 2022-05-06 14:54:09 +0300 |
commit | c7bffc8fa27b4ae2c92e018dc5f8f79e0dfff9b9 (patch) | |
tree | 600d7a6cec1461269a17745f99f996e1c9d7b1ff /source/blender/io/wavefront_obj/importer | |
parent | bdfee6d8318b6dd261adbb08ea2323784f088140 (diff) |
obj: move parsing utilities out of io_common, since they are fairly obj specific
As pointed out in https://developer.blender.org/rB213cd39b6db387bd88f12589fd50ff0e6563cf56#341113,
the utilities are quite OBJ specific due to treating backslash as a line
continuation character. It's unlikely that other formats need that.
No functionality changes, just pure code move (and renamed tests so that
their names reflect obj).
Reviewed By: Campbell Barton
Differential Revision: https://developer.blender.org/D14871
Diffstat (limited to 'source/blender/io/wavefront_obj/importer')
4 files changed, 173 insertions, 4 deletions
diff --git a/source/blender/io/wavefront_obj/importer/obj_import_file_reader.cc b/source/blender/io/wavefront_obj/importer/obj_import_file_reader.cc index be322f49840..fa89b49b605 100644 --- a/source/blender/io/wavefront_obj/importer/obj_import_file_reader.cc +++ b/source/blender/io/wavefront_obj/importer/obj_import_file_reader.cc @@ -8,9 +8,8 @@ #include "BLI_string_ref.hh" #include "BLI_vector.hh" -#include "IO_string_utils.hh" - #include "obj_import_file_reader.hh" +#include "obj_import_string_utils.hh" namespace blender::io::obj { diff --git a/source/blender/io/wavefront_obj/importer/obj_import_mtl.cc b/source/blender/io/wavefront_obj/importer/obj_import_mtl.cc index c2ecd8a37de..f39def0a4af 100644 --- a/source/blender/io/wavefront_obj/importer/obj_import_mtl.cc +++ b/source/blender/io/wavefront_obj/importer/obj_import_mtl.cc @@ -13,13 +13,12 @@ #include "DNA_material_types.h" #include "DNA_node_types.h" -#include "IO_string_utils.hh" - #include "NOD_shader.h" /* TODO: move eMTLSyntaxElement out of following file into a more neutral place */ #include "obj_export_io.hh" #include "obj_import_mtl.hh" +#include "obj_import_string_utils.hh" namespace blender::io::obj { diff --git a/source/blender/io/wavefront_obj/importer/obj_import_string_utils.cc b/source/blender/io/wavefront_obj/importer/obj_import_string_utils.cc new file mode 100644 index 00000000000..c60306c8375 --- /dev/null +++ b/source/blender/io/wavefront_obj/importer/obj_import_string_utils.cc @@ -0,0 +1,99 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +#include "obj_import_string_utils.hh" + +/* Note: we could use C++17 <charconv> from_chars to parse + * floats, but even if some compilers claim full support, + * their standard libraries are not quite there yet. + * LLVM/libc++ only has a float parser since LLVM 14, + * and gcc/libstdc++ since 11.1. So until at least these are + * the minimum spec, use an external library. */ +#include "fast_float.h" +#include <charconv> + +namespace blender::io::obj { + +StringRef read_next_line(StringRef &buffer) +{ + const char *start = buffer.begin(); + const char *end = buffer.end(); + size_t len = 0; + char prev = 0; + const char *ptr = start; + while (ptr < end) { + char c = *ptr++; + if (c == '\n' && prev != '\\') { + break; + } + prev = c; + ++len; + } + + buffer = StringRef(ptr, end); + return StringRef(start, len); +} + +static bool is_whitespace(char c) +{ + return c <= ' ' || c == '\\'; +} + +StringRef drop_whitespace(StringRef str) +{ + while (!str.is_empty() && is_whitespace(str[0])) { + str = str.drop_prefix(1); + } + return str; +} + +StringRef drop_non_whitespace(StringRef str) +{ + while (!str.is_empty() && !is_whitespace(str[0])) { + str = str.drop_prefix(1); + } + return str; +} + +static StringRef drop_plus(StringRef str) +{ + if (!str.is_empty() && str[0] == '+') { + str = str.drop_prefix(1); + } + return str; +} + +StringRef parse_float(StringRef str, float fallback, float &dst, bool skip_space) +{ + if (skip_space) { + str = drop_whitespace(str); + } + str = drop_plus(str); + fast_float::from_chars_result res = fast_float::from_chars(str.begin(), str.end(), dst); + if (res.ec == std::errc::invalid_argument || res.ec == std::errc::result_out_of_range) { + dst = fallback; + } + return StringRef(res.ptr, str.end()); +} + +StringRef parse_floats(StringRef str, float fallback, float *dst, int count) +{ + for (int i = 0; i < count; ++i) { + str = parse_float(str, fallback, dst[i]); + } + return str; +} + +StringRef parse_int(StringRef str, int fallback, int &dst, bool skip_space) +{ + if (skip_space) { + str = drop_whitespace(str); + } + str = drop_plus(str); + std::from_chars_result res = std::from_chars(str.begin(), str.end(), dst); + if (res.ec == std::errc::invalid_argument || res.ec == std::errc::result_out_of_range) { + dst = fallback; + } + return StringRef(res.ptr, str.end()); +} + +} // namespace blender::io::obj diff --git a/source/blender/io/wavefront_obj/importer/obj_import_string_utils.hh b/source/blender/io/wavefront_obj/importer/obj_import_string_utils.hh new file mode 100644 index 00000000000..532224569ac --- /dev/null +++ b/source/blender/io/wavefront_obj/importer/obj_import_string_utils.hh @@ -0,0 +1,72 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +#pragma once + +#include "BLI_string_ref.hh" + +/* + * Various text parsing utilities used by OBJ importer. + * The utilities are not directly usable by other formats, since + * they treat backslash (\) as a whitespace character (OBJ format + * allows backslashes to function as a line-continuation character). + */ + +namespace blender::io::obj { + +/** + * Fetches next line from an input string buffer. + * + * The returned line will not have '\n' characters at the end; + * the `buffer` is modified to contain remaining text without + * the input line. + * + * Note that backslash (\) character is treated as a line + * continuation. + */ +StringRef read_next_line(StringRef &buffer); + +/** + * Drop leading white-space from a StringRef. + * Note that backslash character is considered white-space. + */ +StringRef drop_whitespace(StringRef str); + +/** + * Drop leading non-white-space from a StringRef. + * Note that backslash character is considered white-space. + */ +StringRef drop_non_whitespace(StringRef str); + +/** + * Parse an integer from an input string. + * The parsed result is stored in `dst`. The function skips + * leading white-space unless `skip_space=false`. If the + * number can't be parsed (invalid syntax, out of range), + * `fallback` value is stored instead. + * + * Returns the remainder of the input string after parsing. + */ +StringRef parse_int(StringRef str, int fallback, int &dst, bool skip_space = true); + +/** + * Parse a float from an input string. + * The parsed result is stored in `dst`. The function skips + * leading white-space unless `skip_space=false`. If the + * number can't be parsed (invalid syntax, out of range), + * `fallback` value is stored instead. + * + * Returns the remainder of the input string after parsing. + */ +StringRef parse_float(StringRef str, float fallback, float &dst, bool skip_space = true); + +/** + * Parse a number of white-space separated floats from an input string. + * The parsed `count` numbers are stored in `dst`. If a + * number can't be parsed (invalid syntax, out of range), + * `fallback` value is stored instead. + * + * Returns the remainder of the input string after parsing. + */ +StringRef parse_floats(StringRef str, float fallback, float *dst, int count); + +} // namespace blender::io::obj |