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Codechange: Encode case/gender/plural choice lists without null termination, only length prefix. (#13876)

pull/13862/head
frosch 2025-03-25 20:32:40 +01:00 committed by GitHub
parent 25005cff16
commit c105adcd96
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GPG Key ID: B5690EEEBB952194
3 changed files with 46 additions and 39 deletions
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37
src/newgrf_text.cpp
View File

@ -152,7 +152,7 @@ struct UnmappedChoiceList {
if (this->type == SCC_SWITCH_CASE) {
/*
* Format for case switch:
* <NUM CASES> <CASE1> <LEN1> <STRING1> <CASE2> <LEN2> <STRING2> <CASE3> <LEN3> <STRING3> <STRINGDEFAULT>
* <NUM CASES> <CASE1> <LEN1> <STRING1> <CASE2> <LEN2> <STRING2> <CASE3> <LEN3> <STRING3> <LENDEFAULT> <STRINGDEFAULT>
* Each LEN is printed using 2 bytes in big endian order.
*/
@ -164,6 +164,16 @@ struct UnmappedChoiceList {
}
*d++ = count;
auto add_case = [&](std::string_view str) {
/* "<LENn>" */
uint16_t len = ClampTo<uint16_t>(str.size());
*d++ = GB(len, 0, 8);
*d++ = GB(len, 8, 8);
/* "<STRINGn>" */
dest.write(str.data(), len);
};
for (uint8_t i = 0; i < _current_language->num_cases; i++) {
/* Resolve the string we're looking for. */
int idx = lm->GetReverseMapping(i, false);
@ -173,18 +183,11 @@ struct UnmappedChoiceList {
/* "<CASEn>" */
*d++ = i + 1;
/* "<LENn>": Limit the length of the string to 0xFFFE to leave space for the '\0'. */
size_t len = std::min<size_t>(0xFFFE, str.size());
*d++ = GB(len + 1, 8, 8);
*d++ = GB(len + 1, 0, 8);
/* "<STRINGn>" */
dest.write(str.c_str(), len);
*d++ = '\0';
add_case(str);
}
/* "<STRINGDEFAULT>" */
dest << this->strings[0].rdbuf();
add_case(this->strings[0].view());
} else {
if (this->type == SCC_PLURAL_LIST) {
*d++ = lm->plural_form;
@ -206,20 +209,17 @@ struct UnmappedChoiceList {
for (int i = 0; i < count; i++) {
int idx = (this->type == SCC_GENDER_LIST ? lm->GetReverseMapping(i, true) : i + 1);
const auto &str = this->strings[this->strings.find(idx) != this->strings.end() ? idx : 0].str();
size_t len = str.size() + 1;
if (len > 0xFF) GrfMsg(1, "choice list string is too long");
*d++ = GB(len, 0, 8);
size_t len = str.size();
if (len > UINT8_MAX) GrfMsg(1, "choice list string is too long");
*d++ = ClampTo<uint8_t>(len);
}
/* "<STRINGs>" */
for (int i = 0; i < count; i++) {
int idx = (this->type == SCC_GENDER_LIST ? lm->GetReverseMapping(i, true) : i + 1);
const auto &str = this->strings[this->strings.find(idx) != this->strings.end() ? idx : 0].str();
/* Limit the length of the string we copy to 0xFE. The length is written above
* as a byte and we need room for the final '\0'. */
size_t len = std::min<size_t>(0xFE, str.size());
uint8_t len = ClampTo<uint8_t>(str.size());
dest.write(str.c_str(), len);
*d++ = '\0';
}
}
}
@ -793,8 +793,9 @@ static void ProcessNewGRFStringControlCode(char32_t scc, const char *&str, TextR
/* skip all cases and continue with default case */
uint num = static_cast<uint8_t>(*str++);
for (uint i = 0; i != num; i++) {
str += 3 + (static_cast<uint8_t>(str[1]) << 8) + static_cast<uint8_t>(str[2]);
str += 3 + static_cast<uint8_t>(str[1]) + (static_cast<uint8_t>(str[2]) << 8);
}
str += 2; // length of default
break;
}

28
src/strgen/strgen_base.cpp
View File

@ -292,18 +292,14 @@ std::optional<std::string_view> ParseWord(const char **buf)
* CommandByte <ARG#> <NUM> {Length of each string} {each string} */
static void EmitWordList(Buffer *buffer, const std::vector<std::string> &words)
{
/* Maximum word length in bytes, excluding trailing NULL. */
constexpr size_t MAX_WORD_LENGTH = UINT8_MAX - 2;
buffer->AppendByte(static_cast<uint8_t>(words.size()));
for (size_t i = 0; i < words.size(); i++) {
size_t len = words[i].size() + 1;
if (len >= UINT8_MAX) StrgenFatal("WordList {}/{} string '{}' too long, max bytes {}", i + 1, words.size(), words[i], MAX_WORD_LENGTH);
size_t len = words[i].size();
if (len > UINT8_MAX) StrgenFatal("WordList {}/{} string '{}' too long, max bytes {}", i + 1, words.size(), words[i], UINT8_MAX);
buffer->AppendByte(static_cast<uint8_t>(len));
}
for (size_t i = 0; i < words.size(); i++) {
buffer->append(words[i]);
buffer->AppendByte(0);
}
}
@ -900,11 +896,12 @@ void LanguageWriter::WriteLang(const StringData &data)
_translated = cmdp != &ls->english;
std::optional<size_t> default_case_pos;
if (!ls->translated_cases.empty()) {
/* Need to output a case-switch.
* It has this format
* <0x9E> <NUM CASES> <CASE1> <LEN1> <STRING1> <CASE2> <LEN2> <STRING2> <CASE3> <LEN3> <STRING3> <STRINGDEFAULT>
* Each LEN is printed using 2 bytes in big endian order. */
* <0x9E> <NUM CASES> <CASE1> <LEN1> <STRING1> <CASE2> <LEN2> <STRING2> <CASE3> <LEN3> <STRING3> <LENDEFAULT> <STRINGDEFAULT>
* Each LEN is printed using 2 bytes in little endian order. */
buffer.AppendUtf8(SCC_SWITCH_CASE);
buffer.AppendByte(static_cast<uint8_t>(ls->translated_cases.size()));
@ -917,16 +914,25 @@ void LanguageWriter::WriteLang(const StringData &data)
buffer.AppendByte(0);
/* Write string */
PutCommandString(&buffer, c.string.c_str());
buffer.AppendByte(0); // terminate with a zero
/* Fill in the length */
size_t size = buffer.size() - (pos + 2);
buffer[pos + 0] = GB(size, 8, 8);
buffer[pos + 1] = GB(size, 0, 8);
buffer[pos + 0] = GB(size, 0, 8);
buffer[pos + 1] = GB(size, 8, 8);
}
default_case_pos = buffer.size();
buffer.AppendByte(0);
buffer.AppendByte(0);
}
if (!cmdp->empty()) PutCommandString(&buffer, cmdp->c_str());
if (default_case_pos.has_value()) {
size_t size = buffer.size() - (*default_case_pos + 2);
buffer[*default_case_pos + 0] = GB(size, 0, 8);
buffer[*default_case_pos + 1] = GB(size, 8, 8);
}
this->WriteLength(buffer.size());
this->Write(buffer.data(), buffer.size());
buffer.clear();

20
src/strings.cpp
View File

@ -790,8 +790,7 @@ static const char *ParseStringChoice(const char *b, uint form, StringBuilder &bu
total_len += len;
}
assert(form_len > 0); // len includes a null terminator
builder += std::string_view(b + form_offset, form_len - 1);
builder += std::string_view(b + form_offset, form_len);
return b + total_len;
}
@ -1231,24 +1230,25 @@ static void FormatString(StringBuilder &builder, std::string_view str_arg, Strin
}
case SCC_SWITCH_CASE: { // {Used to implement case switching}
/* <0x9E> <NUM CASES> <CASE1> <LEN1> <STRING1> <CASE2> <LEN2> <STRING2> <CASE3> <LEN3> <STRING3> <STRINGDEFAULT>
* Each LEN is printed using 2 bytes in big endian order. */
/* <0x9E> <NUM CASES> <CASE1> <LEN1> <STRING1> <CASE2> <LEN2> <STRING2> <CASE3> <LEN3> <STRING3> <LENDEFAULT> <STRINGDEFAULT>
* Each LEN is printed using 2 bytes in little endian order. */
uint num = (uint8_t)*str++;
std::optional<std::string_view> found;
for (; num > 0; --num) {
uint8_t index = static_cast<uint8_t>(str[0]);
uint16_t len = (static_cast<uint8_t>(str[1]) << 8) + static_cast<uint8_t>(str[2]);
assert(len > 0); // len includes a null terminator
uint16_t len = static_cast<uint8_t>(str[1]) + (static_cast<uint8_t>(str[2]) << 8);
str += 3;
if (index == case_index) {
/* Found the case */
found.emplace(str, len - 1);
found.emplace(str, len);
}
str += len;
}
const char *end = str_stack.top().end;
if (!found.has_value()) found.emplace(str, end - str);
str = end;
uint16_t default_len = static_cast<uint8_t>(str[0]) + (static_cast<uint8_t>(str[1]) << 8);
str += 2;
if (!found.has_value()) found.emplace(str, default_len);
str += default_len;
assert(str <= str_stack.top().end);
str_stack.emplace(*found, ref_param_offset, case_index); // this may invalidate "str"
break;
}