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Mst::saveMST(): Use the existing differential offset table.

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The resulting MST looks much closer to the original, though it seems
that the original MST tool used string deduplication, so the new one
has extra copies of strings. I don't know if this will break the game.
This commit is contained in:
David Korth 2019-05-27 21:00:24 -04:00
parent 2cb243ed3e
commit 6b019f67a9
1 changed files with 60 additions and 30 deletions
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88
src/Mst.cpp
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@ -614,6 +614,9 @@ int Mst::saveMST(FILE *fp) const
{
if (m_vStrTbl.empty()) {
return -ENODATA; // TODO: Better error code?
} else if (m_vDiffOffTbl.empty()) {
// FIXME: How to generate differential offsets properly?
return -EIO; // TODO: Better error code?
}
// MST header.
@ -636,20 +639,18 @@ int Mst::saveMST(FILE *fp) const
// NOTE: vOffsetTbl will have offsets relative to the
// beginning of each vMsgNames and vMsgText in the first run.
// The base addresses will be added in the second run.
// vOffsetTblType will be used to determine the base address.
vector<uint32_t> vOffsetTbl; // Primary offset table.
vector<uint8_t> vOffsetTblType; // Type of entry for each offset: 0=zero, 1=text, 2=name
vector<char16_t> vMsgText; // Message text.
vector<char> vMsgNames; // Message names.
// TODO: Use m_vDiffOffTbl.
vector<char> vDiffOffTbl; // Differential offset table.
const uint8_t *pDiffOffTbl = m_vDiffOffTbl.data(); // Differential offset table.
const uint8_t *const pDiffOffTblEnd = pDiffOffTbl + m_vDiffOffTbl.size();
// TODO: Better size reservations.
vOffsetTbl.reserve(m_vStrTbl.size() * 3);
vOffsetTblType.reserve(m_vStrTbl.size() * 3);
vMsgText.reserve(m_vStrTbl.size() * 32);
vMsgNames.reserve(m_vStrTbl.size() * 32);
vDiffOffTbl.reserve((m_vStrTbl.size() + 3) & ~(size_t)(3U));
// For strings with both name and text, three offsets will be stored:
// - Name offset
@ -658,8 +659,7 @@ int Mst::saveMST(FILE *fp) const
// For strings with only name, only the name offset will be stored.
// TODO: Compare to MST files and see if maybe a zero is stored too?
bool hasAZero = false; // If true, skip 8 bytes for the next offset.
uint32_t offset_diff;
// String table name.
// NOTE: While this is part of the names table, the offset is stored
@ -679,11 +679,19 @@ int Mst::saveMST(FILE *fp) const
memcpy(vMsgNames.data(), empty_name, sizeof(empty_name));
}
// Skip 4 bytes from the beginning of the WTXT header.
vDiffOffTbl.push_back('A');
// Next offset will skip 8 bytes to skip over the string count.
hasAZero = true;
// Differential offset table initialization:
// - 'A': Skip "WTXT"
// - 'B': Skip string table name offset and count.
offset_diff = getNextDiffOff(&pDiffOffTbl, pDiffOffTblEnd);
if (offset_diff != 4) {
// Invalid differential offset for the string table name...
return -EIO; // TODO: Better error code?
}
offset_diff = getNextDiffOff(&pDiffOffTbl, pDiffOffTblEnd);
if (offset_diff != 8) {
// Invalid differential offset for the string table name...
return -EIO; // TODO: Better error code?
}
}
// Host endianness.
@ -718,10 +726,23 @@ int Mst::saveMST(FILE *fp) const
assert(name_pos <= 16U*1024*1024);
vOffsetTbl.push_back(static_cast<uint32_t>(name_pos));
vOffsetTblType.push_back(2); // Name
// Difference of 4 or 8 bytes, depending on whether or not
// a zero offset was added previously.
vDiffOffTbl.push_back(hasAZero ? 'B' : 'A');
hasAZero = false;
// If the next differential offset is >4, skip some bytes in the offset table.
// NOTE: Offset is always a multiple of 4.
offset_diff = getNextDiffOff(&pDiffOffTbl, pDiffOffTblEnd);
/* TODO: Handle this?
if (offset_diff < 4) {
// Shouldn't be less than 4!
return -EIO; // TODO: Better error code?
} */
if (offset_diff == ~0U) {
// End of offset table.
break;
}
for (; offset_diff > 4; offset_diff -= 4) {
vOffsetTbl.push_back(0);
vOffsetTblType.push_back(0); // Zero
}
// Copy the message text.
// TODO: Add support for writing little-endian files?
@ -748,16 +769,30 @@ int Mst::saveMST(FILE *fp) const
// since vMsgText is char16_t, but vOffsetTbl uses bytes.
assert(text_pos <= 16U*1024*1024);
vOffsetTbl.push_back(static_cast<uint32_t>(text_pos * sizeof(char16_t)));
vOffsetTbl.push_back(0); // Zero entry.
vOffsetTblType.push_back(1); // Text
vOffsetTblType.push_back(0); // Zero
// Difference of 4 bytes from the previous offset,
// and we now have a zero offset.
vDiffOffTbl.push_back('A');
hasAZero = true;
// If the next differential offset is >4, skip some bytes in the offset table.
// NOTE: Offset is always a multiple of 4.
offset_diff = getNextDiffOff(&pDiffOffTbl, pDiffOffTblEnd);
/* TODO: Handle this?
if (offset_diff < 4) {
// Shouldn't be less than 4!
return -EIO; // TODO: Better error code?
} */
if (offset_diff == ~0U) {
// End of offset table.
break;
}
for (; offset_diff > 4; offset_diff -= 4) {
vOffsetTbl.push_back(0);
vOffsetTblType.push_back(0); // Zero
}
}
}
// Offset table always ends with an extra zero.
vOffsetTbl.push_back(0);
vOffsetTblType.push_back(0); // Zero
// Determine the message table base addresses.
const uint32_t text_tbl_base = static_cast<uint32_t>(sizeof(wtxt_header) + (vOffsetTbl.size() * sizeof(uint32_t)));
@ -771,12 +806,7 @@ int Mst::saveMST(FILE *fp) const
vMsgNames.resize(vMsgNames.size() + (4 - (doff_tbl_offset & 3)));
doff_tbl_offset = static_cast<uint32_t>(name_tbl_base + vMsgNames.size());
}
uint32_t doff_tbl_length = static_cast<uint32_t>(vDiffOffTbl.size());
if (doff_tbl_length & 3) {
// Need to align the size to a multiple of 4.
vDiffOffTbl.resize((vDiffOffTbl.size() + 3) & ~(size_t)(3U));
doff_tbl_length = static_cast<uint32_t>(vDiffOffTbl.size());
}
const uint32_t doff_tbl_length = static_cast<uint32_t>(m_vDiffOffTbl.size());
// Update WTXT_Header.
wtxt_header.msg_tbl_name_offset = cpu_to_be32(name_tbl_base);
@ -851,8 +881,8 @@ int Mst::saveMST(FILE *fp) const
return (errno ? -errno : -EIO);
}
errno = 0;
size = fwrite(vDiffOffTbl.data(), 1, vDiffOffTbl.size(), fp);
if (size != vDiffOffTbl.size()) {
size = fwrite(m_vDiffOffTbl.data(), 1, m_vDiffOffTbl.size(), fp);
if (size != m_vDiffOffTbl.size()) {
return (errno ? -errno : -EIO);
}