diff options
Diffstat (limited to 'libqpdf/Pl_LZWDecoder.cc')
| -rw-r--r-- | libqpdf/Pl_LZWDecoder.cc | 115 |
1 files changed, 36 insertions, 79 deletions
diff --git a/libqpdf/Pl_LZWDecoder.cc b/libqpdf/Pl_LZWDecoder.cc index bace3854..34ed1bd7 100644 --- a/libqpdf/Pl_LZWDecoder.cc +++ b/libqpdf/Pl_LZWDecoder.cc @@ -1,14 +1,14 @@ #include <qpdf/Pl_LZWDecoder.hh> +#include <qpdf/QIntC.hh> #include <qpdf/QTC.hh> #include <qpdf/QUtil.hh> -#include <qpdf/QIntC.hh> +#include <assert.h> #include <stdexcept> #include <string.h> -#include <assert.h> -Pl_LZWDecoder::Pl_LZWDecoder(char const* identifier, Pipeline* next, - bool early_code_change) : +Pl_LZWDecoder::Pl_LZWDecoder( + char const* identifier, Pipeline* next, bool early_code_change) : Pipeline(identifier, next), code_size(9), next(0), @@ -29,16 +29,13 @@ Pl_LZWDecoder::~Pl_LZWDecoder() void Pl_LZWDecoder::write(unsigned char* bytes, size_t len) { - for (size_t i = 0; i < len; ++i) - { + for (size_t i = 0; i < len; ++i) { this->buf[next++] = bytes[i]; - if (this->next == 3) - { + if (this->next == 3) { this->next = 0; } this->bits_available += 8; - if (this->bits_available >= this->code_size) - { + if (this->bits_available >= this->code_size) { sendNextCode(); } } @@ -60,8 +57,7 @@ Pl_LZWDecoder::sendNextCode() unsigned int bits_from_high = 8 - this->bit_pos; unsigned int bits_from_med = this->code_size - bits_from_high; unsigned int bits_from_low = 0; - if (bits_from_med > 8) - { + if (bits_from_med > 8) { bits_from_low = bits_from_med - 8; bits_from_med = 8; } @@ -71,20 +67,16 @@ Pl_LZWDecoder::sendNextCode() unsigned int code = 0; code += (this->buf[high] & high_mask) << bits_from_med; code += ((this->buf[med] & med_mask) >> (8 - bits_from_med)); - if (bits_from_low) - { + if (bits_from_low) { code <<= bits_from_low; code += ((this->buf[low] & low_mask) >> (8 - bits_from_low)); this->byte_pos = low; this->bit_pos = bits_from_low; - } - else - { + } else { this->byte_pos = med; this->bit_pos = bits_from_med; } - if (this->bit_pos == 8) - { + if (this->bit_pos == 8) { this->bit_pos = 0; ++this->byte_pos; this->byte_pos %= 3; @@ -98,23 +90,17 @@ unsigned char Pl_LZWDecoder::getFirstChar(unsigned int code) { unsigned char result = '\0'; - if (code < 256) - { + if (code < 256) { result = static_cast<unsigned char>(code); - } - else if (code > 257) - { + } else if (code > 257) { unsigned int idx = code - 258; - if (idx >= table.size()) - { + if (idx >= table.size()) { throw std::runtime_error( "Pl_LZWDecoder::getFirstChar: table overflow"); } Buffer& b = table.at(idx); result = b.getBuffer()[0]; - } - else - { + } else { throw std::runtime_error( "Pl_LZWDecoder::getFirstChar called with invalid code (" + QUtil::int_to_string(code) + ")"); @@ -129,26 +115,20 @@ Pl_LZWDecoder::addToTable(unsigned char next) unsigned char const* last_data = 0; unsigned char tmp[1]; - if (this->last_code < 256) - { + if (this->last_code < 256) { tmp[0] = static_cast<unsigned char>(this->last_code); last_data = tmp; last_size = 1; - } - else if (this->last_code > 257) - { + } else if (this->last_code > 257) { unsigned int idx = this->last_code - 258; - if (idx >= table.size()) - { + if (idx >= table.size()) { throw std::runtime_error( "Pl_LZWDecoder::addToTable: table overflow"); } Buffer& b = table.at(idx); last_data = b.getBuffer(); last_size = QIntC::to_uint(b.getSize()); - } - else - { + } else { throw std::runtime_error( "Pl_LZWDecoder::addToTable called with invalid code (" + QUtil::int_to_string(this->last_code) + ")"); @@ -164,84 +144,61 @@ Pl_LZWDecoder::addToTable(unsigned char next) void Pl_LZWDecoder::handleCode(unsigned int code) { - if (this->eod) - { + if (this->eod) { return; } - if (code == 256) - { - if (! this->table.empty()) - { + if (code == 256) { + if (!this->table.empty()) { QTC::TC("libtests", "Pl_LZWDecoder intermediate reset"); } this->table.clear(); this->code_size = 9; - } - else if (code == 257) - { + } else if (code == 257) { this->eod = true; - } - else - { - if (this->last_code != 256) - { + } else { + if (this->last_code != 256) { // Add to the table from last time. New table entry would // be what we read last plus the first character of what // we're reading now. unsigned char next = '\0'; unsigned int table_size = QIntC::to_uint(table.size()); - if (code < 256) - { + if (code < 256) { // just read < 256; last time's next was code next = static_cast<unsigned char>(code); - } - else if (code > 257) - { + } else if (code > 257) { size_t idx = code - 258; - if (idx > table_size) - { + if (idx > table_size) { throw std::runtime_error("LZWDecoder: bad code received"); - } - else if (idx == table_size) - { + } else if (idx == table_size) { // The encoder would have just created this entry, // so the first character of this entry would have // been the same as the first character of the // last entry. QTC::TC("libtests", "Pl_LZWDecoder last was table size"); next = getFirstChar(this->last_code); - } - else - { + } else { next = getFirstChar(code); } } unsigned int new_idx = 258 + table_size; - if (new_idx == 4096) - { + if (new_idx == 4096) { throw std::runtime_error("LZWDecoder: table full"); } addToTable(next); unsigned int change_idx = new_idx + code_change_delta; - if ((change_idx == 511) || - (change_idx == 1023) || - (change_idx == 2047)) - { + if ((change_idx == 511) || (change_idx == 1023) || + (change_idx == 2047)) { ++this->code_size; } } - if (code < 256) - { + if (code < 256) { unsigned char ch = static_cast<unsigned char>(code); getNext()->write(&ch, 1); - } - else - { + } else { unsigned int idx = code - 258; - if (idx >= table.size()) - { + if (idx >= table.size()) { throw std::runtime_error( "Pl_LZWDecoder::handleCode: table overflow"); } |