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LZMA2 decoder cleanups. Make it require new LZMA properties
also in the first LZMA chunk after a dictionary reset in uncompressed chunk.
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656ec87882
commit
cd70801520
1 changed files with 41 additions and 54 deletions
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@ -70,76 +70,63 @@ lzma2_decode(lzma_coder *restrict coder, lzma_dict *restrict dict,
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// at least one byte of input.
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while (*in_pos < in_size || coder->sequence == SEQ_LZMA)
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switch (coder->sequence) {
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case SEQ_CONTROL:
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if (in[*in_pos] & 0x80) {
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// Get the highest five bits of uncompressed size.
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coder->uncompressed_size
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= (uint32_t)(in[*in_pos] & 0x1F) << 16;
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case SEQ_CONTROL: {
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const uint32_t control = in[*in_pos];
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++*in_pos;
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// Dictionary reset implies that next LZMA chunk has to set
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// new properties.
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if (control >= 0xE0 || control == 1) {
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dict_reset(dict);
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coder->need_dictionary_reset = false;
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coder->need_properties = true;
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} else if (coder->need_dictionary_reset) {
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return LZMA_DATA_ERROR;
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}
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if (control >= 0x80) {
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// LZMA chunk. The highest five bits of the
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// uncompressed size are taken from the control byte.
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coder->uncompressed_size = (control & 0x1F) << 16;
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coder->sequence = SEQ_UNCOMPRESSED_1;
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// See if we need to reset dictionary or state.
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switch ((in[(*in_pos)++] >> 5) & 3) {
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case 3:
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dict_reset(dict);
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coder->need_dictionary_reset = false;
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// Fall through
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case 2:
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if (coder->need_dictionary_reset)
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return LZMA_DATA_ERROR;
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// See if there are new properties or if we need to
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// reset the state.
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if (control >= 0xC0) {
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// When there are new properties, state reset
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// is done at SEQ_PROPERTIES.
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coder->need_properties = false;
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coder->next_sequence = SEQ_PROPERTIES;
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break;
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case 1:
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if (coder->need_properties)
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return LZMA_DATA_ERROR;
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coder->lzma.reset(coder->lzma.coder,
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&coder->options);
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} else if (coder->need_properties) {
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return LZMA_DATA_ERROR;
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} else {
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coder->next_sequence = SEQ_LZMA;
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break;
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case 0:
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if (coder->need_properties)
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return LZMA_DATA_ERROR;
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coder->next_sequence = SEQ_LZMA;
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break;
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// If only state reset is wanted with old
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// properties, do the resetting here for
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// simplicity.
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if (control >= 0xA0)
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coder->lzma.reset(coder->lzma.coder,
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&coder->options);
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}
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} else {
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switch (in[(*in_pos)++]) {
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case 0:
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// End of payload marker
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// End marker
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if (control == 0x00)
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return LZMA_STREAM_END;
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case 1:
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// Dictionary reset
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dict_reset(dict);
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coder->need_dictionary_reset = false;
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// Fall through
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case 2:
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if (coder->need_dictionary_reset)
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return LZMA_DATA_ERROR;
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// Uncompressed chunk; we need to read total
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// size first.
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coder->sequence = SEQ_COMPRESSED_0;
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coder->next_sequence = SEQ_COPY;
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break;
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default:
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// Invalid control values
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if (control > 2)
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return LZMA_DATA_ERROR;
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}
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// It's uncompressed chunk
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coder->sequence = SEQ_COMPRESSED_0;
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coder->next_sequence = SEQ_COPY;
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}
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break;
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}
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case SEQ_UNCOMPRESSED_1:
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coder->uncompressed_size += (uint32_t)(in[(*in_pos)++]) << 8;
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