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authorPatrick Simianer <p@simianer.de>2013-01-21 12:29:43 +0100
committerPatrick Simianer <p@simianer.de>2013-01-21 12:29:43 +0100
commit0d23f8aecbfaf982cd165ebfc2a1611cefcc7275 (patch)
tree8eafa6ea43224ff70635cadd4d6f027d28f4986f /klm/lm/builder/ngram.hh
parentdbc66cd3944321961c5e11d5254fd914f05a98ad (diff)
parent7cac43b858f3b681555bf0578f54b1f822c43207 (diff)
Merge remote-tracking branch 'upstream/master'
Diffstat (limited to 'klm/lm/builder/ngram.hh')
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diff --git a/klm/lm/builder/ngram.hh b/klm/lm/builder/ngram.hh
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+#ifndef LM_BUILDER_NGRAM__
+#define LM_BUILDER_NGRAM__
+
+#include "lm/weights.hh"
+#include "lm/word_index.hh"
+
+#include <cstddef>
+
+#include <assert.h>
+#include <stdint.h>
+#include <string.h>
+
+namespace lm {
+namespace builder {
+
+struct Uninterpolated {
+ float prob; // Uninterpolated probability.
+ float gamma; // Interpolation weight for lower order.
+};
+
+union Payload {
+ uint64_t count;
+ Uninterpolated uninterp;
+ ProbBackoff complete;
+};
+
+class NGram {
+ public:
+ NGram(void *begin, std::size_t order)
+ : begin_(static_cast<WordIndex*>(begin)), end_(begin_ + order) {}
+
+ const uint8_t *Base() const { return reinterpret_cast<const uint8_t*>(begin_); }
+ uint8_t *Base() { return reinterpret_cast<uint8_t*>(begin_); }
+
+ void ReBase(void *to) {
+ std::size_t difference = end_ - begin_;
+ begin_ = reinterpret_cast<WordIndex*>(to);
+ end_ = begin_ + difference;
+ }
+
+ // Would do operator++ but that can get confusing for a stream.
+ void NextInMemory() {
+ ReBase(&Value() + 1);
+ }
+
+ // Lower-case in deference to STL.
+ const WordIndex *begin() const { return begin_; }
+ WordIndex *begin() { return begin_; }
+ const WordIndex *end() const { return end_; }
+ WordIndex *end() { return end_; }
+
+ const Payload &Value() const { return *reinterpret_cast<const Payload *>(end_); }
+ Payload &Value() { return *reinterpret_cast<Payload *>(end_); }
+
+ uint64_t &Count() { return Value().count; }
+ const uint64_t Count() const { return Value().count; }
+
+ std::size_t Order() const { return end_ - begin_; }
+
+ static std::size_t TotalSize(std::size_t order) {
+ return order * sizeof(WordIndex) + sizeof(Payload);
+ }
+ std::size_t TotalSize() const {
+ // Compiler should optimize this.
+ return TotalSize(Order());
+ }
+ static std::size_t OrderFromSize(std::size_t size) {
+ std::size_t ret = (size - sizeof(Payload)) / sizeof(WordIndex);
+ assert(size == TotalSize(ret));
+ return ret;
+ }
+
+ private:
+ WordIndex *begin_, *end_;
+};
+
+const WordIndex kUNK = 0;
+const WordIndex kBOS = 1;
+const WordIndex kEOS = 2;
+
+} // namespace builder
+} // namespace lm
+
+#endif // LM_BUILDER_NGRAM__