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2 /* ====================================================================
3  * Copyright (c) 2009 Carnegie Mellon University.  All rights
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18  * This work was supported in part by funding from the Defense Advanced
19  * Research Projects Agency and the National Science Foundation of the
20  * United States of America, and the CMU Sphinx Speech Consortium.
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22  * THIS SOFTWARE IS PROVIDED BY CARNEGIE MELLON UNIVERSITY ``AS IS'' AND
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37 
38 /**
39  * @file huff_code.h
40  * @brief Huffman code and bitstream implementation
41  *
42  * This interface supports building canonical Huffman codes from
43  * string and integer values.  It also provides support for encoding
44  * and decoding from strings and files, and for reading and writing
45  * codebooks from files.
46  */
47 
48 #ifndef __HUFF_CODE_H__
49 #define __HUFF_CODE_H__
50 
51 #include <stdio.h>
52 
53 #include <sphinxbase/sphinxbase_export.h>
54 #include <sphinxbase/prim_type.h>
55 #include <sphinxbase/cmd_ln.h>
56 
57 typedef struct huff_code_s huff_code_t;
58 
59 /**
60  * Create a codebook from 32-bit integer data.
61  */
62 SPHINXBASE_EXPORT
63 huff_code_t *huff_code_build_int(int32 const *values, int32 const *frequencies, int nvals);
64 
65 /**
66  * Create a codebook from string data.
67  */
68 SPHINXBASE_EXPORT
69 huff_code_t *huff_code_build_str(char * const *values, int32 const *frequencies, int nvals);
70 
71 /**
72  * Read a codebook from a file.
73  */
74 SPHINXBASE_EXPORT
75 huff_code_t *huff_code_read(FILE *infh);
76 
77 /**
78  * Write a codebook to a file.
79  */
80 SPHINXBASE_EXPORT
81 int huff_code_write(huff_code_t *hc, FILE *outfh);
82 
83 /**
84  * Print a codebook to a file as text (for debugging)
85  */
86 SPHINXBASE_EXPORT
87 int huff_code_dump(huff_code_t *hc, FILE *dumpfh);
88 
89 /**
90  * Retain a pointer to a Huffman codec object.
91  */
92 SPHINXBASE_EXPORT
93 huff_code_t *huff_code_retain(huff_code_t *hc);
94 
95 /**
96  * Release a pointer to a Huffman codec object.
97  */
98 SPHINXBASE_EXPORT
99 int huff_code_free(huff_code_t *hc);
100 
101 /**
102  * Attach a Huffman codec to a file handle for input/output.
103  */
104 SPHINXBASE_EXPORT
105 FILE *huff_code_attach(huff_code_t *hc, FILE *fh, char const *mode);
106 
107 /**
108  * Detach a Huffman codec from its file handle.
109  */
110 SPHINXBASE_EXPORT
111 FILE *huff_code_detach(huff_code_t *hc);
112 
113 /**
114  * Encode an integer, writing it to the file handle, if any.
115  */
116 SPHINXBASE_EXPORT
117 int huff_code_encode_int(huff_code_t *hc, int32 sym, uint32 *outcw);
118 
119 /**
120  * Encode a string, writing it to the file handle, if any.
121  */
122 SPHINXBASE_EXPORT
123 int huff_code_encode_str(huff_code_t *hc, char const *sym, uint32 *outcw);
124 
125 /**
126  * Decode an integer, reading it from the file if no data given.
127  */
128 SPHINXBASE_EXPORT
129 int huff_code_decode_int(huff_code_t *hc, int *outval,
130                          char const **inout_data,
131                          size_t *inout_data_len,
132                          int *inout_offset);
133 
134 /**
135  * Decode a string, reading it from the file if no data given.
136  */
137 SPHINXBASE_EXPORT
138 char const *huff_code_decode_str(huff_code_t *hc,
139                                  char const **inout_data,
140                                  size_t *inout_data_len,
141                                  int *inout_offset);
142 
143 #endif /* __HUFF_CODE_H__ */
144