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1 | /* |
2 | * sbcs.c - routines to handle single-byte character sets. |
3 | */ |
4 | |
5 | #include "charset.h" |
6 | #include "internal.h" |
7 | |
8 | /* |
9 | * The charset_spec for any single-byte character set should |
10 | * provide read_sbcs() as its read function, and its `data' field |
11 | * should be a wchar_t string constant containing the 256 entries |
12 | * of the translation table. |
13 | */ |
14 | |
01081d4e |
15 | long int sbcs_to_unicode(const struct sbcs_data *sd, long int input_chr) |
16 | { |
17 | return sd->sbcs2ucs[input_chr]; |
18 | } |
19 | |
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20 | void read_sbcs(charset_spec const *charset, long int input_chr, |
21 | charset_state *state, |
22 | void (*emit)(void *ctx, long int output), void *emitctx) |
23 | { |
24 | const struct sbcs_data *sd = charset->data; |
25 | |
26 | UNUSEDARG(state); |
27 | |
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28 | emit(emitctx, sbcs_to_unicode(sd, input_chr)); |
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29 | } |
30 | |
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31 | long int sbcs_from_unicode(const struct sbcs_data *sd, long int input_chr) |
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32 | { |
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33 | int i, j, k, c; |
34 | |
c6d25d8d |
35 | /* |
36 | * Binary-search in the ucs2sbcs table. |
37 | */ |
38 | i = -1; |
39 | j = sd->nvalid; |
40 | while (i+1 < j) { |
41 | k = (i+j)/2; |
42 | c = sd->ucs2sbcs[k]; |
3cca0edf |
43 | if (input_chr < (long int)sd->sbcs2ucs[c]) |
c6d25d8d |
44 | j = k; |
3cca0edf |
45 | else if (input_chr > (long int)sd->sbcs2ucs[c]) |
c6d25d8d |
46 | i = k; |
47 | else { |
01081d4e |
48 | return c; |
c6d25d8d |
49 | } |
50 | } |
01081d4e |
51 | return ERROR; |
52 | } |
53 | |
54 | int write_sbcs(charset_spec const *charset, long int input_chr, |
55 | charset_state *state, |
56 | void (*emit)(void *ctx, long int output), void *emitctx) |
57 | { |
58 | const struct sbcs_data *sd = charset->data; |
c601368c |
59 | long int ret; |
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60 | |
61 | UNUSEDARG(state); |
62 | |
63 | if (input_chr == -1) |
64 | return TRUE; /* stateless; no cleanup required */ |
65 | |
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66 | ret = sbcs_from_unicode(sd, input_chr); |
67 | if (ret == ERROR) |
68 | return FALSE; |
69 | |
70 | emit(emitctx, ret); |
71 | return TRUE; |
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72 | } |