114 lines
4.9 KiB
C
114 lines
4.9 KiB
C
/*
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*******************************************************************************
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*
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* Copyright (C) 2000-2007, International Business Machines
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* Corporation and others. All Rights Reserved.
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*
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*******************************************************************************
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* file name: genmbcs.h
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* encoding: US-ASCII
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* tab size: 8 (not used)
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* indentation:4
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*
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* created on: 2000jul10
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* created by: Markus W. Scherer
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*/
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#ifndef __GENMBCS_H__
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#define __GENMBCS_H__
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#include "makeconv.h"
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enum {
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/*
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* TODO: Consider using ucnvmbcs.h constants.
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* However, not all values need to be exactly the same, for example
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* the xxx_UTF8_MAX values may be different. (Especially SBCS_UTF8_MAX
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* may be higher in makeconv than in the runtime code because that
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* affects only a small number of .cnv files [if any] but all
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* runtime UConverterSharedData objects.
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*/
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MBCS_STAGE_2_SHIFT=4,
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MBCS_STAGE_2_BLOCK_SIZE=0x40, /* =64=1<<6 for 6 bits in stage 2 */
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MBCS_STAGE_2_BLOCK_SIZE_SHIFT=6, /* log2(MBCS_STAGE_2_BLOCK_SIZE) */
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MBCS_STAGE_2_BLOCK_MASK=0x3f, /* for after shifting by MBCS_STAGE_2_SHIFT */
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MBCS_STAGE_1_SHIFT=10,
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MBCS_STAGE_1_BMP_SIZE=0x40, /* 0x10000>>MBCS_STAGE_1_SHIFT, or 16 for one entry per 1k code points on the BMP */
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MBCS_STAGE_1_SIZE=0x440, /* 0x110000>>MBCS_STAGE_1_SHIFT, or 17*64 for one entry per 1k code points */
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MBCS_STAGE_2_SIZE=0xfbc0, /* 0x10000-MBCS_STAGE_1_SIZE: stages 1 & 2 share a 16-bit-indexed array */
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MBCS_MAX_STAGE_2_TOP=MBCS_STAGE_2_SIZE,
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MBCS_STAGE_2_MAX_BLOCKS=MBCS_STAGE_2_SIZE>>MBCS_STAGE_2_BLOCK_SIZE_SHIFT,
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MBCS_STAGE_2_ALL_UNASSIGNED_INDEX=0, /* stage 1 entry for the all-unassigned stage 2 block */
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MBCS_STAGE_2_FIRST_ASSIGNED=MBCS_STAGE_2_BLOCK_SIZE, /* start of the first stage 2 block after the all-unassigned one */
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MBCS_STAGE_3_BLOCK_SIZE=16, /* =16=1<<4 for 4 bits in stage 3 */
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MBCS_STAGE_3_BLOCK_MASK=0xf,
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MBCS_STAGE_3_FIRST_ASSIGNED=MBCS_STAGE_3_BLOCK_SIZE, /* start of the first stage 3 block after the all-unassigned one */
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MBCS_STAGE_3_GRANULARITY=16, /* =1<<4: MBCS stage 2 indexes are shifted left 4 */
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MBCS_STAGE_3_SBCS_SIZE=0x10000, /* max 64k mappings for SBCS */
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MBCS_STAGE_3_MBCS_SIZE=0x10000*MBCS_STAGE_3_GRANULARITY, /* max mappings for MBCS */
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/*
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* SBCS_UTF8_MAX: Maximum code point with UTF-8-friendly SBCS data structures.
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* Possible values are 0x01ff..0xffff, in steps of 0x100.
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*
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* Unlike for MBCS, this constant only affects the stage 3 block allocation size;
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* there is no additional stage 1/2 table stored in the .cnv file.
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* The max value should be at least 0x7ff to cover 2-byte UTF-8.
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* 0xfff also covers a number other small scripts which have legacy charsets
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* (like Thai).
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* Higher values up to 0x1fff are harmless and potentially useful because
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* that covers small-script blocks which usually have either dense mappings
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* or no mappings at all.
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* Starting at U+2000, there are mostly symbols and format characters
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* with a low density of SBCS mappings, which would result in more wasted
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* stage 3 entries with the larger block size.
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*/
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SBCS_UTF8_MAX=0x1fff,
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/*
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* MBCS_UTF8_MAX: Maximum code point with UTF-8-friendly MBCS data structures.
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* Possible values are 0x01ff..0xffff, in steps of 0x100.
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*
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* Note that with 0xffff, MBCSAddFromUnicode() may overflow the additional UTF-8 stage table
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* with extreme input data. The function checks for this overflow.
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*
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* 0xd7ff is chosen for the majority of common characters including Unihan and Hangul.
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* At U+d800 there are mostly surrogates, private use codes, compatibility characters, etc.
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* Larger values cause slightly larger MBCS .cnv files.
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*/
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MBCS_UTF8_MAX=0xd7ff,
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MBCS_UTF8_LIMIT=MBCS_UTF8_MAX+1, /* =0xd800 */
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MBCS_UTF8_STAGE_SHIFT=6,
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MBCS_UTF8_STAGE_3_BLOCK_SIZE=0x40, /* =64=1<<6 for 6 bits from last trail byte */
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MBCS_UTF8_STAGE_3_BLOCK_MASK=0x3f,
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/* size of the single-stage table for up to U+d7ff (used instead of stage1/2) */
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MBCS_UTF8_STAGE_SIZE=MBCS_UTF8_LIMIT>>MBCS_UTF8_STAGE_SHIFT, /* =0x360 */
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MBCS_FROM_U_EXT_FLAG=0x10, /* UCMapping.f bit for base table mappings that fit into the base toU table */
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MBCS_FROM_U_EXT_MASK=0x0f, /* but need to go into the extension fromU table */
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/* =4 number of regular stage 3 blocks for final UTF-8 trail byte */
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MBCS_UTF8_STAGE_3_BLOCKS=MBCS_UTF8_STAGE_3_BLOCK_SIZE/MBCS_STAGE_3_BLOCK_SIZE,
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MBCS_MAX_FALLBACK_COUNT=8192
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};
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U_CFUNC NewConverter *
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MBCSOpen(UCMFile *ucm);
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/* Test if a 1:1 mapping fits into the MBCS base table's fromUnicode structure. */
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U_CFUNC UBool
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MBCSOkForBaseFromUnicode(UBool utf8Friendly,
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const uint8_t *bytes, int32_t length,
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UChar32 c, int8_t flag);
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U_CFUNC NewConverter *
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CnvExtOpen(UCMFile *ucm);
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#endif /* __GENMBCS_H__ */
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