/*
*******************************************************************************
*
-* Copyright (C) 2000-2003, International Business Machines
+* Copyright (C) 2000-2008, International Business Machines
* Corporation and others. All Rights Reserved.
*
*******************************************************************************
#include "makeconv.h"
enum {
- MBCS_STAGE_2_BLOCK_SIZE=0x40, /* 64; 64=1<<6 for 6 bits in stage 2 */
- MBCS_STAGE_2_BLOCK_SIZE_SHIFT=6, /* log2(MBCS_STAGE_2_BLOCK_SIZE) */
- MBCS_STAGE_1_SIZE=0x440, /* 0x110000>>10, or 17*64 for one entry per 1k code points */
- MBCS_STAGE_2_SIZE=0xfbc0, /* 0x10000-MBCS_STAGE_1_SIZE */
+ /*
+ * TODO: Consider using ucnvmbcs.h constants.
+ * However, not all values need to be exactly the same, for example
+ * the xxx_UTF8_MAX values may be different. (Especially SBCS_UTF8_MAX
+ * may be higher in makeconv than in the runtime code because that
+ * affects only a small number of .cnv files [if any] but all
+ * runtime UConverterSharedData objects.
+ */
+ MBCS_STAGE_2_SHIFT=4,
+ MBCS_STAGE_2_BLOCK_SIZE=0x40, /* =64=1<<6 for 6 bits in stage 2 */
+ MBCS_STAGE_2_BLOCK_SIZE_SHIFT=6, /* log2(MBCS_STAGE_2_BLOCK_SIZE) */
+ MBCS_STAGE_2_BLOCK_MASK=0x3f, /* for after shifting by MBCS_STAGE_2_SHIFT */
+ MBCS_STAGE_1_SHIFT=10,
+ MBCS_STAGE_1_BMP_SIZE=0x40, /* 0x10000>>MBCS_STAGE_1_SHIFT, or 16 for one entry per 1k code points on the BMP */
+ MBCS_STAGE_1_SIZE=0x440, /* 0x110000>>MBCS_STAGE_1_SHIFT, or 17*64 for one entry per 1k code points */
+ MBCS_STAGE_2_SIZE=0xfbc0, /* 0x10000-MBCS_STAGE_1_SIZE: stages 1 & 2 share a 16-bit-indexed array */
MBCS_MAX_STAGE_2_TOP=MBCS_STAGE_2_SIZE,
MBCS_STAGE_2_MAX_BLOCKS=MBCS_STAGE_2_SIZE>>MBCS_STAGE_2_BLOCK_SIZE_SHIFT,
MBCS_STAGE_2_ALL_UNASSIGNED_INDEX=0, /* stage 1 entry for the all-unassigned stage 2 block */
MBCS_STAGE_2_FIRST_ASSIGNED=MBCS_STAGE_2_BLOCK_SIZE, /* start of the first stage 2 block after the all-unassigned one */
- MBCS_STAGE_3_BLOCK_SIZE=16, /* 16; 16=1<<4 for 4 bits in stage 3 */
+ MBCS_STAGE_3_BLOCK_SIZE=16, /* =16=1<<4 for 4 bits in stage 3 */
+ MBCS_STAGE_3_BLOCK_MASK=0xf,
MBCS_STAGE_3_FIRST_ASSIGNED=MBCS_STAGE_3_BLOCK_SIZE, /* start of the first stage 3 block after the all-unassigned one */
+ MBCS_STAGE_3_GRANULARITY=16, /* =1<<4: MBCS stage 2 indexes are shifted left 4 */
+ MBCS_STAGE_3_SBCS_SIZE=0x10000, /* max 64k mappings for SBCS */
+ MBCS_STAGE_3_MBCS_SIZE=0x10000*MBCS_STAGE_3_GRANULARITY, /* max mappings for MBCS */
+
+ /*
+ * SBCS_UTF8_MAX: Maximum code point with UTF-8-friendly SBCS data structures.
+ * Possible values are 0x01ff..0xffff, in steps of 0x100.
+ *
+ * Unlike for MBCS, this constant only affects the stage 3 block allocation size;
+ * there is no additional stage 1/2 table stored in the .cnv file.
+ * The max value should be at least 0x7ff to cover 2-byte UTF-8.
+ * 0xfff also covers a number other small scripts which have legacy charsets
+ * (like Thai).
+ * Higher values up to 0x1fff are harmless and potentially useful because
+ * that covers small-script blocks which usually have either dense mappings
+ * or no mappings at all.
+ * Starting at U+2000, there are mostly symbols and format characters
+ * with a low density of SBCS mappings, which would result in more wasted
+ * stage 3 entries with the larger block size.
+ */
+ SBCS_UTF8_MAX=0x1fff,
+
+ /*
+ * MBCS_UTF8_MAX: Maximum code point with UTF-8-friendly MBCS data structures.
+ * Possible values are 0x01ff..0xffff, in steps of 0x100.
+ *
+ * Note that with 0xffff, MBCSAddFromUnicode() may overflow the additional UTF-8 stage table
+ * with extreme input data. The function checks for this overflow.
+ *
+ * 0xd7ff is chosen for the majority of common characters including Unihan and Hangul.
+ * At U+d800 there are mostly surrogates, private use codes, compatibility characters, etc.
+ * Larger values cause slightly larger MBCS .cnv files.
+ */
+ MBCS_UTF8_MAX=0xd7ff,
+ MBCS_UTF8_LIMIT=MBCS_UTF8_MAX+1, /* =0xd800 */
+
+ MBCS_UTF8_STAGE_SHIFT=6,
+ MBCS_UTF8_STAGE_3_BLOCK_SIZE=0x40, /* =64=1<<6 for 6 bits from last trail byte */
+ MBCS_UTF8_STAGE_3_BLOCK_MASK=0x3f,
+
+ /* size of the single-stage table for up to U+d7ff (used instead of stage1/2) */
+ MBCS_UTF8_STAGE_SIZE=MBCS_UTF8_LIMIT>>MBCS_UTF8_STAGE_SHIFT, /* =0x360 */
+
+ MBCS_FROM_U_EXT_FLAG=0x10, /* UCMapping.f bit for base table mappings that fit into the base toU table */
+ MBCS_FROM_U_EXT_MASK=0x0f, /* but need to go into the extension fromU table */
+
+ /* =4 number of regular stage 3 blocks for final UTF-8 trail byte */
+ MBCS_UTF8_STAGE_3_BLOCKS=MBCS_UTF8_STAGE_3_BLOCK_SIZE/MBCS_STAGE_3_BLOCK_SIZE,
+
MBCS_MAX_FALLBACK_COUNT=8192
};
U_CFUNC NewConverter *
MBCSOpen(UCMFile *ucm);
+struct MBCSData;
+typedef struct MBCSData MBCSData;
+
+/*
+ * Get a dummy MBCSData for use with MBCSOkForBaseFromUnicode()
+ * for creating an extension-only file.
+ * Assume maxCharLength>1.
+ */
+U_CFUNC const MBCSData *
+MBCSGetDummy(void);
+
+/* Test if a 1:1 mapping fits into the MBCS base table's fromUnicode structure. */
+U_CFUNC UBool
+MBCSOkForBaseFromUnicode(const MBCSData *mbcsData,
+ const uint8_t *bytes, int32_t length,
+ UChar32 c, int8_t flag);
+
U_CFUNC NewConverter *
CnvExtOpen(UCMFile *ucm);
-#endif
+#endif /* __GENMBCS_H__ */
projects / apple / icu.git / blobdiff