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Diffstat (limited to 'support/texlab/crates/bibutils_sys/src/gb18030.c')
-rw-r--r-- | support/texlab/crates/bibutils_sys/src/gb18030.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/support/texlab/crates/bibutils_sys/src/gb18030.c b/support/texlab/crates/bibutils_sys/src/gb18030.c new file mode 100644 index 0000000000..b8fdf855fa --- /dev/null +++ b/support/texlab/crates/bibutils_sys/src/gb18030.c @@ -0,0 +1,184 @@ +#include <stdio.h> +#include "gb18030.h" + +/* GB18030-2000 is an encoding of Unicode character used in China + * + * {0x00-0x7f} are one byte characters identical to US-ASCII + * {0x80} is properly undefined, but many GB18030 encodings make + * it the Euro sign (Unicode 0x20AC), so use that + * {0x81-0xFE}{0x40-0x7E,0x80-0xFE} a full superset of GBK (with fallback + * mappings) + * {0x81-0xFE}{0x30-0x39}{0x81-0xFE}{0x30-0x39} maps linearly to ISO 10646 + * GB+81308130 = U+0080 up to U+FFFF + * GB+90308130 = U+10000 up to U+10FFFF skipping mappings already + * defined in 1-byte and 2-byte areas. + * + * Truth is it's a bit of a mess algorithmically as it doesn't multiply + * encode characters, so there are holes in the Unicode mapping that + * should be avoided. + */ + +/* This is a "small" region that needs explicit enumeration */ +#include "gb18030_enumeration.c" + +static int +in_range( unsigned char n, unsigned char low, unsigned char high ) +{ + if ( n < low || n > high ) return 0; + return 1; +} + + +/* Get GB 18030 from Unicode Value in Table */ +static int +gb18030_unicode_table_lookup( unsigned int unicode, unsigned char out[4] ) +{ + int i, j; + if ( unicode >= 0x0080 && unicode <= 0xFFE5 ) { + /* list is sorted, so should do binary search here */ + for ( i=0; i<ngb18030_enums; ++i ) { + if ( unicode == gb18030_enums[i].unicode ) { + for ( j=0; j<gb18030_enums[i].len; ++j ) + out[j] = gb18030_enums[i].bytes[j]; + return gb18030_enums[i].len; + } + } + } + return 0; +} + +static int +gb18030_match( unsigned char *s, const unsigned char *bytes, unsigned char len ) +{ + int i; + for ( i=0; i<len; ++i ) + if ( ( s[i])!=bytes[i] ) return 0; + return 1; +} + +static unsigned int +gb18030_table_lookup( unsigned char *uc, unsigned char len, int *found ) +{ + unsigned int i; + *found = 0; + for ( i=0; i<ngb18030_enums; ++i ) { + if ( gb18030_enums[i].len!=len ) continue; + if ( gb18030_match( &(uc[0]), gb18030_enums[i].bytes, len ) ) { + *found = 1; + return gb18030_enums[i].unicode; + } + } + return '?'; +} + + +static int +gb18030_unicode_range_lookup( unsigned int unicode, unsigned char out[4] ) +{ + return 0; +} + +static int +gb18030_range_lookup( unsigned char *s, /* unsigned char len = 4 only */ int *found ) +{ + *found = 0; + return 0; +#if 0 + <!-- Roundtrip-mappings that can be enumerated + Note that GB 18030 defines roundtrip mappings for all Unicode code points U+0000..U+10ffff. + This would require 1.1 million <a> elements. + However, most four-byte GB 18030 mappings can be enumerated efficiently within distinct ranges. + Therefore, we use <range> elements for all but the 31000 or so assignments above. + --> + <range uFirst="0452" uLast="200F" bFirst="81 30 D3 30" bLast="81 36 A5 31" bMin="81 30 81 30" bMax="FE 39 FE 39"/> + <range uFirst="2643" uLast="2E80" bFirst="81 37 A8 39" bLast="81 38 FD 38" bMin="81 30 81 30" bMax="FE 39 FE 39"/> + <range uFirst="361B" uLast="3917" bFirst="82 30 A6 33" bLast="82 30 F2 37" bMin="81 30 81 30" bMax="FE 39 FE 39"/> + <range uFirst="3CE1" uLast="4055" bFirst="82 31 D4 38" bLast="82 32 AF 32" bMin="81 30 81 30" bMax="FE 39 FE 39"/> + <range uFirst="4160" uLast="4336" bFirst="82 32 C9 37" bLast="82 32 F8 37" bMin="81 30 81 30" bMax="FE 39 FE 39"/> + <range uFirst="44D7" uLast="464B" bFirst="82 33 A3 39" bLast="82 33 C9 31" bMin="81 30 81 30" bMax="FE 39 FE 39"/> + <range uFirst="478E" uLast="4946" bFirst="82 33 E8 38" bLast="82 34 96 38" bMin="81 30 81 30" bMax="FE 39 FE 39"/> + <range uFirst="49B8" uLast="4C76" bFirst="82 34 A1 31" bLast="82 34 E7 33" bMin="81 30 81 30" bMax="FE 39 FE 39"/> + <range uFirst="9FA6" uLast="D7FF" bFirst="82 35 8F 33" bLast="83 36 C7 38" bMin="81 30 81 30" bMax="FE 39 FE 39"/> + <range uFirst="E865" uLast="F92B" bFirst="83 36 D0 30" bLast="84 30 85 34" bMin="81 30 81 30" bMax="FE 39 FE 39"/> + <range uFirst="FA2A" uLast="FE2F" bFirst="84 30 9C 38" bLast="84 31 85 37" bMin="81 30 81 30" bMax="FE 39 FE 39"/> + <range uFirst="FFE6" uLast="FFFF" bFirst="84 31 A2 34" bLast="84 31 A4 39" bMin="81 30 81 30" bMax="FE 39 FE 39"/> + <range uFirst="10000" uLast="10FFFF" bFirst="90 30 81 30" bLast="E3 32 9A 35" bMin="81 30 81 30" bMax="FE 39 FE 39"/> +#endif +} + +unsigned int +gb18030_to_unicode( unsigned char *s, unsigned char len ) +{ + unsigned int ret; + int found; + ret = gb18030_table_lookup( s, len, &found ); + if ( !found && len==4 ) { + ret = gb18030_range_lookup( s, &found ); + if ( !found ) ret = '?'; + } + return ret; +} + +/* + * Convert unicode character to gb18030 + * + * returns number of characters for output + */ +int +gb18030_encode( unsigned int unicode, unsigned char out[4] ) +{ + int len; + if ( unicode < 0x80 ) { + out[0] = unicode; + len = 1; + } else { + len = gb18030_unicode_table_lookup( unicode, out ); + if ( !len ) + len = gb18030_unicode_range_lookup( unicode, out ); + } + return len; +} + +/* + * Decode a gb18030 character into unicode + */ +unsigned int +gb18030_decode( char *s, unsigned int *pi ) +{ + unsigned int c; + unsigned char uc[4]; + int i = *pi; + uc[0] = ( unsigned char ) s[i]; + if ( ( uc[0] & 128 ) == 0 ) { + c = ( unsigned int ) uc[0]; + i += 1; + } else if ( uc[0] == 0x80 ) { + c = 0x20AC; + i += 1; + } else if ( uc[0] != 0xFF ) { /* multi-byte character */ + uc[1] = ( unsigned char ) s[i+1]; + uc[2] = ( unsigned char ) s[i+2]; + uc[3]= ( unsigned char ) s[i+3]; + if ( in_range( uc[1], 0x40, 0x7e ) || in_range( uc[1], 0x80, 0xfe ) ) { + /* two-byte character */ + c = gb18030_to_unicode( &(uc[0]), 2 ); + i += 2; + } else if ( in_range( uc[1], 0x30, 0x39 ) && + in_range( uc[2], 0x81, 0xfe ) && + in_range( uc[3], 0x30, 0x39 ) ) { + /* four-byte character */ + c = gb18030_to_unicode( &(uc[0]), 4 ); + i += 4; + } else { + /* this is an illegal character */ + c = '?'; + i += 1; + } + } else { /* s[i]==0xFF */ + /* this is an illegal character */ + c = '?'; + i += 1; + } + *pi = i; + return c; +} |