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Improve documentation about MULE encoding. 

This commit improves the comments in pg_wchar.h and creates #define symbols
for some formerly hard-coded values.  No substantive code changes.

Tatsuo Ishii and Tom Lane
This commit is contained in:
Tom Lane 2012-07-04 00:29:57 -04:00
parent 47a2adc83c
commit 09022de1f5
3 changed files with 111 additions and 59 deletions
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17
src/backend/utils/mb/conversion_procs/euc_tw_and_big5/euc_tw_and_big5.c
View File

@ -168,7 +168,8 @@ euc_tw2mic(const unsigned char *euc, unsigned char *p, int len)
*p++ = LC_CNS11643_2;
else
{
*p++ = 0x9d; /* LCPRV2 */
/* other planes are MULE private charsets */
*p++ = LCPRV2_B;
*p++ = c1 - 0xa3 + LC_CNS11643_3;
}
*p++ = euc[2];
@ -235,9 +236,9 @@ mic2euc_tw(const unsigned char *mic, unsigned char *p, int len)
*p++ = mic[1];
*p++ = mic[2];
}
else if (c1 == 0x9d &&
else if (c1 == LCPRV2_B &&
mic[1] >= LC_CNS11643_3 && mic[1] <= LC_CNS11643_7)
{ /* LCPRV2? */
{
*p++ = SS2;
*p++ = mic[1] - LC_CNS11643_3 + 0xa3;
*p++ = mic[2];
@ -286,10 +287,9 @@ big52mic(const unsigned char *big5, unsigned char *p, int len)
cnsBuf = BIG5toCNS(big5buf, &lc);
if (lc != 0)
{
/* Planes 3 and 4 are MULE private charsets */
if (lc == LC_CNS11643_3 || lc == LC_CNS11643_4)
{
*p++ = 0x9d; /* LCPRV2 */
}
*p++ = LCPRV2_B;
*p++ = lc; /* Plane No. */
*p++ = (cnsBuf >> 8) & 0x00ff;
*p++ = cnsBuf & 0x00ff;
@ -332,10 +332,9 @@ mic2big5(const unsigned char *mic, unsigned char *p, int len)
if (l < 0)
report_invalid_encoding(PG_MULE_INTERNAL,
(const char *) mic, len);
/* 0x9d means LCPRV2 */
if (c1 == LC_CNS11643_1 || c1 == LC_CNS11643_2 || c1 == 0x9d)
if (c1 == LC_CNS11643_1 || c1 == LC_CNS11643_2 || c1 == LCPRV2_B)
{
if (c1 == 0x9d)
if (c1 == LCPRV2_B)
{
c1 = mic[1]; /* get plane no. */
cnsBuf = (mic[2] << 8) | mic[3];

6
src/backend/utils/mb/wchar.c
View File

@ -742,6 +742,12 @@ pg_mule_dsplen(const unsigned char *s)
{
int len;
/*
* Note: it's not really appropriate to assume that all multibyte charsets
* are double-wide on screen. But this seems an okay approximation for
* the MULE charsets we currently support.
*/
if (IS_LC1(*s))
len = 1;
else if (IS_LCPRV1(*s))

147
src/include/mb/pg_wchar.h
View File

@ -36,36 +36,60 @@ typedef unsigned int pg_wchar;
#define ISSJISHEAD(c) (((c) >= 0x81 && (c) <= 0x9f) || ((c) >= 0xe0 && (c) <= 0xfc))
#define ISSJISTAIL(c) (((c) >= 0x40 && (c) <= 0x7e) || ((c) >= 0x80 && (c) <= 0xfc))
/*
* Leading byte types or leading prefix byte for MULE internal code.
* See http://www.xemacs.org for more details. (there is a doc titled
* "XEmacs Internals Manual", "MULE Character Sets and Encodings"
* section.)
*/
/*
* Is a leading byte for "official" single byte encodings?
*/
#define IS_LC1(c) ((unsigned char)(c) >= 0x81 && (unsigned char)(c) <= 0x8d)
/*
* Is a prefix byte for "private" single byte encodings?
*/
#define IS_LCPRV1(c) ((unsigned char)(c) == 0x9a || (unsigned char)(c) == 0x9b)
/*
* Is a leading byte for "official" multibyte encodings?
*/
#define IS_LC2(c) ((unsigned char)(c) >= 0x90 && (unsigned char)(c) <= 0x99)
/*
* Is a prefix byte for "private" multibyte encodings?
*/
#define IS_LCPRV2(c) ((unsigned char)(c) == 0x9c || (unsigned char)(c) == 0x9d)
/*----------------------------------------------------
* leading characters
* MULE Internal Encoding (MIC)
*
* This encoding follows the design used within XEmacs; it is meant to
* subsume many externally-defined character sets. Each character includes
* identification of the character set it belongs to, so the encoding is
* general but somewhat bulky.
*
* Currently PostgreSQL supports 5 types of MULE character sets:
*
* 1) 1-byte ASCII characters. Each byte is below 0x80.
*
* 2) "Official" single byte charsets such as ISO-8859-1 (Latin1).
* Each MULE character consists of 2 bytes: LC1 + C1, where LC1 is
* an identifier for the charset (in the range 0x81 to 0x8d) and C1
* is the character code (in the range 0xa0 to 0xff).
*
* 3) "Private" single byte charsets such as SISHENG. Each MULE
* character consists of 3 bytes: LCPRV1 + LC12 + C1, where LCPRV1
* is a private-charset flag, LC12 is an identifier for the charset,
* and C1 is the character code (in the range 0xa0 to 0xff).
* LCPRV1 is either 0x9a (if LC12 is in the range 0xa0 to 0xdf)
* or 0x9b (if LC12 is in the range 0xe0 to 0xef).
*
* 4) "Official" multibyte charsets such as JIS X0208. Each MULE
* character consists of 3 bytes: LC2 + C1 + C2, where LC2 is
* an identifier for the charset (in the range 0x90 to 0x99) and C1
* and C2 form the character code (each in the range 0xa0 to 0xff).
*
* 5) "Private" multibyte charsets such as CNS 11643-1992 Plane 3.
* Each MULE character consists of 4 bytes: LCPRV2 + LC22 + C1 + C2,
* where LCPRV2 is a private-charset flag, LC22 is an identifier for
* the charset, and C1 and C2 form the character code (each in the range
* 0xa0 to 0xff). LCPRV2 is either 0x9c (if LC22 is in the range 0xf0
* to 0xf4) or 0x9d (if LC22 is in the range 0xf5 to 0xfe).
*
* "Official" encodings are those that have been assigned code numbers by
* the XEmacs project; "private" encodings have Postgres-specific charset
* identifiers.
*
* See the "XEmacs Internals Manual", available at http://www.xemacs.org,
* for more details. Note that for historical reasons, Postgres'
* private-charset flag values do not match what XEmacs says they should be,
* so this isn't really exactly MULE (not that private charsets would be
* interoperable anyway).
*----------------------------------------------------
*/
/*
* Official single byte encodings (0x81-0x8e)
* Charset identifiers (also called "leading bytes" in the MULE documentation)
*/
/*
* Charset IDs for official single byte encodings (0x81-0x8e)
*/
#define LC_ISO8859_1 0x81 /* ISO8859 Latin 1 */
#define LC_ISO8859_2 0x82 /* ISO8859 Latin 2 */
@ -79,21 +103,19 @@ typedef unsigned int pg_wchar;
#define LC_JISX0201R 0x8a /* Japanese 1 byte Roman */
/* Note that 0x8b seems to be unused as of Emacs 20.7.
* However, there might be a chance that 0x8b could be used
* in later version of Emacs.
* in later versions of Emacs.
*/
#define LC_KOI8_R 0x8b /* Cyrillic KOI8-R */
#define LC_KOI8_U 0x8b /* Cyrillic KOI8-U */
#define LC_ISO8859_5 0x8c /* ISO8859 Cyrillic */
#define LC_ISO8859_9 0x8d /* ISO8859 Latin 5 (not supported yet) */
/* #define FREE 0x8e free (unused) */
/* #define CONTROL_1 0x8f control characters (unused) */
/* Is a leading byte for "official" single byte encodings? */
#define IS_LC1(c) ((unsigned char)(c) >= 0x81 && (unsigned char)(c) <= 0x8d)
/*
* Unused
*/
#define CONTROL_1 0x8f /* control characters (unused) */
/*
* Official multibyte byte encodings (0x90-0x99)
* Charset IDs for official multibyte encodings (0x90-0x99)
* 0x9a-0x9d are free. 0x9e and 0x9f are reserved.
*/
#define LC_JISX0208_1978 0x90 /* Japanese Kanji, old JIS (not supported) */
@ -108,45 +130,70 @@ typedef unsigned int pg_wchar;
#define LC_BIG5_1 0x98 /* Plane 1 Chinese traditional (not supported) */
#define LC_BIG5_2 0x99 /* Plane 1 Chinese traditional (not supported) */
/* Is a leading byte for "official" multibyte encodings? */
#define IS_LC2(c) ((unsigned char)(c) >= 0x90 && (unsigned char)(c) <= 0x99)
/*
* Private single byte encodings (0xa0-0xef)
* Postgres-specific prefix bytes for "private" single byte encodings
* (According to the MULE docs, we should be using 0x9e for this)
*/
#define LC_SISHENG 0xa0/* Chinese SiSheng characters for
* PinYin/ZhuYin (not supported) */
#define LC_IPA 0xa1/* IPA (International Phonetic Association)
* (not supported) */
#define LC_VISCII_LOWER 0xa2/* Vietnamese VISCII1.1 lower-case (not
* supported) */
#define LC_VISCII_UPPER 0xa3/* Vietnamese VISCII1.1 upper-case (not
* supported) */
#define LCPRV1_A 0x9a
#define LCPRV1_B 0x9b
#define IS_LCPRV1(c) ((unsigned char)(c) == LCPRV1_A || (unsigned char)(c) == LCPRV1_B)
/*
* Postgres-specific prefix bytes for "private" multibyte encodings
* (According to the MULE docs, we should be using 0x9f for this)
*/
#define LCPRV2_A 0x9c
#define LCPRV2_B 0x9d
#define IS_LCPRV2(c) ((unsigned char)(c) == LCPRV2_A || (unsigned char)(c) == LCPRV2_B)
/*
* Charset IDs for private single byte encodings (0xa0-0xef)
*/
#define LC_SISHENG 0xa0 /* Chinese SiSheng characters for
* PinYin/ZhuYin (not supported) */
#define LC_IPA 0xa1 /* IPA (International Phonetic Association)
* (not supported) */
#define LC_VISCII_LOWER 0xa2 /* Vietnamese VISCII1.1 lower-case (not
* supported) */
#define LC_VISCII_UPPER 0xa3 /* Vietnamese VISCII1.1 upper-case (not
* supported) */
#define LC_ARABIC_DIGIT 0xa4 /* Arabic digit (not supported) */
#define LC_ARABIC_1_COLUMN 0xa5 /* Arabic 1-column (not supported) */
#define LC_ASCII_RIGHT_TO_LEFT 0xa6 /* ASCII (left half of ISO8859-1) with
* right-to-left direction (not
* supported) */
#define LC_LAO 0xa7/* Lao characters (ISO10646 0E80..0EDF) (not
* supported) */
#define LC_LAO 0xa7 /* Lao characters (ISO10646 0E80..0EDF)
* (not supported) */
#define LC_ARABIC_2_COLUMN 0xa8 /* Arabic 1-column (not supported) */
/*
* Private multibyte encodings (0xf0-0xff)
* Charset IDs for private multibyte encodings (0xf0-0xff)
*/
#define LC_INDIAN_1_COLUMN 0xf0/* Indian charset for 1-column width glypps
* (not supported) */
#define LC_TIBETAN_1_COLUMN 0xf1 /* Tibetan 1 column glyph (not supported) */
#define LC_INDIAN_1_COLUMN 0xf0 /* Indian charset for 1-column width glyphs
* (not supported) */
#define LC_TIBETAN_1_COLUMN 0xf1 /* Tibetan 1-column width glyphs
* (not supported) */
#define LC_ETHIOPIC 0xf5 /* Ethiopic characters (not supported) */
#define LC_CNS11643_3 0xf6 /* CNS 11643-1992 Plane 3 */
#define LC_CNS11643_4 0xf7 /* CNS 11643-1992 Plane 4 */
#define LC_CNS11643_5 0xf8 /* CNS 11643-1992 Plane 5 */
#define LC_CNS11643_6 0xf9 /* CNS 11643-1992 Plane 6 */
#define LC_CNS11643_7 0xfa /* CNS 11643-1992 Plane 7 */
#define LC_INDIAN_2_COLUMN 0xfb/* Indian charset for 2-column width glypps
* (not supported) */
#define LC_INDIAN_2_COLUMN 0xfb /* Indian charset for 2-column width glyphs
* (not supported) */
#define LC_TIBETAN 0xfc /* Tibetan (not supported) */
/* #define FREE 0xfd free (unused) */
/* #define FREE 0xfe free (unused) */
/* #define FREE 0xff free (unused) */
/*----------------------------------------------------
* end of MULE stuff
*----------------------------------------------------
*/
/*
* PostgreSQL encoding identifiers
*