euc_cn_and_mic.c

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/*-------------------------------------------------------------------------
 *
 *    EUC_CN and MULE_INTERNAL
 *
 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *    src/backend/utils/mb/conversion_procs/euc_cn_and_mic/euc_cn_and_mic.c
 *
 *-------------------------------------------------------------------------
 */
 
#include "postgres.h"
#include "fmgr.h"
#include "mb/pg_wchar.h"
 
PG_MODULE_MAGIC_EXT(
                    .name = "euc_cn_and_mic",
                    .version = PG_VERSION
);
 
PG_FUNCTION_INFO_V1(euc_cn_to_mic);
PG_FUNCTION_INFO_V1(mic_to_euc_cn);
 
/* ----------
 * conv_proc(
 *      INTEGER,    -- source encoding id
 *      INTEGER,    -- destination encoding id
 *      CSTRING,    -- source string (null terminated C string)
 *      CSTRING,    -- destination string (null terminated C string)
 *      INTEGER,    -- source string length
 *      BOOL        -- if true, don't throw an error if conversion fails
 * ) returns INTEGER;
 *
 * Returns the number of bytes successfully converted.
 * ----------
 */
 
static int  euc_cn2mic(const unsigned char *euc, unsigned char *p, int len, bool noError);
static int  mic2euc_cn(const unsigned char *mic, unsigned char *p, int len, bool noError);
 
Datum
euc_cn_to_mic(PG_FUNCTION_ARGS)
{
    unsigned char *src = (unsigned char *) PG_GETARG_CSTRING(2);
    unsigned char *dest = (unsigned char *) PG_GETARG_CSTRING(3);
    int         len = PG_GETARG_INT32(4);
    bool        noError = PG_GETARG_BOOL(5);
    int         converted;
 
    CHECK_ENCODING_CONVERSION_ARGS(PG_EUC_CN, PG_MULE_INTERNAL);
 
    converted = euc_cn2mic(src, dest, len, noError);
 
    PG_RETURN_INT32(converted);
}
 
Datum
mic_to_euc_cn(PG_FUNCTION_ARGS)
{
    unsigned char *src = (unsigned char *) PG_GETARG_CSTRING(2);
    unsigned char *dest = (unsigned char *) PG_GETARG_CSTRING(3);
    int         len = PG_GETARG_INT32(4);
    bool        noError = PG_GETARG_BOOL(5);
    int         converted;
 
    CHECK_ENCODING_CONVERSION_ARGS(PG_MULE_INTERNAL, PG_EUC_CN);
 
    converted = mic2euc_cn(src, dest, len, noError);
 
    PG_RETURN_INT32(converted);
}
 
/*
 * EUC_CN ---> MIC
 */
static int
euc_cn2mic(const unsigned char *euc, unsigned char *p, int len, bool noError)
{
    const unsigned char *start = euc;
    int         c1;
 
    while (len > 0)
    {
        c1 = *euc;
        if (IS_HIGHBIT_SET(c1))
        {
            if (len < 2 || !IS_HIGHBIT_SET(euc[1]))
            {
                if (noError)
                    break;
                report_invalid_encoding(PG_EUC_CN, (const char *) euc, len);
            }
            *p++ = LC_GB2312_80;
            *p++ = c1;
            *p++ = euc[1];
            euc += 2;
            len -= 2;
        }
        else
        {                       /* should be ASCII */
            if (c1 == 0)
            {
                if (noError)
                    break;
                report_invalid_encoding(PG_EUC_CN, (const char *) euc, len);
            }
            *p++ = c1;
            euc++;
            len--;
        }
    }
    *p = '\0';
 
    return euc - start;
}
 
/*
 * MIC ---> EUC_CN
 */
static int
mic2euc_cn(const unsigned char *mic, unsigned char *p, int len, bool noError)
{
    const unsigned char *start = mic;
    int         c1;
 
    while (len > 0)
    {
        c1 = *mic;
        if (IS_HIGHBIT_SET(c1))
        {
            if (c1 != LC_GB2312_80)
            {
                if (noError)
                    break;
                report_untranslatable_char(PG_MULE_INTERNAL, PG_EUC_CN,
                                           (const char *) mic, len);
            }
            if (len < 3 || !IS_HIGHBIT_SET(mic[1]) || !IS_HIGHBIT_SET(mic[2]))
            {
                if (noError)
                    break;
                report_invalid_encoding(PG_MULE_INTERNAL,
                                        (const char *) mic, len);
            }
            mic++;
            *p++ = *mic++;
            *p++ = *mic++;
            len -= 3;
        }
        else
        {                       /* should be ASCII */
            if (c1 == 0)
            {
                if (noError)
                    break;
                report_invalid_encoding(PG_MULE_INTERNAL,
                                        (const char *) mic, len);
            }
            *p++ = c1;
            mic++;
            len--;
        }
    }
    *p = '\0';
 
    return mic - start;
}