stringinfo_mb.c

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/*-------------------------------------------------------------------------
 *
 * stringinfo_mb.c
 *      Multibyte encoding-aware additional StringInfo facilities
 *
 * This is separate from common/stringinfo.c so that frontend users
 * of that file need not pull in unnecessary multibyte-encoding support
 * code.
 *
 *
 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    src/backend/utils/mb/stringinfo_mb.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"
 
#include "mb/pg_wchar.h"
#include "mb/stringinfo_mb.h"
 
 
/*
 * appendStringInfoStringQuoted
 *
 * Append up to maxlen bytes from s to str, or the whole input string if
 * maxlen < 0, adding single quotes around it and doubling all single quotes.
 * Add an ellipsis if the copy is incomplete.
 */
void
appendStringInfoStringQuoted(StringInfo str, const char *s, int maxlen)
{
    char       *copy = NULL;
    const char *chunk_search_start,
               *chunk_copy_start,
               *chunk_end;
    int         slen;
    bool        ellipsis;
 
    Assert(str != NULL);
 
    slen = strlen(s);
    if (maxlen >= 0 && maxlen < slen)
    {
        int         finallen = pg_mbcliplen(s, slen, maxlen);
 
        copy = pnstrdup(s, finallen);
        chunk_search_start = copy;
        chunk_copy_start = copy;
 
        ellipsis = true;
    }
    else
    {
        chunk_search_start = s;
        chunk_copy_start = s;
 
        ellipsis = false;
    }
 
    appendStringInfoCharMacro(str, '\'');
 
    while ((chunk_end = strchr(chunk_search_start, '\'')) != NULL)
    {
        /* copy including the found delimiting ' */
        appendBinaryStringInfoNT(str,
                                 chunk_copy_start,
                                 chunk_end - chunk_copy_start + 1);
 
        /* in order to double it, include this ' into the next chunk as well */
        chunk_copy_start = chunk_end;
        chunk_search_start = chunk_end + 1;
    }
 
    /* copy the last chunk and terminate */
    if (ellipsis)
        appendStringInfo(str, "%s...'", chunk_copy_start);
    else
        appendStringInfo(str, "%s'", chunk_copy_start);
 
    if (copy)
        pfree(copy);
}