enhanced qse_mbsxsubst() and qse_wcsxsubst() for buffer size prediction
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@ -125,6 +125,10 @@ struct qse_wcs_t
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qse_size_t capa; /**< buffer capacity */
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};
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#define QSE_MBSSUBST_NOBUF ((qse_mchar_t*)1)
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#define QSE_WCSSUBST_NOBUF ((qse_wchar_t*)1)
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/**
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* The qse_mbssubst_t type defines a callback function for qse_mbsxsubst()
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* and qse_mbsxnsubst() to substitue a new value for an identifier \a ident.
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@ -148,8 +152,10 @@ typedef qse_wchar_t* (*qse_wcssubst_t) (
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);
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#if defined(QSE_CHAR_IS_MCHAR)
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# define QSE_STRSUBST_NOBUF QSE_MBSSUBST_NOBUF
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# define qse_strsubst_t qse_mbssubst_t
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#else
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# define QSE_STRSUBST_NOBUF QSE_WCSSUBST_NOBUF
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# define qse_strsubst_t qse_wcssubst_t
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#endif
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@ -696,6 +702,45 @@ QSE_EXPORT qse_size_t qse_wcsxfncpy (
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* qse_mchar_t buf[25];
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* qse_mbsxsubst (buf, i, QSE_MT("user=${USER},group=${GROUP}"), subst, QSE_NULL);
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* \endcode
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*
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* If \a buf is #QSE_MBSSUBST_NOBUF, the function returns the length of the
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* resulting string that a buffer large enough would be able to hold. You can
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* pass #QSE_MBSSUBST_NOBUF to find out how large a buffer you need to perform
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* substitution without truncation. The substitution callback function should
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* handle this special case for buffer size prediction. The sample callback shown
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* above can be extended to return the buffer pointer without actual copying
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* if the buffer points to #QSE_MBSSUBST_NOBUF as shown belown.
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*
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* \code
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* qse_mchar_t* subst (qse_mchar_t* buf, qse_size_t bsz, const qse_mcstr_t* ident, void* ctx)
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* {
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* if (qse_mcsxcmp (ident->ptr, ident->len, QSE_MT("USER")) == 0)
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* return buf + (buf == QSE_MBSSUBST_NOBUF? 3: qse_mcsxput (buf, bsz, QSE_MT("sam")));
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* else if (qse_mcsxcmp (ident->ptr, ident->len, QSE_MT("GROUP")) == 0)
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* return buf + (buf == QSE_MBSSUBST_NOBUF? 6: qse_mcsxput (buf, bsz, QSE_MT("coders")));
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* return buf;
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* }
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*
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* len = qse_mbsxsubst (QSE_MBSSUBST_NOBUF, 0, QSE_MT("user=${USER},group=${GROUP}"), subst, QSE_NULL);
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* buf = malloc (QSE_SIZEOF(qse_mbs_t) * (len + 1));
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* qse_mbsxsubst (buf, len + 1, QSE_MT("user=${USER},group=${GROUP}"), subst, QSE_NULL);
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* \endcode
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*
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* A ${} segment may contain a default value. For example, the segment
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* ${USER:=Unknown} translates to Unknown if the callback function returns
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* #QSE_NULL for USER. The default value part may contain ${} segments
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* recursively.
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*
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* \code
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* qse_mchar_t* subst (qse_mchar_t* buf, qse_size_t bsz, const qse_mcstr_t* ident, void* ctx)
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* {
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* if (qse_mbsxcmp (ident->ptr, ident->len, QSE_MT("USER")) == 0)
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* return QSE_NULL;
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* else if (qse_mbsxcmp (ident->ptr, ident->len, QSE_MT("GROUP")) == 0)
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* return buf + (buf == QSE_MBSSUBST_NOBUF? 6: qse_wcsxput (buf, bsz, QSE_MT("coders")));
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* return buf;
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* }
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* \endcode
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*/
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QSE_EXPORT qse_size_t qse_mbsxsubst (
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qse_mchar_t* buf,
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@ -731,6 +776,44 @@ QSE_EXPORT qse_size_t qse_mbsxnsubst (
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* qse_wchar_t buf[25];
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* qse_wcsxsubst (buf, i, QSE_WT("user=${USER},group=${GROUP}"), subst, QSE_NULL);
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* \endcode
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*
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* If \a buf is #QSE_WCSSUBST_NOBUF, the function returns the length of the
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* resulting string that a buffer large enough would be able to hold. You can
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* pass #QSE_WCSSUBST_NOBUF to find out how large a buffer you need to perform
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* substitution without truncation. The substitution callback function should
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* handle this special case for buffer size prediction. The sample callback shown
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* above can be extended to return the buffer pointer without actual copying
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*
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* \code
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* qse_mchar_t* subst (qse_mchar_t* buf, qse_size_t bsz, const qse_wcstr_t* ident, void* ctx)
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* {
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* if (qse_wcsxcmp (ident->ptr, ident->len, QSE_WT("USER")) == 0)
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* return buf + (buf == QSE_WCSSUBST_NOBUF? 3: qse_wcsxput (buf, bsz, QSE_WT("sam")));
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* else if (qse_wcsxcmp (ident->ptr, ident->len, QSE_WT("GROUP")) == 0)
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* return buf + (buf == QSE_WCSSUBST_NOBUF? 6: qse_wcsxput (buf, bsz, QSE_WT("coders")));
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* return buf;
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* }
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*
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* len = qse_wcsxsubst (QSE_WCSSUBST_NOBUF, 0, QSE_WT("user=${USER},group=${GROUP}"), subst, QSE_NULL);
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* buf = malloc (QSE_SIZEOF(qse_wcs_t) * (len + 1));
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* qse_wcsxsubst (buf, len + 1, QSE_WT("user=${USER},group=${GROUP}"), subst, QSE_NULL);
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* \endcode
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*
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* A ${} segment may contain a default value. For example, the segment
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* ${USER:=Unknown} translates to Unknown if the callback function returns
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* #QSE_NULL for USER. The default value part may contain ${} segments
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* recursively.
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*
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* \code
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* qse_mchar_t* subst (qse_mchar_t* buf, qse_size_t bsz, const qse_wcstr_t* ident, void* ctx)
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* {
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* if (qse_wcsxcmp (ident->ptr, ident->len, QSE_WT("USER")) == 0)
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* return QSE_NULL;
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* else if (qse_wcsxcmp (ident->ptr, ident->len, QSE_WT("GROUP")) == 0)
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* return buf + (buf == QSE_WCSSUBST_NOBUF? 6: qse_wcsxput (buf, bsz, QSE_WT("coders")));
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* return buf;
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* }
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* \endcode
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*/
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QSE_EXPORT qse_size_t qse_wcsxsubst (
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qse_wchar_t* buf,
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@ -25,6 +25,7 @@
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#undef char_t
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#undef cstr_t
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#undef T
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#undef NOBUF
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#undef strlen
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#undef scan_dollar
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#undef expand_dollar
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@ -35,6 +36,7 @@
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#define char_t qse_mchar_t
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#define cstr_t qse_mcstr_t
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#define T(x) QSE_MT(x)
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#define NOBUF QSE_MBSSUBST_NOBUF
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#define strlen qse_mbslen
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#define scan_dollar mbs_scan_dollar
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#define expand_dollar mbs_expand_dollar
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@ -48,6 +50,7 @@
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#undef char_t
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#undef cstr_t
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#undef T
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#undef NOBUF
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#undef strlen
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#undef scan_dollar
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#undef expand_dollar
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@ -58,6 +61,7 @@
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#define char_t qse_wchar_t
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#define cstr_t qse_wcstr_t
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#define T(x) QSE_WT(x)
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#define NOBUF QSE_WCSSUBST_NOBUF
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#define strlen qse_wcslen
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#define scan_dollar wcs_scan_dollar
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#define expand_dollar wcs_expand_dollar
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@ -122,7 +122,7 @@ qse_size_t strxnsubst (
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const char_t* f = fmt;
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const char_t* fend = fmt + fsz;
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if (bsz <= 0) return 0;
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if (buf != NOBUF && bsz <= 0) return 0;
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while (f < fend)
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{
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@ -144,8 +144,18 @@ qse_size_t strxnsubst (
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if (tmp == QSE_NULL || ident.len <= 0) goto normal;
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f = tmp;
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if (buf != NOBUF)
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{
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b = expand_dollar (b, end - b + 1, &ident, &dfl, subst, ctx);
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if (b >= end) goto fini;
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}
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else
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{
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/* the buffer points to NOBUF. */
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tmp = expand_dollar (buf, bsz, &ident, &dfl, subst, ctx);
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/* increment b by the length of the expanded string */
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b += (tmp - buf);
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}
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continue;
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}
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@ -157,12 +167,16 @@ qse_size_t strxnsubst (
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}
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normal:
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if (buf != NOBUF)
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{
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if (b >= end) break;
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*b++ = *f++;
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*b = *f;
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}
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b++; f++;
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}
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fini:
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*b = T('\0');
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if (buf != NOBUF) *b = T('\0');
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return b - buf;
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}
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@ -172,3 +186,4 @@ qse_size_t strxsubst (
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{
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return strxnsubst (buf, bsz, fmt, strlen(fmt), subst, ctx);
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}
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