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Simplify decoding error handling
* libguile/ports.c (peek_utf8_codepoint, peek_latin1_codepoint): (peek_iconv_codepoint, peek_codepoint): Refactor to push error handling to the leaves, where errors happen. Just return the (possibly substituted) codepoint, without an error code; if there's really an error, we should raise it. (scm_getc, scm_peek_char): Adapt.
This commit is contained in:
Andy Wingo
parent
1953d29038
commit
08c67dbef8
1 changed files with 88 additions and 113 deletions
193
libguile/ports.c
193
libguile/ports.c
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@ -1598,27 +1598,27 @@ utf8_to_codepoint (const scm_t_uint8 *utf8_buf, size_t size)
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return codepoint;
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}
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/* Peek a UTF-8 sequence from PORT. On success, return 0, set
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*CODEPOINT to the codepoint that was read, and set *LEN to the length
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in bytes. Return `EILSEQ' on error, setting *LEN to the shortest
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prefix that cannot begin a valid UTF-8 sequence. */
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static int
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peek_utf8_codepoint (SCM port, scm_t_wchar *codepoint, size_t *len)
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/* Peek a UTF-8 sequence from PORT. On success, return the codepoint
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that was read, and set *LEN to the length in bytes. If there was a
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decoding error and the port conversion strategy was `substitute',
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then return #\? and set *LEN to the length of the shortest prefix
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that cannot begin a valid UTF-8 sequence. Otherwise signal an
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error. */
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static scm_t_wchar
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peek_utf8_codepoint (SCM port, size_t *len)
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{
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#define DECODING_ERROR(bytes) \
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do { *len = bytes; goto decoding_error; } while (0)
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#define RETURN(bytes, codepoint) \
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do { *len = bytes; return codepoint; } while (0)
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int first_byte;
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first_byte = peek_byte_or_eof (port);
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if (first_byte == EOF)
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{
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*codepoint = EOF;
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return 0;
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}
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RETURN (0, EOF);
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else if (first_byte < 0x80)
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{
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*codepoint = first_byte;
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*len = 1;
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return 0;
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}
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RETURN (1, first_byte);
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else if (first_byte >= 0xc2 && first_byte <= 0xdf)
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{
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SCM read_buf = scm_fill_input (port, 2);
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@ -1626,14 +1626,9 @@ peek_utf8_codepoint (SCM port, scm_t_wchar *codepoint, size_t *len)
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const scm_t_uint8 *ptr = scm_port_buffer_take_pointer (read_buf);
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if (can_take < 2 || (ptr[1] & 0xc0) != 0x80)
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{
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*len = 1;
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return EILSEQ;
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}
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DECODING_ERROR (1);
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*codepoint = (first_byte & 0x1f) << 6UL | (ptr[1] & 0x3f);
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*len = 2;
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return 0;
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RETURN (2, (first_byte & 0x1f) << 6UL | (ptr[1] & 0x3f));
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}
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else if ((first_byte & 0xf0) == 0xe0)
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{
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@ -1644,22 +1639,15 @@ peek_utf8_codepoint (SCM port, scm_t_wchar *codepoint, size_t *len)
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if (can_take < 2 || (ptr[1] & 0xc0) != 0x80
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|| (ptr[0] == 0xe0 && ptr[1] < 0xa0)
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|| (ptr[0] == 0xed && ptr[1] > 0x9f))
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{
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*len = 1;
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return EILSEQ;
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}
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DECODING_ERROR (1);
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if (can_take < 3 || (ptr[2] & 0xc0) != 0x80)
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{
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*len = 2;
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return EILSEQ;
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}
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DECODING_ERROR (2);
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*codepoint = ((scm_t_wchar) ptr[0] & 0x0f) << 12UL
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RETURN (3,
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((scm_t_wchar) ptr[0] & 0x0f) << 12UL
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| ((scm_t_wchar) ptr[1] & 0x3f) << 6UL
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| (ptr[2] & 0x3f);
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*len = 3;
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return 0;
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| (ptr[2] & 0x3f));
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}
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else if (first_byte >= 0xf0 && first_byte <= 0xf4)
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{
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@ -1670,56 +1658,55 @@ peek_utf8_codepoint (SCM port, scm_t_wchar *codepoint, size_t *len)
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if (can_take < 2 || (ptr[1] & 0xc0) != 0x80
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|| (ptr[0] == 0xf0 && ptr[1] < 0x90)
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|| (ptr[0] == 0xf4 && ptr[1] > 0x8f))
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{
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*len = 1;
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return EILSEQ;
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}
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DECODING_ERROR (1);
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if (can_take < 3 || (ptr[2] & 0xc0) != 0x80)
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{
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*len = 2;
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return EILSEQ;
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}
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DECODING_ERROR (2);
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if (can_take < 4 || (ptr[3] & 0xc0) != 0x80)
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{
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*len = 3;
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return EILSEQ;
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}
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DECODING_ERROR (3);
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*codepoint = ((scm_t_wchar) ptr[0] & 0x07) << 18UL
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RETURN (4,
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((scm_t_wchar) ptr[0] & 0x07) << 18UL
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| ((scm_t_wchar) ptr[1] & 0x3f) << 12UL
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| ((scm_t_wchar) ptr[2] & 0x3f) << 6UL
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| (ptr[3] & 0x3f);
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*len = 4;
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return 0;
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| (ptr[3] & 0x3f));
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}
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else
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{
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*len = 1;
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return EILSEQ;
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}
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DECODING_ERROR (1);
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decoding_error:
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if (scm_is_eq (SCM_PTAB_ENTRY (port)->conversion_strategy, sym_substitute))
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/* *len already set. */
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return '?';
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scm_decoding_error ("peek-char", EILSEQ, "input decoding error", port);
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/* Not reached. */
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return 0;
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#undef DECODING_ERROR
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#undef RETURN
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}
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/* Peek an ISO-8859-1 codepoint (a byte) from PORT. On success, return
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0, set *CODEPOINT to the codepoint that was peeked, and set *LEN to
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the length in bytes. No encoding error is possible. */
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static int
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peek_latin1_codepoint (SCM port, scm_t_wchar *codepoint, size_t *len)
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the codepoint, and set *LEN to 1. Otherwise on EOF set *LEN to 0. */
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static scm_t_wchar
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peek_latin1_codepoint (SCM port, size_t *len)
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{
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*codepoint = peek_byte_or_eof (port);
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if (*codepoint == EOF)
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*len = 0;
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else
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*len = 1;
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return 0;
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scm_t_wchar ret = peek_byte_or_eof (port);
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*len = ret == EOF ? 0 : 1;
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return ret;
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}
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/* Peek a codepoint from PORT, decoding it through iconv. On success,
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return 0, set *CODEPOINT to the codepoint that was peeked, and set
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*LEN to the length in bytes. Return `EILSEQ' on decoding error. */
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static int
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peek_iconv_codepoint (SCM port, scm_t_wchar *codepoint, size_t *len)
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return the codepoint and set *LEN to the length in bytes. If there
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was a decoding error and the port conversion strategy was
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`substitute', then return #\? and set *LEN to the length of the
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shortest prefix that cannot begin a valid UTF-8 sequence. Otherwise
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signal an error. */
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static scm_t_wchar
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peek_iconv_codepoint (SCM port, size_t *len)
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{
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scm_t_iconv_descriptors *id;
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scm_t_uint8 utf8_buf[SCM_MBCHAR_BUF_SIZE];
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@ -1736,16 +1723,13 @@ peek_iconv_codepoint (SCM port, scm_t_wchar *codepoint, size_t *len)
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if (scm_port_buffer_can_take (read_buf) <= input_size)
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{
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*len = input_size;
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if (input_size == 0)
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/* Normal EOF. */
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{
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*codepoint = (scm_t_wchar) EOF;
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*len = 0;
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return 0;
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}
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else
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return EOF;
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/* EOF found in the middle of a multibyte character. */
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return EILSEQ;
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goto decoding_error;
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}
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input_size++;
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@ -1764,8 +1748,9 @@ peek_iconv_codepoint (SCM port, scm_t_wchar *codepoint, size_t *len)
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/* The input byte sequence did not form a complete
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character. Read another byte and try again. */
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continue;
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else
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return err;
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*len = input_size;
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goto decoding_error;
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}
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else
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{
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@ -1779,36 +1764,35 @@ peek_iconv_codepoint (SCM port, scm_t_wchar *codepoint, size_t *len)
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/* iconv generated output. Convert the UTF8_BUF sequence
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to a Unicode code point. */
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*codepoint = utf8_to_codepoint (utf8_buf, output_size);
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*len = input_size;
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return utf8_to_codepoint (utf8_buf, output_size);
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}
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}
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decoding_error:
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if (scm_is_eq (SCM_PTAB_ENTRY (port)->conversion_strategy, sym_substitute))
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return '?';
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scm_decoding_error ("peek-char", EILSEQ, "input decoding error",
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port);
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/* Not reached. */
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return 0;
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}
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}
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}
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/* Peek a codepoint from PORT and return it in *CODEPOINT. Set *LEN to
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the length in bytes of that representation. Return 0 on success and
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an errno value on error. */
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static SCM_C_INLINE int
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peek_codepoint (SCM port, scm_t_wchar *codepoint, size_t *len)
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static SCM_C_INLINE scm_t_wchar
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peek_codepoint (SCM port, size_t *len)
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{
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int err;
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scm_t_port *pt = SCM_PTAB_ENTRY (port);
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SCM encoding = SCM_PTAB_ENTRY (port)->encoding;
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if (scm_is_eq (pt->encoding, sym_UTF_8))
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err = peek_utf8_codepoint (port, codepoint, len);
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else if (scm_is_eq (pt->encoding, sym_ISO_8859_1))
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err = peek_latin1_codepoint (port, codepoint, len);
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if (scm_is_eq (encoding, sym_UTF_8))
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return peek_utf8_codepoint (port, len);
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else if (scm_is_eq (encoding, sym_ISO_8859_1))
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return peek_latin1_codepoint (port, len);
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else
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err = peek_iconv_codepoint (port, codepoint, len);
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if (err != 0 && scm_is_eq (pt->conversion_strategy, sym_substitute))
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{
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*codepoint = '?';
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err = 0;
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}
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return err;
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return peek_iconv_codepoint (port, len);
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}
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/* Read a codepoint from PORT and return it. */
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@ -1816,13 +1800,10 @@ scm_t_wchar
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scm_getc (SCM port)
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#define FUNC_NAME "scm_getc"
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{
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int err;
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size_t len = 0;
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scm_t_wchar codepoint = EOF;
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scm_t_wchar codepoint;
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err = peek_codepoint (port, &codepoint, &len);
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if (SCM_UNLIKELY (err != 0))
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scm_decoding_error (FUNC_NAME, err, "input decoding error", port);
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codepoint = peek_codepoint (port, &len);
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scm_port_buffer_did_take (SCM_PTAB_ENTRY (port)->read_buf, len);
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if (codepoint == EOF)
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scm_i_clear_pending_eof (port);
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@ -2009,7 +1990,6 @@ SCM_DEFINE (scm_peek_char, "peek-char", 0, 1, 0,
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"sequence when the error is raised.\n")
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#define FUNC_NAME s_scm_peek_char
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{
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int err;
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scm_t_wchar c;
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size_t len = 0;
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@ -2017,14 +1997,9 @@ SCM_DEFINE (scm_peek_char, "peek-char", 0, 1, 0,
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port = scm_current_input_port ();
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SCM_VALIDATE_OPINPORT (1, port);
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err = peek_codepoint (port, &c, &len);
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c = peek_codepoint (port, &len);
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if (err == 0)
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return c == EOF ? SCM_EOF_VAL : SCM_MAKE_CHAR (c);
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scm_decoding_error (FUNC_NAME, err, "input decoding error", port);
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/* Not reached. */
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return SCM_BOOL_F;
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}
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#undef FUNC_NAME
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