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[Guile-commits] 03/05: Simplify decoding error handling
From: |
Andy Wingo |
Subject: |
[Guile-commits] 03/05: Simplify decoding error handling |
Date: |
Tue, 10 May 2016 10:51:24 +0000 (UTC) |
wingo pushed a commit to branch wip-port-refactor
in repository guile.
commit 08c67dbef87e343de19eb744b076d24b31f0508c
Author: Andy Wingo <address@hidden>
Date: Tue May 10 12:09:30 2016 +0200
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.
---
libguile/ports.c | 201 ++++++++++++++++++++++++------------------------------
1 file changed, 88 insertions(+), 113 deletions(-)
diff --git a/libguile/ports.c b/libguile/ports.c
index 6b9c4f5..bbe3867 100644
--- a/libguile/ports.c
+++ b/libguile/ports.c
@@ -1598,27 +1598,27 @@ utf8_to_codepoint (const scm_t_uint8 *utf8_buf, size_t
size)
return codepoint;
}
-/* Peek a UTF-8 sequence from PORT. On success, return 0, set
- *CODEPOINT to the codepoint that was read, and set *LEN to the length
- in bytes. Return `EILSEQ' on error, setting *LEN to the shortest
- prefix that cannot begin a valid UTF-8 sequence. */
-static int
-peek_utf8_codepoint (SCM port, scm_t_wchar *codepoint, size_t *len)
+/* Peek a UTF-8 sequence from PORT. On success, return the codepoint
+ that was read, and set *LEN to the length in bytes. If there was a
+ decoding error and the port conversion strategy was `substitute',
+ then return #\? and set *LEN to the length of the shortest prefix
+ that cannot begin a valid UTF-8 sequence. Otherwise signal an
+ error. */
+static scm_t_wchar
+peek_utf8_codepoint (SCM port, size_t *len)
{
+#define DECODING_ERROR(bytes) \
+ do { *len = bytes; goto decoding_error; } while (0)
+#define RETURN(bytes, codepoint) \
+ do { *len = bytes; return codepoint; } while (0)
+
int first_byte;
first_byte = peek_byte_or_eof (port);
if (first_byte == EOF)
- {
- *codepoint = EOF;
- return 0;
- }
+ RETURN (0, EOF);
else if (first_byte < 0x80)
- {
- *codepoint = first_byte;
- *len = 1;
- return 0;
- }
+ RETURN (1, first_byte);
else if (first_byte >= 0xc2 && first_byte <= 0xdf)
{
SCM read_buf = scm_fill_input (port, 2);
@@ -1626,14 +1626,9 @@ peek_utf8_codepoint (SCM port, scm_t_wchar *codepoint,
size_t *len)
const scm_t_uint8 *ptr = scm_port_buffer_take_pointer (read_buf);
if (can_take < 2 || (ptr[1] & 0xc0) != 0x80)
- {
- *len = 1;
- return EILSEQ;
- }
+ DECODING_ERROR (1);
- *codepoint = (first_byte & 0x1f) << 6UL | (ptr[1] & 0x3f);
- *len = 2;
- return 0;
+ RETURN (2, (first_byte & 0x1f) << 6UL | (ptr[1] & 0x3f));
}
else if ((first_byte & 0xf0) == 0xe0)
{
@@ -1644,22 +1639,15 @@ peek_utf8_codepoint (SCM port, scm_t_wchar *codepoint,
size_t *len)
if (can_take < 2 || (ptr[1] & 0xc0) != 0x80
|| (ptr[0] == 0xe0 && ptr[1] < 0xa0)
|| (ptr[0] == 0xed && ptr[1] > 0x9f))
- {
- *len = 1;
- return EILSEQ;
- }
+ DECODING_ERROR (1);
if (can_take < 3 || (ptr[2] & 0xc0) != 0x80)
- {
- *len = 2;
- return EILSEQ;
- }
+ DECODING_ERROR (2);
- *codepoint = ((scm_t_wchar) ptr[0] & 0x0f) << 12UL
- | ((scm_t_wchar) ptr[1] & 0x3f) << 6UL
- | (ptr[2] & 0x3f);
- *len = 3;
- return 0;
+ RETURN (3,
+ ((scm_t_wchar) ptr[0] & 0x0f) << 12UL
+ | ((scm_t_wchar) ptr[1] & 0x3f) << 6UL
+ | (ptr[2] & 0x3f));
}
else if (first_byte >= 0xf0 && first_byte <= 0xf4)
{
@@ -1670,56 +1658,55 @@ peek_utf8_codepoint (SCM port, scm_t_wchar *codepoint,
size_t *len)
if (can_take < 2 || (ptr[1] & 0xc0) != 0x80
|| (ptr[0] == 0xf0 && ptr[1] < 0x90)
|| (ptr[0] == 0xf4 && ptr[1] > 0x8f))
- {
- *len = 1;
- return EILSEQ;
- }
+ DECODING_ERROR (1);
if (can_take < 3 || (ptr[2] & 0xc0) != 0x80)
- {
- *len = 2;
- return EILSEQ;
- }
+ DECODING_ERROR (2);
if (can_take < 4 || (ptr[3] & 0xc0) != 0x80)
- {
- *len = 3;
- return EILSEQ;
- }
+ DECODING_ERROR (3);
- *codepoint = ((scm_t_wchar) ptr[0] & 0x07) << 18UL
- | ((scm_t_wchar) ptr[1] & 0x3f) << 12UL
- | ((scm_t_wchar) ptr[2] & 0x3f) << 6UL
- | (ptr[3] & 0x3f);
- *len = 4;
- return 0;
+ RETURN (4,
+ ((scm_t_wchar) ptr[0] & 0x07) << 18UL
+ | ((scm_t_wchar) ptr[1] & 0x3f) << 12UL
+ | ((scm_t_wchar) ptr[2] & 0x3f) << 6UL
+ | (ptr[3] & 0x3f));
}
else
- {
- *len = 1;
- return EILSEQ;
- }
+ DECODING_ERROR (1);
+
+ decoding_error:
+ if (scm_is_eq (SCM_PTAB_ENTRY (port)->conversion_strategy, sym_substitute))
+ /* *len already set. */
+ return '?';
+
+ scm_decoding_error ("peek-char", EILSEQ, "input decoding error", port);
+ /* Not reached. */
+ return 0;
+#undef DECODING_ERROR
+#undef RETURN
}
/* Peek an ISO-8859-1 codepoint (a byte) from PORT. On success, return
- 0, set *CODEPOINT to the codepoint that was peeked, and set *LEN to
- the length in bytes. No encoding error is possible. */
-static int
-peek_latin1_codepoint (SCM port, scm_t_wchar *codepoint, size_t *len)
+ the codepoint, and set *LEN to 1. Otherwise on EOF set *LEN to 0. */
+static scm_t_wchar
+peek_latin1_codepoint (SCM port, size_t *len)
{
- *codepoint = peek_byte_or_eof (port);
- if (*codepoint == EOF)
- *len = 0;
- else
- *len = 1;
- return 0;
+ scm_t_wchar ret = peek_byte_or_eof (port);
+
+ *len = ret == EOF ? 0 : 1;
+
+ return ret;
}
/* Peek a codepoint from PORT, decoding it through iconv. On success,
- return 0, set *CODEPOINT to the codepoint that was peeked, and set
- *LEN to the length in bytes. Return `EILSEQ' on decoding error. */
-static int
-peek_iconv_codepoint (SCM port, scm_t_wchar *codepoint, size_t *len)
+ return the codepoint and set *LEN to the length in bytes. If there
+ was a decoding error and the port conversion strategy was
+ `substitute', then return #\? and set *LEN to the length of the
+ shortest prefix that cannot begin a valid UTF-8 sequence. Otherwise
+ signal an error. */
+static scm_t_wchar
+peek_iconv_codepoint (SCM port, size_t *len)
{
scm_t_iconv_descriptors *id;
scm_t_uint8 utf8_buf[SCM_MBCHAR_BUF_SIZE];
@@ -1736,16 +1723,13 @@ peek_iconv_codepoint (SCM port, scm_t_wchar *codepoint,
size_t *len)
if (scm_port_buffer_can_take (read_buf) <= input_size)
{
+ *len = input_size;
if (input_size == 0)
/* Normal EOF. */
- {
- *codepoint = (scm_t_wchar) EOF;
- *len = 0;
- return 0;
- }
- else
- /* EOF found in the middle of a multibyte character. */
- return EILSEQ;
+ return EOF;
+
+ /* EOF found in the middle of a multibyte character. */
+ goto decoding_error;
}
input_size++;
@@ -1764,8 +1748,9 @@ peek_iconv_codepoint (SCM port, scm_t_wchar *codepoint,
size_t *len)
/* The input byte sequence did not form a complete
character. Read another byte and try again. */
continue;
- else
- return err;
+
+ *len = input_size;
+ goto decoding_error;
}
else
{
@@ -1779,36 +1764,35 @@ peek_iconv_codepoint (SCM port, scm_t_wchar *codepoint,
size_t *len)
/* iconv generated output. Convert the UTF8_BUF sequence
to a Unicode code point. */
- *codepoint = utf8_to_codepoint (utf8_buf, output_size);
*len = input_size;
- return 0;
+ return utf8_to_codepoint (utf8_buf, output_size);
}
}
+
+ decoding_error:
+ if (scm_is_eq (SCM_PTAB_ENTRY (port)->conversion_strategy, sym_substitute))
+ return '?';
+
+ scm_decoding_error ("peek-char", EILSEQ, "input decoding error",
+ port);
+ /* Not reached. */
+ return 0;
}
/* Peek a codepoint from PORT and return it in *CODEPOINT. Set *LEN to
the length in bytes of that representation. Return 0 on success and
an errno value on error. */
-static SCM_C_INLINE int
-peek_codepoint (SCM port, scm_t_wchar *codepoint, size_t *len)
+static SCM_C_INLINE scm_t_wchar
+peek_codepoint (SCM port, size_t *len)
{
- int err;
- scm_t_port *pt = SCM_PTAB_ENTRY (port);
+ SCM encoding = SCM_PTAB_ENTRY (port)->encoding;
- if (scm_is_eq (pt->encoding, sym_UTF_8))
- err = peek_utf8_codepoint (port, codepoint, len);
- else if (scm_is_eq (pt->encoding, sym_ISO_8859_1))
- err = peek_latin1_codepoint (port, codepoint, len);
+ if (scm_is_eq (encoding, sym_UTF_8))
+ return peek_utf8_codepoint (port, len);
+ else if (scm_is_eq (encoding, sym_ISO_8859_1))
+ return peek_latin1_codepoint (port, len);
else
- err = peek_iconv_codepoint (port, codepoint, len);
-
- if (err != 0 && scm_is_eq (pt->conversion_strategy, sym_substitute))
- {
- *codepoint = '?';
- err = 0;
- }
-
- return err;
+ return peek_iconv_codepoint (port, len);
}
/* Read a codepoint from PORT and return it. */
@@ -1816,13 +1800,10 @@ scm_t_wchar
scm_getc (SCM port)
#define FUNC_NAME "scm_getc"
{
- int err;
size_t len = 0;
- scm_t_wchar codepoint = EOF;
+ scm_t_wchar codepoint;
- err = peek_codepoint (port, &codepoint, &len);
- if (SCM_UNLIKELY (err != 0))
- scm_decoding_error (FUNC_NAME, err, "input decoding error", port);
+ codepoint = peek_codepoint (port, &len);
scm_port_buffer_did_take (SCM_PTAB_ENTRY (port)->read_buf, len);
if (codepoint == EOF)
scm_i_clear_pending_eof (port);
@@ -2009,7 +1990,6 @@ SCM_DEFINE (scm_peek_char, "peek-char", 0, 1, 0,
"sequence when the error is raised.\n")
#define FUNC_NAME s_scm_peek_char
{
- int err;
scm_t_wchar c;
size_t len = 0;
@@ -2017,14 +1997,9 @@ SCM_DEFINE (scm_peek_char, "peek-char", 0, 1, 0,
port = scm_current_input_port ();
SCM_VALIDATE_OPINPORT (1, port);
- err = peek_codepoint (port, &c, &len);
-
- if (err == 0)
- return c == EOF ? SCM_EOF_VAL : SCM_MAKE_CHAR (c);
+ c = peek_codepoint (port, &len);
- scm_decoding_error (FUNC_NAME, err, "input decoding error", port);
- /* Not reached. */
- return SCM_BOOL_F;
+ return c == EOF ? SCM_EOF_VAL : SCM_MAKE_CHAR (c);
}
#undef FUNC_NAME