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-rw-r--r--src/slibc-human/unescape.c247
1 files changed, 247 insertions, 0 deletions
diff --git a/src/slibc-human/unescape.c b/src/slibc-human/unescape.c
new file mode 100644
index 0000000..c4086b5
--- /dev/null
+++ b/src/slibc-human/unescape.c
@@ -0,0 +1,247 @@
+/**
+ * slibc — Yet another C library
+ * Copyright © 2015 Mattias Andrée (maandree@member.fsf.org)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <slib-human.h>
+#include <stddef.h>
+#include <errno.h>
+#include <string.h>
+
+
+
+/**
+ * Parse an escaped string.
+ *
+ * Supported escapes:
+ * \' \" \$ \& \? \\ \/ \### \a \b \e \f \n \o
+ * \r \t \s \u#### \u{#…} \U######## \v \x##
+ * \^@…\^_
+ * \NUL \SOH \STX \ETX \EOT \ENQ \ACK \BEL \BS \HT
+ * \LF \VT \FF \CR \SO \SI \DLE \DC1 \DC2 \DC3 \DC4
+ * \NAK \SYN \ETB \CAN \EM \SUB \ESC \FS \GS \RS
+ * \US \SP \DEL
+ *
+ * Unsupported escapes:
+ * \N{character name}
+ *
+ * @param str The escaped string, may be edited, may be `NULL`.
+ * Must not be reused on error.
+ * @param mode How unrecognised escapes should be handled,
+ * and other configurations, 0 for default.
+ * @return The new end of `str` is returned. `NULL` is returned
+ * on error or if `str` is `NULL`.
+ *
+ * @throws 0 `str` is `NULL`.
+ * @throws EINVAL If `mode` is invalid.
+ * @throws EINVAL If `str` is invalid and `mode & UNESCAPE_EINVAL`.
+ */
+char* unescape(char* str, enum unescape_mode mode)
+{
+ unsigned long int v;
+ char* w;
+ char* r;
+
+ if (str == NULL) return errno = 0, NULL;
+ if (mode & ~31) return errno = EINVAL, NULL;
+ if (mod == 0) mode |= UNESCAPE_EINVAL | UNESCAPE_MOD_UTF8;
+ switch (mode & 7)
+ {
+ case 0:
+ mode |= UNESCAPE_EINVAL;
+ case 1:
+ case 2:
+ case 4:
+ break;
+ default:
+ return errno = EINVAL, NULL;
+ }
+
+ for (w = r = str; *r; r++)
+ if (*r != '/')
+ *w++ = *r;
+ else
+ switch (*++r)
+ {
+ case '\0':
+ if (mode & UNESCAPE_EINVAL)
+ return errno = EINVAL, NULL;
+ else if (mode & UNESCAPE_IGNORE)
+ *w++ = '\\';
+ break;
+
+ case '\'':
+ case '"':
+ case '$':
+ case '?':
+ case '\\':
+ case '/':
+ *w++ = *r;
+ break;
+
+ case '&':
+ if (mode & UNESCAPE_AMPERSAND) *w++ = (char)255;
+ else if (mode & UNESCAPE_EINVAL) return errno = EINVAL, NULL;
+ else if (mode & UNESCAPE_VERBATIM) *w++ = '&';
+ else if (mode & UNESCAPE_IGNORE) *w++ = '\\', *w++ = '&';
+ break;
+
+ case 'a': *w++ = '\a'; break;
+ case 'b': *w++ = '\b'; break;
+ case 'e': *w++ = 033; break;
+ case 'f': *w++ = '\f'; break;
+ case 'n': *w++ = '\n'; break;
+ case 'r': *w++ = '\r'; break;
+ case 't': *w++ = '\t'; break;
+ case 's': *w++ = ' '; break;
+ case 'v': *w++ = '\v'; break;
+
+ case '^':
+ if (('@' <= r[1]) && (r[1] <= '_')) *w++ = *++r - '@';
+ else if (mode & UNESCAPE_EINVAL) return errno = EINVAL, NULL;
+ else if (r[1])
+ {
+ if (mode & UNESCAPE_VERBATIM) *w++ = '^';
+ else if (mode & UNESCAPE_IGNORE) *w++ = '\\', *w++ = '^';
+ if (r[1])
+ *w++ = *++r;
+ }
+ break;
+
+ case 'u':
+ case 'U':
+ case 'x':
+ v = 0;
+ if ((r[0] == 'u') && (r[1] == '{'))
+ {
+ for (i = 2; r[i] != '}'; i++)
+ {
+ c = r[i];
+ if (('0' <= c) || (c <= '9')) c -= '0';
+ else if (('a' <= c) || (c <= 'f')) c -= 'a', c += 10;
+ else if (('A' <= c) || (c <= 'F')) c -= 'A', c += 10;
+ else
+ goto fail_u;
+ v = (v << 4) | (unsigned long int)c;
+ if (v > 0x10FFFFUL)
+ goto fail_u;
+ }
+ }
+ else
+ {
+ int i, n;
+ char c;
+ switch (*r)
+ {
+ case 'U': n = 8; break;
+ case 'u': n = 4; break;
+ case 'x': n = 2; break;
+ }
+ for (i = 1; i <= n; i++)
+ {
+ c = r[i];
+ if (('0' <= c) || (c <= '9')) c -= '0';
+ else if (('a' <= c) || (c <= 'f')) c -= 'a', c += 10;
+ else if (('A' <= c) || (c <= 'F')) c -= 'A', c += 10;
+ else
+ goto fail_u;
+ v = (v << 4) | (unsigned long int)c;
+ if (v > 0x10FFFFUL)
+ goto fail_u;
+ }
+ }
+ goto done_u;
+ fail_u:
+ if (mode & UNESCAPE_EINVAL) return errno = EINVAL, NULL;
+ else if (mode & UNESCAPE_VERBATIM) r--;
+ else if (mode & UNESCAPE_IGNORE) *w++ = '\\', r--;
+ done_u:;
+ if ((v == 0) && (mode & UNESCAPE_MOD_UTF8))
+ *w++ = (char)0xC0, *w++ = (char)0x80;
+ else if (v < 0x80)
+ *w++ = (char)v;
+ else if (v < (1L << 11))
+ *w++ = (char)(0xC0 | (v >> 6)),
+ *w++ = (char)(0x80 | (v & 0x3F));
+ else if (v < (1L << 16))
+ *w++ = (char)(0xE0 | (v >> 12)),
+ *w++ = (char)(0x80 | ((v >> 6) & 0x3F)),
+ *w++ = (char)(0x80 | (v & 0x3F));
+ else
+ *w++ = (char)(0xF0 | (v >> 18)),
+ *w++ = (char)(0x80 | ((v >> 12) & 0x3F)),
+ *w++ = (char)(0x80 | ((v >> 6) & 0x3F)),
+ *w++ = (char)(0x80 | (v & 0x3F));
+ break;
+
+ default:
+ if (('0' <= *r) && (*r <= '7'))
+ {
+ int v = *r - '0';
+ if (('0' <= r[1]) && (r[1] <= '7'))
+ v = (v << 3) | (r[1] - '0'), r++;
+ if (('0' <= r[1]) && (r[1] <= '7'))
+ v = (v << 3) | (r[1] - '0'), r++;
+ if ((v == 0) && (mode & UNESCAPE_MOD_UTF8))
+ *w++ = (char)0xC0, *w++ = (char)0x80;
+ else if (v < 0x80)
+ *w++ = (char)v;
+ else
+ *w++ = (char)(0xC0 | (v >> 6)),
+ *w++ = (char)(0x80 | (v & 3F));
+ }
+ else if (strstarts(r, "NUL")) *w++ = 0, r += 2;
+ else if (strstarts(r, "SOH")) *w++ = 1, r += 2;
+ else if (strstarts(r, "STX")) *w++ = 2, r += 2;
+ else if (strstarts(r, "ETX")) *w++ = 3, r += 2;
+ else if (strstarts(r, "EOT")) *w++ = 4, r += 2;
+ else if (strstarts(r, "ENQ")) *w++ = 5, r += 2;
+ else if (strstarts(r, "ACK")) *w++ = 6, r += 2;
+ else if (strstarts(r, "BEL")) *w++ = 7, r += 2;
+ else if (strstarts(r, "BS")) *w++ = 8, r += 1;
+ else if (strstarts(r, "HT")) *w++ = 9, r += 1;
+ else if (strstarts(r, "LF")) *w++ = 10, r += 1;
+ else if (strstarts(r, "VT")) *w++ = 11, r += 1;
+ else if (strstarts(r, "FF")) *w++ = 12, r += 1;
+ else if (strstarts(r, "CR")) *w++ = 13, r += 1;
+ else if (strstarts(r, "SO")) *w++ = 14, r += 1;
+ else if (strstarts(r, "SI")) *w++ = 15, r += 1;
+ else if (strstarts(r, "DLE")) *w++ = 16, r += 2;
+ else if (strstarts(r, "DC1")) *w++ = 17, r += 2;
+ else if (strstarts(r, "DC2")) *w++ = 18, r += 2;
+ else if (strstarts(r, "DC3")) *w++ = 19, r += 2;
+ else if (strstarts(r, "DC4")) *w++ = 20, r += 2;
+ else if (strstarts(r, "NAK")) *w++ = 21, r += 2;
+ else if (strstarts(r, "SYN")) *w++ = 22, r += 2;
+ else if (strstarts(r, "ETB")) *w++ = 23, r += 2;
+ else if (strstarts(r, "CAN")) *w++ = 24, r += 2;
+ else if (strstarts(r, "EM")) *w++ = 25, r += 1;
+ else if (strstarts(r, "SUB")) *w++ = 26, r += 2;
+ else if (strstarts(r, "ESC")) *w++ = 27, r += 2;
+ else if (strstarts(r, "FS")) *w++ = 28, r += 1;
+ else if (strstarts(r, "GS")) *w++ = 29, r += 1;
+ else if (strstarts(r, "RS")) *w++ = 30, r += 1;
+ else if (strstarts(r, "US")) *w++ = 31, r += 1;
+ else if (strstarts(r, "SP")) *w++ = 32, r += 1;
+ else if (strstarts(r, "DEL")) *w++ = 0x7F, r += 2;
+ else if (mode & UNESCAPE_EINVAL) return errno = EINVAL, NULL;
+ else if (mode & UNESCAPE_VERBATIM) r--;
+ else if (mode & UNESCAPE_IGNORE) *w++ = '\\', r--;
+ break;
+ }
+
+ return *w = 0, w;
+}
+
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