From e297debdbd5b8abdd3f71c8fcc4f9a76445e54cf Mon Sep 17 00:00:00 2001
From: Kubat <mael.martin31@gmail.com>
Date: Mon, 18 Jan 2021 11:41:50 +0100
Subject: [PATCH] JSON: Decode strings correctly
---
src/base/json.c | 99 +++++++++++++++++++++++++++++--------------------
1 file changed, 58 insertions(+), 41 deletions(-)
diff --git a/src/base/json.c b/src/base/json.c
index 70f6b2bd..9423ed41 100644
--- a/src/base/json.c
+++ b/src/base/json.c
@@ -99,30 +99,46 @@ __hex_val(const char *c, uint32_t *result)
return 0;
}
-static inline int
-__decode_codepoint(uint32_t codepoint)
+/* sizeof(utf8) == 4 */
+static struct {
+ int32_t lo;
+ int32_t hi;
+} utf8[] = {
+ { 0xd800, 0xdfff }, /* forbidden range: surrogates */
+ { 0, 0x7f },
+ { 0x80, 0x7ff },
+ { 0x800, 0xffff },
+ { 0x10000, 0x10ffff }
+};
+
+static inline size_t
+__encode_codepoint(char p[4], int32_t codepoint)
{
- union __utf8_codepoint {
- uint32_t codepoint;
- char chars[4];
- };
-
- union __utf8_codepoint s = { .codepoint = codepoint };
-
- /* Count # of leading 1 bits */
- int k = s.chars[0] ? __builtin_clz(~(s.chars[0] << 24)) : 0;
- /* All 1's with k leading 0's */
- int mask = (1 << (8 - k)) - 1;
- int value = s.chars[0] & mask;
- int i = 1;
-
- /* NOTE: k = #total bytes, and #total bytes <= 4 */
- for (--k; k > 0 && i < 4; --k, ++i) {
- value <<= 6;
- value += (s.chars[i] & 0x3F);
+ size_t i, n= 0; /* number of bytes to be written */
+
+ while (n< sizeof(utf8)) {
+ if (utf8[n].lo <= codepoint && codepoint <= utf8[n].hi)
+ break;
+ n++;
}
- return value;
+ if (n < 1 || n >= sizeof(utf8)) {
+ /* Invalid! */
+ return 0;
+ }
+
+ if (n == 1)
+ p[0] = codepoint;
+
+ else {
+ for (i = n - 1; i > 0; i--) {
+ p[i] = 0x80 | (0x3f & codepoint);
+ codepoint >>= 6;
+ }
+ p[0] = (0xf00 >> n) | codepoint;
+ }
+
+ return n;
}
static inline void
@@ -130,27 +146,26 @@ __decode_json(char *string, size_t len)
{
char *offset = string;
int size = 0;
- char *target = NULL;
+ size_t written = 0;
uint32_t codepoint = 0;
+ char *string_end = string + len;
while ((offset = strchr(offset, '\\'))) {
- len = len - (offset - string);
- target = NULL;
-
switch (offset[1]) {
-#define __case_single(c, sub) \
- case c: \
- size = 2; \
- target = sub; \
+#define __case_single(c, sub) \
+ case c: \
+ size = 2; \
+ written = 1; \
+ offset[0] = sub; \
break;
- __case_single('"', "\"")
- __case_single('\\', "\\")
- __case_single('/', "/" )
- __case_single('f', "\f")
- __case_single('b', "\b")
- __case_single('n', "\n")
- __case_single('r', "\r")
- __case_single('t', "\t")
+ __case_single('"', '\"')
+ __case_single('\\', '\\')
+ __case_single('/', '/' )
+ __case_single('f', '\f')
+ __case_single('b', '\b')
+ __case_single('n', '\n')
+ __case_single('r', '\r')
+ __case_single('t', '\t')
#undef __case_single
/* UTF-8 decode, 4 hex digits */
@@ -159,9 +174,9 @@ __decode_json(char *string, size_t len)
LOG_ERROR("JSON", "Invalid unicode string, abort decoding");
return;
}
- size = 5; /* u + 4 hex digits */
+ size = 6; /* \u + 4 hex digits */
__hex_val(&offset[2], &codepoint);
- printf("\\u%04x => %lc\n", codepoint, __decode_codepoint(codepoint));
+ written = __encode_codepoint(offset, codepoint);
break;
/* Oups */
@@ -170,9 +185,11 @@ __decode_json(char *string, size_t len)
return;
}
- /* Simple, replace <size> characters by <target> from 'offset' */
-
+ /* Now move the rest of the string of (size - written) characters*/
+ memmove(&offset[written], &offset[size], (string_end - &offset[size]) * sizeof(char));
+ string_end -= (size - written);
}
+ string_end[0] = '\0';
}
LKT_PUSH
--
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