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Make regex code in utils thread-safe

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regex_context_t is only 520 bytes on platforms with 8-byte pointers,
which is reasonable to allocate on the stack instead of as a global in
a userland program.
This commit is contained in:
Evan Ramos
2021-02-26 15:08:34 -06:00
parent aea0ceac03
commit a89f0f332d
1 changed files with 25 additions and 18 deletions
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43
src/utils.cpp
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@ -1280,24 +1280,14 @@ extern "C" {
/* Typedef'd pointer to get abstract datatype. */
typedef struct regex_t *re_t;
typedef struct regex_context_t *re_ctx_t;
/* Compile regex string pattern to a regex_t-array. */
static re_t re_compile(const char *pattern);
static re_t re_compile(re_ctx_t context, const char *pattern);
/* Find matches of the compiled pattern inside text. */
static int re_matchp(const char *text, re_t pattern, int *matchlen);
int re_match(const char *text, const char *pattern)
{
int dummy;
return re_matchp(text, re_compile(pattern), &dummy);
}
int re_find(const char *text, const char *pattern, int *matchlen)
{
return re_matchp(text, re_compile(pattern), matchlen);
}
/* Definitions: */
#define MAX_REGEXP_OBJECTS 30 /* Max number of regex symbols in expression. */
@ -1317,6 +1307,26 @@ extern "C" {
} u;
} regex_t;
typedef struct regex_context_t {
/* MAX_REGEXP_OBJECTS is the max number of symbols in the expression.
MAX_CHAR_CLASS_LEN determines the size of buffer for chars in all char-classes in the expression. */
regex_t re_compiled[MAX_REGEXP_OBJECTS];
unsigned char ccl_buf[MAX_CHAR_CLASS_LEN];
} regex_context_t;
int re_match(const char *text, const char *pattern)
{
regex_context_t context;
int dummy;
return re_matchp(text, re_compile(&context, pattern), &dummy);
}
int re_find(const char *text, const char *pattern, int *matchlen)
{
regex_context_t context;
return re_matchp(text, re_compile(&context, pattern), matchlen);
}
/* Private function declarations: */
static int matchpattern(regex_t *pattern, const char *text, int *matchlen);
static int matchcharclass(char c, const char *str);
@ -1359,13 +1369,10 @@ extern "C" {
return -1;
}
re_t re_compile(const char *pattern)
re_t re_compile(re_ctx_t context, const char *pattern)
{
/* The sizes of the two static arrays below substantiates the static RAM usage of this module.
MAX_REGEXP_OBJECTS is the max number of symbols in the expression.
MAX_CHAR_CLASS_LEN determines the size of buffer for chars in all char-classes in the expression. */
static regex_t re_compiled[MAX_REGEXP_OBJECTS];
static unsigned char ccl_buf[MAX_CHAR_CLASS_LEN];
regex_t * const re_compiled = context->re_compiled;
unsigned char * const ccl_buf = context->ccl_buf;
int ccl_bufidx = 1;
char c; /* current char in pattern */