xml parser CHANGE optimize using dynamically allocated memory
When possible, use references into the original string instead of
allocating memory for storing strings which are the same as in the
input string. Dynamically allocated buffer is needed only in case
the input string must be modified because of character or entity
reference.
diff --git a/src/xml.c b/src/xml.c
index 4af078d..db25d70 100644
--- a/src/xml.c
+++ b/src/xml.c
@@ -193,7 +193,7 @@
}
LY_ERR
-lyxml_get_string(struct lyxml_context *context, const char **input, char **buffer, size_t *buffer_size)
+lyxml_get_string(struct lyxml_context *context, const char **input, char **buffer, size_t *buffer_size, char **output, size_t *length, int *dynamic)
{
#define BUFSIZE 4096
#define BUFSIZE_STEP 4096
@@ -205,10 +205,10 @@
}
struct ly_ctx *ctx = context->ctx; /* shortcut */
- const char *in = (*input);
- char *buf, delim;
+ const char *in = (*input), *start;
+ char *buf = NULL, delim;
size_t offset; /* read offset in input buffer */
- size_t len; /* write offset in output buffer */
+ size_t len; /* length of the output string (write offset in output buffer) */
size_t size; /* size of the output buffer */
void *p;
uint32_t n;
@@ -229,6 +229,7 @@
delim = '<';
empty_content = true;
}
+ start = in;
if (empty_content) {
/* only when processing element's content - try to ignore whitespaces used to format XML data
@@ -244,26 +245,31 @@
(*input) = in + offset;
return LY_EINVAL;
}
- } else {
- /* init */
- offset = 0;
}
+ /* init */
+ offset = len = 0;
- /* prepare output buffer */
- if (*buffer) {
- buf = *buffer;
- size = *buffer_size;
- } else {
- buf = malloc(BUFSIZE);
- size = BUFSIZE;
-
- LY_CHECK_ERR_RET(!buf, LOGMEM(ctx), LY_EMEM);
+ if (0) {
+getbuffer:
+ /* prepare output buffer */
+ if (*buffer) {
+ buf = *buffer;
+ size = *buffer_size;
+ } else {
+ buf = malloc(BUFSIZE);
+ size = BUFSIZE;
+ LY_CHECK_ERR_RET(!buf, LOGMEM(ctx), LY_EMEM);
+ }
}
- len = 0;
/* parse */
while (in[offset]) {
if (in[offset] == '&') {
+ if (!buf) {
+ /* it is necessary to modify the input, so we will need a dynamically allocated buffer */
+ goto getbuffer;
+ }
+
if (offset) {
/* store what we have so far */
BUFSIZE_CHECK(ctx, buf, size, len, offset);
@@ -339,12 +345,14 @@
}
} else if (in[offset] == delim) {
/* end of string */
- if (len + offset >= size) {
- buf = ly_realloc(buf, len + offset + 1);
- LY_CHECK_ERR_RET(!buf, LOGMEM(ctx), LY_EMEM);
- size = len + offset + 1;
+ if (buf) {
+ if (len + offset >= size) {
+ buf = ly_realloc(buf, len + offset + 1);
+ LY_CHECK_ERR_RET(!buf, LOGMEM(ctx), LY_EMEM);
+ size = len + offset + 1;
+ }
+ memcpy(&buf[len], in, offset);
}
- memcpy(&buf[len], in, offset);
len += offset;
/* in case of element content, keep the leading <,
* for attribute's value move after the terminating quotation mark */
@@ -372,23 +380,34 @@
return LY_EVALID;
success:
- if (!(*buffer) && size != len + 1) {
- /* not using provided buffer, so fit the allocated buffer to what we really have inside */
- p = realloc(buf, len + 1);
- /* ignore realloc fail because we are reducing the buffer,
- * so just return bigger buffer than needed */
- if (p) {
- size = len + 1;
- buf = p;
+ if (buf) {
+ if (!(*buffer) && size != len + 1) {
+ /* not using provided buffer, so fit the allocated buffer to what we really have inside */
+ p = realloc(buf, len + 1);
+ /* ignore realloc fail because we are reducing the buffer,
+ * so just return bigger buffer than needed */
+ if (p) {
+ size = len + 1;
+ buf = p;
+ }
}
+ /* set terminating NULL byte */
+ buf[len] = '\0';
}
- /* set terminating NULL byte */
- buf[len] = '\0';
context->status -= 1;
(*input) = in;
- (*buffer) = buf;
- (*buffer_size) = size;
+ if (buf) {
+ (*buffer) = buf;
+ (*buffer_size) = size;
+ (*output) = buf;
+ (*dynamic) = 1;
+ } else {
+ (*output) = (char*)start;
+ (*dynamic) = 0;
+ }
+ (*length) = len;
+
return LY_SUCCESS;
#undef BUFSIZE