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parser: Optimize memory buffer I/O

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Reenable zero-copy IO for zero-terminated static memory buffers.

Don't stream zero-terminated dynamic memory buffers on top of creating
a copy.
This commit is contained in:
Nick Wellnhofer 2024-07-07 16:11:08 +02:00
parent 34c9108f15
commit 7148b77820
2 changed files with 49 additions and 77 deletions
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8
parser.c
View File

@ -7988,13 +7988,17 @@ xmlLoadEntityContent(xmlParserCtxtPtr ctxt, xmlEntityPtr entity) {
}
length = xmlBufUse(input->buf->buffer);
content = xmlBufDetach(input->buf->buffer);
if (length > INT_MAX) {
xmlErrMemory(ctxt);
goto error;
}
content = xmlStrndup(xmlBufContent(input->buf->buffer), length);
if (content == NULL) {
xmlErrMemory(ctxt);
goto error;
}
for (i = 0; i < length; ) {
int clen = length - i;
int c = xmlGetUTF8Char(content + i, &clen);

118
xmlIO.c
View File

@ -1748,7 +1748,6 @@ xmlParserInputBufferCreateFd(int fd, xmlCharEncoding enc) {
}
typedef struct {
char *mem;
const char *cur;
size_t size;
} xmlMemIOCtxt;
@ -1771,8 +1770,6 @@ static int
xmlMemClose(void *vctxt) {
xmlMemIOCtxt *ctxt = vctxt;
if (ctxt->mem != NULL)
xmlFree(ctxt->mem);
xmlFree(ctxt);
return(0);
}
@ -1792,42 +1789,46 @@ xmlParserInputBufferPtr
xmlNewInputBufferMemory(const void *mem, size_t size, int flags,
xmlCharEncoding enc) {
xmlParserInputBufferPtr ret;
xmlMemIOCtxt *ctxt;
char *copy = NULL;
if ((flags & XML_INPUT_BUF_STATIC) == 0) {
if (size + 1 == 0)
if ((flags & XML_INPUT_BUF_STATIC) &&
((flags & XML_INPUT_BUF_ZERO_TERMINATED) == 0)) {
xmlMemIOCtxt *ctxt;
/*
* Static buffer without zero terminator.
* Stream memory to avoid a copy.
*/
ret = xmlAllocParserInputBuffer(enc);
if (ret == NULL)
return(NULL);
copy = xmlMalloc(size + 1);
if (copy == NULL)
ctxt = xmlMalloc(sizeof(*ctxt));
if (ctxt == NULL) {
xmlFreeParserInputBuffer(ret);
return(NULL);
memcpy(copy, mem, size);
copy[size] = 0;
}
mem = copy;
ctxt->cur = mem;
ctxt->size = size;
ret->context = ctxt;
ret->readcallback = xmlMemRead;
ret->closecallback = xmlMemClose;
} else {
ret = xmlMalloc(sizeof(*ret));
if (ret == NULL)
return(NULL);
memset(ret, 0, sizeof(xmlParserInputBuffer));
ret->compressed = -1;
ret->buffer = xmlBufCreateMem((const xmlChar *) mem, size,
(flags & XML_INPUT_BUF_STATIC ? 1 : 0));
if (ret->buffer == NULL) {
xmlFree(ret);
return(NULL);
}
}
ret = xmlAllocParserInputBuffer(enc);
if (ret == NULL) {
xmlFree(copy);
return(NULL);
}
ctxt = xmlMalloc(sizeof(*ctxt));
if (ctxt == NULL) {
xmlFreeParserInputBuffer(ret);
xmlFree(copy);
return(NULL);
}
ctxt->mem = copy;
ctxt->cur = mem;
ctxt->size = size;
ret->context = ctxt;
ret->readcallback = xmlMemRead;
ret->closecallback = xmlMemClose;
return(ret);
}
@ -1889,31 +1890,6 @@ xmlParserInputBufferCreateStatic(const char *mem, int size,
return(xmlNewInputBufferMemory(mem, size, XML_INPUT_BUF_STATIC, enc));
}
typedef struct {
const char *str;
} xmlStringIOCtxt;
static int
xmlStringRead(void *vctxt, char *buf, int size) {
xmlStringIOCtxt *ctxt = vctxt;
const char *zero;
size_t len;
zero = memchr(ctxt->str, 0, size);
len = zero ? zero - ctxt->str : size;
memcpy(buf, ctxt->str, len);
ctxt->str += len;
return(len);
}
static int
xmlStringClose(void *vctxt) {
xmlFree(vctxt);
return(0);
}
/**
* xmlNewInputBufferString:
* @str: C string
@ -1926,28 +1902,20 @@ xmlStringClose(void *vctxt) {
xmlParserInputBufferPtr
xmlNewInputBufferString(const char *str, int flags) {
xmlParserInputBufferPtr ret;
xmlStringIOCtxt *ctxt;
if ((flags & XML_INPUT_BUF_STATIC) == 0)
return(xmlNewInputBufferMemory(str, strlen(str), flags,
XML_CHAR_ENCODING_NONE));
ret = xmlAllocParserInputBuffer(XML_CHAR_ENCODING_NONE);
ret = xmlMalloc(sizeof(*ret));
if (ret == NULL)
return(NULL);
return(NULL);
memset(ret, 0, sizeof(xmlParserInputBuffer));
ret->compressed = -1;
ctxt = xmlMalloc(sizeof(*ctxt));
if (ctxt == NULL) {
xmlFreeParserInputBuffer(ret);
return(NULL);
ret->buffer = xmlBufCreateMem((const xmlChar *) str, strlen(str),
(flags & XML_INPUT_BUF_STATIC ? 1 : 0));
if (ret->buffer == NULL) {
xmlFree(ret);
return(NULL);
}
ctxt->str = str;
ret->context = ctxt;
ret->readcallback = xmlStringRead;
ret->closecallback = xmlStringClose;
return(ret);
}