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Improve performance of jsonToStrInternal() and jsonFromStrInternal().

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Most strings do not contain escape/d characters, so optimize the path where the string contains few or no escape/d characters.

This means far fewer calls to strCatChr() in favor of strCatZN(), which is much more efficient.
This commit is contained in:
David Steele 2020-03-25 18:52:20 -04:00
parent 88d7ee6215
commit 10b4b9af87
1 changed files with 90 additions and 21 deletions
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111
src/common/type/json.c
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@ -242,12 +242,24 @@ jsonToStrInternal(const char *json, unsigned int *jsonPos)
MEM_CONTEXT_TEMP_BEGIN()
{
// Skip the beginning "
(*jsonPos)++;
// Track portion of string with no escapes
const char *noEscape = NULL;
size_t noEscapeSize = 0;
while (json[*jsonPos] != '"')
{
if (json[*jsonPos] == '\\')
{
// Copy portion of string without escapes
if (noEscapeSize > 0)
{
strCatZN(result, noEscape, noEscapeSize);
noEscapeSize = 0;
}
(*jsonPos)++;;
switch (json[*jsonPos])
@ -293,12 +305,20 @@ jsonToStrInternal(const char *json, unsigned int *jsonPos)
if (json[*jsonPos] == '\0')
THROW(JsonFormatError, "expected '\"' but found null delimiter");
strCatChr(result, json[*jsonPos]);
// If escape string is zero size then start it
if (noEscapeSize == 0)
noEscape = json + *jsonPos;
noEscapeSize++;
}
(*jsonPos)++;;
};
// Copy portion of string without escapes
if (noEscapeSize > 0)
strCatZN(result, noEscape, noEscapeSize);
// Advance the character array pointer to the next element after the string
(*jsonPos)++;;
}
@ -670,6 +690,10 @@ jsonFromStrInternal(String *json, const String *string)
{
strCatChr(json, '"');
// Track portion of string with no escapes
const char *noEscape = NULL;
size_t noEscapeSize = 0;
for (unsigned int stringIdx = 0; stringIdx < strSize(string); stringIdx++)
{
char stringChr = strPtr(string)[stringIdx];
@ -677,39 +701,84 @@ jsonFromStrInternal(String *json, const String *string)
switch (stringChr)
{
case '"':
strCat(json, "\\\"");
break;
case '\\':
strCat(json, "\\\\");
break;
case '\n':
strCat(json, "\\n");
break;
case '\r':
strCat(json, "\\r");
break;
case '\t':
strCat(json, "\\t");
break;
case '\b':
strCat(json, "\\b");
break;
case '\f':
strCat(json, "\\f");
{
// Copy portion of string without escapes
if (noEscapeSize > 0)
{
strCatZN(json, noEscape, noEscapeSize);
noEscapeSize = 0;
}
switch (stringChr)
{
case '"':
{
strCat(json, "\\\"");
break;
}
case '\\':
{
strCat(json, "\\\\");
break;
}
case '\n':
{
strCat(json, "\\n");
break;
}
case '\r':
{
strCat(json, "\\r");
break;
}
case '\t':
{
strCat(json, "\\t");
break;
}
case '\b':
{
strCat(json, "\\b");
break;
}
case '\f':
{
strCat(json, "\\f");
break;
}
}
break;
}
default:
strCatChr(json, stringChr);
{
// If escape string is zero size then start it
if (noEscapeSize == 0)
noEscape = strPtr(string) + stringIdx;
noEscapeSize++;
break;
}
}
}
// Copy portion of string without escapes
if (noEscapeSize > 0)
strCatZN(json, noEscape, noEscapeSize);
strCatChr(json, '"');
}