yyjson_ptr_get_sint() returns false for positive integer

[chad-earthscope]

Describe the bug
The yyjson_ptr_get_sint() function returns false for positive integer values, unexpectedly. Demonstration code in following comment.

The same value can be access as expected with yyjson_ptr_get_uint(), and negative values work as expected with yyjson_ptr_get_sint().

This was discovered on v0.8.0 and tested against the current master at f1867b0

Your environment

• OS: Ubuntu 20.04 x64, and macOS 14.2
• Compiler: gcc 11.4.0 on Ubuntu and clang 15.0.0 on macos

[chad-earthscope]

Demonstration code

//cc -Wall -I. yyjson.c yytest.c -o yytest

#include "yyjson.h"
#include "inttypes.h"

int
main ()
{
  const char *jsonstr = "{\"posvalue\": 123, \"negvalue\": -123, \"strvalue\": \"hello\"}";

  yyjson_doc *doc  = NULL;
  yyjson_val *root = NULL;
  int64_t sintvalue = 0;
  uint64_t uintvalue = 0;
  const char *strvalue = NULL;

  doc = yyjson_read (jsonstr, strlen(jsonstr), 0);
  root = yyjson_doc_get_root(doc);

  if (root) {
    printf ("JSON string parsed\n");

    if (yyjson_ptr_get_sint (root, "/posvalue", &sintvalue)) {
      printf ("posvalue(sint): %"PRId64"\n", sintvalue);
    }
    else {
      printf ("posvalue(sint) ERROR\n");
    }

    if (yyjson_ptr_get_uint (root, "/posvalue", &uintvalue)) {
      printf ("posvalue(uint): %"PRIu64"\n", uintvalue);
    }
    else {
      printf ("posvalue(uint) ERROR\n");
    }

    if (yyjson_ptr_get_sint (root, "/negvalue", &sintvalue)) {
      printf ("negvalue(sint): %"PRId64"\n", sintvalue);
    }
    else {
      printf ("negvalue(sint) ERROR\n");
    }

    if (yyjson_ptr_get_str (root, "/strvalue", &strvalue)) {
      printf ("strvalue: %s\n", strvalue);
    }
    else {
      printf ("strvalue ERROR\n");
    }

    yyjson_doc_free(doc);
  }

  return 0;
}

Output:

% cc -Wall -I. yyjson.c yytest.c -o yytest
% ./yytest
JSON string parsed
posvalue(sint) ERROR
posvalue(uint): 123
negvalue(sint): -123
strvalue: hello

[ibireme]

The uint and sint are two different types here, and the function will return false if the types don't match:

yyjson/src/yyjson.h

Lines 7751 to 7755 in f1867b0

	/**
	Set provided `value` if the JSON Pointer (RFC 6901) exists and is type sint.
	Returns true if value at `ptr` exists and is the correct type, otherwise false.
	*/
	yyjson_api_inline bool yyjson_ptr_get_sint(

I think we should add auto-type conversion to this function, which would return true if the integer can be converted without overflowing.

[chad-earthscope]

I note that basic getters of values has a yyjson_get_int() which appears to do the uint or sint functionality. (unfortunately it also truncates to int so the full range of the [u]int64_t is lost). Maybe that approach would work for the ptr versions as well.

[ibireme]

Added to master: b63b3e1

[chad-earthscope]

that's perfect, thanks @ibireme!