Fix clang -Wfloat-equal warning

This commit is contained in:
Paweł Malowany 2019-06-10 10:59:31 +02:00
parent 3c8935676a
commit c9e8a68b00
5 changed files with 26 additions and 6 deletions

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@ -47,6 +47,7 @@ if (ENABLE_CUSTOM_COMPILER_FLAGS)
-Wmissing-variable-declarations -Wmissing-variable-declarations
-Wused-but-marked-unused -Wused-but-marked-unused
-Wswitch-enum -Wswitch-enum
-Wfloat-equal
) )
elseif("${CMAKE_C_COMPILER_ID}" STREQUAL "MSVC") elseif("${CMAKE_C_COMPILER_ID}" STREQUAL "MSVC")
# Disable warning c4001 - nonstandard extension 'single line comment' was used # Disable warning c4001 - nonstandard extension 'single line comment' was used

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@ -34,7 +34,7 @@ else
CFLAGS += -fstack-protector CFLAGS += -fstack-protector
endif endif
R_CFLAGS = -fPIC -std=c89 -pedantic -Wall -Werror -Wstrict-prototypes -Wwrite-strings -Wshadow -Winit-self -Wcast-align -Wformat=2 -Wmissing-prototypes -Wstrict-overflow=2 -Wcast-qual -Wc++-compat -Wundef -Wswitch-default -Wconversion $(CFLAGS) R_CFLAGS = -fPIC -std=c89 -pedantic -Wall -Werror -Wstrict-prototypes -Wwrite-strings -Wshadow -Winit-self -Wcast-align -Wformat=2 -Wmissing-prototypes -Wstrict-overflow=2 -Wcast-qual -Wc++-compat -Wundef -Wswitch-default -Wconversion -Wfloat-equal $(CFLAGS)
uname := $(shell sh -c 'uname -s 2>/dev/null || echo false') uname := $(shell sh -c 'uname -s 2>/dev/null || echo false')

12
cJSON.c
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@ -480,6 +480,12 @@ static void update_offset(printbuffer * const buffer)
buffer->offset += strlen((const char*)buffer_pointer); buffer->offset += strlen((const char*)buffer_pointer);
} }
/* securely comparison of floating-point variables */
static cJSON_bool compare_double(double a, double b)
{
return (fabs(a - b) <= a * CJSON_DOUBLE_PRECIION);
}
/* Render the number nicely from the given item into a string. */ /* Render the number nicely from the given item into a string. */
static cJSON_bool print_number(const cJSON * const item, printbuffer * const output_buffer) static cJSON_bool print_number(const cJSON * const item, printbuffer * const output_buffer)
{ {
@ -497,7 +503,7 @@ static cJSON_bool print_number(const cJSON * const item, printbuffer * const out
} }
/* This checks for NaN and Infinity */ /* This checks for NaN and Infinity */
if ((d * 0) != 0) if (!compare_double(d * 0, 0))
{ {
length = sprintf((char*)number_buffer, "null"); length = sprintf((char*)number_buffer, "null");
} }
@ -507,7 +513,7 @@ static cJSON_bool print_number(const cJSON * const item, printbuffer * const out
length = sprintf((char*)number_buffer, "%1.15g", d); length = sprintf((char*)number_buffer, "%1.15g", d);
/* Check whether the original double can be recovered */ /* Check whether the original double can be recovered */
if ((sscanf((char*)number_buffer, "%lg", &test) != 1) || ((double)test != d)) if ((sscanf((char*)number_buffer, "%lg", &test) != 1) || !compare_double((double)test, d))
{ {
/* If not, print with 17 decimal places of precision */ /* If not, print with 17 decimal places of precision */
length = sprintf((char*)number_buffer, "%1.17g", d); length = sprintf((char*)number_buffer, "%1.17g", d);
@ -2876,7 +2882,7 @@ CJSON_PUBLIC(cJSON_bool) cJSON_Compare(const cJSON * const a, const cJSON * cons
return true; return true;
case cJSON_Number: case cJSON_Number:
if (a->valuedouble == b->valuedouble) if (compare_double(a->valuedouble, b->valuedouble))
{ {
return true; return true;
} }

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@ -137,6 +137,11 @@ typedef int cJSON_bool;
#define CJSON_NESTING_LIMIT 1000 #define CJSON_NESTING_LIMIT 1000
#endif #endif
/* Precision of double variables comparison */
#ifndef CJSON_DOUBLE_PRECIION
#define CJSON_DOUBLE_PRECIION .00001
#endif
/* returns the version of cJSON as a string */ /* returns the version of cJSON as a string */
CJSON_PUBLIC(const char*) cJSON_Version(void); CJSON_PUBLIC(const char*) cJSON_Version(void);

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@ -39,6 +39,7 @@
#include <stdlib.h> #include <stdlib.h>
#include <stdio.h> #include <stdio.h>
#include <limits.h> #include <limits.h>
#include <math.h>
#if defined(_MSC_VER) #if defined(_MSC_VER)
#pragma warning (pop) #pragma warning (pop)
@ -105,6 +106,13 @@ static int compare_strings(const unsigned char *string1, const unsigned char *st
return tolower(*string1) - tolower(*string2); return tolower(*string1) - tolower(*string2);
} }
/* securely comparison of floating-point variables */
static cJSON_bool compare_double(double a, double b)
{
return (fabs(a - b) <= a * CJSON_DOUBLE_PRECIION);
}
/* Compare the next path element of two JSON pointers, two NULL pointers are considered unequal: */ /* Compare the next path element of two JSON pointers, two NULL pointers are considered unequal: */
static cJSON_bool compare_pointers(const unsigned char *name, const unsigned char *pointer, const cJSON_bool case_sensitive) static cJSON_bool compare_pointers(const unsigned char *name, const unsigned char *pointer, const cJSON_bool case_sensitive)
{ {
@ -595,7 +603,7 @@ static cJSON_bool compare_json(cJSON *a, cJSON *b, const cJSON_bool case_sensiti
{ {
case cJSON_Number: case cJSON_Number:
/* numeric mismatch. */ /* numeric mismatch. */
if ((a->valueint != b->valueint) || (a->valuedouble != b->valuedouble)) if ((a->valueint != b->valueint) || (!compare_double(a->valuedouble, b->valuedouble)))
{ {
return false; return false;
} }
@ -1135,7 +1143,7 @@ static void create_patches(cJSON * const patches, const unsigned char * const pa
switch (from->type & 0xFF) switch (from->type & 0xFF)
{ {
case cJSON_Number: case cJSON_Number:
if ((from->valueint != to->valueint) || (from->valuedouble != to->valuedouble)) if ((from->valueint != to->valueint) || (compare_double(from->valuedouble, to->valuedouble)))
{ {
compose_patch(patches, (const unsigned char*)"replace", path, NULL, to); compose_patch(patches, (const unsigned char*)"replace", path, NULL, to);
} }