146 lines
4.3 KiB
C
146 lines
4.3 KiB
C
/*
|
|
* Contributed by Jacob Teplitsky <jacob.teplitsky@ericsson.com>
|
|
*
|
|
* libcbor is free software; you can redistribute it and/or modify
|
|
* it under the terms of the MIT license. See LICENSE for details.
|
|
*/
|
|
|
|
/**
|
|
* This code demonstrates how cJSON (https://github.com/DaveGamble/cJSON)
|
|
* callbacks can be used in conjuction with the streaming parser to translate
|
|
* JSON to CBOR. Please note that cbor_builder_* APIs are internal and thus
|
|
* subject to change.
|
|
*
|
|
* The example will only be compiled when cJSON is available
|
|
*/
|
|
|
|
#include <cjson/cJSON.h>
|
|
#include <float.h>
|
|
#include <math.h>
|
|
#include <string.h>
|
|
#include "cbor.h"
|
|
#include "cbor/internal/builder_callbacks.h"
|
|
#include "cbor/internal/loaders.h"
|
|
|
|
typedef void (*cbor_load_callback_t)(cJSON *, const struct cbor_callbacks *,
|
|
void *);
|
|
|
|
cbor_item_t *cjson_cbor_load(void *source,
|
|
cbor_load_callback_t cbor_load_callback) {
|
|
static struct cbor_callbacks callbacks = {
|
|
.uint64 = &cbor_builder_uint64_callback,
|
|
.negint64 = &cbor_builder_negint64_callback,
|
|
.string = &cbor_builder_string_callback,
|
|
.array_start = &cbor_builder_array_start_callback,
|
|
.map_start = &cbor_builder_map_start_callback,
|
|
.null = &cbor_builder_null_callback,
|
|
.boolean = &cbor_builder_boolean_callback,
|
|
.float4 = &cbor_builder_float4_callback,
|
|
};
|
|
|
|
/* Context stack */
|
|
struct _cbor_stack stack = _cbor_stack_init();
|
|
|
|
/* Target for callbacks */
|
|
struct _cbor_decoder_context context = (struct _cbor_decoder_context){
|
|
.stack = &stack,
|
|
};
|
|
|
|
cbor_load_callback(source, &callbacks, &context);
|
|
|
|
return context.root;
|
|
}
|
|
|
|
void cjson_cbor_stream_decode(cJSON *source,
|
|
const struct cbor_callbacks *callbacks,
|
|
void *context) {
|
|
switch (source->type) {
|
|
case cJSON_False: {
|
|
callbacks->boolean(context, false);
|
|
return;
|
|
}
|
|
case cJSON_True: {
|
|
callbacks->boolean(context, true);
|
|
return;
|
|
}
|
|
case cJSON_NULL: {
|
|
callbacks->null(context);
|
|
return;
|
|
}
|
|
case cJSON_Number: {
|
|
// This is stupid -- ints and doubles cannot are not distinguished
|
|
if (fabs(source->valuedouble - source->valueint) > DBL_EPSILON) {
|
|
callbacks->float4(context, source->valuedouble);
|
|
} else {
|
|
// XXX: This is not portable
|
|
if (source->valueint >= 0) {
|
|
callbacks->uint64(context, source->valueint);
|
|
} else {
|
|
callbacks->negint64(context, source->valueint + 1);
|
|
}
|
|
}
|
|
return;
|
|
}
|
|
case cJSON_String: {
|
|
// XXX: Assume cJSON handled unicode correctly
|
|
callbacks->string(context, (unsigned char *)source->valuestring,
|
|
strlen(source->valuestring));
|
|
return;
|
|
}
|
|
case cJSON_Array: {
|
|
callbacks->array_start(context, cJSON_GetArraySize(source));
|
|
cJSON *item = source->child;
|
|
while (item != NULL) {
|
|
cjson_cbor_stream_decode(item, callbacks, context);
|
|
item = item->next;
|
|
}
|
|
return;
|
|
}
|
|
case cJSON_Object: {
|
|
callbacks->map_start(context, cJSON_GetArraySize(source));
|
|
cJSON *item = source->child;
|
|
while (item != NULL) {
|
|
callbacks->string(context, (unsigned char *)item->string,
|
|
strlen(item->string));
|
|
cjson_cbor_stream_decode(item, callbacks, context);
|
|
item = item->next;
|
|
}
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
void usage(void) {
|
|
printf("Usage: cjson [input JSON file]\n");
|
|
exit(1);
|
|
}
|
|
|
|
int main(int argc, char *argv[]) {
|
|
if (argc != 2) usage();
|
|
FILE *f = fopen(argv[1], "rb");
|
|
if (f == NULL) usage();
|
|
/* Read input file into a buffer (cJSON doesn't work with streams) */
|
|
fseek(f, 0, SEEK_END);
|
|
size_t length = (size_t)ftell(f);
|
|
fseek(f, 0, SEEK_SET);
|
|
char *json_buffer = malloc(length + 1);
|
|
fread(json_buffer, length, 1, f);
|
|
json_buffer[length] = '\0';
|
|
|
|
/* Convert between JSON and CBOR */
|
|
cJSON *json = cJSON_Parse(json_buffer);
|
|
cbor_item_t *cbor = cjson_cbor_load(json, cjson_cbor_stream_decode);
|
|
|
|
/* Print out CBOR bytes */
|
|
unsigned char *buffer;
|
|
size_t buffer_size;
|
|
cbor_serialize_alloc(cbor, &buffer, &buffer_size);
|
|
|
|
fwrite(buffer, 1, buffer_size, stdout);
|
|
|
|
free(buffer);
|
|
fflush(stdout);
|
|
cJSON_Delete(json);
|
|
cbor_decref(&cbor);
|
|
}
|