blob: a86720b60224f4e32454fbaf49c1a4d8b73059d0 [file] [log] [blame]
#include "bej_dictionary.h"
#include <stdbool.h>
#include <stdio.h>
/**
* @brief Get the index for a property offset. First property will be at index
* 0.
*
* @param[in] propertyOffset - a valid property offset.
* @return index of the property.
*/
static uint16_t bejGetPropertyEntryIndex(uint16_t propertyOffset)
{
return (propertyOffset - bejDictGetPropertyHeadOffset()) /
sizeof(struct BejDictionaryProperty);
}
/**
* @brief Validate a property offset.
*
* @param[in] propertyOffset - offset needed to be validated.
* @return true if propertyOffset is a valid offset.
*/
static bool bejValidatePropertyOffset(uint16_t propertyOffset)
{
// propertyOffset should be greater than or equal to first property offset.
if (propertyOffset < bejDictGetPropertyHeadOffset())
{
fprintf(
stderr,
"Invalid property offset. Pointing to Dictionary header data\n");
return false;
}
// propertyOffset should be a multiple of sizeof(BejDictionaryProperty)
// starting from first property within the dictionary.
if ((propertyOffset - bejDictGetPropertyHeadOffset()) %
sizeof(struct BejDictionaryProperty))
{
fprintf(stderr, "Invalid property offset. Does not point to beginning "
"of property\n");
return false;
}
return true;
}
uint16_t bejDictGetPropertyHeadOffset()
{
// First property is present soon after the dictionary header.
return sizeof(struct BejDictionaryHeader);
}
uint16_t bejDictGetFirstAnnotatedPropertyOffset()
{
// The first property available is the "Annotations" set which is the parent
// for all properties. Next immediate property is the first property we
// need.
return sizeof(struct BejDictionaryHeader) +
sizeof(struct BejDictionaryProperty);
}
int bejDictGetProperty(const uint8_t* dictionary,
uint16_t startingPropertyOffset, uint16_t sequenceNumber,
const struct BejDictionaryProperty** property)
{
uint16_t propertyOffset = startingPropertyOffset;
const struct BejDictionaryHeader* header =
(const struct BejDictionaryHeader*)dictionary;
if (!bejValidatePropertyOffset(propertyOffset))
{
return bejErrorInvalidPropertyOffset;
}
uint16_t propertyIndex = bejGetPropertyEntryIndex(propertyOffset);
for (uint16_t index = propertyIndex; index < header->entryCount; ++index)
{
const struct BejDictionaryProperty* p =
(const struct BejDictionaryProperty*)(dictionary + propertyOffset);
if (p->sequenceNumber == sequenceNumber)
{
*property = p;
return 0;
}
propertyOffset += sizeof(struct BejDictionaryProperty);
}
return bejErrorUnknownProperty;
}
const char* bejDictGetPropertyName(const uint8_t* dictionary,
uint16_t nameOffset, uint8_t nameLength)
{
if (nameLength == 0)
{
return "";
}
return (const char*)(dictionary + nameOffset);
}