Momentum-Apps/fields.c

/* Copyright (C) 2022-2023 Salvatore Sanfilippo -- All Rights Reserved
 * See the LICENSE file for information about the license.
 *
 * Protocol fields implementation. */

#include "app.h"

/* Create a new field of the specified type. Without populating its
 * type-specific value. */
static ProtoViewField *field_new(ProtoViewFieldType type, const char *name) {
    ProtoViewField *f = malloc(sizeof(*f));
    f->type = type;
    f->name = strdup(name);
    return f;
}

/* Free a field an associated data. */
static void field_free(ProtoViewField *f) {
    free(f->name);
    switch(f->type) {
    case FieldTypeStr: free(f->str); break;
    case FieldTypeBytes: free(f->bytes); break;
    default: break; // Nothing to free for other types.
    }
    free(f);
}

/* Return the type of the field as string. */
const char *field_get_type_name(ProtoViewField *f) {
    switch(f->type) {
    case FieldTypeStr:          return "str";
    case FieldTypeSignedInt:    return "int";
    case FieldTypeUnsignedInt:  return "uint";
    case FieldTypeBinary:       return "bin";
    case FieldTypeHex:          return "hex";
    case FieldTypeBytes:        return "bytes";
    case FieldTypeFloat:        return "float";
    }
    return "unknown";
}

/* Set a string representation of the specified field in buf. */
int field_to_string(char *buf, size_t len, ProtoViewField *f) {
    switch(f->type) {
    case FieldTypeStr:
        return snprintf(buf,len,"%s", f->str);
    case FieldTypeSignedInt:
        return snprintf(buf,len,"%lld", (long long) f->value);
    case FieldTypeUnsignedInt:
        return snprintf(buf,len,"%llu", (unsigned long long) f->uvalue);
    case FieldTypeBinary:
        {
            uint64_t test_bit = (1 << (f->len-1));
            uint64_t idx = 0;
            while(idx < len-1 && test_bit) {
                buf[idx++] = (f->uvalue & test_bit) ? '1' : '0';
                test_bit >>= 1;
            }
            buf[idx] = 0;
            return idx;
        }
    case FieldTypeHex:
        return snprintf(buf, len, "%*llX", (int)(f->len+7)/8, f->uvalue);
    case FieldTypeFloat:
        return snprintf(buf, len, "%.*f", (int)f->len, (double)f->fvalue);
    case FieldTypeBytes:
        {
            uint64_t idx = 0;
            while(idx < len-1 && idx < f->len) {
                const char *charset = "0123456789ABCDEF";
                uint32_t nibble = idx & 1 ?
                    (f->bytes[idx/2] & 0xf) :
                    (f->bytes[idx/2] >> 4);
                buf[idx++] = charset[nibble];
            }
            buf[idx] = 0;
            return idx;
        }
    }
    return 0;
}

/* Set the field value from its string representation in 'buf'.
 * The field type must already be set and the field should be valid.
 * The string represenation 'buf' must be null termianted. Note that
 * even when representing binary values containing zero, this values
 * are taken as representations, so that would be the string "00" as
 * the Bytes type representation.
 *
 * The function returns true if the filed was successfully set to the
 * new value, otherwise if the specified value is invalid for the
 * field type, false is returned. */
bool field_set_from_string(ProtoViewField *f, char *buf, size_t len) {
    // Initialize values to zero since the Flipper sscanf() implementation
    // is fuzzy... may populate only part of the value.
    long long val = 0;
    unsigned long long uval = 0;
    float fval = 0;

    switch(f->type) {
    case FieldTypeStr:
        free(f->str);
        f->len = len;
        f->str = malloc(len+1);
        memcpy(f->str,buf,len+1);
        break;
    case FieldTypeSignedInt:
        if (!sscanf(buf,"%lld",&val)) return false;
        f->value = val;
        break;
    case FieldTypeUnsignedInt:
        if (!sscanf(buf,"%llu",&uval)) return false;
        f->uvalue = uval;
        break;
    case FieldTypeBinary:
        {
            uint64_t bit_to_set = (1 << (len-1));
            uint64_t idx = 0;
            uval = 0;
            while(buf[idx]) {
                if (buf[idx] == '1') uval |= bit_to_set;
                else if (buf[idx] != '0') return false;
                bit_to_set >>= 1;
                idx++;
            }
            f->uvalue = uval;
        }
        break;
    case FieldTypeHex:
        if (!sscanf(buf,"%llx",&uval) &&
            !sscanf(buf,"%llX",&uval)) return false;
        f->uvalue = uval;
        break;
    case FieldTypeFloat:
        if (!sscanf(buf,"%f",&fval)) return false;
        f->fvalue = fval;
        break;
    case FieldTypeBytes:
        {
            if (len > f->len) return false;
            uint64_t idx = 0;
            while(buf[idx]) {
                uint8_t nibble = 0;
                char c = toupper(buf[idx]);
                if (c >= '0' && c <= '9') nibble = c-'0';
                else if (c >= 'A' && c <= 'F') nibble = 10+(c-'A');
                else return false;

                if (idx & 1) {
                    f->bytes[idx/2] = 
                        (f->bytes[idx/2] & 0xF0) | nibble;
                } else {
                    f->bytes[idx/2] = 
                        (f->bytes[idx/2] & 0x0F) | (nibble<<4);
                }
                idx++;
            }
            buf[idx] = 0;
        }
        break;
    }
    return true;
}

/* Increment the specified field value of 'incr'. If the field type
 * does not support increments false is returned, otherwise the
 * action is performed. */
bool field_incr_value(ProtoViewField *f, int incr) {
    switch(f->type) {
        case FieldTypeStr: return false;
        case FieldTypeSignedInt: {
            /* Wrap around depending on the number of bits (f->len)
             * the integer was declared to have. */
            int64_t max = (1ULL << (f->len-1))-1;
            int64_t min = -max-1;
            int64_t v = (int64_t)f->value + incr;
            if (v > max) v = min+(v-max-1);
            if (v < min) v = max+(v-min+1);
            f->value = v;
            break;
        }
        case FieldTypeBinary:
        case FieldTypeHex:
        case FieldTypeUnsignedInt: {
            /* Wrap around like for the unsigned case, but here
             * is simpler. */
            uint64_t max = (1ULL << f->len)-1; // Broken for 64 bits.
            uint64_t uv = (uint64_t)f->value + incr;
            if (uv > max) uv = uv & max;
            f->uvalue = uv;
            break;
        }
        case FieldTypeFloat:
            f->fvalue += incr;
            break;
        case FieldTypeBytes: {
            // For bytes we only support single unit increments.
            if (incr != -1 && incr != 1) return false;
            for (int j = f->len-1; j >= 0; j--) {
                uint8_t nibble = (j&1) ? (f->bytes[j/2] & 0x0F) :
                                         ((f->bytes[j/2] & 0xF0) >> 4);

                nibble += incr;
                nibble &= 0x0F;

                f->bytes[j/2] = (j&1) ? ((f->bytes[j/2] & 0xF0) | nibble) :
                                        ((f->bytes[j/2] & 0x0F) | (nibble<<4));

		/* Propagate the operation on overflow of this nibble. */
		if ((incr == 1 && nibble == 0) ||
		    (incr == -1 && nibble == 0xf))
		{
		    continue;
		}
		break; // Otherwise stop the loop here.
            }
            break;
        }
    }
    return true;
}


/* Free a field set and its contained fields. */
void fieldset_free(ProtoViewFieldSet *fs) {
    for (uint32_t j = 0; j < fs->numfields; j++)
        field_free(fs->fields[j]);
    free(fs->fields);
    free(fs);
}

/* Allocate and init an empty field set. */
ProtoViewFieldSet *fieldset_new(void) {
    ProtoViewFieldSet *fs = malloc(sizeof(*fs));
    fs->numfields = 0;
    fs->fields = NULL;
    return fs;
}

/* Append an already allocated field at the end of the specified field set. */
static void fieldset_add_field(ProtoViewFieldSet *fs, ProtoViewField *field) {
    fs->numfields++;
    fs->fields = realloc(fs->fields,sizeof(ProtoViewField*)*fs->numfields);
    fs->fields[fs->numfields-1] = field;
}

/* Allocate and append an integer field. */
void fieldset_add_int(ProtoViewFieldSet *fs, const char *name, int64_t val, uint8_t bits) {
    ProtoViewField *f = field_new(FieldTypeSignedInt,name);
    f->value = val;
    f->len = bits;
    fieldset_add_field(fs,f);
}

/* Allocate and append an unsigned field. */
void fieldset_add_uint(ProtoViewFieldSet *fs, const char *name, uint64_t uval, uint8_t bits) {
    ProtoViewField *f = field_new(FieldTypeUnsignedInt,name);
    f->uvalue = uval;
    f->len = bits;
    fieldset_add_field(fs,f);
}

/* Allocate and append a hex field. This is an unsigned number but
 * with an hex representation. */
void fieldset_add_hex(ProtoViewFieldSet *fs, const char *name, uint64_t uval, uint8_t bits) {
    ProtoViewField *f = field_new(FieldTypeHex,name);
    f->uvalue = uval;
    f->len = bits;
    fieldset_add_field(fs,f);
}

/* Allocate and append a bin field. This is an unsigned number but
 * with a binary representation. */
void fieldset_add_bin(ProtoViewFieldSet *fs, const char *name, uint64_t uval, uint8_t bits) {
    ProtoViewField *f = field_new(FieldTypeBinary,name);
    f->uvalue = uval;
    f->len = bits;
    fieldset_add_field(fs,f);
}

/* Allocate and append a string field. */
void fieldset_add_str(ProtoViewFieldSet *fs, const char *name, const char *s) {
    ProtoViewField *f = field_new(FieldTypeStr,name);
    f->str = strdup(s);
    f->len = strlen(s);
    fieldset_add_field(fs,f);
}

/* Allocate and append a bytes field. Note that 'count' is specified in
 * nibbles (bytes*2). */
void fieldset_add_bytes(ProtoViewFieldSet *fs, const char *name, const uint8_t *bytes, uint32_t count_nibbles) {
    uint32_t numbytes = (count_nibbles+count_nibbles%2)/2;
    ProtoViewField *f = field_new(FieldTypeBytes,name);
    f->bytes = malloc(numbytes);
    memcpy(f->bytes,bytes,numbytes);
    f->len = count_nibbles;
    fieldset_add_field(fs,f);
}

/* Allocate and append a float field. */
void fieldset_add_float(ProtoViewFieldSet *fs, const char *name, float val, uint32_t digits_after_dot) {
    ProtoViewField *f = field_new(FieldTypeFloat,name);
    f->fvalue = val;
    f->len = digits_after_dot;
    fieldset_add_field(fs,f);
}