some cursory review
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e0781d0536
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2 changed files with 37 additions and 29 deletions
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@ -24,6 +24,10 @@ static const struct hash_info {
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{ MH_H_BLAKE2S, "blake2s", 32 }
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{ MH_H_BLAKE2S, "blake2s", 32 }
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};
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};
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// REVIEW NOTE:
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// This could just be a table where the index into the array is the hash
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// function. This would make the lookups much simpler.
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mh_assert_static(sizeof(hash_infos) / sizeof(hash_infos[0]) == MH_H_COUNT);
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mh_assert_static(sizeof(hash_infos) / sizeof(hash_infos[0]) == MH_H_COUNT);
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// Searches for given hash in hash info table
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// Searches for given hash in hash info table
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@ -40,7 +44,8 @@ static const struct hash_info *find_hash(int hash) {
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const char *mh_hash_name(int hash) {
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const char *mh_hash_name(int hash) {
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const struct hash_info *info = find_hash(hash);
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const struct hash_info *info = find_hash(hash);
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return info ? info->name : NULL;
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return (info != NULL) ? info->name : NULL;
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// I prefer explicit checks against null pointers
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}
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}
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@ -10,66 +10,69 @@
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#define VARINT_MASK (1 << 7)
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#define VARINT_MASK (1 << 7)
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static int check_len(size_t len) {
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static int check_len(size_t len) {
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if (len < 1) {
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if (len < 1)
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return MH_E_TOO_SHORT;
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return MH_E_TOO_SHORT;
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} else if (len >= 128) {
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else if (len >= 128)
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return MH_E_TOO_LONG;
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return MH_E_TOO_LONG;
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}
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return MH_E_NO_ERROR;
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return 0;
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}
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}
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static int check_multihash(const unsigned char mh[], size_t len) {
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static int check_multihash(const unsigned char mh[], size_t len) {
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int error;
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int err;
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if (len < 3)
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if (len < 3)
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return MH_E_TOO_SHORT;
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return MH_E_TOO_SHORT;
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if (mh[0] & VARINT_MASK) {
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if (mh[0] & VARINT_MASK) {
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// In near future multihash format will be
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// This value is a varint, but there are currently no supported values
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// extended with varints, this is how we are protecting
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// that require more than a single byte to represent.
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// against it.
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return MH_E_VARINT_NOT_SUPPORTED;
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return MH_E_VARINT_NOT_SUPPORTED;
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} else if (mh[1] & VARINT_MASK) {
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} else if (mh[1] & VARINT_MASK) {
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return MH_E_VARINT_NOT_SUPPORTED;
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return MH_E_VARINT_NOT_SUPPORTED;
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}
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}
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error = check_len(mh[1]);
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err = check_len(mh[1]);
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if (error)
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if (err)
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return error;
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return err;
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return MH_E_NO_ERROR;
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return 0;
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}
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}
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// returns hash code or error (which is < 0)
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// returns hash code or error (which is < 0)
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int mh_multihash_hash(const unsigned char *mh, size_t len) {
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int mh_multihash_hash(const unsigned char *mh, size_t len) {
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if (check_multihash(mh, len))
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int err;
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return check_multihash(mh, len);
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err = check_multihash(mh, len);
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return err;
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return (int) mh[0];
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return (int) mh[0];
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}
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}
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// returns length of multihash or error (which is < 0)
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// returns length of multihash or error (which is < 0)
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int mh_multihash_length(const unsigned char *mh, size_t len) {
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int mh_multihash_length(const unsigned char *mh, size_t len) {
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if (check_multihash(mh, len))
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int err;
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return check_multihash(mh, len);
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err = check_multihash(mh, len);
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if (err)
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return err;
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return (int) mh[1];
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return (int) mh[1];
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}
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}
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// gives access to raw digset inside multihash buffer
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// gives access to raw digest inside multihash buffer
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// returns 0 or negative error
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// returns 0 or negative error
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int mh_multihash_digset(unsigned char *multihash, size_t len, unsigned char **digset,
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int mh_multihash_digest(unsigned char *multihash, size_t len, unsigned char **digest,
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size_t *digset_len) {
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size_t *digest_len) {
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int error = check_multihash(multihash, len);
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int error = check_multihash(multihash, len);
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if (error)
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if (error)
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return error;
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return error;
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(*digset_len) = (size_t) mh_multihash_length(multihash, len);
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(*digest_len) = (size_t) mh_multihash_length(multihash, len);
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(*digset) = multihash + 2; // Always true without varint
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(*digest) = multihash + 2; // Always true without varint
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return MH_E_NO_ERROR;
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return 0;
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}
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}
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int mh_new_length(int code, size_t hash_len) {
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int mh_new_length(int code, size_t hash_len) {
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@ -79,17 +82,17 @@ int mh_new_length(int code, size_t hash_len) {
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return 2 + hash_len;
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return 2 + hash_len;
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}
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}
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int mh_new(unsigned char *buffer, int code, const unsigned char *digset,
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int mh_new(unsigned char *buffer, int code, const unsigned char *digest,
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size_t digset_len) {
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size_t digest_len) {
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if (code & VARINT_MASK)
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if (code & VARINT_MASK)
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return MH_E_VARINT_NOT_SUPPORTED;
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return MH_E_VARINT_NOT_SUPPORTED;
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if (digset_len > 127)
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if (digest_len > 127)
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return MH_E_DIGSET_TOO_LONG;
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return MH_E_DIGSET_TOO_LONG;
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buffer[0] = (unsigned char) ((unsigned int) code) & 255;
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buffer[0] = (unsigned char) ((unsigned int) code) & 255;
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buffer[1] = (unsigned char) digset_len;
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buffer[1] = (unsigned char) digest_len;
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memcpy(buffer + 2, digset, digset_len);
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memcpy(buffer + 2, digest, digest_len);
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return MH_E_NO_ERROR;
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return 0;
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}
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}
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