diff options
Diffstat (limited to 'common.h')
| -rw-r--r-- | common.h | 89 |
1 files changed, 87 insertions, 2 deletions
@@ -19,8 +19,8 @@ #include <errno.h> #include <limits.h> #include <stdarg.h> -#include <stdio.h> #include <stdlib.h> +#include <string.h> #if defined(__GNUC__) @@ -118,6 +118,50 @@ struct pepper { /** + * Structure used for doing truncated text concatenation + * + * This structure is laid out so that `{buf, size, 0u}` will + * properly initialise the state to use a buffer and have + * it's size properly set, and have the resulting length + * initialised to zero. This will not change. + */ +struct concat_state { + /** + * Where the function shall write to + * + * Update to an offset of it by the called function. + * Shall be set to the beginning of the output buffer + * before the first function call. + */ + char *buf; + + /** + * The (remaining) size of the output buffer + * + * This is decremented by the called function + * Shall be set to the size of the output buffer + * before the first function call. + */ + size_t size; + + /** + * The length the constructed text would + * have had if it wasn't truncated + * + * This length does not include NUL termination + * which is added by every function + * + * This is increased by the called function. + * Should be set to 0 before the first function call. + * + * After the last concatenation call, this field + * is read to get the final size before truncation + */ + size_t len; +}; + + +/** * The real type of `LIBRECRYPT_CONTEXT` */ struct librecrypt_context { @@ -330,10 +374,51 @@ const struct librecrypt_algorithm *librecrypt_find_first_algorithm_(const char * * @throws EINVAL The size of the pepper is unsupported * for the hash algorithm `algo` */ -LIBRECRYPT_NONNULL_1__ +LIBRECRYPT_NONNULL_1__ HIDDEN struct pepper *librecrypt_get_pepper_(LIBRECRYPT_CONTEXT *ctx, enum librecrypt_hash_algorithm algo, size_t len); +LIBRECRYPT_NONNULL_1__ HIDDEN +inline size_t +librecrypt_concat_void_(struct concat_state *state, size_t len) /* TODO doc */ +{ + size_t n = state->size ? MIN(state->size - 1u, len) : 0u; + if (len > SIZE_MAX - state->len) + abort(); /* TODO not covered */ + state->len += len; + if (n) { + state->buf = &state->buf[n]; + state->size -= n; + } + if (state->size) + state->buf[0u] = '\0'; + return n; +} + + +LIBRECRYPT_NONNULL_1__ LIBRECRYPT_READ_MEM__(2, 3) HIDDEN +inline void +librecrypt_concat_mem_(struct concat_state *state, const char *text, size_t len) /* TODO doc */ +{ + char *buf = state->buf; + size_t n = librecrypt_concat_void_(state, len); + if (n) + memcpy(buf, text, n); +} + + +LIBRECRYPT_NONNULL_1__ LIBRECRYPT_READ_STR__(2) HIDDEN +inline void +librecrypt_concat_str_(struct concat_state *state, const char *text) /* TODO doc */ +{ + librecrypt_concat_mem_(state, text, strlen(text)); +} + + +LIBRECRYPT_NONNULL_1__ HIDDEN +void librecrypt_concat_uint_(struct concat_state *state, uintmax_t value); /* TODO doc */ + + #ifdef TEST # include "libtest/libtest.h" |