diff options
Diffstat (limited to 'reftable/basics.h')
| -rw-r--r-- | reftable/basics.h | 253 |
1 files changed, 236 insertions, 17 deletions
diff --git a/reftable/basics.h b/reftable/basics.h index c8fec68d4e..fd59cbb772 100644 --- a/reftable/basics.h +++ b/reftable/basics.h @@ -14,12 +14,143 @@ https://developers.google.com/open-source/licenses/bsd */ #include "system.h" +#include "reftable-basics.h" + +#define REFTABLE_UNUSED __attribute__((__unused__)) + +struct reftable_buf { + size_t alloc; + size_t len; + char *buf; +}; +#define REFTABLE_BUF_INIT { 0 } + +/* + * Initialize the buffer such that it is ready for use. This is equivalent to + * using REFTABLE_BUF_INIT for stack-allocated variables. + */ +void reftable_buf_init(struct reftable_buf *buf); + +/* + * Release memory associated with the buffer. The buffer is reinitialized such + * that it can be reused for subsequent operations. + */ +void reftable_buf_release(struct reftable_buf *buf); + +/* + * Reset the buffer such that it is effectively empty, without releasing the + * memory that this structure holds on to. This is equivalent to calling + * `reftable_buf_setlen(buf, 0)`. + */ +void reftable_buf_reset(struct reftable_buf *buf); + +/* + * Trim the buffer to a shorter length by updating the `len` member and writing + * a NUL byte to `buf[len]`. Returns 0 on success, -1 when `len` points outside + * of the array. + */ +int reftable_buf_setlen(struct reftable_buf *buf, size_t len); + +/* + * Lexicographically compare the two buffers. Returns 0 when both buffers have + * the same contents, -1 when `a` is lexicographically smaller than `b`, and 1 + * otherwise. + */ +int reftable_buf_cmp(const struct reftable_buf *a, const struct reftable_buf *b); + +/* + * Append `len` bytes from `data` to the buffer. This function works with + * arbitrary byte sequences, including ones that contain embedded NUL + * characters. As such, we use `void *` as input type. Returns 0 on success, + * REFTABLE_OUT_OF_MEMORY_ERROR on allocation failure. + */ +int reftable_buf_add(struct reftable_buf *buf, const void *data, size_t len); + +/* Equivalent to `reftable_buf_add(buf, s, strlen(s))`. */ +int reftable_buf_addstr(struct reftable_buf *buf, const char *s); + +/* + * Detach the buffer from the structure such that the underlying memory is now + * owned by the caller. The buffer is reinitialized such that it can be reused + * for subsequent operations. + */ +char *reftable_buf_detach(struct reftable_buf *buf); /* Bigendian en/decoding of integers */ -void put_be24(uint8_t *out, uint32_t i); -uint32_t get_be24(uint8_t *in); -void put_be16(uint8_t *out, uint16_t i); +static inline void reftable_put_be16(void *out, uint16_t i) +{ + unsigned char *p = out; + p[0] = (uint8_t)((i >> 8) & 0xff); + p[1] = (uint8_t)((i >> 0) & 0xff); +} + +static inline void reftable_put_be24(void *out, uint32_t i) +{ + unsigned char *p = out; + p[0] = (uint8_t)((i >> 16) & 0xff); + p[1] = (uint8_t)((i >> 8) & 0xff); + p[2] = (uint8_t)((i >> 0) & 0xff); +} + +static inline void reftable_put_be32(void *out, uint32_t i) +{ + unsigned char *p = out; + p[0] = (uint8_t)((i >> 24) & 0xff); + p[1] = (uint8_t)((i >> 16) & 0xff); + p[2] = (uint8_t)((i >> 8) & 0xff); + p[3] = (uint8_t)((i >> 0) & 0xff); +} + +static inline void reftable_put_be64(void *out, uint64_t i) +{ + unsigned char *p = out; + p[0] = (uint8_t)((i >> 56) & 0xff); + p[1] = (uint8_t)((i >> 48) & 0xff); + p[2] = (uint8_t)((i >> 40) & 0xff); + p[3] = (uint8_t)((i >> 32) & 0xff); + p[4] = (uint8_t)((i >> 24) & 0xff); + p[5] = (uint8_t)((i >> 16) & 0xff); + p[6] = (uint8_t)((i >> 8) & 0xff); + p[7] = (uint8_t)((i >> 0) & 0xff); +} + +static inline uint16_t reftable_get_be16(const void *in) +{ + const unsigned char *p = in; + return (uint16_t)(p[0]) << 8 | + (uint16_t)(p[1]) << 0; +} + +static inline uint32_t reftable_get_be24(const void *in) +{ + const unsigned char *p = in; + return (uint32_t)(p[0]) << 16 | + (uint32_t)(p[1]) << 8 | + (uint32_t)(p[2]) << 0; +} + +static inline uint32_t reftable_get_be32(const void *in) +{ + const unsigned char *p = in; + return (uint32_t)(p[0]) << 24 | + (uint32_t)(p[1]) << 16 | + (uint32_t)(p[2]) << 8| + (uint32_t)(p[3]) << 0; +} + +static inline uint64_t reftable_get_be64(const void *in) +{ + const unsigned char *p = in; + return (uint64_t)(p[0]) << 56 | + (uint64_t)(p[1]) << 48 | + (uint64_t)(p[2]) << 40 | + (uint64_t)(p[3]) << 32 | + (uint64_t)(p[4]) << 24 | + (uint64_t)(p[5]) << 16 | + (uint64_t)(p[6]) << 8 | + (uint64_t)(p[7]) << 0; +} /* * find smallest index i in [0, sz) at which `f(i) > 0`, assuming that f is @@ -37,9 +168,12 @@ size_t binsearch(size_t sz, int (*f)(size_t k, void *args), void *args); */ void free_names(char **a); -/* parse a newline separated list of names. `size` is the length of the buffer, - * without terminating '\0'. Empty names are discarded. */ -void parse_names(char *buf, int size, char ***namesp); +/* + * Parse a newline separated list of names. `size` is the length of the buffer, + * without terminating '\0'. Empty names are discarded. Returns a `NULL` + * pointer when allocations fail. + */ +char **parse_names(char *buf, int size); /* compares two NULL-terminated arrays of strings. */ int names_equal(const char **a, const char **b); @@ -53,22 +187,107 @@ void *reftable_malloc(size_t sz); void *reftable_realloc(void *p, size_t sz); void reftable_free(void *p); void *reftable_calloc(size_t nelem, size_t elsize); +char *reftable_strdup(const char *str); -#define REFTABLE_ALLOC_ARRAY(x, alloc) (x) = reftable_malloc(st_mult(sizeof(*(x)), (alloc))) +static inline int reftable_alloc_size(size_t nelem, size_t elsize, size_t *out) +{ + if (nelem && elsize > SIZE_MAX / nelem) + return -1; + *out = nelem * elsize; + return 0; +} + +#define REFTABLE_ALLOC_ARRAY(x, alloc) do { \ + size_t alloc_size; \ + if (reftable_alloc_size(sizeof(*(x)), (alloc), &alloc_size) < 0) { \ + errno = ENOMEM; \ + (x) = NULL; \ + } else { \ + (x) = reftable_malloc(alloc_size); \ + } \ + } while (0) #define REFTABLE_CALLOC_ARRAY(x, alloc) (x) = reftable_calloc((alloc), sizeof(*(x))) -#define REFTABLE_REALLOC_ARRAY(x, alloc) (x) = reftable_realloc((x), st_mult(sizeof(*(x)), (alloc))) -#define REFTABLE_ALLOC_GROW(x, nr, alloc) \ - do { \ - if ((nr) > alloc) { \ - alloc = 2 * (alloc) + 1; \ - if (alloc < (nr)) \ - alloc = (nr); \ - REFTABLE_REALLOC_ARRAY(x, alloc); \ +#define REFTABLE_REALLOC_ARRAY(x, alloc) do { \ + size_t alloc_size; \ + if (reftable_alloc_size(sizeof(*(x)), (alloc), &alloc_size) < 0) { \ + errno = ENOMEM; \ + (x) = NULL; \ + } else { \ + (x) = reftable_realloc((x), alloc_size); \ } \ } while (0) +static inline void *reftable_alloc_grow(void *p, size_t nelem, size_t elsize, + size_t *allocp) +{ + void *new_p; + size_t alloc = *allocp * 2 + 1, alloc_bytes; + if (alloc < nelem) + alloc = nelem; + if (reftable_alloc_size(elsize, alloc, &alloc_bytes) < 0) { + errno = ENOMEM; + return p; + } + new_p = reftable_realloc(p, alloc_bytes); + if (!new_p) + return p; + *allocp = alloc; + return new_p; +} + +#define REFTABLE_ALLOC_GROW(x, nr, alloc) ( \ + (nr) > (alloc) && ( \ + (x) = reftable_alloc_grow((x), (nr), sizeof(*(x)), &(alloc)), \ + (nr) > (alloc) \ + ) \ +) + +#define REFTABLE_ALLOC_GROW_OR_NULL(x, nr, alloc) do { \ + size_t reftable_alloc_grow_or_null_alloc = alloc; \ + if (REFTABLE_ALLOC_GROW((x), (nr), reftable_alloc_grow_or_null_alloc)) { \ + REFTABLE_FREE_AND_NULL(x); \ + alloc = 0; \ + } else { \ + alloc = reftable_alloc_grow_or_null_alloc; \ + } \ +} while (0) + +#define REFTABLE_FREE_AND_NULL(p) do { reftable_free(p); (p) = NULL; } while (0) + +#ifndef REFTABLE_ALLOW_BANNED_ALLOCATORS +# define REFTABLE_BANNED(func) use_reftable_##func##_instead +# undef malloc +# define malloc(sz) REFTABLE_BANNED(malloc) +# undef realloc +# define realloc(ptr, sz) REFTABLE_BANNED(realloc) +# undef free +# define free(ptr) REFTABLE_BANNED(free) +# undef calloc +# define calloc(nelem, elsize) REFTABLE_BANNED(calloc) +# undef strdup +# define strdup(str) REFTABLE_BANNED(strdup) +#endif + +#define REFTABLE_SWAP(a, b) do { \ + void *_swap_a_ptr = &(a); \ + void *_swap_b_ptr = &(b); \ + unsigned char _swap_buffer[sizeof(a) - 2 * sizeof(a) * (sizeof(a) != sizeof(b))]; \ + memcpy(_swap_buffer, _swap_a_ptr, sizeof(a)); \ + memcpy(_swap_a_ptr, _swap_b_ptr, sizeof(a)); \ + memcpy(_swap_b_ptr, _swap_buffer, sizeof(a)); \ +} while (0) + /* Find the longest shared prefix size of `a` and `b` */ -struct strbuf; -int common_prefix_size(struct strbuf *a, struct strbuf *b); +size_t common_prefix_size(struct reftable_buf *a, struct reftable_buf *b); + +uint32_t hash_size(enum reftable_hash id); + +/* + * Format IDs that identify the hash function used by a reftable. Note that + * these constants end up on disk and thus mustn't change. The format IDs are + * "sha1" and "s256" in big endian, respectively. + */ +#define REFTABLE_FORMAT_ID_SHA1 ((uint32_t) 0x73686131) +#define REFTABLE_FORMAT_ID_SHA256 ((uint32_t) 0x73323536) #endif |