From 1c9eb9fb3e8d3f44b03a621166058dbff25610d1 Mon Sep 17 00:00:00 2001 From: Cody P Schafer Date: Sat, 5 Sep 2015 21:21:03 -0400 Subject: [PATCH] mem: add mem helper functions Signed-off-by: Cody P Schafer Signed-off-by: David Gibson --- ccan/mem/mem.c | 24 +++++++ ccan/mem/mem.h | 157 ++++++++++++++++++++++++++++++++++++++++++++ ccan/mem/test/api.c | 37 ++++++++++- 3 files changed, 217 insertions(+), 1 deletion(-) diff --git a/ccan/mem/mem.c b/ccan/mem/mem.c index 853f975d..91c9961a 100644 --- a/ccan/mem/mem.c +++ b/ccan/mem/mem.c @@ -40,3 +40,27 @@ void *memrchr(const void *s, int c, size_t n) return NULL; } #endif + +void *mempbrkm(const void *data_, size_t len, const void *accept_, size_t accept_len) +{ + const char *data = data_, *accept = accept_; + size_t i, j; + + for (i = 0; i < len; i++) + for (j = 0; j < accept_len; j++) + if (accept[j] == data[i]) + return (void *)&data[i]; + return NULL; +} + +void *memcchr(void const *data, int c, size_t data_len) +{ + char const *p = data; + size_t i; + + for (i = 0; i < data_len; i++) + if (p[i] != c) + return (void *)&p[i]; + + return NULL; +} diff --git a/ccan/mem/mem.h b/ccan/mem/mem.h index dcb44b86..89b16d42 100644 --- a/ccan/mem/mem.h +++ b/ccan/mem/mem.h @@ -5,6 +5,7 @@ #include "config.h" #include +#include #if !HAVE_MEMMEM void *memmem(const void *haystack, size_t haystacklen, @@ -15,4 +16,160 @@ void *memmem(const void *haystack, size_t haystacklen, void *memrchr(const void *s, int c, size_t n); #endif +/** + * mempbrkm - locates the first occurrence in @data of any bytes in @accept + * @data: where we search + * @len: length of data in bytes + * @accept: array of bytes we search for + * @accept_len: # of bytes in accept + * + * Returns a pointer to the byte in @data that matches one of the bytes in + * @accept, or NULL if no such byte is found. + * + * Example: + * char otherbytes[] = "Hello \0world"; + * size_t otherbytes_len = sizeof(otherbytes) - 1; + * char *r = mempbrkm(otherbytes, otherbytes_len, "\0b", 2); + * if (r) { + * printf("Found %c\n", *r); + * } else { + * printf("Nada\n"); + * } + * + */ +void *mempbrkm(const void *data, size_t len, const void *accept, size_t accept_len); + +/** + * mempbrk - locates the first occurrence in @data of any bytes in @accept + * @data: where we search + * @len: length of data in bytes + * @accept: NUL terminated string containing the bytes we search for + * + * Returns a pointer to the byte in @data that matches one of the bytes in + * @accept, or NULL if no such byte is found. + * + * Example: + * + * r = mempbrk(otherbytes, otherbytes_len, "abcde"); + * if (r) { + * printf("Found %c\n", *r); + * } else { + * printf("Nada\n"); + * } + */ +static inline char *mempbrk(const void *data, size_t len, const char *accept) +{ + return mempbrkm(data, len, accept, strlen(accept)); +} + +/** + * memcchr - scan memory until a character does _not_ match @c + * @data: pointer to memory to scan + * @data_len: length of data + * @c: character to scan for + * + * The complement of memchr(). + * + * Returns a pointer to the first character which is _not_ @c. If all memory in + * @data is @c, returns NULL. + * + * Example: + * char somebytes[] = "HI By\0e"; + * size_t bytes_len = sizeof(somebytes) - 1; + * r = memcchr(somebytes, ' ', bytes_len); + * if (r) { + * printf("Found %c after trimming spaces\n", *r); + * } + */ +void *memcchr(void const *data, int c, size_t data_len); + +/** + * memeq - Are two byte arrays equal? + * @a: first array + * @al: bytes in first array + * @b: second array + * @bl: bytes in second array + * + * Example: + * if (memeq(somebytes, bytes_len, otherbytes, otherbytes_len)) { + * printf("memory blocks are the same!\n"); + * } + */ +static inline bool memeq(const void *a, size_t al, const void *b, size_t bl) +{ + return al == bl && !memcmp(a, b, bl); +} + +/** + * memstarts - determine if @data starts with @prefix + * @data: does this begin with @prefix? + * @data_len: bytes in @data + * @prefix: does @data begin with these bytes? + * @prefix_len: bytes in @prefix + * + * Returns true if @data starts with @prefix, otherwise return false. + * + * Example: + * if (memstarts(somebytes, bytes_len, otherbytes, otherbytes_len)) { + * printf("somebytes starts with otherbytes!\n"); + * } + */ +static inline bool memstarts(void const *data, size_t data_len, + void const *prefix, size_t prefix_len) +{ + if (prefix_len > data_len) + return false; + return memeq(data, prefix_len, prefix, prefix_len); +} + +/** + * memeqstr - Is a byte array equal to a NUL terminated string? + * @data: byte array + * @length: length of @data in bytes + * @string: NUL terminated string + * + * The '\0' byte is ignored when checking if @bytes == @string. + * + * Example: + * if (memeqstr(somebytes, bytes_len, "foo")) { + * printf("somebytes == 'foo'!\n"); + * } + */ +static inline bool memeqstr(const void *data, size_t length, const char *string) +{ + return memeq(data, length, string, strlen(string)); +} + +/** + * memstarts_str - Does this byte array start with a string prefix? + * @a: byte array + * @al: length in bytes + * @s: string prefix + * + * Example: + * if (memstarts_str(somebytes, bytes_len, "It")) { + * printf("somebytes starts with 'It'\n"); + * } + */ +static inline bool memstarts_str(const void *a, size_t al, const char *s) +{ + return memstarts(a, al, s, strlen(s)); +} + +/** + * memends - Does this byte array end with a given byte-array suffix? + * @s: byte array + * @s_len: length in bytes + * @suffix: byte array suffix + * @suffix_len: length of suffix in bytes + * + * Returns true if @suffix appears as a substring at the end of @s, + * false otherwise. + */ +static inline bool memends(const void *s, size_t s_len, const void *suffix, size_t suffix_len) +{ + return (s_len >= suffix_len) && (memcmp((const char *)s + s_len - suffix_len, + suffix, suffix_len) == 0); +} + #endif /* CCAN_MEM_H */ diff --git a/ccan/mem/test/api.c b/ccan/mem/test/api.c index 2ee15c58..89b6acb4 100644 --- a/ccan/mem/test/api.c +++ b/ccan/mem/test/api.c @@ -8,9 +8,11 @@ int main(void) char haystack2[] = "ab\0ab\0ab\0ab"; char needle1[] = "ab"; char needle2[] = "d\0e"; + char scan1[] = "aaaab"; + char scan2[] = "\0\0\0b"; /* This is how many tests you plan to run */ - plan_tests(19); + plan_tests(42); ok1(memmem(haystack1, sizeof(haystack1), needle1, 2) == haystack1); ok1(memmem(haystack1, sizeof(haystack1), needle1, 3) == NULL); @@ -37,6 +39,39 @@ int main(void) ok1(memrchr(needle1, '\0', 2) == NULL); +#define S(x) (x), sizeof(x) - 1 + ok1(mempbrkm(S(haystack1), S("\0efgh")) == haystack1 + 4); + ok1(mempbrkm(S(haystack1), S("jklmn")) == NULL); + ok1(mempbrkm(S(haystack1), S("sd\0a")) == haystack1 + 0); + + ok1(mempbrk(haystack1, sizeof(haystack1), "bcd\0a") == haystack1 + 1); + ok1(mempbrk(haystack1, sizeof(haystack1), "\0") == NULL); + + ok1(memcchr(scan1, 'a', sizeof(scan1)) == scan1 + 4); + ok1(memcchr(scan1, 'b', sizeof(scan1)) == scan1); + ok1(memcchr(scan2, '\0', sizeof(scan2)) == scan2 + 3); + ok1(memcchr(scan2, '\0', sizeof(scan2) - 2) == NULL); + + ok1(memeq(haystack1, sizeof(haystack1), haystack1, sizeof(haystack1))); + ok1(!memeq(haystack1, sizeof(haystack1), haystack2, sizeof(haystack2))); + + ok1(memeqstr(scan1, sizeof(scan1) - 1, scan1)); + ok1(!memeqstr(scan1, sizeof(scan1), scan1)); + ok1(!memeqstr(scan1, sizeof(scan1), "aaaa")); + + ok1(memstarts(S("a\0bcdef"), S("a\0bc"))); + ok1(!memstarts(S("a\0bcdef"), S("a\0bcG"))); + ok1(!memstarts(S("a\0bcdef"), S("a\0bcdefg"))); + + ok1(memstarts_str(scan1, sizeof(scan1), scan1)); + ok1(!memstarts_str(scan1, sizeof(scan1), "ab")); + + ok1(memends(S("abcdef"), S("abcdef"))); + ok1(!memends(S("abcdef"), S("abcdefg"))); + ok1(!memends(S("a\0bcdef"), S("a\0b"))); + ok1(memends(S("a\0bcdef"), S("ef"))); + + /* This exits depending on whether all tests passed */ return exit_status(); } -- 2.39.2