#ifndef __PERF_STRBUF_H #define __PERF_STRBUF_H /* * Strbuf's can be use in many ways: as a byte array, or to store arbitrary * long, overflow safe strings. * * Strbufs has some invariants that are very important to keep in mind: * * 1. the ->buf member is always malloc-ed, hence strbuf's can be used to * build complex strings/buffers whose final size isn't easily known. * * It is NOT legal to copy the ->buf pointer away. * `strbuf_detach' is the operation that detachs a buffer from its shell * while keeping the shell valid wrt its invariants. * * 2. the ->buf member is a byte array that has at least ->len + 1 bytes * allocated. The extra byte is used to store a '\0', allowing the ->buf * member to be a valid C-string. Every strbuf function ensure this * invariant is preserved. * * Note that it is OK to "play" with the buffer directly if you work it * that way: * * strbuf_grow(sb, SOME_SIZE); * ... Here, the memory array starting at sb->buf, and of length * ... strbuf_avail(sb) is all yours, and you are sure that * ... strbuf_avail(sb) is at least SOME_SIZE. * strbuf_setlen(sb, sb->len + SOME_OTHER_SIZE); * * Of course, SOME_OTHER_SIZE must be smaller or equal to strbuf_avail(sb). * * Doing so is safe, though if it has to be done in many places, adding the * missing API to the strbuf module is the way to go. * * XXX: do _not_ assume that the area that is yours is of size ->alloc - 1 * even if it's true in the current implementation. Alloc is somehow a * "private" member that should not be messed with. */ #include #include #include #include #include extern char strbuf_slopbuf[]; struct strbuf { size_t alloc; size_t len; char *buf; }; #define STRBUF_INIT { 0, 0, strbuf_slopbuf } /*----- strbuf life cycle -----*/ int strbuf_init(struct strbuf *buf, ssize_t hint); void strbuf_release(struct strbuf *buf); char *strbuf_detach(struct strbuf *buf, size_t *); /*----- strbuf size related -----*/ static inline ssize_t strbuf_avail(const struct strbuf *sb) { return sb->alloc ? sb->alloc - sb->len - 1 : 0; } int strbuf_grow(struct strbuf *buf, size_t); static inline int strbuf_setlen(struct strbuf *sb, size_t len) { if (!sb->alloc) { int ret = strbuf_grow(sb, 0); if (ret) return ret; } assert(len < sb->alloc); sb->len = len; sb->buf[len] = '\0'; return 0; } /*----- add data in your buffer -----*/ int strbuf_addch(struct strbuf *sb, int c); int strbuf_add(struct strbuf *buf, const void *, size_t); static inline int strbuf_addstr(struct strbuf *sb, const char *s) { return strbuf_add(sb, s, strlen(s)); } __attribute__((format(printf,2,3))) int strbuf_addf(struct strbuf *sb, const char *fmt, ...); /* XXX: if read fails, any partial read is undone */ ssize_t strbuf_read(struct strbuf *, int fd, ssize_t hint); #endif /* __PERF_STRBUF_H */ ='2'/>context:space:mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2017-02-08 16:06:10 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-08 16:06:10 -0800
commit507053d23b886fdedc8336ca2233883fe4c82aa2 (patch)
treea64839493e04ac8608c52156d97d40ecd1c78be8
parentbe11f436a80b19cb5ef4cdfba7371a5178bd43cd (diff)
parenta810007afe239d59c1115fcaa06eb5b480f876e9 (diff)
Merge branch 'akpm' (patches from Andrew)
Merge fixes from Andrew Morton: "4 fixes" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: mm/slub.c: fix random_seq offset destruction cpumask: use nr_cpumask_bits for parsing functions mm: avoid returning VM_FAULT_RETRY from ->page_mkwrite handlers kernel/ucount.c: mark user_header with kmemleak_ignore()
Diffstat