#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 */ >

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