54 lines
1.8 KiB
C
54 lines
1.8 KiB
C
/*
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* strbuf.h — safe growable printf buffer
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*
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* Replaces snprintf(buf+off, sizeof(buf)-off, ...) chains that crash
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* on overflow (snprintf returns un-truncated size, offset exceeds buffer,
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* next call gets negative size → FORTIFY abort on Bionic/Android).
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*
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* Usage:
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* struct strbuf sb = strbuf_new();
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* strbuf_addf(&sb, "{\"ver\":\"%d\"", ver);
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* strbuf_addf(&sb, ",\"name\":\"%s\"", name);
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* strbuf_addf(&sb, "}");
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* // use strbuf_str(&sb) or strbuf_detach(&sb)
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* strbuf_free(&sb);
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*/
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#ifndef STRBUF_H
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#define STRBUF_H
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#include <stddef.h>
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#include <stdarg.h>
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struct strbuf {
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char *buf; /* allocated buffer, always null-terminated */
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size_t cap; /* total capacity (including '\0') */
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size_t len; /* current length (excluding '\0') */
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};
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/* zero-init on stack: struct strbuf sb = {0}; */
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#define strbuf_new() ((struct strbuf){NULL, 0, 0})
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void strbuf_init(struct strbuf *sb, size_t initial_cap);
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void strbuf_free(struct strbuf *sb);
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/* returns buf and detaches — caller must u_free(). sb is reset to empty */
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char *strbuf_detach(struct strbuf *sb);
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/* reset len=0, keep allocation */
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void strbuf_reset(struct strbuf *sb);
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/* printf-like append. auto-grows. returns written bytes or -1 on OOM */
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int strbuf_addf(struct strbuf *sb, const char *fmt, ...)
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__attribute__((format(printf, 2, 3)));
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/* Добавить JSON-строку с кавычками и полным экранированием; NULL означает пустую строку. 0/-1. */
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int strbuf_add_json_string(struct strbuf* sb, const char* text);
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void strbuf_addc(struct strbuf *sb, char c);
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void strbuf_adds(struct strbuf *sb, const char *s);
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/* safe accessor — never returns NULL */
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#define strbuf_str(sb) ((sb)->buf ? (sb)->buf : "")
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#endif /* STRBUF_H */
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