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55 lines
1.7 KiB
C
55 lines
1.7 KiB
C
#if 0
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/*─────────────────────────────────────────────────────────────────╗
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│ To the extent possible under law, Justine Tunney has waived │
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│ all copyright and related or neighboring rights to this file, │
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│ as it is written in the following disclaimers: │
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│ • http://unlicense.org/ │
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│ • http://creativecommons.org/publicdomain/zero/1.0/ │
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╚─────────────────────────────────────────────────────────────────*/
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#endif
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#include "libc/calls/calls.h"
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#include "libc/fmt/fmt.h"
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/**
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* @fileoverview Fast Growable Strings Tutorial
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*/
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struct Buffer {
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size_t i, n;
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char *p;
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};
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int AppendFmt(struct Buffer *b, const char *fmt, ...) {
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int n;
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char *p;
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va_list va, vb;
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va_start(va, fmt);
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va_copy(vb, va);
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n = vsnprintf(b->p + b->i, b->n - b->i, fmt, va);
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if (n >= b->n - b->i) {
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do {
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if (b->n) {
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b->n += b->n >> 1; /* this is the important line */
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} else {
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b->n = 16;
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}
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} while (b->i + n + 1 > b->n);
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b->p = realloc(b->p, b->n);
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vsnprintf(b->p + b->i, b->n - b->i, fmt, vb);
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}
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va_end(vb);
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va_end(va);
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b->i += n;
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return n;
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}
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int main(int argc, char *argv[]) {
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struct Buffer b = {0};
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AppendFmt(&b, "hello ");
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AppendFmt(&b, " world\n");
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AppendFmt(&b, "%d arg%s\n", argc, argc == 1 ? "" : "s");
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AppendFmt(&b, "%s\n", "have a nice day");
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write(1, b.p, b.i);
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free(b.p);
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return 0;
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}
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