BSON_WRITER_T(3)

💖 BSON_WRITER_T(3) 💖

okay so this is a page from libbson, bestie — and the whole vibe is bulk BSON serialization abstraction, no cap. like, it's literally called that. let's get into it 🦋

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✨ SYNOPSIS ✨

first things first, you gotta pull in the header:

#include <bson/bson.h>

then say hi to the type itself — she's opaque, she's iconic:

typedef struct _bson_writer_t bson_writer_t;

and here are the two functions that do the whole thing, like, the entire main character energy of this page:

bson_writer_t *
bson_writer_new (uint8_t **buf,
                 size_t *buflen,
                 size_t offset,
                 bson_realloc_func realloc_func,
                 void *realloc_func_ctx);
void
bson_writer_destroy (bson_writer_t *writer);

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🌸 DESCRIPTION 🌸

so the bson_writer_t API is basically an abstraction layer for serializing, like, so many BSON documents into one single memory region. one buffer. all of them. together. 💅

that memory region can be dynamically allocated and re-allocated as more memory gets demanded — so she grows as needed, she's flexible, she's adaptable, we stan.

and why would you even want this? okay so it's highkey useful when you're building network packets from a high-level language. the example the original gives: you can serialize a Python Dictionary directly into a single buffer that's destined for a TCP packet. like, no middleman, straight to the packet. obsessed. 🫶

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🎀 EXAMPLE 🎀

here's the whole thing, verbatim, don't @ me:

#include <bson/bson.h>

int
main (int argc, char *argv[])
{
   bson_writer_t *writer;
   uint8_t *buf = NULL;
   size_t buflen = 0;
   bson_t *doc;

   writer = bson_writer_new (&buf, &buflen, 0, bson_realloc_ctx, NULL);

   for (int i = 0; i < 1000; i++) {
      bson_writer_begin (writer, &doc);
      BSON_APPEND_INT32 (doc, "i", i);
      bson_writer_end (writer);
   }

   bson_writer_destroy (writer);

   bson_free (buf);

   return 0;
}

like, look at her go — 1000 documents, one buffer, begin/end begin/end begin/end, then bson_writer_destroy and bson_free because we clean up after ourselves in this house. periodt. 🔥

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⭐ AUTHOR ⭐

MongoDB, Inc — yeah, that MongoDB. the whole thing. 👑

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🌈 COPYRIGHT 🌈

2009-present, MongoDB, Inc. — all rights reserved, respect the legacy bestie 🎀

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and that's the whole page!! go forth and serialize, you got this 💜

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okay bye, this was libbson 2.5.6, dated Oct 09, 2026, page BSON_WRITER_T(3) — catch you on the flip side, bestie 🦋✨🍓