NativeElixirPdfUtilities.Merge (native_elixir_pdf_utilities v0.2.0)

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Minimal PDF utilities for merging PDF binaries using the tokenizer.

Notes and constraints:

  • Emits a classic PDF 1.7 header and builds a fresh xref + trailer.
  • Copies all objects from inputs, renumbering to avoid collisions.
  • Adjusts indirect references (n g R) to the new numbering.
  • Collects Page objects and builds a new Catalog + Pages tree that references them.
  • Leaves stream bytes untouched and preserves declared /Length (direct or indirect ref), only renumbering indirect references as needed.
  • Does not decode filters or resolve xref streams; expects classic PDFs tokenizable by the tokenizer.

The merger is conservative and pragmatic, targeting structural correctness for common PDFs.

Summary

Types

id_map()

Mapping from original object id to new object id.

obj_rec()

Object record captured while indexing inputs.

offsets_map()

Byte-offset table for xref: object id -> {byte_offset, generation}.

pdf_bin()
token()

A single token as produced by NativeElixirPdfUtilities.Tokenizer.

tokens()

A list of PDF tokens.

Functions

merge(bins)

Merge a list of PDF binaries into a single PDF binary.

Types

id_map()

@type id_map() :: %{optional(integer()) => integer()}

Mapping from original object id to new object id.

obj_rec()

@type obj_rec() :: %{obj: integer(), gen: integer(), tokens: tokens()}

Object record captured while indexing inputs.

offsets_map()

@type offsets_map() :: %{
  optional(integer()) => {non_neg_integer(), non_neg_integer()}
}

Byte-offset table for xref: object id -> {byte_offset, generation}.

pdf_bin()

@type pdf_bin() :: binary()

token()

@type token() :: NativeElixirPdfUtilities.Tokenizer.token()

A single token as produced by NativeElixirPdfUtilities.Tokenizer.

tokens()

@type tokens() :: [token()]

A list of PDF tokens.

Functions

merge(bins)

@spec merge([pdf_bin()]) :: {:ok, pdf_bin()}

Merge a list of PDF binaries into a single PDF binary.

This is a best-effort merger for classic PDFs. It renumbers all objects of each input, collects Page objects, and emits a new Catalog/Pages tree that references all pages.