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>>>>> tag v1.26.5+1 for changeset b74429b0f5c4
author Franz Glasner <fzglas.hg@dom66.de>
date Sat, 11 Oct 2025 17:17:30 +0200
parents b50eed0cc0ef
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1 # Coding Style
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3 This is a basic overview of the MuPDF coding style used in the C library.
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5 ## Indentation
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7 There are two hard rules:
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9 1. Indent with hard tabs.
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10 2. Do not vertically align anything beyond the left edge!
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12 If you want a different indentation level, configure your editor to use
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13 whichever tab width you prefer. If you follow the two rules above, everything
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14 will work out perfectly.
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16 The rest you should be able to infer from the source around you:
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18 - Curly braces on their own line.
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19 - Put a space between `if`, `for`, `while`, and their expression.
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21 ## Names
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23 Functions should be named according to one of the following schemes:
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25 - verb_noun
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26 - verb_noun_with_noun
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27 - noun_attribute
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28 - set_noun_attribute
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29 - noun_from_noun -- convert from one type to another (avoid noun_to_noun)
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31 Prefixes are mandatory for exported functions, macros, enums, globals and
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32 types.
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34 - fz for common code
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35 - pdf, xps, etc., for interpreter specific code
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37 Prefixes are optional (but encouraged) for private functions and types.
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39 Avoid using 'get' as this is a meaningless and redundant filler word.
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41 These words are reserved for reference counting schemes:
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43 - new, create, find, load, open, keep -- return objects that you are responsible for freeing.
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44 - drop -- relinquish ownership of the object passed in.
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46 When searching for an object or value, the name used depends on whether
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47 returning the value is passing ownership:
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49 - lookup -- return a value or borrowed pointer
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50 - find -- return an object that the caller is responsible for freeing
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52 ## Types
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54 Various different integer types are used throughout MuPDF.
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56 In general:
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58 - int is assumed to be 32bit at least.
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59 - short is assumed to be exactly 16 bits.
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60 - char is assumed to be exactly 8 bits.
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61 - array sizes, string lengths, and allocations are measured using size_t.
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62 - size_t is 32bit in 32bit builds, and 64bit on all 64bit builds.
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63 - buffers of data use unsigned chars (or uint8_t).
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64 - Offsets within files/streams are represented using int64_t.
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66 In addition, we use floats (and avoid doubles when possible), assumed to be
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67 IEEE compliant.
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69 ## Reference counting
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71 Reference counting uses special words in functions to make it easy to remember
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72 and follow the rules.
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74 Words that take ownership: new, find, load, open, keep.
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76 Words that release ownership: drop.
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78 If an object is returned by a function with one of the special words that take
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79 ownership, you are responsible for freeing it by calling "drop" or "free", or
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80 "close" before you return. You may pass ownership of an owned object by return
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81 it only if you name the function using one of the special words.
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83 Any objects returned by functions that do not have any of these special words,
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84 are borrowed and have a limited life time. Do not hold on to them past the
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85 duration of the current function, or stow them away inside structs. If you need
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86 to keep the object for longer than that, you have to either "keep" it or make
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87 your own copy.