commit f7fd0b587fe3e4ff0809d208b91c04efa66fd820 Author: ns Date: Thu Mar 13 22:51:06 2025 -0500 first commit diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..2a38bf9 --- /dev/null +++ b/.gitignore @@ -0,0 +1,7 @@ +# testing files +build +build.ninja +ngen.toml +tree.c +tree.pdf +tv.c diff --git a/LICENSE.txt b/LICENSE.txt new file mode 100644 index 0000000..0a04128 --- /dev/null +++ b/LICENSE.txt @@ -0,0 +1,165 @@ + GNU LESSER GENERAL PUBLIC LICENSE + Version 3, 29 June 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + + This version of the GNU Lesser General Public License incorporates +the terms and conditions of version 3 of the GNU General Public +License, supplemented by the additional permissions listed below. + + 0. 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Such new +versions will be similar in spirit to the present version, but may +differ in detail to address new problems or concerns. + + Each version is given a distinguishing version number. If the +Library as you received it specifies that a certain numbered version +of the GNU Lesser General Public License "or any later version" +applies to it, you have the option of following the terms and +conditions either of that published version or of any later version +published by the Free Software Foundation. If the Library as you +received it does not specify a version number of the GNU Lesser +General Public License, you may choose any version of the GNU Lesser +General Public License ever published by the Free Software Foundation. + + If the Library as you received it specifies that a proxy can decide +whether future versions of the GNU Lesser General Public License shall +apply, that proxy's public statement of acceptance of any version is +permanent authorization for you to choose that version for the +Library. diff --git a/README.md b/README.md new file mode 100644 index 0000000..fb837dc --- /dev/null +++ b/README.md @@ -0,0 +1,33 @@ +# treeviz +A header-only C library which uses [graphviz](https://www.graphviz.org/) to +visualize recursive data structures. + +This library is intended mostly for debugging purposes, as it can oftentimes +be useful to visualize your program's data layout. This is especially true with +deeply nested recursive data structures. + +The methods in this library use two functions that end-user must write +themselves: + +1. One that iterates over a node's children, +1. And another that represents a node's data. + +This design allows the library to work with **any recursive data structure.** +As it turns out, these two functions are all you need to generalize the task +of visualization. + +## Dependencies +You must have graphviz installed, and the `dot` executable in your path. That's +it. + +*Optional:* Becuase this library renders your tree to a pdf (for now), it is +nice to have a pdf viewer that updates the screen automatically upon an update +to the file being viewed. [Zathura](https://github.com/pwmt/zathura) is one such +viewer, but there are many available. + +## TODO: write documentation +There are some notes in the header file that may guide you before I write the +actual docs. + +--- +Copyright (C) Noah Swerhun under the terms of the LGPLv3 (see LICENSE.txt). diff --git a/treeviz.h b/treeviz.h new file mode 100644 index 0000000..989a15c --- /dev/null +++ b/treeviz.h @@ -0,0 +1,168 @@ +#ifndef TREEVIZ_H +#define TREEVIZ_H + +// TreeViz context. Contains settings for the visualizer functions. This +// is wrapped in a struct so you don't have to always pass the same options +// to every funcion call. However, if you want to do that, you can use the +// `TV_vizl` function. +typedef struct TVCtx_T { + // Output filename. Should end in `.pdf` + char *filename; + + // Function that takes a reference to a node, and returns a string + // representing the node's data. The representation should not include any + // information about children, just the data stored in the node that the + // function was called on. + char *(*represent_data)(void *node); + + // A function that takes a node, and iteratively returns each child of the + // node on each successive call, setting `done` to 1 when all children have + // been processed. Be sure to use `cur_idx` to track the function's progress: + // this function will be called in a recursive context, so using static memory + // introduces some funny bugs. + void *(*next_child)(void *root_node, int *done, int *cur_idx); +} TVCtx; + +// Visualize the tree rooted at `root_node`, using the settings found in `ctx`. +void TV_vizv(void *root_node, TVCtx *ctx); + +// Visualize the tree rooted at `root_node`, using the settings specifed. See +// the `TVCtx` struct. +void TV_vizl(void *root_node, char *filename, + char *(*represent_data)(void *root_node), + void *(*next_child)(void *root_node, int *done, int *cur_idx)); + +#endif + +#ifdef TREEVIZ_IMPLEMENTATION +#ifndef TREEVIZ_IMPL_ALREADY +#define TREEVIZ_IMPL_ALREADY + +#include +#include +#include +#include +#include +#include +#include +#include + +#define ERRCHECK(...) \ + if (errno != 0) { \ + fprintf(stderr, "error: %s (errno %d)\n", strerror(errno), errno); \ + fprintf(stderr, __VA_ARGS__); \ + fputc('\n', stderr); \ + assert(errno == 0); \ + } + +#define NOT_NULL(x) assert(x != NULL) + +void _TV_write_dot(void *root_node, int fd, TVCtx *ctx, size_t *id) { + void *(*next_child)(void *root_node, int *done, int *cur_idx) = + ctx->next_child; + char *(*represent_data)(void *node) = ctx->represent_data; + + char *repr = represent_data(root_node); + + size_t cur_id = *id; + ++(*id); + + errno = 0; + if (root_node == NULL) { + dprintf(fd, "%zu [style=filled,fillcolor=gray,label=\"%s\"];", cur_id, + repr); + } else { + dprintf(fd, "%zu [label=\"%s\"];", cur_id, repr); + } + ERRCHECK("TreeViz: _TV_write_dot: could not write to pipe"); + + free(repr); + + if (root_node == NULL) { + return; + } + + int done = 0; + int iter = 0; + while (!done) { + void *child = next_child(root_node, &done, &iter); + + errno = 0; + dprintf(fd, "%zu->%zu;", cur_id, *id); + ERRCHECK("TreeViz: _TV_write_dot: could not write to pipe"); + + _TV_write_dot(child, fd, ctx, id); + } +} + +void TV_vizv(void *root_node, TVCtx *ctx) { + int pipe_stdin[2]; + + errno = 0; + pipe(pipe_stdin); + ERRCHECK("TreeViz: TV_vizv: could not create pipe to dot") + + int child_stdin_write = pipe_stdin[1]; + int child_stdin_read = pipe_stdin[0]; + + char o_argument[1024] = "-o"; + strncat(o_argument, ctx->filename, 1021); + + errno = 0; + pid_t pid = fork(); + ERRCHECK("TreeViz: TV_vizv: could not fork process"); + + if (pid == 0) { + //// CHILD PROCESS + close(child_stdin_write); + ERRCHECK("TreeViz: TV_vizv: CHILD: could not close old pipe, write end"); + + dup2(child_stdin_read, STDIN_FILENO); + ERRCHECK("TreeViz: TV_vizv: CHILD: could not set stdin fileno"); + + close(child_stdin_read); + ERRCHECK("TreeViz: TV_vizv: CHILD: could not close old pipe, read end"); + + char *run = "dot"; + execlp(run, run, "-Tpdf", o_argument); + ERRCHECK("TreeViz: TV_vizv: CHILD: could not exec `%s`.\n\nDo you have " + "graphviz installed and in your PATH?\n", + run); + } else { + //// PARENT PROCESS + close(child_stdin_read); + ERRCHECK("TreeViz: TV_vizv: could not close old pipe, read end"); + + dprintf(child_stdin_write, "digraph{node [shape=rect];"); + ERRCHECK("TreeViz: TV_vizv: could not write to pipe"); + + size_t id = 0; + _TV_write_dot(root_node, child_stdin_write, ctx, &id); + + errno = 0; + dprintf(child_stdin_write, "}"); + ERRCHECK("TreeViz: TV_vizv: could not write to pipe"); + + close(child_stdin_write); + ERRCHECK("TreeViz: TV_vizv: could not close old pipe, write end"); + + int status; + wait(&status); + ERRCHECK("TreeViz: TV_vizv: could not wait on child process"); + if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) { + fprintf(stderr, "TreeViz: TV_vizv: dot process failed. " + "terminating immediately.\n"); + assert(status == 0); + } + } +} + +void TV_vizl(void *root_node, char *filename, + char *(*represent_data)(void *root_node), + void *(*next_child)(void *root_node, int *done, int *cur_idx)) { + TVCtx ctx = {filename, represent_data, next_child}; + TV_vizv(root_node, &ctx); +} + +#endif +#endif