Graphviz: lib/util/agxbuf.h File Reference

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Dynamically expanding string buffers. More...

#include <assert.h>
#include <limits.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <util/alloc.h>
#include <util/unused.h>

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Data Structures
struct	agxbuf

Macros
#define	PRINTF_LIKE(index, first) /* nothing */

Enumerations
enum	agxbuf_loc_t { AGXBUF_INLINE_SIZE_0 = 0 , AGXBUF_ON_HEAP = 255 }
	a description of where a buffer is located More...

Functions
static bool	agxbuf_is_inline (const agxbuf *xb)

static void	agxbfree (agxbuf *xb)
	free any malloced resources

static char *	agxbstart (agxbuf *xb)
	return pointer to beginning of buffer

static size_t	agxblen (const agxbuf *xb)
	return number of characters currently stored

static size_t	agxbsizeof (const agxbuf *xb)

static int	agxbpop (agxbuf *xb)
	removes last character added, if any

static void	agxbmore (agxbuf *xb, size_t ssz)
	expand buffer to hold at least ssz more bytes

static char *	agxbnext (agxbuf *xb)
	next position for writing

static int	vagxbprint (agxbuf xb, const char fmt, va_list ap)
	vprintf-style output to an agxbuf

static int	agxbprint (agxbuf xb, const char fmt,...)
	Printf-style output to an agxbuf.

static size_t	agxbput_n (agxbuf xb, const char s, size_t ssz)
	append string s of length ssz into xb

static size_t	agxbput (agxbuf xb, const char s)
	append string s into xb

static int	agxbputc (agxbuf *xb, char c)
	add character to buffer

static void	agxbclear (agxbuf *xb)
	resets pointer to data

static WUR char *	agxbuse (agxbuf *xb)

static char *	agxbdisown (agxbuf *xb)

static void	agxbuf_trim_zeros (agxbuf *xb)

Detailed Description

Incrementally constructing a string in C is not something easily available out-of-the-box. You either need to statically know the size of the string upfront or rely on non-standard APIs like asprintf and open_memstream.

This header implements a self-contained, reasonably efficient alternative. You can think of this as similar to C++’s std::ostringstream or Python’s io.StringIO.

agxbuf includes Short String Optimization (SSO), a technique to pack small strings into the bytes of the structure itself rather than an out-of-line heap buffer. The point of this is to save memory and/or runtime by avoiding allocator calls. In contrast to most other SSO implementations (e.g. those in the std::string implementations of many C++ standard libraries), agxbuf biases heavily towards saving memory over runtime performance. That is, the maximum length of string is eligible for SSO, at the expense of more runtime code branches. The thinking here (that should periodically be reconsidered) is that expensive Graphviz runs typically hit memory limits before runtime limits, and thus would benefit more from saving memory than running faster.

Definition in file agxbuf.h.

Macro Definition Documentation

◆ PRINTF_LIKE

#define PRINTF_LIKE	(	index,
		first
	)	/* nothing */

Definition at line 248 of file agxbuf.h.

Enumeration Type Documentation

◆ agxbuf_loc_t

enum agxbuf_loc_t

Enumerator
AGXBUF_INLINE_SIZE_0
AGXBUF_ON_HEAP	buffer is dynamically allocated

Definition at line 49 of file agxbuf.h.

Function Documentation

◆ agxbclear()

static void agxbclear ( agxbuf * xb )

inlinestatic

Definition at line 312 of file agxbuf.h.

References AGXBUF_INLINE_SIZE_0, agxbuf_is_inline(), agxbuf::located, and agxbuf::size.

Referenced by addEdgeGraphics(), addEdgeGraphics(), addEdgeLabelGraphics(), addEdgeLabelGraphics(), addNodeGraphics(), addNodeGraphics(), addNodeLabelGraphics(), addNodeLabelGraphics(), agerr_va(), agxbuse(), extoken_fn(), and pango_textlayout().

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◆ agxbdisown()

static char * agxbdisown ( agxbuf * xb )

inlinestatic

Definition at line 345 of file agxbuf.h.

References agxblen(), agxbputc(), agxbuf_is_inline(), agxbuf::buf, gv_strndup(), and agxbuf::store.

Referenced by aglasterr(), appendFItemList(), appendFItemList(), buildBindings(), compile(), concat(), endstr(), endstr(), fmtquote(), gdk_set_mimedata_from_file(), getName(), getName(), gv_get_font(), gv_postprocess(), gvconfig(), gvpr_select(), htmlEntityUTF8(), latin1ToUTF8(), lexname(), make_simple_label(), pango_psfontResolve(), parseBracket(), parseString(), pov_color_as_str(), ps_string(), renderresult(), sprintXDot(), strdup_and_subst_obj0(), and utf8ToLatin1().

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◆ agxbfree()

static void agxbfree ( agxbuf * xb )

inlinestatic

Definition at line 97 of file agxbuf.h.

References AGXBUF_ON_HEAP, agxbuf::buf, free(), and agxbuf::located.

Referenced by aagerror(), agconcat(), attach_attrs_and_arrows(), attach_edge_colors(), bboxPDF(), cairogen_begin_anchor(), cccomps(), ccomps(), clearHTMLlexer(), clone_graph(), cloneNode(), colorx(), colorxlate(), colorxlate(), concat(), concat(), concatPort(), concatPort(), createEdgeId(), createGraphId(), createNodeId(), createOneBlock(), deref(), Dot_SetClusterColor(), emit_begin_edge(), emit_edge(), emit_edge_graphics(), emit_edge_label(), emit_page(), expandPercentsEval(), exsub(), fig_bezier(), findCComp(), gdk_format(), get_font_mapping(), get_metrics_for_font_family(), getval(), global_def(), gml_to_gv(), gml_to_gv(), graph_init(), gvloadimage(), gvloadimage_process_surface(), gvplugin_graph(), gvplugin_library_load(), gvplugin_load(), gvprintf(), gvprintpointf(), gvrender_resolve_color(), initAnchor(), initObjMapData(), jsonXDot_Op(), lookup(), main(), make_html_label(), make_simple_label(), makeBlockGraph(), makeDotGraph(), mkBlock(), mkBlock(), mkStmts(), on_gvprbuttonload_clicked(), pango_textlayout(), parseCase(), parseHTML(), parseString(), pccomps(), plot_dot_map(), plot_dot_polygons(), pov_bezier(), pov_color_as_str(), pov_ellipse(), pov_textspan(), printdouble(), printFloat(), printint(), printPolyline(), printRect(), printXDot_Op(), process(), processClusterEdges(), processClusters(), put_escaping_backslashes(), readLine(), rec_attach_bb(), refval(), resolve(), resolveColor(), run_gvpr(), setcolor(), setval(), spanning_tree(), stringOf(), svg_size(), traverse(), vgpane(), writeHdr(), xdot_end_graph(), xdot_gradient_fillcolor(), and xdot_style().

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◆ agxblen()

static size_t agxblen ( const agxbuf * xb )

inlinestatic

Definition at line 108 of file agxbuf.h.

References AGXBUF_INLINE_SIZE_0, agxbuf_is_inline(), agxbuf::located, and agxbuf::size.

Referenced by aagerror(), addEdgePoint(), addEdgePoint(), agxbdisown(), agxbmore(), agxbnext(), agxbpop(), agxbput_n(), agxbputc(), agxbuf_trim_zeros(), agxbuse(), beginstr(), beginstr(), beginstr(), dgsprintxy(), htmllex(), make_simple_label(), parse_style(), renderresult(), vagxbprint(), xdot_end_edge(), xdot_end_graph(), and xdot_end_node().

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◆ agxbmore()

static void agxbmore	(	agxbuf *	xb,
		size_t	ssz
	)

inlinestatic

Definition at line 150 of file agxbuf.h.

References agxblen(), agxbsizeof(), AGXBUF_ON_HEAP, agxbuf::buf, agxbuf::capacity, cnt(), gv_calloc(), gv_recalloc(), agxbuf::located, agxbuf::size, and agxbuf::store.

Referenced by agxbput_n(), agxbputc(), and vagxbprint().

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◆ agxbnext()

static char * agxbnext ( agxbuf * xb )

inlinestatic

Definition at line 175 of file agxbuf.h.

References agxblen(), agxbuf_is_inline(), agxbuf::buf, len(), and agxbuf::store.

Referenced by vagxbprint().

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◆ agxbpop()

static int agxbpop ( agxbuf * xb )

inlinestatic

Definition at line 130 of file agxbuf.h.

References agxblen(), AGXBUF_INLINE_SIZE_0, agxbuf_is_inline(), agxbuf::buf, len(), agxbuf::located, agxbuf::size, and agxbuf::store.

Referenced by attach_attrs_and_arrows(), and xdot_gradient_fillcolor().

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◆ agxbprint()

static int agxbprint	(	agxbuf *	xb,
		const char *	fmt,
			...
	)

inlinestatic

Definition at line 252 of file agxbuf.h.

References vagxbprint().

Referenced by aagerror(), addEdgeLabelGraphics(), addEdgeLabelGraphics(), addEdgePoint(), addEdgePoint(), addNodeGraphics(), addNodeGraphics(), attach_attrs_and_arrows(), auto_output_filename(), blockName(), buildBindings(), cairogen_begin_anchor(), cccomps(), ccomps(), chkGraphName(), clone_graph(), cloneNode(), clustNode(), color_string(), colorx(), colorxlate(), compile(), concat(), concat(), concat(), concatPort(), concatPort(), createEdgeId(), createGraphId(), createNodeId(), createOneBlock(), default_pencolor(), deparseAttr(), deparseAttr(), dgsprintxy(), emit_edge_label(), exdump(), expandPercentsEval(), fig_bezier(), findCComp(), findPath(), fullColor(), gdk_format(), gdk_set_mimedata_from_file(), gen(), get_avail_faces(), get_metrics_for_font_family(), getName(), getName(), getObjId(), graph_init(), gv_get_font(), gv_postprocess(), gvconfig(), gvloadimage(), gvloadimage_process_surface(), gvplugin_graph(), gvplugin_library_load(), gvplugin_list(), gvplugin_load(), gvpr_select(), gvrender_resolve_color(), hue2rgb(), initAnchor(), layerPagePrefix(), lexname(), LIST(), makeBlockGraph(), makeDotGraph(), mkBlock(), mkStmts(), nameOf(), pango_psfontResolve(), pango_textlayout(), pccomps(), pov_bezier(), pov_color_as_str(), pov_ellipse(), pov_textspan(), print(), printdouble(), printFloat(), printint(), printPolyline(), printRect(), process(), processClusters(), rec_attach_bb(), resolve(), rgb2hex(), run_gvpr(), scan(), scanEntity(), set_record_rects(), spanning_tree(), sprintXDot(), strdup_and_subst_obj0(), toGradString(), traverse(), vgpane(), writeHdr(), xdot_color_stop(), xdot_fmt_num(), xdot_points(), xdot_str_color_xbuf(), xdot_str_xbuf(), xdot_style(), and xdot_textspan().

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◆ agxbput()

static size_t agxbput	(	agxbuf *	xb,
		const char *	s
	)

inlinestatic

Definition at line 288 of file agxbuf.h.

References agxbput_n().

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◆ agxbput_n()

static size_t agxbput_n	(	agxbuf *	xb,
		const char *	s,
		size_t	ssz
	)

inlinestatic

Definition at line 268 of file agxbuf.h.

References agxblen(), agxbmore(), agxbsizeof(), agxbuf_is_inline(), agxbuf::buf, len(), agxbuf::located, agxbuf::size, and agxbuf::store.

Referenced by agxbput(), expandPercentsEval(), exsub(), global_def(), gv_string_writer(), parse_style(), replace(), resolve(), rgb2hex(), and storeFileName().

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◆ agxbputc()

static int agxbputc	(	agxbuf *	xb,
		char	c
	)

inlinestatic

Definition at line 295 of file agxbuf.h.

References agxblen(), agxbmore(), agxbsizeof(), agxbuf_is_inline(), agxbuf::buf, len(), agxbuf::located, agxbuf::size, and agxbuf::store.

Referenced by aagerror(), addEdgeGraphics(), addEdgeGraphics(), addEdgeLabelGraphics(), addEdgeLabelGraphics(), addEdgePoint(), addEdgePoint(), addNodeGraphics(), addNodeGraphics(), addNodeLabelGraphics(), addNodeLabelGraphics(), agxbdisown(), agxbuse(), attach_attrs_and_arrows(), auto_output_filename(), canoncolor(), colorxlate(), colorxlate(), copyUpper(), cvtAndAppend(), deparseList(), deparseList(), dgsprintxy(), endBracket(), endString(), exdump(), expandPercentsEval(), extoken_fn(), gen(), getNum(), gv_get_font(), htmlEntityUTF8(), latin1ToUTF8(), make_simple_label(), nameOf(), parse_style(), parseString(), print(), ps_string(), put_escaping_backslashes(), readc(), readLine(), replace(), scan(), scanEntity(), strdup_and_subst_obj0(), svg_size(), toGradString(), utf8ToLatin1(), xdot_color_stop(), xdot_fmt_num(), xdot_gradient_fillcolor(), and xdot_style().

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◆ agxbsizeof()

static size_t agxbsizeof ( const agxbuf * xb )

inlinestatic

get the capacity of the backing memory of a buffer

In contrast to agxblen, this is the total number of usable bytes in the backing store, not the total number of currently stored bytes.

Parameters

xb	Buffer to operate on

Returns: Number of usable bytes in the backing store

Definition at line 122 of file agxbuf.h.

References agxbuf_is_inline(), agxbuf::capacity, and agxbuf::store.

Referenced by agxbmore(), agxbput_n(), agxbputc(), and vagxbprint().

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◆ agxbstart()

static char * agxbstart ( agxbuf * xb )

inlinestatic

Definition at line 103 of file agxbuf.h.

References agxbuf_is_inline(), agxbuf::buf, and agxbuf::store.

Referenced by agxbuf_trim_zeros(), and agxbuse().

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◆ agxbuf_is_inline()

static bool agxbuf_is_inline ( const agxbuf * xb )

inlinestatic

Definition at line 90 of file agxbuf.h.

References AGXBUF_ON_HEAP, agxbuf::located, and agxbuf::store.

Referenced by agxbclear(), agxbdisown(), agxblen(), agxbnext(), agxbpop(), agxbput_n(), agxbputc(), agxbsizeof(), agxbstart(), agxbuf_trim_zeros(), agxbuse(), and vagxbprint().

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◆ agxbuf_trim_zeros()

static void agxbuf_trim_zeros ( agxbuf * xb )

inlinestatic

trim extraneous trailing information from a printed floating point value

tl;dr:

“42.00” → “42”
“42.01” → “42.01”
“42.10” → “42.1”
“-0.0” → “0”

Printing a double or float via, for example, agxbprint("%.02f", 42.003) can result in output like “42.00”. If this data is destined for something that does generalized floating point parsing/decoding (e.g. SVG viewers) the “.00” is unnecessary. “42” would be interpreted identically. This function can be called after such a agxbprint to normalize data.

Parameters

xb	Buffer to operate on

Definition at line 382 of file agxbuf.h.

References agxblen(), agxbstart(), AGXBUF_INLINE_SIZE_0, agxbuf_is_inline(), len(), agxbuf::located, agxbuf::size, and SIZE_MAX.

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◆ agxbuse()

static WUR char * agxbuse ( agxbuf * xb )

inlinestatic

Definition at line 325 of file agxbuf.h.

References agxbclear(), agxblen(), agxbputc(), agxbstart(), AGXBUF_INLINE_SIZE_0, agxbuf_is_inline(), and agxbuf::store.

Referenced by aagerror(), addEdgeGraphics(), addEdgeGraphics(), addEdgeLabelGraphics(), addEdgeLabelGraphics(), addEdgePos(), addEdgePos(), addNodeGraphics(), addNodeGraphics(), addNodeLabelGraphics(), addNodeLabelGraphics(), attach_attrs_and_arrows(), attach_edge_colors(), auto_output_filename(), blockName(), cairogen_begin_anchor(), cccomps(), ccomps(), chkGraphName(), clone_graph(), cloneNode(), clustNode(), colorx(), colorxlate(), colorxlate(), concat(), concat(), concatPort(), concatPort(), createEdgeId(), createGraphId(), createNodeId(), createOneBlock(), default_pencolor(), deparse(), Dot_SetClusterColor(), emit_edge(), emit_edge_label(), emit_page(), endstr(), endstr_html(), expandPercentsEval(), exsub(), extoken_fn(), fig_bezier(), findCComp(), findPath(), fullColor(), gdk_format(), get_avail_faces(), get_metrics_for_font_family(), getNum(), getObjId(), global_def(), graph_init(), gvloadimage(), gvloadimage_process_surface(), gvplugin_graph(), gvplugin_library_load(), gvplugin_list(), gvplugin_load(), gvprintf(), gvprintpointf(), gvrender_resolve_color(), htmllex(), hue2rgb(), initAnchor(), jsonXDot_Op(), makeBlockGraph(), makeDotGraph(), mkBlock(), mkStmts(), nameOf(), nameOf(), nameOf(), on_gvprbuttonload_clicked(), pango_textlayout(), parse_style(), pccomps(), plot_dot_map(), plot_dot_polygons(), pov_bezier(), pov_color_as_str(), pov_ellipse(), pov_textspan(), printdouble(), printFloat(), printint(), printPolyline(), printRect(), printXDot_Op(), process(), processClusters(), put_escaping_backslashes(), readLine(), rec_attach_bb(), resolve(), run_gvpr(), setcolor(), spanning_tree(), storeFileName(), svg_size(), traverse(), unknown(), unknown(), vgpane(), writeHdr(), xdot_end_cluster(), xdot_end_edge(), xdot_end_graph(), xdot_end_node(), xdot_gradient_fillcolor(), xdot_style(), and yyparse().

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◆ vagxbprint()

static int vagxbprint	(	agxbuf *	xb,
		const char *	fmt,
		va_list	ap
	)

inlinestatic

Definition at line 181 of file agxbuf.h.

References agxblen(), agxbmore(), agxbnext(), agxbsizeof(), agxbuf_is_inline(), agxbuf::located, NULL, agxbuf::size, and agxbuf::store.

Referenced by agerr_va(), agxbprint(), and gvprintf().

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Data Structures

Macros

Enumerations

Functions

Detailed Description

Macro Definition Documentation

◆ PRINTF_LIKE

Enumeration Type Documentation

◆ agxbuf_loc_t

Function Documentation

◆ agxbclear()

◆ agxbdisown()

◆ agxbfree()

◆ agxblen()

◆ agxbmore()

◆ agxbnext()

◆ agxbpop()

◆ agxbprint()

◆ agxbput()

◆ agxbput_n()

◆ agxbputc()

◆ agxbsizeof()

◆ agxbstart()

◆ agxbuf_is_inline()

◆ agxbuf_trim_zeros()

◆ agxbuse()

◆ vagxbprint()