Annotation of libwww/Library/src/HTChunk.html, revision 2.34
2.8 timbl 1: <HTML>
2: <HEAD>
2.32 frystyk 3: <!-- Changed by: Henrik Frystyk Nielsen, 13-Jul-1996 -->
2.33 frystyk 4: <TITLE>W3C Sample Code Library libwww Chunk Class</TITLE>
2.11 frystyk 5: </HEAD>
2.6 timbl 6: <BODY>
2.31 frystyk 7: <H1>
8: The Chunk Class
9: </H1>
2.11 frystyk 10: <PRE>
11: /*
2.16 frystyk 12: ** (c) COPYRIGHT MIT 1995.
2.11 frystyk 13: ** Please first read the full copyright statement in the file COPYRIGH.
14: */
15: </PRE>
2.31 frystyk 16: <P>
17: The Chunk Class defines a way to automatically handle dynamic strings
18: and other data types. You create a chunk with an initial size and it will
19: then automatically grow to accomodate added data to the chunk. It is a general
20: utility module. It is garanteed that the array is <CODE>'\0' </CODE>terminated
21: at all times (and hence is a valid C type string). The method
22: <A HREF="HTChunk.html#Terminate">HTChunkTerminate</A> can be used to explicitly
23: add a terminating <CODE>'\0'</CODE> and then to include this character in
24: the chunk size. If left out, the terminating character is <I>not</I> considered
25: part of the chunk.
26: <P>
27: <B>Note</B>: The names without a "_" (made as a <CODE>#define</CODE>'s) are
28: only provided for backwards compatibility and should not be used.
29: <P>
30: This module is implemented by <A HREF="HTChunk.c">HTChunk.c</A>, and it is
2.34 ! frystyk 31: a part of the <A HREF="http://www.w3.org/Library/"> W3C Sample Code
2.31 frystyk 32: Library</A>.
2.10 frystyk 33: <PRE>
34: #ifndef HTCHUNK_H
2.9 frystyk 35: #define HTCHUNK_H
2.12 roeber 36:
2.9 frystyk 37: </PRE>
2.31 frystyk 38: <H2>
39: The Chunk Class
40: </H2>
41: <P>
42: This structure should not be referenced outside this module! We only keep
43: it here to maintain high performance. <B>Don't </B>use it directly!
2.18 frystyk 44: <PRE>
45: typedef struct {
2.1 timbl 46: int size; /* In bytes */
47: int growby; /* Allocation unit in bytes */
48: int allocated; /* Current size of *data */
49: char * data; /* Pointer to malloced area or 0 */
50: } HTChunk;
2.18 frystyk 51: </PRE>
2.31 frystyk 52: <H2>
53: Create new chunk
54: </H2>
55: <P>
56: Create a new chunk and specify the number of bytes to allocate at a time
57: when the chunk is later extended. Arbitrary but normally a trade-off time
58: vs. memory
2.6 timbl 59: <PRE>
2.22 frystyk 60: #define HTChunkCreate(growby) HTChunk_new(growby)
61: extern HTChunk * HTChunk_new (int growby);
2.18 frystyk 62: </PRE>
2.31 frystyk 63: <H2>
64: Free a chunk
65: </H2>
66: <P>
2.18 frystyk 67: Free a chunk created by <CODE>HTChunkCreate</CODE>from memory
2.6 timbl 68: <PRE>
2.22 frystyk 69: #define HTChunkFree(ch) HTChunk_delete(ch)
70: extern void HTChunk_delete (HTChunk * ch);
2.18 frystyk 71: </PRE>
2.31 frystyk 72: <H2>
73: Clear a chunk
74: </H2>
75: <P>
76: Keep the chunk in memory but clear all data kept inside. This can be used
77: if you know that you can reuse the allocated memory instead of allocating
78: new memory.
2.6 timbl 79: <PRE>
2.22 frystyk 80: #define HTChunkClear(ch) HTChunk_clear(ch)
81: extern void HTChunk_clear (HTChunk * ch);
2.18 frystyk 82: </PRE>
2.31 frystyk 83: <H2>
84: Ensure a Chunk has a Certain Amount of Free Space
85: </H2>
86: <P>
87: Make sure that a chunk has a certain size. If this is not the case then the
88: chunk is expanded. Nothing is done if the current size if bigger than the
89: size requested.
2.6 timbl 90: <PRE>
2.22 frystyk 91: #define HTChunkEnsure(ch, s) HTChunk_ensure(ch, s)
92: extern void HTChunk_ensure (HTChunk * ch, int s);
2.18 frystyk 93: </PRE>
2.31 frystyk 94: <H2>
95: Append a character to a chunk
96: </H2>
97: <P>
2.18 frystyk 98: Add the character and increment the size of the chunk by one character
99: <PRE>
2.22 frystyk 100: #define HTChunkPutc(ch, c) HTChunk_putc(ch, c)
101: extern void HTChunk_putc (HTChunk * ch, char c);
2.6 timbl 102: </PRE>
2.31 frystyk 103: <H2>
104: Append a string to a chunk
105: </H2>
106: <P>
107: Add the string and increment the size of the chunk by the length of the string
108: (without the trailing zero)
2.18 frystyk 109: <PRE>
2.22 frystyk 110: #define HTChunkPuts(ch, str) HTChunk_puts(ch, str)
2.25 frystyk 111: extern void HTChunk_puts (HTChunk * ch, const char *str);
2.22 frystyk 112: </PRE>
2.31 frystyk 113: <H2>
114: Append a block to a chunk
115: </H2>
116: <P>
2.22 frystyk 117: Add the block and increment the size of the chunk by the len
118: <PRE>
2.25 frystyk 119: extern void HTChunk_putb (HTChunk * ch, const char *block, int len);
2.31 frystyk 120:
2.6 timbl 121: </PRE>
2.31 frystyk 122: <H2>
123: Zero Terminate a chunk
124: </H2>
125: <P>
126: As a chunk often is a dynamic string, it needs to be terminated by a zero
127: in order to be used in C. However, <B>by default</B> any chunk is
128: <I>always</I> zero terminated, so the only purpose of this function is to
129: increment the size counter with one corresponding to the zero.
2.6 timbl 130: <PRE>
2.24 frystyk 131: #define HTChunkTerminate(ch) HTChunk_terminate(ch)
132: #define HTChunk_terminate(ch) HTChunk_putc((ch), '\0')
2.18 frystyk 133: </PRE>
2.31 frystyk 134: <H2>
135: Return Pointer to Data
136: </H2>
137: <P>
138: This define converts a chunk to a normal char pointer so that it can be parsed
139: to any ANSI C string function.
140: <PRE>
141: #define HTChunkData(me) ((me) ? (me)->data : NULL)
142: #define HTChunk_data(me) ((me) ? (me)->data : NULL)
143: </PRE>
144: <H2>
145: CString conversions
146: </H2>
147: <P>
148: A Chunk may be build from an allocated string. The chunk assumes control
2.27 eric 149: of the passes string, elminating the need for additional allocations and
150: string copies.<BR>
2.31 frystyk 151: Once a string is built, the chunk may be destroyed and the string kept around.
2.27 eric 152: <PRE>
2.32 frystyk 153: extern HTChunk * HTChunk_fromCString (char * str, int grow);
154: extern char * HTChunk_toCString (HTChunk * ch);
2.6 timbl 155: </PRE>
2.31 frystyk 156: <H2>
157: Return Current Size
158: </H2>
159: <P>
2.18 frystyk 160: Returns the current size of the chunk
2.6 timbl 161: <PRE>
2.31 frystyk 162: #define HTChunkSize(me) ((me) ? (me)->size : -1)
163: #define HTChunk_size(me) ((me) ? (me)->size : -1)
2.6 timbl 164: </PRE>
165: <PRE>
2.18 frystyk 166: #endif
167: </PRE>
2.31 frystyk 168: <P>
169: <HR>
2.29 frystyk 170: <ADDRESS>
2.34 ! frystyk 171: @(#) $Id: HTChunk.html,v 2.33 1997/02/16 18:42:04 frystyk Exp $
2.29 frystyk 172: </ADDRESS>
2.31 frystyk 173: </BODY></HTML>
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