1 /*
2 * io_dp.c
3 *
4 * Implements the dynamic pointer interface.
5 *
6 * Based on GD.pm code by Lincoln Stein for interfacing to libgd.
7 * Added support for reading as well as support for 'tell' and 'seek'.
8 *
9 * As will all I/O modules, most functions are for local use only (called
10 * via function pointers in the I/O context).
11 *
12 * gdDPExtractData is the exception to this: it will return the pointer to
13 * the internal data, and reset the internal storage.
14 *
15 * Written/Modified 1999, Philip Warner.
16 *
17 */
18
19 #include <math.h>
20 #include <string.h>
21 #include <stdlib.h>
22 #include "gd.h"
23 #include "gdhelpers.h"
24
25 #define TRUE 1
26 #define FALSE 0
27
28 /* this is used for creating images in main memory */
29 typedef struct dpStruct
30 {
31 void *data;
32 int logicalSize;
33 int realSize;
34 int dataGood;
35 int pos;
36 int freeOK;
37 } dynamicPtr;
38
39 typedef struct dpIOCtx
40 {
41 gdIOCtx ctx;
42 dynamicPtr *dp;
43 } dpIOCtx;
44
45 typedef struct dpIOCtx *dpIOCtxPtr;
46
47 /* these functions operate on in-memory dynamic pointers */
48 static int allocDynamic (dynamicPtr * dp, int initialSize, void *data);
49 static int appendDynamic (dynamicPtr * dp, const void *src, int size);
50 static int gdReallocDynamic (dynamicPtr * dp, int required);
51 static int trimDynamic (dynamicPtr * dp);
52 static void gdFreeDynamicCtx (struct gdIOCtx *ctx);
53 static dynamicPtr *newDynamic (int initialSize, void *data, int freeOKFlag);
54
55 static int dynamicPutbuf (struct gdIOCtx *, const void *, int);
56 static void dynamicPutchar (struct gdIOCtx *, int a);
57
58 static int dynamicGetbuf (gdIOCtxPtr ctx, void *buf, int len);
59 static int dynamicGetchar (gdIOCtxPtr ctx);
60
61 static int dynamicSeek (struct gdIOCtx *, const int);
62 static long dynamicTell (struct gdIOCtx *);
63
64 /* return data as a dynamic pointer */
gdNewDynamicCtx(int initialSize,void * data)65 gdIOCtx * gdNewDynamicCtx (int initialSize, void *data)
66 {
67 return gdNewDynamicCtxEx(initialSize, data, 1);
68 }
69
gdNewDynamicCtxEx(int initialSize,void * data,int freeOKFlag)70 gdIOCtx * gdNewDynamicCtxEx (int initialSize, void *data, int freeOKFlag)
71 {
72 dpIOCtx *ctx;
73 dynamicPtr *dp;
74
75 ctx = (dpIOCtx *) gdMalloc (sizeof (dpIOCtx));
76
77 dp = newDynamic(initialSize, data, freeOKFlag);
78
79 ctx->dp = dp;
80
81 ctx->ctx.getC = dynamicGetchar;
82 ctx->ctx.putC = dynamicPutchar;
83
84 ctx->ctx.getBuf = dynamicGetbuf;
85 ctx->ctx.putBuf = dynamicPutbuf;
86
87 ctx->ctx.seek = dynamicSeek;
88 ctx->ctx.tell = dynamicTell;
89
90 ctx->ctx.gd_free = gdFreeDynamicCtx;
91
92 return (gdIOCtx *) ctx;
93 }
94
gdDPExtractData(struct gdIOCtx * ctx,int * size)95 void * gdDPExtractData (struct gdIOCtx *ctx, int *size)
96 {
97 dynamicPtr *dp;
98 dpIOCtx *dctx;
99 void *data;
100
101 dctx = (dpIOCtx *) ctx;
102 dp = dctx->dp;
103
104 /* clean up the data block and return it */
105 if (dp->dataGood) {
106 trimDynamic (dp);
107 *size = dp->logicalSize;
108 data = dp->data;
109 } else {
110 *size = 0;
111 data = NULL;
112 if (dp->data != NULL && dp->freeOK) {
113 gdFree(dp->data);
114 }
115 }
116
117 dp->data = NULL;
118 dp->realSize = 0;
119 dp->logicalSize = 0;
120
121 return data;
122 }
123
gdFreeDynamicCtx(struct gdIOCtx * ctx)124 static void gdFreeDynamicCtx (struct gdIOCtx *ctx)
125 {
126 dynamicPtr *dp;
127 dpIOCtx *dctx;
128
129 dctx = (dpIOCtx *) ctx;
130 dp = dctx->dp;
131
132 gdFree(ctx);
133
134 dp->realSize = 0;
135 dp->logicalSize = 0;
136
137 gdFree(dp);
138 }
139
dynamicTell(struct gdIOCtx * ctx)140 static long dynamicTell (struct gdIOCtx *ctx)
141 {
142 dpIOCtx *dctx;
143
144 dctx = (dpIOCtx *) ctx;
145
146 return (dctx->dp->pos);
147 }
148
dynamicSeek(struct gdIOCtx * ctx,const int pos)149 static int dynamicSeek (struct gdIOCtx *ctx, const int pos)
150 {
151 int bytesNeeded;
152 dynamicPtr *dp;
153 dpIOCtx *dctx;
154
155 dctx = (dpIOCtx *) ctx;
156 dp = dctx->dp;
157
158 if (!dp->dataGood) {
159 return FALSE;
160 }
161
162 bytesNeeded = pos;
163 if (bytesNeeded > dp->realSize) {
164 /* 2.0.21 */
165 if (!dp->freeOK) {
166 return FALSE;
167 }
168 gdReallocDynamic (dp, dp->realSize * 2);
169 }
170
171 /* if we get here, we can be sure that we have enough bytes to copy safely */
172
173 /* Extend the logical size if we seek beyond EOF. */
174 if (pos > dp->logicalSize) {
175 dp->logicalSize = pos;
176 }
177
178 dp->pos = pos;
179
180 return TRUE;
181 }
182
183 /* return data as a dynamic pointer */
newDynamic(int initialSize,void * data,int freeOKFlag)184 static dynamicPtr * newDynamic (int initialSize, void *data, int freeOKFlag)
185 {
186 dynamicPtr *dp;
187 dp = (dynamicPtr *) gdMalloc (sizeof (dynamicPtr));
188
189 allocDynamic (dp, initialSize, data);
190
191 dp->pos = 0;
192 dp->freeOK = freeOKFlag;
193
194 return dp;
195 }
196
197 static int
dynamicPutbuf(struct gdIOCtx * ctx,const void * buf,int size)198 dynamicPutbuf (struct gdIOCtx *ctx, const void *buf, int size)
199 {
200 dpIOCtx *dctx;
201 dctx = (dpIOCtx *) ctx;
202
203 appendDynamic (dctx->dp, buf, size);
204
205 if (dctx->dp->dataGood)
206 {
207 return size;
208 }
209 else
210 {
211 return -1;
212 };
213
214 }
215
dynamicPutchar(struct gdIOCtx * ctx,int a)216 static void dynamicPutchar (struct gdIOCtx *ctx, int a)
217 {
218 unsigned char b;
219 dpIOCtxPtr dctx;
220
221 b = a;
222 dctx = (dpIOCtxPtr) ctx;
223
224 appendDynamic(dctx->dp, &b, 1);
225 }
226
dynamicGetbuf(gdIOCtxPtr ctx,void * buf,int len)227 static int dynamicGetbuf (gdIOCtxPtr ctx, void *buf, int len)
228 {
229 int rlen, remain;
230 dpIOCtxPtr dctx;
231 dynamicPtr *dp;
232
233 dctx = (dpIOCtxPtr) ctx;
234 dp = dctx->dp;
235
236 remain = dp->logicalSize - dp->pos;
237 if (remain >= len) {
238 rlen = len;
239 } else {
240 if (remain == 0) {
241 return EOF;
242 }
243 rlen = remain;
244 }
245
246 memcpy(buf, (void *) ((char *) dp->data + dp->pos), rlen);
247 dp->pos += rlen;
248
249 return rlen;
250 }
251
dynamicGetchar(gdIOCtxPtr ctx)252 static int dynamicGetchar (gdIOCtxPtr ctx)
253 {
254 unsigned char b;
255 int rv;
256
257 rv = dynamicGetbuf (ctx, &b, 1);
258 if (rv != 1) {
259 return EOF;
260 } else {
261 return b; /* (b & 0xff); */
262 }
263 }
264
265 /* *********************************************************************
266
267 * InitDynamic - Return a dynamically resizable void*
268 *
269 * *********************************************************************
270 */
271 static int
allocDynamic(dynamicPtr * dp,int initialSize,void * data)272 allocDynamic (dynamicPtr * dp, int initialSize, void *data)
273 {
274
275 if (data == NULL) {
276 dp->logicalSize = 0;
277 dp->dataGood = FALSE;
278 dp->data = gdMalloc(initialSize);
279 } else {
280 dp->logicalSize = initialSize;
281 dp->dataGood = TRUE;
282 dp->data = data;
283 }
284
285 dp->realSize = initialSize;
286 dp->dataGood = TRUE;
287 dp->pos = 0;
288
289 return TRUE;
290 }
291
292 /* append bytes to the end of a dynamic pointer */
appendDynamic(dynamicPtr * dp,const void * src,int size)293 static int appendDynamic (dynamicPtr * dp, const void *src, int size)
294 {
295 int bytesNeeded;
296 char *tmp;
297
298 if (!dp->dataGood) {
299 return FALSE;
300 }
301
302 /* bytesNeeded = dp->logicalSize + size; */
303 bytesNeeded = dp->pos + size;
304
305 if (bytesNeeded > dp->realSize) {
306 /* 2.0.21 */
307 if (!dp->freeOK) {
308 return FALSE;
309 }
310 gdReallocDynamic(dp, bytesNeeded * 2);
311 }
312
313 /* if we get here, we can be sure that we have enough bytes to copy safely */
314 /*printf("Mem OK Size: %d, Pos: %d\n", dp->realSize, dp->pos); */
315
316 tmp = (char *) dp->data;
317 memcpy((void *) (tmp + (dp->pos)), src, size);
318 dp->pos += size;
319
320 if (dp->pos > dp->logicalSize) {
321 dp->logicalSize = dp->pos;
322 }
323
324 return TRUE;
325 }
326
327 /* grow (or shrink) dynamic pointer */
gdReallocDynamic(dynamicPtr * dp,int required)328 static int gdReallocDynamic (dynamicPtr * dp, int required)
329 {
330 void *newPtr;
331
332 /* First try gdRealloc(). If that doesn't work, make a new memory block and copy. */
333 if ((newPtr = gdRealloc(dp->data, required))) {
334 dp->realSize = required;
335 dp->data = newPtr;
336 return TRUE;
337 }
338
339 /* create a new pointer */
340 newPtr = gdMalloc(required);
341
342 /* copy the old data into it */
343 memcpy(newPtr, dp->data, dp->logicalSize);
344 gdFree(dp->data);
345 dp->data = newPtr;
346
347 dp->realSize = required;
348
349 return TRUE;
350 }
351
352 /* trim pointer so that its real and logical sizes match */
trimDynamic(dynamicPtr * dp)353 static int trimDynamic (dynamicPtr * dp)
354 {
355 /* 2.0.21: we don't reallocate memory we don't own */
356 if (!dp->freeOK) {
357 return FALSE;
358 }
359 return gdReallocDynamic(dp, dp->logicalSize);
360 }
361
