1 #include "EXTERN.h"
2 #include "perl.h"
3 #include "XSUB.h"
4 #include "byterun.h"
5
6 /* Something arbitary for a buffer size */
7 #define BYTELOADER_BUFFER 8096
8
9 int
bl_getc(struct byteloader_fdata * data)10 bl_getc(struct byteloader_fdata *data)
11 {
12 dTHX;
13 if (SvCUR(data->datasv) <= (STRLEN)data->next_out) {
14 int result;
15 /* Run out of buffered data, so attempt to read some more */
16 *(SvPV_nolen (data->datasv)) = '\0';
17 SvCUR_set (data->datasv, 0);
18 data->next_out = 0;
19 result = FILTER_READ (data->idx + 1, data->datasv, BYTELOADER_BUFFER);
20
21 /* Filter returned error, or we got EOF and no data, then return EOF.
22 Not sure if filter is allowed to return EOF and add data simultaneously
23 Think not, but will bullet proof against it. */
24 if (result < 0 || SvCUR(data->datasv) == 0)
25 return EOF;
26 /* Else there must be at least one byte present, which is good enough */
27 }
28
29 return *((U8 *) SvPV_nolen (data->datasv) + data->next_out++);
30 }
31
32 int
bl_read(struct byteloader_fdata * data,char * buf,size_t size,size_t n)33 bl_read(struct byteloader_fdata *data, char *buf, size_t size, size_t n)
34 {
35 dTHX;
36 char *start;
37 STRLEN len;
38 size_t wanted = size * n;
39
40 start = SvPV (data->datasv, len);
41 if (len < (data->next_out + wanted)) {
42 int result;
43
44 /* Shuffle data to start of buffer */
45 len -= data->next_out;
46 if (len) {
47 memmove (start, start + data->next_out, len + 1);
48 SvCUR_set (data->datasv, len);
49 } else {
50 *start = '\0'; /* Avoid call to memmove. */
51 SvCUR_set (data->datasv, 0);
52 }
53 data->next_out = 0;
54
55 /* Attempt to read more data. */
56 do {
57 result = FILTER_READ (data->idx + 1, data->datasv, BYTELOADER_BUFFER);
58
59 start = SvPV (data->datasv, len);
60 } while (result > 0 && len < wanted);
61 /* Loop while not (EOF || error) and short reads */
62
63 /* If not enough data read, truncate copy */
64 if (wanted > len)
65 wanted = len;
66 }
67
68 if (wanted > 0) {
69 memcpy (buf, start + data->next_out, wanted);
70 data->next_out += wanted;
71 wanted /= size;
72 }
73 return (int) wanted;
74 }
75
76 static I32
byteloader_filter(pTHX_ int idx,SV * buf_sv,int maxlen)77 byteloader_filter(pTHX_ int idx, SV *buf_sv, int maxlen)
78 {
79 OP *saveroot = PL_main_root;
80 OP *savestart = PL_main_start;
81 struct byteloader_state bstate;
82 struct byteloader_fdata data;
83 int len;
84
85 data.next_out = 0;
86 data.datasv = FILTER_DATA(idx);
87 data.idx = idx;
88
89 bstate.bs_fdata = &data;
90 bstate.bs_obj_list = Null(void**);
91 bstate.bs_obj_list_fill = -1;
92 bstate.bs_sv = Nullsv;
93 bstate.bs_iv_overflows = 0;
94
95 /* KLUDGE */
96 if (byterun(aTHX_ &bstate)
97 && (len = SvCUR(data.datasv) - (STRLEN)data.next_out))
98 {
99 PerlIO_seek(PL_rsfp, -len, SEEK_CUR);
100 PL_rsfp = NULL;
101 }
102 filter_del(byteloader_filter);
103
104 if (PL_in_eval) {
105 OP *o;
106
107 PL_eval_start = PL_main_start;
108
109 o = newSVOP(OP_CONST, 0, newSViv(1));
110 PL_eval_root = newLISTOP(OP_LINESEQ, 0, PL_main_root, o);
111 PL_main_root->op_next = o;
112 PL_eval_root = newUNOP(OP_LEAVEEVAL, 0, PL_eval_root);
113 o->op_next = PL_eval_root;
114
115 PL_main_root = saveroot;
116 PL_main_start = savestart;
117 }
118
119 return 0;
120 }
121
122 MODULE = ByteLoader PACKAGE = ByteLoader
123
124 PROTOTYPES: ENABLE
125
126 void
127 import(package="ByteLoader", ...)
128 char *package
129 PREINIT:
130 SV *sv = newSVpvn ("", 0);
131 PPCODE:
132 if (!sv)
133 croak ("Could not allocate ByteLoader buffers");
134 filter_add(byteloader_filter, sv);
135