| 1 | /* Copyright (C) 2001, 2006, 2009, 2011, 2014 Free Software Foundation, Inc. |
| 2 | * |
| 3 | * This library is free software; you can redistribute it and/or |
| 4 | * modify it under the terms of the GNU Lesser General Public License |
| 5 | * as published by the Free Software Foundation; either version 3 of |
| 6 | * the License, or (at your option) any later version. |
| 7 | * |
| 8 | * This library is distributed in the hope that it will be useful, but |
| 9 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 11 | * Lesser General Public License for more details. |
| 12 | * |
| 13 | * You should have received a copy of the GNU Lesser General Public |
| 14 | * License along with this library; if not, write to the Free Software |
| 15 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 16 | * 02110-1301 USA |
| 17 | */ |
| 18 | |
| 19 | \f |
| 20 | |
| 21 | /* This is the C part of the (ice-9 rw) module. */ |
| 22 | |
| 23 | #ifdef HAVE_CONFIG_H |
| 24 | # include <config.h> |
| 25 | #endif |
| 26 | |
| 27 | #include <errno.h> |
| 28 | #include <string.h> |
| 29 | |
| 30 | #include "libguile/_scm.h" |
| 31 | #include "libguile/fports.h" |
| 32 | #include "libguile/ports.h" |
| 33 | #include "libguile/root.h" |
| 34 | #include "libguile/rw.h" |
| 35 | #include "libguile/strings.h" |
| 36 | #include "libguile/validate.h" |
| 37 | #include "libguile/modules.h" |
| 38 | #include "libguile/strports.h" |
| 39 | |
| 40 | #include <unistd.h> |
| 41 | #ifdef HAVE_IO_H |
| 42 | #include <io.h> |
| 43 | #endif |
| 44 | |
| 45 | \f |
| 46 | |
| 47 | #if defined (EAGAIN) |
| 48 | #define SCM_MAYBE_EAGAIN || errno == EAGAIN |
| 49 | #else |
| 50 | #define SCM_MAYBE_EAGAIN |
| 51 | #endif |
| 52 | |
| 53 | #if defined (EWOULDBLOCK) |
| 54 | #define SCM_MAYBE_EWOULDBLOCK || errno == EWOULDBLOCK |
| 55 | #else |
| 56 | #define SCM_MAYBE_EWOULDBLOCK |
| 57 | #endif |
| 58 | |
| 59 | /* MAYBE there is EAGAIN way of defining this macro but now I EWOULDBLOCK. */ |
| 60 | #define SCM_EBLOCK(errno) \ |
| 61 | (0 SCM_MAYBE_EAGAIN SCM_MAYBE_EWOULDBLOCK) |
| 62 | |
| 63 | SCM_DEFINE (scm_read_string_x_partial, "read-string!/partial", 1, 3, 0, |
| 64 | (SCM str, SCM port_or_fdes, SCM start, SCM end), |
| 65 | "Read characters from a port or file descriptor into a\n" |
| 66 | "string @var{str}. A port must have an underlying file\n" |
| 67 | "descriptor --- a so-called fport. This procedure is\n" |
| 68 | "scsh-compatible and can efficiently read large strings.\n" |
| 69 | "It will:\n\n" |
| 70 | "@itemize\n" |
| 71 | "@item\n" |
| 72 | "attempt to fill the entire string, unless the @var{start}\n" |
| 73 | "and/or @var{end} arguments are supplied. i.e., @var{start}\n" |
| 74 | "defaults to 0 and @var{end} defaults to\n" |
| 75 | "@code{(string-length str)}\n" |
| 76 | "@item\n" |
| 77 | "use the current input port if @var{port_or_fdes} is not\n" |
| 78 | "supplied.\n" |
| 79 | "@item\n" |
| 80 | "return fewer than the requested number of characters in some\n" |
| 81 | "cases, e.g., on end of file, if interrupted by a signal, or if\n" |
| 82 | "not all the characters are immediately available.\n" |
| 83 | "@item\n" |
| 84 | "wait indefinitely for some input if no characters are\n" |
| 85 | "currently available,\n" |
| 86 | "unless the port is in non-blocking mode.\n" |
| 87 | "@item\n" |
| 88 | "read characters from the port's input buffers if available,\n" |
| 89 | "instead from the underlying file descriptor.\n" |
| 90 | "@item\n" |
| 91 | "return @code{#f} if end-of-file is encountered before reading\n" |
| 92 | "any characters, otherwise return the number of characters\n" |
| 93 | "read.\n" |
| 94 | "@item\n" |
| 95 | "return 0 if the port is in non-blocking mode and no characters\n" |
| 96 | "are immediately available.\n" |
| 97 | "@item\n" |
| 98 | "return 0 if the request is for 0 bytes, with no\n" |
| 99 | "end-of-file check.\n" |
| 100 | "@end itemize") |
| 101 | #define FUNC_NAME s_scm_read_string_x_partial |
| 102 | { |
| 103 | char *dest; |
| 104 | size_t offset; |
| 105 | long read_len; |
| 106 | long chars_read = 0; |
| 107 | int fdes; |
| 108 | |
| 109 | { |
| 110 | size_t last; |
| 111 | |
| 112 | SCM_VALIDATE_STRING (1, str); |
| 113 | scm_i_get_substring_spec (scm_i_string_length (str), |
| 114 | start, &offset, end, &last); |
| 115 | read_len = last - offset; |
| 116 | } |
| 117 | |
| 118 | if (scm_is_integer (port_or_fdes)) |
| 119 | fdes = scm_to_int (port_or_fdes); |
| 120 | else |
| 121 | { |
| 122 | SCM port = (SCM_UNBNDP (port_or_fdes)? |
| 123 | scm_current_input_port () : port_or_fdes); |
| 124 | |
| 125 | SCM_VALIDATE_OPFPORT (2, port); |
| 126 | SCM_VALIDATE_INPUT_PORT (2, port); |
| 127 | |
| 128 | /* if there's anything in the port buffers, use it, but then |
| 129 | don't touch the file descriptor. otherwise the |
| 130 | "return immediately if something is available" rule may |
| 131 | be violated. */ |
| 132 | str = scm_i_string_start_writing (str); |
| 133 | dest = scm_i_string_writable_chars (str) + offset; |
| 134 | chars_read = scm_take_from_input_buffers (port, dest, read_len); |
| 135 | scm_i_string_stop_writing (); |
| 136 | fdes = SCM_FPORT_FDES (port); |
| 137 | } |
| 138 | |
| 139 | if (chars_read == 0 && read_len > 0) /* don't confuse read_len == 0 with |
| 140 | EOF. */ |
| 141 | { |
| 142 | str = scm_i_string_start_writing (str); |
| 143 | dest = scm_i_string_writable_chars (str) + offset; |
| 144 | SCM_SYSCALL (chars_read = read (fdes, dest, read_len)); |
| 145 | scm_i_string_stop_writing (); |
| 146 | if (chars_read == -1) |
| 147 | { |
| 148 | if (SCM_EBLOCK (errno)) |
| 149 | chars_read = 0; |
| 150 | else |
| 151 | SCM_SYSERROR; |
| 152 | } |
| 153 | else if (chars_read == 0) |
| 154 | { |
| 155 | scm_remember_upto_here_1 (str); |
| 156 | return SCM_BOOL_F; |
| 157 | } |
| 158 | } |
| 159 | |
| 160 | scm_remember_upto_here_1 (str); |
| 161 | return scm_from_long (chars_read); |
| 162 | } |
| 163 | #undef FUNC_NAME |
| 164 | |
| 165 | SCM_DEFINE (scm_write_string_partial, "write-string/partial", 1, 3, 0, |
| 166 | (SCM str, SCM port_or_fdes, SCM start, SCM end), |
| 167 | "Write characters from a string @var{str} to a port or file\n" |
| 168 | "descriptor. A port must have an underlying file descriptor\n" |
| 169 | "--- a so-called fport. This procedure is\n" |
| 170 | "scsh-compatible and can efficiently write large strings.\n" |
| 171 | "It will:\n\n" |
| 172 | "@itemize\n" |
| 173 | "@item\n" |
| 174 | "attempt to write the entire string, unless the @var{start}\n" |
| 175 | "and/or @var{end} arguments are supplied. i.e., @var{start}\n" |
| 176 | "defaults to 0 and @var{end} defaults to\n" |
| 177 | "@code{(string-length str)}\n" |
| 178 | "@item\n" |
| 179 | "use the current output port if @var{port_of_fdes} is not\n" |
| 180 | "supplied.\n" |
| 181 | "@item\n" |
| 182 | "in the case of a buffered port, store the characters in the\n" |
| 183 | "port's output buffer, if all will fit. If they will not fit\n" |
| 184 | "then any existing buffered characters will be flushed\n" |
| 185 | "before attempting\n" |
| 186 | "to write the new characters directly to the underlying file\n" |
| 187 | "descriptor. If the port is in non-blocking mode and\n" |
| 188 | "buffered characters can not be flushed immediately, then an\n" |
| 189 | "@code{EAGAIN} system-error exception will be raised (Note:\n" |
| 190 | "scsh does not support the use of non-blocking buffered ports.)\n" |
| 191 | "@item\n" |
| 192 | "write fewer than the requested number of\n" |
| 193 | "characters in some cases, e.g., if interrupted by a signal or\n" |
| 194 | "if not all of the output can be accepted immediately.\n" |
| 195 | "@item\n" |
| 196 | "wait indefinitely for at least one character\n" |
| 197 | "from @var{str} to be accepted by the port, unless the port is\n" |
| 198 | "in non-blocking mode.\n" |
| 199 | "@item\n" |
| 200 | "return the number of characters accepted by the port.\n" |
| 201 | "@item\n" |
| 202 | "return 0 if the port is in non-blocking mode and can not accept\n" |
| 203 | "at least one character from @var{str} immediately\n" |
| 204 | "@item\n" |
| 205 | "return 0 immediately if the request size is 0 bytes.\n" |
| 206 | "@end itemize") |
| 207 | #define FUNC_NAME s_scm_write_string_partial |
| 208 | { |
| 209 | const char *src; |
| 210 | scm_t_off write_len; |
| 211 | int fdes; |
| 212 | |
| 213 | { |
| 214 | size_t offset; |
| 215 | size_t last; |
| 216 | |
| 217 | SCM_VALIDATE_STRING (1, str); |
| 218 | src = scm_i_string_chars (str); |
| 219 | scm_i_get_substring_spec (scm_i_string_length (str), |
| 220 | start, &offset, end, &last); |
| 221 | src += offset; |
| 222 | write_len = last - offset; |
| 223 | } |
| 224 | |
| 225 | if (write_len == 0) |
| 226 | return SCM_INUM0; |
| 227 | |
| 228 | if (scm_is_integer (port_or_fdes)) |
| 229 | fdes = scm_to_int (port_or_fdes); |
| 230 | else |
| 231 | { |
| 232 | SCM port = (SCM_UNBNDP (port_or_fdes)? |
| 233 | scm_current_output_port () : port_or_fdes); |
| 234 | scm_t_port *pt; |
| 235 | scm_t_off space; |
| 236 | |
| 237 | SCM_VALIDATE_OPFPORT (2, port); |
| 238 | SCM_VALIDATE_OUTPUT_PORT (2, port); |
| 239 | pt = SCM_PTAB_ENTRY (port); |
| 240 | /* filling the last character in the buffer would require a flush. */ |
| 241 | space = pt->write_end - pt->write_pos - 1; |
| 242 | if (space >= write_len) |
| 243 | { |
| 244 | memcpy (pt->write_pos, src, write_len); |
| 245 | pt->write_pos += write_len; |
| 246 | return scm_from_long (write_len); |
| 247 | } |
| 248 | if (pt->write_pos > pt->write_buf) |
| 249 | scm_flush_unlocked (port); |
| 250 | fdes = SCM_FPORT_FDES (port); |
| 251 | } |
| 252 | { |
| 253 | long rv; |
| 254 | |
| 255 | SCM_SYSCALL (rv = write (fdes, src, write_len)); |
| 256 | if (rv == -1) |
| 257 | { |
| 258 | if (SCM_EBLOCK (errno)) |
| 259 | rv = 0; |
| 260 | else |
| 261 | SCM_SYSERROR; |
| 262 | } |
| 263 | |
| 264 | scm_remember_upto_here_1 (str); |
| 265 | return scm_from_long (rv); |
| 266 | } |
| 267 | } |
| 268 | #undef FUNC_NAME |
| 269 | |
| 270 | SCM |
| 271 | scm_init_rw_builtins () |
| 272 | { |
| 273 | #include "libguile/rw.x" |
| 274 | |
| 275 | return SCM_UNSPECIFIED; |
| 276 | } |
| 277 | |
| 278 | void |
| 279 | scm_init_rw () |
| 280 | { |
| 281 | scm_c_define_gsubr ("%init-rw-builtins", 0, 0, 0, scm_init_rw_builtins); |
| 282 | } |
| 283 | |
| 284 | /* |
| 285 | Local Variables: |
| 286 | c-file-style: "gnu" |
| 287 | End: |
| 288 | */ |