Rename YARP filepaths to prism filepaths

author: Kevin Newton <[email protected]> 2023-09-27 12:22:36 -0400
committer: Kevin Newton <[email protected]> 2023-09-27 13:57:38 -0400
commit: 8ab56869a64fdccc094f4a83c6367fb23b72d38b (patch)
tree: 46ef2bd5c51d5b7f923eda6a60edefc7a08200db /prism/util/pm_string.c
parent: 7e0971eb5d679bb6219abb0ec238139aa6502c5a (diff)
1 files changed, 200 insertions, 0 deletions
diff --git a/prism/util/pm_string.c b/prism/util/pm_string.c
new file mode 100644
index 0000000000..9ee25155a3
--- /dev/null
+++ b/prism/util/pm_string.c
@@ -0,0 +1,200 @@
+#include "yarp/util/yp_string.h"
+
+// The following headers are necessary to read files using demand paging.
+#ifdef _WIN32
+#include <windows.h>
+#else
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#endif
+
+// Initialize a shared string that is based on initial input.
+void
+yp_string_shared_init(yp_string_t *string, const uint8_t *start, const uint8_t *end) {
+    assert(start <= end);
+
+    *string = (yp_string_t) {
+        .type = YP_STRING_SHARED,
+        .source = start,
+        .length = (size_t) (end - start)
+    };
+}
+
+// Initialize an owned string that is responsible for freeing allocated memory.
+void
+yp_string_owned_init(yp_string_t *string, uint8_t *source, size_t length) {
+    *string = (yp_string_t) {
+        .type = YP_STRING_OWNED,
+        .source = source,
+        .length = length
+    };
+}
+
+// Initialize a constant string that doesn't own its memory source.
+void
+yp_string_constant_init(yp_string_t *string, const char *source, size_t length) {
+    *string = (yp_string_t) {
+        .type = YP_STRING_CONSTANT,
+        .source = (const uint8_t *) source,
+        .length = length
+    };
+}
+
+static void
+yp_string_mapped_init_internal(yp_string_t *string, uint8_t *source, size_t length) {
+    *string = (yp_string_t) {
+        .type = YP_STRING_MAPPED,
+        .source = source,
+        .length = length
+    };
+}
+
+// Returns the memory size associated with the string.
+size_t
+yp_string_memsize(const yp_string_t *string) {
+    size_t size = sizeof(yp_string_t);
+    if (string->type == YP_STRING_OWNED) {
+        size += string->length;
+    }
+    return size;
+}
+
+// Ensure the string is owned. If it is not, then reinitialize it as owned and
+// copy over the previous source.
+void
+yp_string_ensure_owned(yp_string_t *string) {
+    if (string->type == YP_STRING_OWNED) return;
+
+    size_t length = yp_string_length(string);
+    const uint8_t *source = yp_string_source(string);
+
+    uint8_t *memory = malloc(length);
+    if (!memory) return;
+
+    yp_string_owned_init(string, memory, length);
+    memcpy((void *) string->source, source, length);
+}
+
+// Returns the length associated with the string.
+YP_EXPORTED_FUNCTION size_t
+yp_string_length(const yp_string_t *string) {
+    return string->length;
+}
+
+// Returns the start pointer associated with the string.
+YP_EXPORTED_FUNCTION const uint8_t *
+yp_string_source(const yp_string_t *string) {
+    return string->source;
+}
+
+// Free the associated memory of the given string.
+YP_EXPORTED_FUNCTION void
+yp_string_free(yp_string_t *string) {
+    void *memory = (void *) string->source;
+
+    if (string->type == YP_STRING_OWNED) {
+        free(memory);
+    } else if (string->type == YP_STRING_MAPPED && string->length) {
+#if defined(_WIN32)
+        UnmapViewOfFile(memory);
+#else
+        munmap(memory, string->length);
+#endif
+    }
+}
+
+bool
+yp_string_mapped_init(yp_string_t *string, const char *filepath) {
+#ifdef _WIN32
+    // Open the file for reading.
+    HANDLE file = CreateFile(filepath, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
+
+    if (file == INVALID_HANDLE_VALUE) {
+        perror("CreateFile failed");
+        return false;
+    }
+
+    // Get the file size.
+    DWORD file_size = GetFileSize(file, NULL);
+    if (file_size == INVALID_FILE_SIZE) {
+        CloseHandle(file);
+        perror("GetFileSize failed");
+        return false;
+    }
+
+    // If the file is empty, then we don't need to do anything else, we'll set
+    // the source to a constant empty string and return.
+    if (file_size == 0) {
+        CloseHandle(file);
+        uint8_t empty[] = "";
+        yp_string_mapped_init_internal(string, empty, 0);
+        return true;
+    }
+
+    // Create a mapping of the file.
+    HANDLE mapping = CreateFileMapping(file, NULL, PAGE_READONLY, 0, 0, NULL);
+    if (mapping == NULL) {
+        CloseHandle(file);
+        perror("CreateFileMapping failed");
+        return false;
+    }
+
+    // Map the file into memory.
+    uint8_t *source = (uint8_t *) MapViewOfFile(mapping, FILE_MAP_READ, 0, 0, 0);
+    CloseHandle(mapping);
+    CloseHandle(file);
+
+    if (source == NULL) {
+        perror("MapViewOfFile failed");
+        return false;
+    }
+
+    yp_string_mapped_init_internal(string, source, (size_t) file_size);
+    return true;
+#else
+    // Open the file for reading
+    int fd = open(filepath, O_RDONLY);
+    if (fd == -1) {
+        perror("open");
+        return false;
+    }
+
+    // Stat the file to get the file size
+    struct stat sb;
+    if (fstat(fd, &sb) == -1) {
+        close(fd);
+        perror("fstat");
+        return false;
+    }
+
+    // mmap the file descriptor to virtually get the contents
+    size_t size = (size_t) sb.st_size;
+    uint8_t *source = NULL;
+
+    if (size == 0) {
+        close(fd);
+        uint8_t empty[] = "";
+        yp_string_mapped_init_internal(string, empty, 0);
+        return true;
+    }
+
+    source = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
+    if (source == MAP_FAILED) {
+        perror("Map failed");
+        return false;
+    }
+
+    close(fd);
+    yp_string_mapped_init_internal(string, source, size);
+    return true;
+#endif
+}
+
+// Returns the size of the yp_string_t struct. This is necessary to allocate the
+// correct amount of memory in the FFI backend.
+YP_EXPORTED_FUNCTION size_t
+yp_string_sizeof(void) {
+    return sizeof(yp_string_t);
+}
author	Kevin Newton <[email protected]>	2023-09-27 12:22:36 -0400
committer	Kevin Newton <[email protected]>	2023-09-27 13:57:38 -0400
commit	8ab56869a64fdccc094f4a83c6367fb23b72d38b (patch)
tree	46ef2bd5c51d5b7f923eda6a60edefc7a08200db /prism/util/pm_string.c
parent	7e0971eb5d679bb6219abb0ec238139aa6502c5a (diff)